ibizacupra
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« Reply #45 on: December 27, 2012, 03:00:10 AM »
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someone should tell VAG they have made a huge mystake in raising their compression ratios on the 2ltr FSi Turbo motors..
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nokiafix
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« Reply #46 on: December 27, 2012, 03:52:43 AM »
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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.
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« Last Edit: December 27, 2012, 08:17:35 AM by nokiafix »
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prj
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« Reply #47 on: December 27, 2012, 04:43:25 AM »
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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. I disagree. Even a standard K03 will make more power on 8.5:1. BTDT. 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 guess we are tuning different engines then. Also, it's MBT... did I read somewhere Prj tunes to knock, running lean the richening up on the onset of knock No, you did not. Tune via knock prevention by management of the fuel and a hell of a lot more power can be extracted. 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. someone should tell VAG they have made a huge mystake in raising their compression ratios on the 2ltr FSi Turbo motors.. Look up direct injection. Also, this was done purely for emissions, not from a power perspective.
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« Last Edit: December 27, 2012, 04:52:33 AM by prj »
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prj
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« Reply #48 on: December 27, 2012, 04:55:55 AM »
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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.
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« Last Edit: December 27, 2012, 04:58:40 AM by prj »
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nokiafix
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« Reply #49 on: December 27, 2012, 04:58:14 AM »
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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
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prj
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« Reply #50 on: December 27, 2012, 05:40:51 AM »
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Seems like ur doing summat wrong dude... Plenty of cars running here in the uk with upto 450bhp and stock pistons with stock CR.. 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? Infact we will post the logs, dyno plots and videos of the live mapping session with his 9.25:1 setup. And that will show absolutely nothing unless you take the same car, stack the head-gasket and re-tune it.
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« Last Edit: December 27, 2012, 05:49:56 AM by prj »
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nokiafix
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« Reply #51 on: December 27, 2012, 05:51:10 AM »
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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
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prj
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« Reply #52 on: December 27, 2012, 06:12:22 AM »
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AGU large port heads stock. This was on small port head. Your fuel and tuning stratergy is nothing like mine. 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. 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. The ECU on that car was reading knock just fine, confirmed with detcans, as I always do on any engine with forged internals. Put it this way my timing graphs won't look like a saw blade nor will it have and interventions. 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.
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« Last Edit: December 27, 2012, 06:20:38 AM by prj »
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nokiafix
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« Reply #53 on: December 27, 2012, 06:26:12 AM »
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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
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prj
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« Reply #54 on: December 27, 2012, 06:36:29 AM »
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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.
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« Last Edit: December 27, 2012, 06:38:24 AM by prj »
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nokiafix
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« Reply #55 on: December 27, 2012, 07:41:31 AM »
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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.
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prj
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« Reply #56 on: December 27, 2012, 08:17:50 AM »
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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. 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). 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. 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.
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« Last Edit: December 27, 2012, 08:35:29 AM by prj »
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ibizacupra
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« Reply #57 on: December 27, 2012, 09:23:39 AM »
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What is being "deemed" high compression here EXACTLY?
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matchew
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« Reply #58 on: December 27, 2012, 09:31:46 AM »
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What is being "deemed" high compression here EXACTLY?
Not an FSI motor.
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ibizacupra
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« Reply #59 on: December 27, 2012, 09:39:02 AM »
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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.........
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