NefMoto

Hi

Im building a GTX3071r 1.8T with 82mm pistons (9.25:1 CR), supertech valves, top mount manifold, 4" maf housing with tial 38mm wastegate.

Im looking at injectors and need some advice.  Ill be running a ME7.5 BAM ecu.

What size injectors do people recommend?  Ive heard 680cc's will do the job, but I want plenty headroom so they not running a high DC.  Also what make is the better ones?  Ive read a bit able misfires on idle, spray patterns etc so just wondering what people have had experience of on here and what they would recommend.

Chris

What fuel are you running?
Your compression ratio is very high (too high for pump gasoline and this turbo), could it be that you are planning to run E85?

I have just reached 90% duty cycle on this turbo on 870cc injectors, so these are a bare minimum.

Rick

What fuel, what fuel pressure?
GTX3071R with a 0.63 A/R housing is a sub-500hp turbo on pump fuel.
Unless you are running E85, this just means the fuel pressure is tapering. 870cc @ 3bar injectors with a 4 bar FPR on gasoline are enough for a GT35R on this engine.

Ideally I will be on 3bar pressure, but my setup should take 4bar easily.

Fuel using will be UK Super unleaded (vpower  or equivilant (97 and 99RON))

If you have a 044 fuel pump in there anyway, then you can just use 4 bar pressure.
But you have bigger issues with your setup than injectors - you need to do something about the too high compression ratio if you want to run pump fuel.
If changing pistons is not possible or too expensive, then at least fit a compression dropping head gasket, or you won't really get much power out of the engine.

750cc EV14's at will provide you with enough fuel even at 3 bar either way, and if you need more in the future, you can just drop in a 4 bar FPR.
I tuned 825cc's with 4 bar fuel pressure and had 72% IDC with 2.1 bar boost at 7200 rpm. The turbo was quite a big bigger though - 58mm inducer vs your 53mm.

Hmm, I was hoping pistons would be ok....THeres a few people here in UK that run 600bhp on 9.25 or 9.5 compression ratio.

Was hoping the 9.25:1 would give me a pretty quick spool but not cause too much knock up top end and eat power.  Only other option was 8.5:1.

We have 97-99RON fuel here so hoping my guy who does mapping can work something out.

Also be running water meth.

You can do it on that compression, it's not my chosen way but a lot do.

Rick

Water/meth will improve it quite a bit, but I have no idea why you went with that high compression ratio.
No, 9.25 will not give you better spool at all. 8.5:1 or 8.0:1 would give you much better spool.
This stupid myth of "the engine will be weaker down low with lower compression ratio" is making a lot of people choose their engine components incorrectly. You have a turbocharged engine, not a normally aspirated one!

This only starts to hold true when you go below 8.0:1... Until then, the lower, the better and more responsive the car will be in the entire rev range, because the engine is highly knock limited.
The only thing you will lose is low-load cruise efficiency, meaning slightly higher fuel consumption on the motorway.

This is of course if you are using gasoline as fuel. If using other fuels, such as LPG or E85, then the "break even" point arrives at a different ratio.

Interesting.  I alwaus thought it was the higher compression aided spool a bit and the lower gave you a bit more grunt later on in rev range.

Provided the knock can be controlled well enough should still be ok though?

And any other word on injectors?  What make best to go for etc?

What made you think this?

Ive spoke to a good few people and read a fair bit on the net about it.  I like to do my research before buying parts :)

Seems your research has failed and you have bought the wrong parts then.
Lowering CR would only ever hurt spool if you were not knock limited. Any time you go anywhere near WOT you are instantly knock limited even at 8.0:1 on this engine.

No idea where that "high CR is good for spool" myth comes from, but it sure as hell has nothing to do with a turbo engine on pump gas.

Agreed. Lower compression is a big win (across the board) on FI cars and pump gas.

I read that the higher CR would give me more responsiveness off boost. Which is also more efficient. The lower CR turbos would need more boost and timing to reach the same figures of that from a higher CR engine.

If knock and hear can be mapped around,  then surely there's no reason for this setup not to work? More efficient engine using less boost to get same power figures.

There's are many guys running a big turbo over here in uk with an above 9:1 compression ratio and plenty in the USA.

You will make more torque throughout the rev range with 8.5:1 than with 9.25:1. What you say holds true at around the 7.0:1 mark, as you go lower. Not at 9+.
Load of complete rubbish. You will never reach the same figures unless you use a fuel on which the engine never knocks. Which you are not doing.

Well, why don't you go 20:1 compression ratio then? It doesn't work like that, plain and simple, because fuel has something called an "octane rating".

A 1.8T 20V with 8.0:1 will outspool, outpower and outtorque the same engine with anything higher on pump gas, any time you go near WOT. Whether on boost or off boost.
A 8.0:1 engine will make 70-80 more horsepower and up to 100nm more torque compared to your 9.2 engine with that turbo. And it will be more responsive in the entire rev range. Furthermore, because you are able to utilize fuel more efficiently at WOT (10+ degrees more spark advance without encountering knock), you will have lower EGT's and less waste heat.
The only thing that will suffer is fuel economy on light load cruise, that's it.

As a background - there is a "break-even" compression ratio for every engine with every fuel, where you start noticeably losing torque down low and the engine becomes an "on-off" switch. But for this to occur you must be able to run non-knock limited MBT any time you are off boost.
This does not happen even at 8.0:1 CR on the 1.8T 20V with pump gas. Anyone who has *any* experience tuning these engines on a steady state dyno can confirm this.

Just because there are lots of guys running 9+CR doesn't mean the setup is optimized. Get a thicker headgasket, or stack a couple MLS gaskets. The car will run better.

It seems a pretty popular myth with the 1.8T crowd...
I had a couple clients with 1.8T's who were saying exactly the same thing as the OP, and had bought high compression ratio pistons. Oddly enough I have never had any issues with 2.7TT and audi I5 people, they seem to understand compression ratio a lot better and don't try to buy stupid high CR pistons.
I always ask first what fuel people are going to run, because if they are running E85 then the higher CR can be beneficial, as E85 has very good knock resistance.

But people getting high CR on coke bottle sized engines, which they are going to try to boost to 30 psi on pump gas is just a badly made decision.

I very much agree with you. Just because people repeat the same mistake over and over again, it does not make it right.

Forced induction engines are built to reduce compression, whereas naturally aspirated engines are built to increase it. I think that's where people get confused.What works well for one has the complete opposite effect on another. Try arguing with the diesel crowd :)

So I'll ask a question since compression ratio has come up. (Sorry to the op for being ot). On a turbo charged car (I can't imagine that size makes that much of a difference 1.8 vs 2.7?), what compression ratio do you advocate? I see you mention 8.5, and then go on to say 8.0. This question is for a daily, not a track car, running 93 or E85. Thanks, and apologies again, I just find this topic fascinating, especially since it seems most 1.8t forums have a lot of misinformation.

P.S.- Happy Holidays

8.5:1 is an ideal balance for a street car. 8:1 if you're going for high boost and big power, but you can lose a little bit of off boost response if you go much lower than that. That might be fine for a drag car, but linear power delivery won't be in your vocabulary. You can do a lot more and still keep cylinder pressures sane if you keep CR lower. A high CR isn't required in boosted applications to develop power, it's useful in NA to squeeze as much air into the cylinders as possible, and they still have very poor volumetric efficiency vs forced induction. Once you get up to 9:1 you're pulling back timing to keep detonation at bay.

The OP is looking to reduce by .25 of a cR from standard anyway on an increased capacity build. I have seen many BT builds running all kinds of management on this CR with no issues at all. We have decent fuel over here in the UK. As i understand it, the standard fuel in the US is effectively below what our "normal" fuel is. This seems to be where the confusion comes from. I am perfectly happy with my 1985cc stroker on an 058 block with CR 9.25-1. No problems with knock on my CR of 9.25-1 and it's tuned with ME7.5 with standard sensitivity of knock sensing ATM. I have more to come when I build my head.

You could not be more wrong. And your engine would make more power and more torque with a lower compression ratio.
Also, your UK fuel isn't anything special.

What cr do you suggest? I assume the same as ddillenger for a street car.

Interesting topic indeed.

I have been contemplating going higher CR on my 1.8t, about 10.5:1 running on e85 at ~30psi boost.

This was back before I had my setup up and running, I thought it would feel sluggish before ~3500rpm, but boy was I wrong. The car still feels peppy, and I have more tuning to do to improve it also, even on pump gas.

Im definatly not going higher compression ratio, in fact im just going to stick to my stock 9.3:1 pistons and just upgrade my rods. There will be more than enough grunt down low anyway. I will be running e85 during summer and pump gas during winter, and my new goal on the e85 is to try max the turbo out :)

prj, could you make an educated guess on under what load one are not knock limited on a stock 1.8t motor, 9.3:1 and 98 pump gas?

