NefMoto

Hi guys.

Bazaa and I were recently discussing the Revo Technik stage 2 remap for the 225 & 240 PS Audi 1.8T engine variants so I suggested I post up my VAG-COM logs during WOT runs in 3rd and 4th gear for general interest/discussion. I included a sub-set of these results in my 'beginner's guide to ECU remapping' document.

The background to these logging runs was my general disbelief of the rolling road dynamometer results obtained before and after the remap. The agent estimates transmission losses during a run down from peak engine speed and adds this on to the wheel output which gave peak outputs of 256 bhp & 350+ lbft. I felt the bhp was maybe 8-10% too low and the torque far too high, so I sought some alternative ways of estimating or calculating this from engine parameters.

BHP is estimated from the tried and tested expression BHP = MAF/0.8 for 1.8T motors, but I have also logged block 120 which has some measurement of torque and then back-calculated BHP from this. I don't know how this figure is measured/calculated and would be grateful for advice on that. Suffice to say that it is much lower than the dyno figures. The data in blue type are all calculated from the logged parameters.

Bazaa commented that there was some general dissatisfaction with Revo remaps on forums relating to rich running, etc., but the view on the forum I was previously a member of was that the outputs were highly optimised and very satisfactory with little evidence of undesirable side effects. However, you can see some rather high IDCs (up to 148%) on the 4th gear run compared to maximum of 98% on the 3rd gear run. I would like to credit Morgan Evans of Vagcheck in Staines, U.K. for his advice on this.

There was also a great deal of discussion about the supposed benefits/advantages of higher octane super or premium unleaded fuels in terms of peak outputs and greater fuel economy, but nobody ever investigated it or obtained any objective data so all arguments were based on hearsay, opinion and the good ol' butt dyno only. Most TT owners, whether remapped or not slavishly stuck to the premium or super unleaded products with Shell V-Power 99 RON being the most popular. I grew rather tired of this and sought to find out whether the standard supermarket 95 RON fuels were significantly worse in terms of fuel economy and require greater individual cylinder timing corrections during WOT runs to cope with more knock events from fuel of higher calorific value.

I have not repeated the WOT runs with supermarket 95 RON fuel yet, but am currently nearing the end of my second tankful of the cheaper fuel during which I have deployed 'hypermiling' techniques including gentle acceleration and cruising at 60 mph on the highway. All my mileage nowadays consists of 36 mile round trips, of which, 95%+ is cruising in relatively light traffic two lane highway (dual carriageway in the UK) giving a consistent baseline for comparison. So far, I have been able to EASILY add 50 miles to my range and 3-4 mpg by driving carefully.

Continued in second post due to character limitation..

My working hypothesis is that the higher octane 99 RON super unleaded fuels are not worth the 5 to 8 pence per liter premium over 95 RON standard fuel because:

(a) Any small improvement in fuel economy is likely to be greatly outweighed by variation in driving technique/style and traffic/weather conditions

(b) There won't be significantly more knock events at high loads with the lower RON/higher calorific value fuel such that the ECU will pull sufficient individual cylinder timing correction for there to be a noticeable reduction in peak output.

However, I'll see in due course...

Doug

Hi Doug
Thanks for posting your logs
Those IDC's are extremely high are they standard injectors and fuel pump your running,
As an injector can only really be 100% max/open all the time i guess that's got to be a commanded value opposed to real injector value,but i notice they are only exceeding this at very high revs so probably exceeding the IPW .Might be time for some larger injectors with those figures .lol

Hi Bazaa.

Yep, stock 3 barg fuel pump and stock 386 cc injectors. The injector pulse width values are real, measured values and the IDC is just calculated from them in the normal way using the expression

100 x (IPW/((2 x 60 x1000)/RPM))

Such high IDCs are unexpected and such a big difference between the two runs is a bit of a mystery. Clearly, actual EGT will be higher for longer under sustained full load therefore the ECU is trying to enrich to reduce it. My understanding is that the stock Bosch injectors have a maximum pulse width of 25 ms and at 7160 rpm on the 4th gear WOT run it is practically maxed out at 24.82 ms. But duty cycle takes into account engine speed too, so for any given on-time, the higher the engine speed, the less time is available for injection/ignition events. The only way to go, as you say, is a higher flow rate to get the required fuel injected in the available cycle time. :-/ Hmm.

I sort of justified or excused this 'feature' of the Revo map with the view that sustained full loads like that are rare, even in sporty or enthusiatic driving and on European roads where sports cars like the TT come into their own, you're only maxing out like that briefly for overtaking, powering out of slow bends, etc. Therefore, it is reasonable to push the boundaries of the ECU fuelling regimes to extract big headline output figures.