I have been going with > 120%, I am knock limited on 98. I have not really tuned low load timing much either, just because I dont really know at what kind of load I could expect to be able to over advance it. This assuming load is sane and not scaled.

No, it's not that simple. Put it on a dyno, and you will know.
But from my experience if you go WOT on a GT35R at 3000 RPM on a dyno, where absolutely nothing happens boost wise then at the resulting load site then your MBT is still knock limited even at 8.0:1.

What turbo are you planning to run? There is no "magic number"...
It depends quite a bit on a plethora of factors, such as fuel, the engine in question and so on.
Greatly simplified (would need some corrections to be 100% correct) - dropping compression ratio will result in more power and torque everywhere, where you were knock limited before, and less power and torque everywhere, where you weren't.
To prevent the car from being sluggish down low, you have to stop dropping CR when you are no longer knock limited off boost, and that's pretty much it.
The only time your car will feel sluggish with lowered CR is if you are flooring it, there is no boost yet, and you are not knock limited anymore. But to reach that, you have to go rather low on pump gas.

I never said our fuel was special but it's rated differently so it's not a direct comparison.


How strange that I have seen the exact opposite of what you describe on cars dyno'd on lower and higher CR....

Must be a geographical problem of somekind, like in the US the WHP figure always appear to be the calculated  FWHP we achieve over here. Having looked on here our tuning methods do not differ enough to make the difference. I'm going to agree to disagree as my experience has shown different to what you are describing

No, it's not. RON and AKI are directly comparable with a conversion factor applied.
So next thing you want to tell me that laws of physics do not apply in the UK? Or that your 1.8 lump is somehow special because it is in UK?

Just out of curiosity, how many engines have you mapped on a dyno?
How many of those engines made more than 300hp/liter?

How about you counter any of the physical facts stated instead of just vaguely going on about "that works and that doesn't" ?

The fuel in the UK no better than what is available in the NA market. What you mention is yet another common myth, because people do not understand how the 2 nations define 'octane' and how to compare them.


What actual measured timing values do you have at peak torque? at what rpm and boost?

correct on the fuel, thanks for that.

It's not special, It's a built engine running 9.25CR without problems and without it self destructing

What physical facts, all i have seen here is you stating it won't work, when others here have plainly seen different.

I have personally tuned none, I have however been present when many engines have been tuned, including low and high CR engines. Viewing the logs and interpreting the information I have not seen what you speak of in real life.

Explain to me how a larger capacity engine with higher CR will possibly have poorer spool and off boost performance?

The engine will surely breath easier and make power easier off boost, then the increased air flow through the engine will surely drive the turbine to spool the turbo faster?

Explain?

deleted, cos it was pointless

No one ever said it will self destruct. I simply stated that with lower CR it will make more torque/power throughout the range any time you are WOT. Do you disagree then?
Because your fuel is only 97 or 99 RON, it's not 120+ RON.
When you floor the car from 2000 RPM, your high compression engine will make significantly less torque due to the fact that it will be knock limited, and the lower compression engine will not be. Your high compression engine will not be able to extract as much power from the same amount of gasoline, as it will be operating at a reduced ignition angle, thus lowering the very efficiency, you are searching for.

Because the high compression ratio engine will make less torque, the revs will rise slower. Because the revs rise slower, you will get up to boost slower.
What's so hard to understand? This is really the basics.

The *only* downside for say 8.5:1 on V-Power or Momentum would be slightly decreased fuel economy. And the reason for that is, that at low load, the high compression ratio engine will not be knock limited, so it can run optimal spark advance, and the lower compression ratio engine will lose out on efficiency.

If you saw any kind of gains for a higher CR anywhere (off boost or on boost) at WOT, then something else was at fault.

He said its not the ideal way.


So you have personally seen (not tuned or been involved with tuning) 2 identical setup engines just with different compression ratios? At what power level are you talking?


Explain to me what makes a turbo spin?

In my experience, all things being equal, a low compression 2.7t makes more torque and spools faster than a stock 2.7t on pump gas (regardless of the turbos), for all the reasons prj outlined. As he said, the limitation isn't VE related, but rather knock related.

Silly VE tricks (like "cold air" intake games) are for people stuck with N/A motors. For some reason, a lot of their voodoo explanations for things (unfortunately) leaked into FI tuner strategies.

YMMV.

what you say makes some sense, but is opposite to what ive seen. Hybrid 1.8t's on 9.0-1 making 20 BHP less than the 9.5 CR Variant given the same spec turbos, LP heads,same add odds and the same results from several tuners.

In any case, I apologise for my rant.
 I personally much prefer to be able to drive my car around at less than WOT it's not all about maxboost and power, higher cr=lower boost and earlier torque in the cars i have experienced personally.

I don't have my plot and logs to hand to show what mine is doing as my valve guides need doing so I am rebuilding the head shortly, will have details then as I had the tuning aborted due to excessive overrun smoke( guides)

it was around 283 hp@ 1bar and 350 torques from memory at 5 k ish , It's late now I'd have to double check, but i'm sure it's not miles from that.

Can someone explain the US fuel then, I thought you had a fuel "worse" than out std 95 ron stuff then almost the same and your next one being around 97 not 99 like V-power.Ignoring super race fuels and the like

We have 91 on the west coast, 94 on the east coast (octane, not RON), and a hodgepodge in between.

Well, then their spec was different or the tune was different, very simple. Or let me guess, you are taking numbers from random dynos on different days?
Or do you think that Audi also went to 9.0 CR from 9.5 with K04, just for shits and giggles?
Why am I even bothering replying to you. You do not understand anything about what goes on in the combustion chamber, you just regurgitate "I have seen" "Others say" over and over and over again. It's getting old and you are starting to sound like a broken record.

It doesn't work like you say it does, period. No matter how many times you repeat it, it's not going to magically come true.
Read a book and educate yourself, you really need it. Stop just repeating and looking at others, figure things out yourself, understand how and why things work.

I don't need to look at what "others say" and "others do". Because I have personal experience with these things and understanding why something works the way it does. Lots of it.
More than a couple things you have seen here and there from some "tuners" or read on some forum.
You already said you have zero experience mapping an internal combustion engine. I've done 100's. Why are you still here arguing? You are yet to counter a single fact that was posted.
Your claims are in complete opposition of physics. To someone who understands the combustion process you are basically claiming that the world is flat. That's how outrageous it is.

Dynamic compression ratio, as opposed to mechanical compression ratio.  sqrt((boost+14.7)/14.7) * CR = effective compression ratio.  Dropping CR allows a greater effective CR (therefore greater oxygen with which to combine with fuel).  Say you drop from 9:1 CR to 8:1, which allows an increase in boost from 15 psi to 18 psi without detonation onset and all else being fairly equal.  You've lost 3-4% in power potential as a result of the decrease in mechanical compression ratio, but you've gained 10% in absolute potential, for a net increase of 6-7%.  Could be wrong, but I doubt most people could tell the difference in throttle response in off-boost situations between 8:1 and 9:1.  There is a point where a lower CR will not be enjoyable in off-boost conditions, but I don't think 8:1 or 8.5:1 is it.

Interesting discussion.

@AARDQ,

Don't forget, that if your engine was knock-limited before at a load site, then by dropping compression ratio you will lose those same 3-4% from it, but gain back 10+% from being able to advance the timing and actually use the fuel to push the piston, compared to blowing it as heat out of the exhaust.

The reason behind this is, that the more you compress, the hotter the charge gets, so the likely the fuel is to start detonating instead of burning normally.
This is where most people go wrong, they always think they are running a perfect fuel. And if you had an imaginary fuel with infinitely high octane rating, then you would always gain when increasing compression, however no fuel has an infinitely high octane rating, so it's always a tradeoff.
Where that breaking point is depends on the fuel used and on combustion chamber design.

My hopes and dreams are a 2.0 conversion, and currently I own, but have yet to install a Garrett GT2860RS. 93 Oct, and at the track E85 or 104 Oct.

I'm really glad this got brought up. This discussion, especially with the examples given, has painted a more vivid picture of what happens in the (FI) internal combustion engine. Even thanks to those who pissed off prj, without you I'm not sure he would have explained the process so in depth to prove you wrong. ;D (and I mean that, no sarcasm)

Absolutely true.  An engine is a system; everything must be considered in concert.

Seems everyone is saying that boost makes the power in these engines?? I've seen less boost applications make more power than those with higher levels of boost and the power made from timing?

Either way,  soon see what happens when I blow 30psi through it and if it makes power.

Boost in concert with proper timing for the fuel.  Not boost ignoring everything else.

Yes, I figured that. I just got the feeling from your posts regarding MBT that the "threshold" is much lower than I thought, and maybe I could get a better ballpark than my current. Take a look at the graph I attached, pretty much anything over 70rl on my setup and we are in boost.

Thanks, that only confirms it, was that 35R on straight pump gas?

Im going to visit a dynapack in the new year, is it even viable to tune non-knock limited MBT without an emulator? I mean, sure it ~can be done flashing, but I would imagine it would take many hours to do 2 timing tables properly.

Regarding power vs. CR, I did read a very good line a couple years ago: It is all about where you compress the air.

Reason hybrids make more power on higher compression is because you are limited by the max boost the hybrid can make at redline. Typically the k04 hybrid will hold a max of 21psi ( or for another want, x amount of lbs of air or flow) at 7200rpm. With this, where you can't add more boost/flow into the engine you can only increase cr to squeeze more power out.

someone should tell VAG they have made a huge mystake in raising their compression ratios on the 2ltr FSi Turbo motors..
 ;D

I have never come across a knock threshold while live emulation dialing in MTB via steady state testing at 9.5:1 sub 450bhp on the 1.8T, I cannot comment for 2.7T.

I have found the higher CR setups perform better than the same setups with lower CR.

Maybe on an old design engine the lower CR would have had to been a must to run higher boost, but the 1.8t 20v setup has a very good combustion chamber by design.

Look at a 2.0tfsi on stock ko4 30psi @ 3600rpm taking 18deg advance with zero knock at 9:1 due to combustion effichency.

Mapping plays a huge part, (did I read somewhere Prj tunes to knock, running lean the richening up on the onset of knock). Maybe it was someone else.  But if tuning this method then knock will be an issue on a higher boost/ CR setup.   Tune via knock prevention by management of the fuel and a hell of a lot more power can be extracted.

I disagree. Even a standard K03 will make more power on 8.5:1. BTDT.

I guess we are tuning different engines then. Also, it's MBT...

No, you did not.
Right-o, so you are at 0.75 lambda and still knocking, what do you do? A 5 valve 1.8T engine with 9.0:1 CR can run about 2-6 (peak torque - redline) timing at 30 PSI on stock head.
9.5:1 at 450 hp? Give me a break.
We are talking about port-injected engines here, not direct injected, where compression ratio is a completely different subject. Using these engines interchangeably and comparing them to each other is just huge misinformation.

Look up direct injection. Also, this was done purely for emissions, not from a power perspective.

Oh, and since everyone is posting random things without any data to back it up, let's just post a graph from 30 psi on a 5v 1.8T with 9.0:1 CR and stock head at 30 psi, shall we?
Note how timing starts to get pulled due to knock before any boost actually builds in the engine.

Seems like ur doing summat wrong dude... Plenty of cars running here in the uk with upto 450bhp and stock pistons with stock CR..

We will have to agree to disagree on here dude.

But I know who the op will be opting to tune his car.

Infact we will post the logs, dyno plots and videos of the live mapping session with his 9.25:1 setup.

MTB MTB = iPhone thinking its better lol

First of all, no one said that they can't make 450 hp with stock pistons and stock CR.
They can, but if they'd drop CR on the exact same car on pump gas, they will make 500+, while gaining responsiveness throughout the revrange which has been my point all along.

No, I am not doing anything "wrong". This is how it is.
I posted a log to back this up, and this has been the same on every 9.0:1 with stock head.
If the head is modified it is a different story.

But since you are "all that", maybe you would like to say what exactly I am doing wrong based on that log?

And that will show absolutely nothing unless you take the same car, stack the head-gasket and re-tune it.

AGU large port heads stock.

Your fuel and tuning stratergy is nothing like mine. 
 For one I would not be using feeback from the oe knock control, I would be using standalone detcans on the dyno as I know for a fact the ecu can read 4 5cf with out any pinking at all.

We will have to wait until the live mapping on the OPs car is finished and I will supply all the logs and data during the session.  I will even post logs of when we do run into issues and the methods I use to tackle them.    Put it this way my timing graphs won't look like a saw blade nor will it have and inverventions. 

I will keep u updated on this one

This was on small port head.
Full boost on that log is about 5000 RPM, the car is at 0.8 lambda from 4500 rpm. I am sorry if I don't immediately flood the car the moment someone goes near the throttle.
The ECU on that car was reading knock just fine, confirmed with detcans, as I always do on any engine with forged internals.
This car had no intervention whatsoever up top. The graphed timing is zwout. And if you care to look you can see that the spikes are at the points where timing is pulled from cylinders.

Oh and, if you do tune this, turn the meth injection off. As that is equivalent to running race fuel all the time.
My RS4 makes up to 10 deg more timing up top with meth injection. Obviously then 9.0:1 starts looking better than it is on pump gas.

WMi ftw! But as an additive to the map afterwards. Tune without WMi then on final day of tuning set it up for WMi via corrections based on AIT.

You will be shocked how much of a difference the large port head makes over the small ports.    I not got a clue why as I am more of a hands on tuner treating every job and setup unique and go at them blind.

Most of my high power customers switch to a large port head setup

A large port head still isn't magically going to win you 10 deg at 9.5:1 CR.
As I said, take a stock 1.8T 5V 9.0:1 engine, big port or small port and put 30 psi into it on pump gas, then see what timing figures you come up with.

Obviously you should be doing cams, head, and so on, but if you are not, then it is a different story.
The stock cams are also pretty brutal, don't forget that. If you are running cams with overlap, then in fact your dynamic compression ratio is lower, so you can not compare CR directly.

Been doing these for long time now and getting some awesome results and feedback from my methods.

I had a T304e hybrid at 430bhp 30psi 9.2:1 CR stock AGU head 21deg at 6800rpm advance and head room to run 50shot of nos.   

The increments of timing advance plays as huge part,  befoe I started to use the ols300 timing setup was primitive and I would run a lot less timing, but with ols300 and live mapping with knock off I can make work my way around issues with trial and error testing.

If I get unhappy customers and dead engines then I will re evaluate my methods and hardware recomendations.

That does not sound right for pump fuel, and it's a pretty useless number without knowing more about the setup.
Also, I have serious doubts of that turbo making 30 psi at 6800 rpm, as if it did, you'd make much more than 430 bhp running that timing.
Sorry, your numbers don't match up. The log that I posted - the car made about 430 even with that crap timing (more exactly, 350 whp).

I use emulation as well, but an emulator is not needed at all on ME7 to adjust timing in real time on the dyno per load cell.

Talking pump gas:

1. No one ever stated high CR does not work, it was stated that lowering CR will allow you to extract more power.
2. You will not notice any difference driving the car until about 8.0:1, because down low throttle response is governed by pedal mapping more than anything on DBW cars, the difference in CR is not really noticeable.
3. With higher CR rpm vs boost will look better, but time vs boost and time vs RPM will look worse.
4. The factory runs high CR due to emissions and even the factory drops the CR on the K04 engines, although this is travesty from their standpoint of emissions.

What is being "deemed" high compression here EXACTLY?

Not an FSI motor.

9:1 (210/225) or 9.5:1 (150/180) motor...

Talking 1.8t's are'nt we as base line?  Where does it Start being High CR and Low CR according to the experts here then?



Yes we know 2.0 tfsi run higher CR.........  ;)

Going back to the OPs question....  Is where we needed to be at.


There is a reason your last 9:1 tune is seeing so little advance at 30psi this needs looking into.

I personally know I can run 400-450bhp with same CR on 98ron fuel and make 20deg+ advance in the power band.    I would have a bet the Ibiza dude above would have seen the same results??    As I know one of his customers running 400bhp+ 9.5:1 with oem Ibiza pistons 20deg+ with zero knock.

I won't argue the matter anymore, I will do my usual trick and prove the fact that 400bhp+ 1.8t large port AGU at 9.25:1 will run to 20deg+ advance  4500rpm+ without  knock/pinking.

The ols300 emulator is perfect for setting timing up in real time with steady state plotting.

Surely the principles of a Forced indution engine are the same?  1.8T runs a 9.5 or a 9.0 on a BAM and the Edition 30 BYD lump runs a 9.8:1 compression ratio?    So surely the air entering the cylinder through the inlet is the same as that of the lower compression engine?  So why have VW opted for a higher CR engine on a FI engine?

Matchew - I think he meant in a 1.8T application

Surely If I can run more boost on a lower CR application, does this not cause excess heat produced by the turbo and higher exhaust gas temperatures?  Something which should be as controlled as possible??? as im sure we all know what happens when EGT gets too high..

Surely if this is going to be a weekend car, not something im going to solely use gonig down the 1/4 mile strip then I will be wanting some drivability off boost and not have the car feeling dead unless I was constantly on WOT throttle....and I cant see that happening with 500BHP+ going through the wheels as I dont think my license would last long doing that everywhere I drove.  (although was fun in AGU k03s @ 250bhp)

PRJ - your points (excuse my lack of mapping knowledge on this one)

Talking pump gas:

1. No one ever stated high CR does not work, it was stated that lowering CR will allow you to extract more power.
You said my setup had serious issues in your first post on this thread due to running a High CR on GTX3071r?