Doug

Doug,
As a 1.8t owner your approach is exactly what I wanted to hear. Forums are usually breeding grounds for nonsense so an evidence based approach is so refreshing.

Agreed, but this forum is much better than the usual! Besides, as a ex-scientist (of sorts) and an engineer in training, there can be no other way than objective evidence. B.S. has never cut it anywhere I've ever worked, so I don't see why I should lapse into it on internet forums. It's disrespectful and irritating to the peer group.

Doug

I agree 148.1% ;D
where in the uk can you really sustain full load and drive at high rpm for any time and the expence upgrading would as you say will be uneconomical for minimal gain .I know i couldn't jusify it.
Bazaa

I will comment on few things that caught my eyes:


Fuel octane rating: for normal driving it doesn't absolutely matter how low octane the fuel is, it only matters when you step and you WOT. At cruising load levels there won't be any knock (octane rating is really a resistance to pre-detenonation which is really the purity of fuel) and hence no improvement in economy.

IDC: now that one is a mystery, kind of, until you realize what IDC really is. 100% of IDC is basically a term that describes an injector being open for 100% of its OPTIMAL (capitalized on purpose) injection time where intake valves are open.

If injector is lacking flow though and ECU knows about it, the ECU can pre-inject fuel before the valves are open and that's when 100%+ IDC shwos up. Since the air is moving so fast at that time, that pre-injection and fuel stalling for few ms in the manifold don't really matter and you don't get weird AFRs etc so it all works out.

The problem is that injctors relay on sub 100% IDC since they use the fuel to cool them so you are stepping beyond design envelope here.

Hi Julex. A good contribution, thanks.

Although I failed to mention it, I think I realised intuitively that for economical cruising and hardly any/no full load acceleration, knock events will be limited so there is no advantage yo using the premium fuel as you say.

I had also rationalized >100% IDC as pre-injection based on the odd fuelling regimes I read about in the lean burn type strategies deployed in the FSi engines. I'd rather it was <100% but EGT seems to be under control so I don't worry.

Doug

Doug

Julex,

are you sure that's correct re IDC's?!  It certainly isn't when talking in traditional ECU language.  Nearly all engines will become pseudo batch fire as you describe at high loads.  100%+ duty cycle is where the injector needs to be held open longer than the time for one complete engine cycle.

Rick   

Reminder: a FULL cycle is two rotations!

So yea, rick, I agree. 100% is static, as in, fully open for two full crank rotations.

yea, one cycle = 720 degrees.

Incidentally, the 'hypermiling' experiments extend to my wife's car, a MY2005 E12 model Toyota Corolla 2.0 D4-D 5-door hatchback with a 55 litre (12.1 imperial gallon) fuel tank. Specs here:

http://www.toyota.co.uk/vs2/oldpdf/05/CO6_63_spec.pdf

My previous best range was 508 miles from a brimmed tank to the low fuel warning light illuminating but my wife typically gets maybe 400-420 miles before she is near the bottom of the fuel gauge and has to refill (not to LFW though).

We recently took a week long break with the car carrying two adults and a full load of stuff which involved 160 miles of motorway driving. I drove economically at all times and stuck to 60 mph on the motorway. The low fuel warning light came on at 549 miles. I think 575 is possible but my wife had driven the first 74 miles at an indicated average 47 mpg so I was on the back foot from the start.

It's not much use talking about indicated fuel consumption because the offset appears to be large (maybe 25%) and highly variable, but indicated fuel consumption when I refuelled was 63.2 mpg. When I refuelled and drove the remaining 17 miles home, the displayed mpg was showing 76 mpg and was as high as 84 mpg at one point. So irrespective of the actual numbers, there are big gains to be had by driving sensibly.

Doug

Which usually cause nothing but frustration to cars around you, such as anybody stuck behind 4 prius's running abreast on the freeway at 54 mph.

But that's only typical of stupid (yes I mean it) US drivers who have exactly ZERO driving education and even less courtesy ending in asshole(s)/(lettes) (yes I mean it again) driving in left lane at or below speed limit.

When I see priuses I just shiver and basically absolutely rudely cut in front of them once I manage to pass one after that ass blocking fast lane for the last 5 minutes.

Every european driver is told and enforced by law to sit in right lane unless he/she is passing which implies going far above speed limit.

I central europe/east europe you're guaranteed to have somebody riding your ass/flashing lights/etc if you anything below 2x speed limit on the left lane. Cops will give you a ticket for violating law b/c you drove left lane constantly without intent to pass.

In US I noticed that having 3k HIDs in fog lights and having them on 24/7 (by re-wiring the harness) gets peoples' attention to GTFO of your way. :). I get lots of "V"s from audi/VW folks too.

Sorry for rude post but the post above just struck some nerves there.