2. You will not notice any difference driving the car until about 8.0:1, because down low throttle response is governed by pedal mapping more than anything on DBW cars, the difference in CR is not really noticeable.
I think I will be going for linear throttle mapping on this one, to retain how a cable driven throttle body would function....Not into this you get 80% power at 50% throttle position crap from stock VW mapping

3. With higher CR rpm vs boost will look better, but time vs boost and time vs RPM will look worse.
Back to my above point of more boost equals more heat??  killer of engines?

4. The factory runs high CR due to emissions and even the factory drops the CR on the K04 engines, although this is travesty from their standpoint of emissions.
If anything, thats quite the opposite that happened.....Early 1.8T engines (AGU for example @ CR of 9.5:1 )with no emissions stuff such as VVT or SAI ran a HIGHER compression than those of the later variety using SAI and VVT for emission purposes where CR was dropped to 9.0?

So you are saying that the OP would not make more power on lower CR?
What's there to look into? It is completely normal that this is going on.
Boost any 5 valve head to this amount and you will see exactly the same thing. Take a stock 2.7TT, boost it to 30 psi, you will see the same timing advance.
Take a RS4, boost it to 30 psi, it's almost as bad.

You completely ignored that I pointed out your numbers did not match up. Or am I a super mega tuner and can make the same power as you at 3 deg advance, as you at 21 deg advance? Fact of the matter, you were not running 30 psi @ 6800 rpm, or your setup had other issues.
I see lots of statements but no logs. I can make 450 hp on 10:1, I will just have to rev the crap out of the engine. What is your point?
My point is, that these engines are forced induction, not N/A.

You got it completely wrong. You don't need to run more boost to make more power at a lower compression ratio.
For the final time, you are not running a perfect fuel. Your fuel has an octane rating. Get that through your head and everything will make sense.

Yes, because I like cars to make power.
You will see gains across the power band by dropping CR, that is why I said it is not optimal. Plain and simple.

That doesn't matter. You will not notice any difference between 8.0:1 and 9.0:1 on part throttle.
Also, the throttle on cable cars is not "linear". Low down the range, you have effectively full power output at 50% and lower of the throttle, simply because the engine can not breathe anymore and the throttle is not the restriction.
The reason the OEM maps the car the way it does, is to give the engine a linear feel between off-boost and on-boost behavior. So that you do not instinctively floor it, then lift the throttle when the car starts coming on boost, as you do with a DBW throttle. The idea is to map a certain produced torque to a pedal position in all RPM ranges, that is why it is calibrated the way it is.
Dissing the stock calibration without understanding it seems a really popular thing.

If you actually understood anything of what I am saying, you would understand that this was describing spool characteristics.
Breaking it down for you. If you plot the car WOT from 2000 to 4000 rpm, then a lower CR engine will get from 2000 RPM to 4000 RPM quicker than the higher CR engine, unless the CR is so low that it is not restricting timing anymore. Now re-read what I wrote with this in mind, and you will understand.

Incorrect. Go and educate yourself a little bit on the compression ratios of different 1.8T engines.

I have the compression ratios from VW ELSAWIN system in front of my now......It quite clearly states BAM is 9.0:1 and AGU is 9.5:1....unless I am somehow reading the wrong figures?

Because BAM is a K04 car and AGU is a K03 car. Exactly as I said before.
The factory dropped CR on the K04 cars, because they needed to run more boost pressure without overheating the car to make advertised power.

....and nothing to do with them running lambda=1 apart from last column of 0.953 and rely on egt protection to kick in when it reaches 920'c
Compared to other wideband k03 based cars which have a very different fuel strategy... and run them richer with load.. down into the 0.7x lambda region in comparison

You say overheating?  We see egt's far higher on the lower CR K04 cars than their k03 cousins with higher CR... and its the tune which causes this.... and their approach to keep it lambda 1 as much as possible.

Is 30psi your chosen boost number?  You do refer to it a lot....

The reason they keep them at lambda 1 this much, is so they can guarantee emissions, very simple.
The reason the calibration changed is because these cars got real EGT sensors, whereas the others did not have them.
CR was dropped because otherwise ignition angle efficiency would suffer at high load and the car would no longer make advertised power while staying within component tolerances.
You do realize that the OEM's advertised power is made in all sorts of adverse conditions, not only on one pull on the dyno?
You also might want to familiarize yourself with changes between Euro II and Euro III emissions.

What's your point?
You really want to say that at lower CR a car produces less emissions?

Are you really that thick?    Now thats rude dude..

At least he can tune a car at 9:1 and run enough timing to aid the boost..lol

IMO Ibizacurpa is one of the best high power 1.8T tuners in the UK, he is running more 450bhp+ 1.8T car than maybe all the the other Uk tuners out there.  His own 1.8T is a 600+bhp monster.


Nick

Hmmm.
Lets compare lambda 1 strategy from K04 car with K03 car which enriches on lamfa etc
ign
(http://badger-5.com/bin/kfzw-k04-k03.JPG)
and the other ign
(http://badger-5.com/bin/kfzw2-k04-k03.JPG)

Despite their lower CR, their ign timing does not run to the same numbers... and in your mind this is Nothing to do with how they have chosen to Fuel the respective setups and all to do with the compression ratios of the two engines..


 ;) ;) ;)

Are you blind ? The TT has 3-5 degrees more advance at the same load sites all over the power band.

Going back to the log you posted up..................


Do you tune many high power 1.8T setups?

Why so lean pre 3500rpm?   This setup would respond better running .9 / .89 in the upto 3500rpm. then IMO you would have no CF.

Is this the car in question?  With $5 air filter?
http://prj-tuning.com/wp-content/uploads/2012/10/20121019_144042-700x525.jpg

I mostly tune high power 2.2T setups. I've done a few 1.8T.
Because absolutely nothing happens pre-3500 rpm.
Stop looking at small details and see the big picture. You are the one who claims you can run 21 deg timing at 30 psi on a 5v head with 9.5:1, not me.
If you look at the OEM timing map it's pretty clear this claim is ridiculous.
Running 0.9 or 0.8 or w/e lambda upto 3500 is not affecting pretty much anything, tested back and forth. You are not going to magically gain 10 degrees of timing from 0.05-0.1 lambda.

You also commented something about "sawtooth" - this is how it looks if you are running different timing per cylinder, and this is not torque intervention, which looks completely different.
Maybe someone needs to revisit ZUE?

Oh cool, you found my website and are going to launch personal attacks against my clients?
Can I see yours?

How about you start playing ball, not the player.

I've done a few 1.8T       Rest my case....

Between me and Ibizacupra over the last 10 years is more like a 1.8T 1000+cars each.

I am being straight with you dude, IMHO something not right on that setup hardware or mapping wise.  Without seeing/logging the car I cannot tell you what the issues is.

Nick

wtf are you looking at...  Its Clearly visible...

fair play.... you are a piece of work.. Rude and arrogant..  

You are knowledgable, but beyond arrogant and no one else could possible know as much as you or be able to tune car...  
~That Pretty much sums you up as I and others see it..

Shame..
you might be a decent enough guy, but your mannerism on here is abysmal..

maybe its lost in translation..?  Estonian to English.. I dont know.

Oh cool, you found my website and are going to launch personal attacks against my clients?
Can I see yours?

Dude I am not like that at all, dont worry about that at all mate.


My company is R-Tech Performance tuning.

What is clearly visible? Come again.
You posted two timing maps. Do you realize that the load axes are different between the timing maps?
The lower compression engine runs more timing everywhere in the power band.

Do you disagree with this?

Well, it didn't seem that way just a moment ago.
But I sure hope so.

We have gone way off topic here...

Hi

Im building a GTX3071r 1.8T with 82mm pistons (9.25:1 CR), supertech valves, top mount manifold, 4" maf housing with tial 38mm wastegate.

Im looking at injectors and need some advice.  Ill be running a ME7.5 BAM ecu.

What size injectors do people recommend?  Ive heard 680cc's will do the job, but I want plenty headroom so they not running a high DC.  Also what make is the better ones?  Ive read a bit able misfires on idle, spray patterns etc so just wondering what people have had experience of on here and what they would recommend.

Chris



I would go with the ID720cc injectors thats what I am running on my Golf with 9.5:1 at 430bhp on a T304E .64 hybrid @2bar.

yep.. I do disagree

Relative loads being 0-Full between them (yes I am ignoring the numbers..)
Full load, full revs...   all is clear to see.

Huh? Why are you ignoring the numbers when load equals to cylinder filling?
Let's put it this way. The lower compression ratio engine can run more timing and extract more power at the same cylinder filling as the lower compression ratio engine.
There is no "0-full". Load is already a percentage, you are trying to calculate a percentage of a percentage.

How you can compare timing at DIFFERENT load sites is beyond me.
What do you think would happen if you dropped the CR to 9.0:1 on the Leon engine? You could run the same timing as the TT runs at the same load spots.
Except maybe up top, where the smaller turbo would equate to more backpressure, but you would still run more timing across the range.

And you do not think this would make more power?

My comment about $5 filter was to plug at the fact there could be hardware issues, which is the issues I am running into all day long, I spend 4-5days just trying to get the hardware right in cars so I can tune the SW.  I have hit brick walls on many cars, silly timing pull, low power, silly egts ect... only to find part of the hardware not right or a a maf reading wrong.   I do more fault finding pre tuning than I do tuning.

You might come across the same setup one day and manage to get more advance from the setup then scratch your head, I have been there many times.

Nick

I agree, it is exactly the same here. Don't worry about the filter though, it's not 5$ and it did not pose a restriction (I tried a different one).
However, that car had an AJQ engine in it, with a stock small port head and stock cams, and I did not see anything wrong with the timing.
That setup ran 2.4 taper 2.1 bar. I have boosted a S4 2.7TT before to 2 bar, and the timing looked exactly the same on stock cams. Different cams - different timing, some headwork, and again massively different timing.
If I could run 20 degrees of timing at 30 psi at 6800 rpm on 9.5:1 CR on a stock head and only see the car make 430 hp, I would try to see and understand what is wrong. Probably first thing on the list would be a leak down test and look for excessive blow-by as my experience would suggest that something is very off with the dynamic compression of the engine.

I've come across this many times where an engine would not knock but also would not make any power without huge timing advance. Most of the time the leak down test would be pretty bad and it would start smoking quite soon after, because all the air was going past the rings. Other cases the valves were not sealing as well as they should.

you have said, lower CR will make more power, and this suggests the opposite is also true.. Does it not.. Your arguement, not mine or others.

Timing can be run higher on the lower CR engine you also say, yes?

Post up a timing map from the tt on your website. stock CR on it, 9:1, retune when lowered you comment on your site.

I will say this.. I run hybrid Precision62/GT3582 on 1900cc 1.8t, in a race car.. It runs currently a 9.5:1 CR engine on its build spec.. Previously 8.5:1 motor.  It happily runs 26deg of ign advance on vpower pump fuel, no extras..  It has run more timingwith zero det (on cans). (cyl pressures will be too high however)

It is also >300bhp/ltr in race trim, more if I turn it up (which I dont need to do for the c'ship I compete in)

I chose higher CR deliberatly for this engine... It has in no way hurt anything, but has helped it "pep" up and response out of the corners is greatly improved.  Response out of the slower corners is on par with the atmo cars I race against, as I am not completely reliant on the turbo's spool for its performance.

If the op reads your opinion on the CR his engine will explode at any minute... When clearly it would not.

Others manage it, yet you wont open your mind to the remote chance that others are making it work... and you dont have to deck the CR to get a turbo motor to work.. In the 80's perhaps with clockwork ecu's, but now... its just not the same thankfully.


You seem to have a fixation on 30psi boost levels?  Bizarre.. No wonder you cant run much timing when you make them so hot in the first place...  You dont have to wind the wick up on the boost to drive decent power/torque and engine response.  There are Other ways.

I have not said lower CR will always make more power.
The timing maps you posted clearly show that lower CR makes more power in this application (1.8T k03 vs 1.8T k04 factory).
If you look at what LOAD means in ME7, you will see that your comment about 0-full was not adequate and that in fact to compare timing between these two engines you should compare timing at the same load sites.
This is how Motronic has worked since the early 80's. This how it works until today, where from factory load = cylinder filling.

On the GT3582 you are for sure not running stock cams nor stock head. You are running big cams with big overlap.
With big overlap comes the fact, that not all the air that goes into the cylinder gets compressed. This results in low dynamic compression, even at a high compression ratio.
An extreme case can be seen in NASCAR where they run very high compression ratio, because the airflow is choked through a restrictor.

You need to understand that compression ratio heavily depends on the head and cam configuration. I am mostly talking standard head here, your race car is an exact opposite.
Making conclusions from what you see on that, at high RPM and then applying that to a car on stock head is not a correct approach.

Of course it would not explode, I just think it will make more power ;)

The question is all about extracting power for me, not about "making it work". You can make things "work" with just about anything you put on the car, but that's not the point, is it ?
I don't see any reason for your 30 psi comments besides personal offense. It is just a number used as an example, because it is nice and round, nothing more, nothing less.
As to making power, you can either run lots of boost, or you can rev very high or have a very good VE.

I don't see any reason for your 30 psi comments besides personal offense.
[/quote]
Offence?? LMAO... READ YOUR OWN POSTs....

You are an Arrogant & Rude man.. End of discussion.


You feel you are free to throw insults out to others etc, yet you also feel someone's causing you personal offence if Your own comments are redirected back at you.

Get a life FFS... STOP being a nasty Arse on the forum... You are clearly more intelligent than that, and let yourself down badly with your abrupt, rude, responses.

You are NOT the only guy on the planet tuning these engines and getting Good Results from them.  Be less blinkered. More open minded...  Its a big world out there..

;)

Personally, I think I would rather see less power, but have a car that is going to respond well to different throttle applications, and have a nice graph plotted on a dyno with the car having plenty of drivability, and also power held nicely across the revs (needless to say probably more suited to the smaller k03/k04 turbos, but lets use that as an example).  I have seen plots of power and boost of these turbos using less boost but making more power....however, what you say to make power is lots of boost or good flow of a engine.....How does that work if here in the UK we are seeing better figures and dyno plots if we use less boost  ??? ???

How would you recommend to tune a k03/k04 turbo'd engine to produce a strong stage 2 map?  What boost? What lambda? What timing does it run? What are the EGTs like?

It hurts you a lot being wrong about something as simple as LOAD in a ME7 ECU, doesn't it?
Maybe you would like to throw in a few other cliche insults, such as "get laid" and so on, to convince me of your superior intelligence?

Where do you get the assumption that the car is going to respond any worse to the throttle with the lower CR in your application?
You keep repeating that over and over again, it does not make it true if you keep repeating it. This is simply not the case.

Point out where I said this. Because I never did.
I'll ask you - what makes power in an internal combustion engine? Go on.

here??



From that it would appear that you say that to make power you need lots of boost and also rev the engine very high?  Tuning is certainly not my forte however, from what I have seen, the need to rev high, especially on a smaller k03/k04 turbo car is un-necessary, as ive seen many hundreds of cars tuned with those turbos on making their peak power at 4500-5000rpm.


Answer my question?  How would you tune a k03/k04 car?

Then I would like you to read more carefully.
Note how I said or between every single statement.

So, what makes power in an internal combustion engine?

Do you hear voices in your head?
where do you dream up this stuff?? lmao.. sorry but you really do seem quite insecure and sad, responding like you do in forum posts.

I'll leave you to throw out the insults.. you are far more adept at it..  Practice makes perfect... and damn, you do get to practice a lot - lmao

"have a nice day"

i agree turbo engine does not need high CR pistons as much as NA engine but i think most of us would like to talk about static CR. Although  the most important thing is dynamic CR which depends on many factors (as cams profile , cc head chamber , engine dilpacement etc......)

Well....I just stumbled on this little gem of a thread poking around for injector info, and while I didn't find much of that, what a scintillating discussion on compression ratio!  Anyway, I was a little disappointed that no one answered prj's question, so here goes.

What makes power in an internal combustion engine?  Converting the chemical energy contained in a fuel into the most useful work possible, as fast as possible.

Or it could just be the bangity things.

Exactly, and the more knock restricted we are, and the later the ignition timing, the more work is wasted and blown out of the exhaust as heat.
Thus dropping CR has only ever a penalty in those areas where MBT is attainable before encountering knock.

I'm going to have to ask nokiafix and ibizacurpa to calm down a little here.

Both of you are taking this too far, have provided no proof and making some odd claims.  If you guys want to play the game, post up logs.

If you look at the post dates, then you will see this is quite old.

This is 100% true.  If MBT cannot be reached with a given fuel before hitting the knock limit, reducing the compression ratio can only help.  It is important to remember that there's a balance to strike between the timing gained and the thermal efficiency lost by reducing the compression ratio, but in support of your point, I think in most forced-induction port-injected engines running pump gas, it pays to reduce CR.

Also, sorry prj - didn't mean to get you in trouble!

You're right, last post from them was Dec 2012.  The posts on this last page were from this year so I didn't think of it much (I've never read this thread before today).

My post was entirely towards the other two and not you PRJ FWIW.

Exactly, to get the same power as before dropping CR you will need more timing, but as long as you are knock limited in the area you are interested in, you can not really lose power by dropping CR.

Higher CR is beneficial when not knock limited, such as when using E85 or other exotic fuels.
Or indeed in a high revving naturally aspirated engine.

As usual, I agree with prj.

My real life experience also backs up theory; with crappy gas, dropping CR and bringing timing up from the basement is a HUGE gain, just about ... everywhere you aren't near MBT.

Which, on pump gas and a lot of boost, is basically everywhere power matters.

Absolutely I agree

Hi guys,

I've never worked with forced induction engines. But I couldn't agree more with prj's theory wrt lower revs for forced induction engines.