Nope, Nyet, I'm still not biting!  ;)

That particular issue is one for you Stateside boys to get steamed up about, but being a driver and person who is easily frustrated, I try to make sure my 'sensible' driving doesn't bug anyone else. Luckily, this is not difficult to achieve:

On the uncongested motorway/three-lane freeway in Scotland, most people can and do pass at will. The inner lane is mostly occupied by road freight which are limited to 60 mph (practically 56 mph) in the U.K. anyway. This is potentially good news for the hypermiler as you can get in the dead air behind an articulated truck.

On the normal highway, the 'fourteen apoplectic people stuck behind you speed' is more like 43 mph and that's in fact what it was on the first 50 miles of our outward journey.

On rural roads, average speeds on the twisty roads barely get above 35 mph, so trust me, if you can average 60 mph in Britain these days, you deserve a medal, even though most senior citizens seem to regard this as unforgiveably reckless.

It is fascinating to moderate your driving and see the results, actually. Especially for someone like me who normally likes to push on and gets wound up easily. You start viewing lines of slower traffic as chances to save even more fuel, rather than fourteen people I would like to mow down with a machine gun.

For the record, I detest Priuses and their owners.

Off topic but always a good one for rants!

Doug

I hate driving because of  this reason...

The speed limit is 50 and some jerk has drive at 35 on a single lane and hold up about 20 cars or have two cars in front of you driving at 45 in both lanes when the speed limit is 55 and you can't get around them cuz they are both blocking your way!!! Thats what gets me the most!

Old people shouldn't be allowed to drive unless they can actually handle driving the speed limit!

/rant

Curses!

random topic direction!

Hi.

I have repeated the 3rd and 4th gear WOT logging runs this morning with 95 RON standard unleaded fuel and uploaded the revised spreadsheet both to my first post and this one. My suspicions were wrong because the differences are significant and quite dramatic. I haven't fully digested the new data because I've just finished a 12 hour night shift, but the headlines are as follows:

- Individual cylinder corrections to ignition angle are much greater (up to 9.8 degrees crank).
- Peak MAF reading and therefore BHP are down by 11-16%.
- IDCs at the end of the 4th gear WOT run with 95 RON fuel are well below 100% whereas with the 99 RON fuel and higher output, they were >> 100%.

I will stick with 95 RON fuel for now because of the reasons discussed in my earlier posts, but at last I have some objective data to quantify the power loss under WOT conditions between standard and premium fuel. If you like to indulge in traffic light grands prix, then shell out the extra cents and go for the premium fuels!

Doug

91 octane tuning (stateside) is very very very challenging.

It may as well be an entirely different motor when compared to tuning with decent fuel.

TTQS: if you are keeping up, 91oct IS premium here on the west coast of the US. I don't know what the RON equivalent is. I imagine it is actually worse than your 95.

Worse than our 95? Jeeeezus. I feel for you guys. Maybe that's part of the reason why large displacement NA engines have always been popular in the US.

Doug

some info about fuel :

http://en.wikipedia.org/wiki/Octane_rating

United States: in the US octane rating is displayed in AKI. In the Rocky Mountain (high elevation) states, 85 AKI (90 RON) is the minimum octane, and 91 AKI (95 RON) is the maximum octane available in fuel.

So, yes, aren't we lucky guys us europeans..  Perhaps this 'luck' is measured in the price
we pay for a litre or gallon petrol over here. BIG difference with the states... 

Cheers,

PvL

Sorry to ask you mates but how can i measure idc? Because the last few days that i am starting to proper tune my car i get 24ms in lower than 5000rpm. I think that i need to change to bigger injectors.I have an 180ps 1.8t with 4 bar fpr.

Hi Giannis,

I think the best way, to do this, is to start a NEW thread on this forum.

Let's start-off with your car's specs there, and ecu-number. Then a more in-depth
analysis can be made.

Thanks,

PvL

Ok thank you for the reply and sorry for the off topic :)

Hi Giannis.

You can't measure IDC directly. It's derived from injector on-time in milliseconds and RPM:

IDC = 100*(Injector on-time/((2*60*1000)/RPM))

If you have a 4 bar FPR, then you will only need to recalibrate your fuel mass to injector on-time conversion factor and this should help with fuelling. If you don't recalibrate it will overfuel under all conditions which will manifest itself as rough idle.

I'm running ca. 270 bhp & ca. 300 lbft on my Stage 2 remap and the stock 3 bar FPR and stock injectors are good for almost all conditions.

Doug

thank you very much for the answer. So i have to export logs to an excel file and aply the given formula. As for the fpr i have allready recalibrate my file. I am getting about +-1.8 correction all the time. thanks again.

What settings are you running on the revo tune?

ECUxPlot will calculate IDC for you.