My exp wrt naturally aspirated engines tell me that increasing CR has to be backed with suitable fuel, else it is a waste.

But, one doubt still bothers me : increasing CR and advancing timinng will both take u towards knocking. So how are 2 things diff. Maybe the dynamics are diff for forced induction engines. Is it so prj?

They may both take you in the same direction, but not at the same speed!

Another thing which I have noticed is that increasing the CR gives more torque at high revs (close to peak power band) and not much improvement at low revs.

Hi i just came a cross this topic, and got interested  about the info about the CR…
What I don’t get is how it is possible to make a lot of power lets say 300~400hp with high CR and not have trouble with knock.  On normal fuel not Race or E85.
Because my own engine has a lot of timing pull due to knock and I’m only making like 260-270hp  at 2400mbar(1.4boost) at +-8~10 degree this is with stock pistons of my AUM engine 1.8T Cr 9.5.

So I was thinking of dropping it to 8.5 and at the same time go bigger bore and stoke.
But if a then read te post about the hi power witk “high” CR I think that is maybe is not woth all the work and that maybe there is more to get out of the engine without all the work :D

Or is it possible my engine is not realy knocking yet but he ECU is a bit “to soon” in recognizing knock and that there lies the difference with other tunes with higher power on the same CR.
My knock control is a bit changed but not a lot want it to be safe not killing the engine ofcourse :D

If you want to make power you need to drop CR.

^This.

I think there is quite a bit of misinformation that circulates various forums these days concerning the levels of power that are supposedly made with stock compression ratios.  I'm not saying 300-400hp isn't possible running 9.5:1 combined with a highly knock resistant fuel and/or some water-meth injection, but if you're looking for those figures on pump gas without a lot of headache you'll be dropping your CR.

It's interesting to see people's aversion to dropping their compression ratios in forced induction applications.  You'll certainly take a hit on your freeway fuel economy, but you're going to see gains virtually everywhere else.  I wonder if it stems from carry-over from the NA crowd where high compression and crazy high rev-limiters make power.

Absolutely. They have no other alternative, so it became "conventional wisdom" that if you do a motor rebuild, you want to use some crazy high CR and/or never lower it.

Well, if that's their cup of tea they can always run straight toluene in the thing.

I know both nokiafix and ibizacupra and both are getting some of the best results from OEM turbos ive seen here in the UK.

What grade fuel do you guys use?  Over here in UK we are using 98-99 octane fuels  which could be a bit higher than other EU countries?

No, UK fuel is nothing special.

Figures must deceive the facts then ;)

i always use 98 octaine "best" you can get here at the pump like Shel V-power (98) or Total or Q8 or the cheaper fuel near my home "maes" but still 98. And they give me all the same beheivior in Knock retard on the ingition.

But when i drove trough Germany and Austria there they have "BP 102" octane and "shell 100-102" then there the care felt a bit beter litle more power en agresive on top :D

Shame whe dont have those fuels in Belguim :D

If you plan only run with PumGAs go down with compression!!!

Look my Car Stock 8.9 Compression with 102 ARAL (BP) GAS... Verry Bad Ignition Timings. This run are on dyno, on street i dont can drive above 13 degree.. I have planed to run this car with e85 it was only a test how much i can go with PumpGAs

Leo

This topic is such an old gem. Here's some input from me, hope someone will find it useful. Comments are welcome.

The car is a 2 litre stroker from a 1.8T BAM, ME 7.5. The crank and pistons are from 2 TFSI. CR is about 9.8-10:1. GTX3071R Gen 2 @ 1.7-1.8 Bar reached at 4200 rpm, 0.5 bar at 3000 rpm. I run a 4 bar MAP, so the readings are little off, don't get confused by the log. The cams are 'aggressive' stock cams from an AGN NA motor. There is no CAM overlap (VVTI swtiched off completely).

The graph is with Bardahl Octane Booster, so 0 timing pull from KR. If I run just pump gas I get about 1.5-3 degrees timing pull from KR.

The injectors are bosch 630cc @ 3 bar, but I am maxing the out as you can see.

....

Run that at WOT for any significant amount of time and you will drop an exhaust valve due to the insane EGT.
That timing is not safe even with octane boosting, and on pump fuel it's even worse. CR needs to be 8.0 for pump fuel and this turbo or you need E85.

Let me guess, no EGT sensor? Or not flooring it for longer than 5 seconds at a time?

4 EGT sensors, one on each cylinder, but yes not flooring it for too long. Temp goes to about 860 C on a single WOT pull, will probably go higher due to temp accumulation if I do many without cooling down.

Valves are Supertech, so hopefully they will hold.

Here's a log on pump gas only. I decided to bump up the ignition timing with the octane booster to decrease the EGT. Why don't you consider it safe when it doesn't knock and EGT is lower with higher timing? What timing is considered safe with this setup?

860C on single WOT pull of what 4-5 seconds? And it's not in the log anyway, so whatever.
You have random screenshots that don't show time, no csv's.

I'll let you drop the valve and trash the motor as a learning experience.
Maybe you'll build it with the correct CR after.

Your supertech valves have nothing to do with the fact that the exhaust valve will drop from it's seat, that's usually what goes first on 5 valve heads with too high egt. The motor is trash after of course, usually the turbine wheel goes as well.
Or you will just melt a piston.

Nothing you posted here is safe. It's actually a very good example of why correct CR needs to be used.
Your engine is only good for E85 or MS109.

Been there, but none of that goes first. What goes first is the turbine wheel heat shield. Opens like a can cover and the rest is history. I've had motors that held up at 1000C without too many upgraded parts inside, so I consider 860 a success.

This setup was little experimental and it was too late to change so we closed with this CR. What EGT do we consider safe? Lowering boost is always an option.


This is actually a WOT 4th and 5th to do 100-200km/h, 860 is at end of 5th @ 200km/h (my gears are short). The stock EGT is out, so it's not in the log indeed.

Thats pretty good timing for such a high cr even on a pump gas

Yeah so very short log. On the autobahn you will melt it.
Removing the EGT sensor means you don't even have protection and the tune isn't EGT stable.

On pump it's 3 deg in mid and 6 deg up top.
Not safe for any reasonable amount of time.
Octane booster timing is better, but I don't like these engines below 15 deg timing up top.

Seems like there's two different philosophies at play here.
When I was still tuning and building cars for customers, I gave them to customers so that they could floor it as long as they liked and everything would stay together, no strings attached.
So there was not a limit "oh, you can't hold it WOT for more than 10 seconds".

If this is what you guys are going for, go ahead. But actually saying this is OK - I will shut that down every time.

This setup is definitely conditional, the car is not a daily any more and in no way is this "safe for a customer", I am with you on this one.


As you can see the car runs rich at any point, so EGT control not really needed. TABGTA is set to 550 C pretty much in the whole range to avoid intervention.

So given there's octane booster always available, can the ignition timing be increased to let's say 13-14-15, as long as KR doesn't pull timing? What would be the highest ignition one would go with octane booster if it doesn't retard? I've had a setup with big port head where it ran 20 degrees @ 2 bar. CR was 9:1 and it didn't pull timing, I always found that weird.

With that boost, and that CR your AFR is to high. You need more fuel to cool down that engine and keep it safe

10:1 CR na 1.8 bar boost at pump gas and 12 AFR . I must say I am impressed. 1.8T engines are real bulletproof

I didnt say 'awesome' or something like that
And personally am always aiming at least at 10 @mid for the same reasons
But
I saw much worse timing on a stock cr running past map pressure and those cars living for years (not at track i believe)
And then there is a community sayin 'R*vo tune rocks! and you just cant do the things like them blah blah' so nah guys, take your cookie with 5 deg timing and no worries if it blows. Youve got what you want  ::)
Yes its stupid. Yes i know that and ill never done that in my personal setup. Its a choice between stupidity and a budget, not a philosophy  :-\

LOL
It is hilarious how you are so blissfully unaware of your own ignorance, and keep pushing your narrative.
Your tune is a ticking timebomb, no amount of whitewashing is going to change that. Even with lambda 0.75 you will probably melt the thing.

KFZWOP.

What is hilarious is how 9/10s of what you write is useless passive aggressive shit, but luckily that 1/10th is useful and people put up with you :) You remind me of Sheldon Cooper :D Thanks for the input though, now please stop.

Adding personal attacks won't make your shit tune any better. But serves as a good example for others to learn from your mistakes.

You're lol-ing and calling me ignorant, I call your writing useless. Notice a difference? Who is personally attacking who here?

I saw a log from you few posts up with a -6 degrees at spool, I am not sure how you have the nerve to call my tune shit with such an abominable results of your own.

EGT protection is off, CR is too high, EGT is high, do E85 ... what else are you gonna bitch about? It sounds to me your whole tuning style is of a little scared pussy that doesn't have the balls to make some power. If I tell you I run mafless now you're probably shit your pants, aren't you?

Let's stop this please, we are ruining the dude's topic. Unless you have something useful to add, please just don't reply. Thanks!

It is more like 11.7 with octane booster always, lower and we start losing power I've noticed. Will try lower and will compare EGT, see if it helps, if the injectors make it.


So I am guessing everyone here thinks that 11 degrees on this CR with this boost, even though it is not retarding, is stupid and this engine will break any minute now due to high EGT and that's it :) Point taken, will start collecting parts for 8:1 :D Thanks.

1. A few posts up. You mean ten years ago? Were were you ten years ago? In school?
2. It was specifically posted to illustrate the point of what happens when you have too high CR on an engine. That literal graph was there to illustrate the point.
3. You can't even read - at spool there's 20 deg in that graph, -5 degrees is at 30 psi. Do you think the car was tuned to run that boost or timing after? Of course not. The boost was backed the fuck down. It was a short linearization run for KFLDIMX/KFLDRL in that example.

You seem to think 3 deg is good ignition timing though.
I don't "bitch" about anything. I don't give a fuck how you run your car. But I put my words in here so that other people who might hit this thread see how not to tune.
I've probably made more power than you will make in your lifetime, considering I did it full time on a dyno for 10 years.

LOL at mafless comment. I am the one who made speed density for M2.3.2 in 2010, and I did the SD mod 8 years go for ME7.
I don't run my cars in limp mode on alpha/n though, because it drives like shit.

You're just a nobody getting called out on your bullshit.
From your posts it is clear you don't know what you are doing, but you have a big mouth at the same time. Shitty combination.

Dude, please. That's yet another useless post from you, nothing on topic.


Where did you see 3 deg and that I think it's good? The same place I saw your -6? Do you think it was left like this, it was apparently work in progress.

Of course I am not a tuner, nice investigation work! It takes a click to check my posts, all about the same car for 6 years. Show me one place where I claimed otherwise? Big mouth? Where? Bullshit? What was bullshit exactly? Not only do you "bitch", but now you're also making stuff up to compensate for something.

What part of my tune is shit exactly? The fact that it reaches 860 C EGT? Ask people around with 8:1 what EGT they're running, I'd like to know. Do you even know what power this car makes? Ridiculous...

We don't know what EGT it reaches and how quick, because there's no logs. So it's just your random claims without any basis for verification.

What is shit?
Hardware wise: the fact that you ended up with an engine that is only good for race fuel or E85, because even with octane booster it's unsafe, but you want to use it on pump fuel. Why? Who knows. Maybe the 9.5 pistons were on special on eBay.
Tuning wise: You come here and say hey, it's so cool to run 5 deg of ignition at 7000 rpm. Well it's not, and it's going to blow up if you hold it for any reasonable amount of time.
If I put it on my dyno, it won't even make a single dyno run before something melts with that timing. Seen plenty of hotshots like you who come in to my dyno to measure their hot shit, it blows up and they pay the cleaning fee. "But on the street it was fine!!111", yes when you push it WOT for <8 seconds it usually is...

If you were a normal person you would just put E85 or race fuel into it, and you would do just fine.
Maybe dual 1.2mm jets with pure meth could help you a little. Not that it's reasonable either.
But none of that is pump fuel anymore. Octane booster isn't pump fuel either.

But you are not a normal person, because you are trying to somehow say that what you did was right.
It's not, it will never be right, and it's precisely the reason this thread exists.

I mean everyone here with any experience can see that, because half of what you post has nothing to do with reality, no investigation needed here.

Where did I say that? Please quote me, you seem to know the quote button very well!

I came here sharing logs and information ON TOPIC and possibly asking for an opinion, which I got plenty of from you albeit useless for the most part. I also said that this tune is conditional and it will always run octane booster at least (where the F did you see that I want to run it on pump gas?). I also never said that it will not run E85, maybe it will, haven't decided. On top of that there's no 5 degrees on any of my logs (except that intermediate one that I put for reference, same thing with your -6 log), please you're making claims that are FALSE - plain and simple!

Please, read twice, three times before you reply, you seem to be making things up.

There were other people who expressed their option so simple and not provocative, be like them.

You got plenty of opinions, especially after you said "I don't need EGT control"  ;D
In your screens you have KR even with the current timing.

You are doing super short pulls.

Try to see what happens with timing and KR on a dyno with at least a 13-14 second long pull.
You won't be able to run that timing, and you will most likely have a chain knock event where the timing will go negative, since it'll get too hot, and it's a chain reaction from there.
Hence me saying it's not safe to run that boost with standard fuel, octane booster or not.

On E85 it would be fine, on MS109 also. But not on this pump+.
Anyway, I think that much is clear. But of course according to you everyone who does not want to melt their shit is a "pussy" ;D
I just never chose 9+ CR for more than 200 hp/l on MPI engines, unless they were going to be running ethanol.

It's exactly the choice between making power absolutely safely and reliably or making less power without any safety for 6-7sec runs.
Why? To save 0.2L/100km fuel? Really?

Its pretty well with an octane booster (8-12 iirc) and absolutely worse on a pump (3@5000)

Only one question here - why?

Factory setups with a high CR, low boost are good for mileage, emissions and driveability
Low CR, high boost good for top end power

Youll try to catch benefits from those both strategies but in fact its just a fight with EGTs with no mileage reward (octane booster costs more) so whats the point?

As I mentioned this setup was 'little experimental', meaning we used what we had. Honestly did not think about CR until I noticed the crazy timing pull from previous tune, so call it a mistake or an oversight or whatever, doesn't matter. Still I want to have the car perform as good as it can, so I am pushing what can be pushed, clearly knowing it is not good to have high EGT and low advance. This is why I put octane booster to make the best of it. The goal was achieved, the car is much faster now, but yes, theoretically this is not a correct approach. I care little if this engine melts, it is not about mileage, this is not a daily, and it is not for economy, same reason. Car is full carbon fiber body kit, 6 speed dog box gearbox, under 3000lbs, it is just for fun. I just saw prj's abysmal graph and decided to share mine and get some opinions. Moreover the topic is about injectors on high CR, so I wanted to show that 630cc are actually maxed out with such a setup.

That's it, plain and simple. This whole other crazy back and forth with this dude was actually a complete shock to me and I apologize to all the innocent bystanders :)

I actually plan to add another 1 or 2 degrees up top, see what happens and pay closer attention to EGT.

This dude... listen man, thanks for the advice on E85, I appreciate it, I know this is a good advice, but again please read more than once before you express an unmeasured opinion. Let's do step by step: how does EGT protection work in ME7, what does it do when it senses high EGT? As we established I am not a tuner and you are the greatest, this should be simple.


WHERE? That random - 0.75 @ 7200 rpm where it is obvious it was from fuel cut due to the rev limiter?

If you want to be of use to people you can give your opinion in what timing is best and/or what is a safe EGT, then you can be useful. The rest, as I said multiple times, is 90% useless .....

You seem to be obsessed with telling others what to do.
The world doesn't work that way.
Nobody gives a shit about what you want.

But we arrived at the final conclusion - you screwed up the hardware so now you're trying to bodge it to work somehow.

Yes, your abysmal graph matches exactly the abysmal graph i posted to illustrate what happens with too high CR and too much boost. What a surprise?
If you had any clue about ME7 you would know that knock detection is blended out for those cylinders that are in cutoff mask.
Do a pull with a reasonable length, your super duper tune will fall apart immediately.

For EGT your ECU has a real actual EGT input and closed loop control.

P.S. If it was my engine I'd pull the head and put a compression lowering head gasket in there, not the best way, but much better than trying to polish a turd.

Alright man, I don't want to start a war here, not sure where 'telling people what to do' came from either, but it doesn't matter.

Here are some logs I just did, in case anyone is interested. Gave it 1 more degree up top, seems to be holding. EGT apparently is irrelevant unless you floor it for 30 minutes straight, but during the short pulls on 4th it went to about 750 C.

edit: doesn't seem to take 5mb files, will have to reduce later and reupload

where have you installed the egt sensor?

Do you have possibility to instal WMI?  I think it might best solution for what you have now

I have 4 additionally installed probes with gauges, one in each runner of the exhaust manifold.


It is definitely an option, been considering that actually.

Here are the csvs, removed the dummy rows, left the wot pulls only.

So what EGTs do people run, is this some sort of a secret?

I am not a professional tuner either, really far from that, but I call bullshit on the 750C EGTs with pump gas measured in the runners.

Seems too low? What do you get?

Right.

So I have a few things to add to this whole deal. Just now I am actually rebuilding my car and valves were on the thing I put extensive research into. You probably know there is a whole fiasco about stock exhaust valves in 1.8T and 2.7T how they are weak and blablalala.. Well they arent, because of sodium and decent material usage.
The issues come from a multitude of things one being the insane EGT's people try to run stock compressions and such.