Hi Robin.

Unfortunately, the tuning agent didn't tell me and I forgot to ask at the time because I had a 2 hour journey home and just wanted to get away. When I subsequently e-mailed them, they didn't have a record of the settings. I don't have the Revo serial port switch because I don't really feel the need to alter the settings and it wouldn't gain me any functionality I would want for £199. If I knew exactly what was changed in the ECU code and how I might consider it, but from what I gather, it's just a 'volume control' for a small number of parameters. Feel free to enlighten me though.

Doug

I have a program found in an other forum that can change revo 2 timing and boost settings via the vagcom diagnostic cable. But i don't know if i am allowed to post it here, and have not tested it as i don't have revo software. If anyone is interesting we can ask Tony if i can put it here.

If you want to PM me the link, I'll check it out. I'm not keen on changing settings because I'm happy with what I've got, but I'll certainly see if it can read them via OBDII. I have a genuine Ross-Tech interface cable.

Do you mean this?

http://www.unitronic-chipped.com/downloads/UniSettingsBoschME7.zip

If so, I downloaded the software and it's so basic, I wouldn't want to adjust anything on my car with it. For example, under a number of the adjustable parameters, the VAG control range states "No adjustment allowed".

Doug

Unisettings changes adaptation channels in the EE, the Revo software is actually changing tables in the map data.

It can have a drastic effect on how the car runs, especially if the Revo agent isn't experienced in setting them up or gets too aggressive. I'd think you should find that out before you go further, especially seeing CFs of 9.

Being in the UK, I'm sure you could drive to a dealer within a half hour and have them confirm your settings. Nearest was 2hr away? Where are you located? Note that fuel adjustment is not possible on your narrowband ECU... so disregard that number.

I did see some discussion on changing adaptations on the UniTronics discussion I briefly read. So was Giannis referring to Lemmiwinks then?

I am happy with the settings and output and happy that the agent is experienced in setting them up. Remember that I observed the CFs of 9 with standard (95 RON, UK) octane fuel. Revo and the agent stipulate that the car is tuned with and for 99 RON U.K. high octane fuel. I used 95 RON just for comparison on fuel economy and WOT performance. I didn't like what I saw so have switched back to 99 RON Tesco Momentum fuel.

http://www.tesco.com/Momentum99/files/Tesco-Momentum-99-Fuel-Report.pdf

Since the TT has a wideband ECU, that's when I began to dislike the statements I was seeing on the UnitTronics interface software.

Doug

No i am not talking about unisettings this program changes the addaptation channels that excist in every ME 7.x ecu. The program i am talking about, seams to change some "special" channels that excist only in revo software. And you can change boost from scale 1 to 9 and timing from 1 to 9 also. The most popular settings in Greece for 100octane in boost 7 timing 8. I must search my hard drive to find the program but better is to post the link from the other forum. I don't want to take credits for someone else's work. I will inform you soon.

Just re-read it and noticed the 95 RON. Gotcha.

Just keep in mind that no matter the 1.8T ECU, even a late model wideband, the software was just not written to target lambda by the fuel setting. Its only enabled on some of the N/A ECUs and the later MED9 stuff.

Thanks for the heads-up. I'm interested in the software but only for establishing my settings for curiosity's sake.

Doug

I say again this program found in another forum http://www.gtcclub.com/forum/ and has been written by somebody else.

Thanks Giannis. I'll download it and report back when I'm back home after my vacation.

Doug

Thanks Giannis. I'll download it and report back when I'm back home after my vacation.

Doug

Any news about the program? Did anyone test it?

I haven't had chance to download it yet due to being on vacation so it will be probably this Saturday before I can give it a go.

Doug

Hi Giannis.

I tried out the RYTM_REVO.exe file with my genuine Ross Tech interface just now but couldn't get it to do anything. Firstly, the character set must be mostly Greek because there were mostly question marks (see attached image file). I will need more advice from you because the web link you sent is to a Greek tuning forum.

The second issue is that the cable is USB and in VCDS, I get options for COM1 to COM4 and USB, but this software only offers COM1 to COM4. In everything except COM3, I get a rude message from Mr T of the A-Team calling me a sucker.

I tried the interface in both intelligent and dumb mode to no avail.

I was therefore unable to discover my settings.

Doug

Yes this the questionmarks are greek letters but it doesn't matter they just tell the order to perform the 5 steps required. 1select com port. 2 select from stock mode to performance mode 3 select boost 4 select timing. I beleive this program doesn't work with "real" usb cables but with cheap clones witch have a serial port emulation inside or older serial cables. Someone with programming knowledge mayby can rewrite the program to support usb cables as well. I suspect that revo has some addaptation channels in their code and use sps(i think this is their interface name) to change these settings like lemmings does.