I actually reached out to Supertech , multiple OE replacements (for solid valves) companies such as Mahle and TRW(Kolben), aswell as an actual major valve steel supplier.
Found out that if you are looking for replacement solid valves TRW makes the best one because they use the best material available DIN 1.4882, Mahle comes second because of inferior material (predecessor of 1.4882). However do not replace the stock valves if they arent worn(but usually they are at this mileage of engines). TRW's valve is actually superiour to Supertechs stainless series or on par, the only thing Supertech they have over them is the coating ofcourse.

Now what kind of temps can some of these valves take?

DIN 1.4882 contains titanium hence its strong properties and good resistance which is qualifed up to 820C on the valve. Lets put it on a comparison: Inconel. Supertechs valves are made from Inconel 751
which is qualified for 860C on the valve with this info coming straight from valve steel supplier.
The stock EGT system was created using 4 sensors in multiple locations, the FR gives an exact description on the whole system both an EGT input model and modeled EGT.

Now you know that gas temp will not equate to the same temps on the valve but you get an idea. Porsche made a paper about this when they ran one of their cars with state of the art sensor to see whats up. Have a read its good stuff:
https://www.porscheengineering.com/filestore/download/peg/en/pemagazin-01-2015-artikel-07/default/506ac10b-bdd2-11e5-8bd4-0019999cd470/Optical-Measurement-of-the-Valve-Temperature-A-Precise-Measuring-Method-Porsche-Engineering-Magazine-01-2015.pdf

Yes the 1.8T and ME7 is quite bulletproof and idiot proof but it does not mean you cannot do bad things in extreme scenarios.

Why is that graph "bad" and why its a decent example of what happens with big turbos and stock CR AND pump fuel?

prj is right. That timing is bad for power bad for everything. In the last few months or even years I dont think I have seen a decent log of an 1.8T with double digit numbers or decent peak torque timing.

Actually few years ago during the start of my campaign here I actually decided to turbocharge my car which happend to be 1.8NA with 10.3CR. Fast forward few years , its still here but let me tell you from experience, please learn the importance of CR in a turbocharged car.

I ran 5-6 degrees of timing at peak torque and barerly double digits towards redline ofcourse with fuel dump as its necessary with under or max 1 bar boost with slighly smaller turbo . It is still here getting built to the next stage, but trust me you can do better. However in my case I knew what I was running into and had the necessary paths to deal with em, higher octanes and toulene was no problem.

Where can you get some base numbers of what you should be running?
Funny you should ask since Bosch did that for you to a certain degree. For a base take a look at KFZWOP and then you'll see how far off you are :) and few degrees make a huge difference in operation of an ICE. IIRC kfzwop was done using 120 RON fuel, correct me if wrong.

You have your car in the current state yes, now take in what people are saying and take the correct steps to make it even more reliable and useable for the purpose it was built for. Dont be like certain people or certain groups.  I had people tell me VAG engineers were retarded for dropping CR in the 225+ (even some 210) models to 9 in an environiment where power was second goal. Oh yeah dont forget they did that cause people "usually" seem to forget that :)))
Oh also dont forget back in the 4 cylinder turbo era of F1, they ran on 6.x CR and like 70% toulene to be able to run 4 bar or so boost so that they can make power.

Where can you find a quick remedy to your issues? such as a compression dropping headgasket?

A company in Germany- WP Spezialteile makes comp dropping headgaskets for less than 100 euro. They take an original OEM Elring headgasket and put in a nicely machined spacer, and reseal it I have some pics if you wish, but I am really impressed by the quality of the work and effort. You can also find comp dropping headgaskets from other companies , more expensive ofcourse.


All in all, the amount of ppl that underestimate CR limitations on pump fuel is seriously funny. It also seems people are scared about lower compression ratio, really all its needed is to remind them that VAG dropped the CR by half a point just to go a K04 and few degrees of timing to make some more power. How much should you go on a triple sized turbo and other supporting mods on simple 95 RON or >100 RON fuel :)
Yes higher CR is good IF you can run the necessary fuel for it. Otherwise what you lose in mechanical 'power',over the dynamic operation of the engine you will gain much much more, than being severly knock limited and pushing components to there extremes.

I have logs on hand on friends with WIP builds and let me tell you its not pretty pump fuel and big turbo dont go well together on stock comp.

TLDR: Drop your compression , as for topic it will also relieve some pressure from injectors as you dont have to fuel dump as much,for which you wouldnt have the capacity to do anyway because of the internal components of the engine :)

@Blazius this is a lot of time put into this post, I am sure everyone appreciates it, I sure do!

To be clear, I don't think anyone thinks that pump gas, high boost and high CR is a good ,healthy or optimal thing, me included! I am not an advocate for that in any way, I have a feeling that people think I came here to try and convince them this was good. Not the case, at all!

The idea was to get an opinion of what is the best one can do, given that this hardware setup is already in place. We saw that it would be best to drop the engine and rebuild it, go E85, go compression dropping headgasket, or lower boost significantly - I think everyone got that, didn't they?

What nobody shared is what EGTs they run and/or what EGTs are considered safe, also it would be interesting to see people with correct hardware setups share that same thing. On top of that it would be good to also see what timing people run with correct hardware setups, but yet nobody is sharing that either.

This is general information that can be found all over the internet when it comes to turbo charged petrol engines with forged internals. Checkout some of the old dsm forums or honda forums and do some reading. There is no magical answer here, and this has been covered so many times on other forums its kind of dumb to hijack a 10 year old thread over it.

Read my first post, what did I hijack? Shared a log, shared information and that's it. I did not even expect there to be a discussion. Information in these forums is here to stay, doesn't matter if it's 10 years old. Why even bother writing this reply?

You keep asking what EGT.
VAG runs 980C continuous at the turbine with the stock engine. It's in the ECU.
0.9 and then fuel dump closed loop to not go past 980C.

But your engine is not VAG anymore. So who knows what the max allowed EGT is.
Your sensors are also not in the stock location (by the turbine) and who knows how precise they are.
Couple that with the fact that you are doing 6-7 second pulls...

Over here we have something called "One Mile Challenge". It's an event where people go WOT for 1 mile and then get a ranking based on trap speed.
Every car I tuned locally has to be able to take part in that event. Yours would not be able to unless you run it on MS109 or E85, as it would blow up half way.

....

Thanks! The question was more towards setups with BTs, but this is also helpful.

I learned a lot in here, thank you. 

Note that in the US, doing a full WOT 1 mile+ pull is rare except on road courses (and even then, they're rare - the longest straights don't go that far, and nobody HPDEs on an oval). So it isn't surprising you see both hail mary pulls and hail mary tunes that really only are subjected to 10 sec WOT at a time at the extreme end.

Water meth solutions also don't last long on track, you have to bring way too much meth with you on track day.

Most of us run race gas and race gas tunes when tracking for this reason.

By and large, high hp chasing dyno queens almost never run pump gas either - you'll never get anyone to be willing to "compete" using pump gas. It just doesn't happen.

There's also Autobahns in Germany and there are chances your client can go there.
In German they call it "Vollgasfest". And it is a good philosophy to apply to tuning.

I've tuned a strong four digits of cars and I can count engine failures on my fingers, and only 1 or 2 where it could be argued that it was tuning related rather than hardware issues.
And that's with many of them subjected to the 30 seconds of WOT described above.

Understood. Just saying, most tuners are willing to hand off grenades to their clients to win HP dick waving contests, knowing (or assuming) the client won't do anything but street light racing and 3/4 gear pulls on the freeway

Most tuners have to do it because of clientele. If your 1.9TDI gets beaten by your buddy's 1.9TDI, your tuner's ass's going to itch from all the cursing. :D

That aside, there's always ways to get best of both worlds (given the situation): boost controllers, map switching. Using MDBGRGA and KFMDBGRG to limit torque on high gear is a good option, most highway and long time WOT is done on highest gear anyway, so no need to torture the car there, but still good for 3rd/4th pulls. Flooring it for a mile won't really be a problem.

No, it is done because of lack of knowledge and doing a shit job.
On Diesel you only have to set a reasonable EGT and IAT limit, that's all there is to it. And by setting correct EOI (most diesel tuners don't even know what that means), you will have better performance everywhere and lower EGT.

Correctly tuned there will not be any difference between the cars performance.
Except one will blow up in extreme conditions and the other one will limit the output at that point and stay together.

This thinking that somehow you need a tune for power, economy etc is complete bullshit done to sell more of the same shit.
ECU has full 3D mapping. ME7 has ways to limit requested load during too much knock intervention/low ignition efficiency and the 1.8T variant even has real closed loop EGT control.
The only excuse for having non-fullthrottle safe tunes is laziness and ignorance, which this thread reeks of.

Agree. I didn't mean to imply safe tuning imposes performance limits. Safe tuning just requires knowledge/effort.

But see that still does not explain or excuse the high CR stock motors and pump fuel, because if you put the same car with same boost same everything but with lower CR and 10 more degrees of timing at peak torque and so on, which one is likelier to 'win' ? :)

If that was the way Audi wouldve kept 9.5 CR on the higher HP models too, just boost increase and turbo change.