Per-cylinder timing corrections?

[blazarov]

Hi,
i decided to have a look at how my ignition timing goes during hard 100-200 pulls. IAT is around 35-40C in this run.
It seems the car is pulling (applying negative corrections) up to 4.5 degrees on some cylinders and there is also considerable cylinder to cylinder variance.

My car has Evolve Stage 2 tune and catless downpipes. Brand new injectors and coils, didnt replace the spark plugs as the mechanic told me they are good, asked them to gap them at 0.022" as suggested by Evolve. I plan to swap them next time the car visits repair shop anyways.

Anyone else with any observations? I am wondering is this "normal" and what are other people seeing. I will look at more logs under different conditions in order to try to find a pattern

The car does around 6.5 for 100-200 depending on conditions.

Link to full log if interested: https://datazap.me/u/blazarov/22may2...8&zoom=212-274

[M6Roar]

Originally Posted by blazarov

Hi,
i decided to have a look at how my ignition timing goes during hard 100-200 pulls. IAT is around 35-40C in this run.
It seems the car is pulling (applying negative corrections) up to 4.5 degrees on some cylinders and there is also considerable cylinder to cylinder variance.

My car has Evolve Stage 2 tune and catless downpipes. Brand new injectors and coils, didnt replace the spark plugs as the mechanic told me they are good, asked them to gap them at 0.022" as suggested by Evolve. I plan to swap them next time the car visits repair shop anyways.

Anyone else with any observations? I am wondering is this "normal" and what are other people seeing. I will look at more logs under different conditions in order to try to find a pattern

The car does around 6.5 for 100-200 depending on conditions.

Link to full log if interested: https://datazap.me/u/blazarov/22may2...8&zoom=212-274

Did you reset adaptation after replacing these parts?

[blazarov]

No,
The guys at the shop forgot to do it, however i already did around 2000km so imagine whatever needs to adapt is done.

[M6Roar]

Originally Posted by blazarov

No,
The guys at the shop forgot to do it, however i already did around 2000km so imagine whatever needs to adapt is done.

Notice your STFT1 vs STFT2 & LTFT1 vs LTFT2.

One is adding fuel and the other is removing fuel in addition to the timing DME2 is 2 degree higher & Wastegate as compensation for the air leak. try and reset fueling adaptation and then smoke test for slight air leak.

That is just my opinion I might be mistaken, small deviation isn't a big deal to give yourself that much of headache. Reset fuel adaption, relearn VANOS and Valvatronic via ISTA and you will be fine I guess. If that didn't help increase your fuel grading.

[blazarov]

Hi,
actually the discrepancy between the two banks STFT and LTFT has been my main concern ever since i am datalogging.
My expectation (or shall i say hope) was for this to equalize after injector and coil change, but it didnt. I know it is very lame to not reset the adaptations, but this is what it is - "specialized //M shop"

I also suspected MAF, however i switched them and that didnt alter the STFT/LTFT discrepancy anyways, so for now i rule out the MAFs.

Checking for leaks on intake and exhaust is a good idea, i will try to see if someone local can do that.

Nice catch about WGDC discrepancy, i have no baseline to compare with, however my expectation would be that 2-5% discrepancy in the banks would be "normal" as this is quite complex physical system and each turbine probably has some specific wear.

[M6Roar]

Do a fuel reset and let us see how it goes.

[ajm55]

https://datazap.me/u/ajm55/23-april-...?log=0&data=22

This is a data log of a 4th gear pull on mine. Running a BPM tune but at 5,500 feet above sea level so turbos drop boost below target higher up in the rev range. I don't think there's an issue with yours. Add some octane booster or better quality fuel. stfts and WGDC are hardly ever going to be an exact match on the two banks.

[M6Roar]

Originally Posted by ajm55

https://datazap.me/u/ajm55/23-april-...?log=0&data=22

This is a data log of a 4th gear pull on mine. Running a BPM tune but at 5,500 feet above sea level so turbos drop boost below target higher up in the rev range. I don't think there's an issue with yours. Add some octane booster or better quality fuel. stfts and WGDC are hardly ever going to be an exact match on the two banks.

What is your opinion on BPM tune? since you run one? I changed my charge coolers to a larger one and I'm short 2 PSIs and I got them back using JB4 but the logging on JB4 isnt that great. Not looking for custom just a tune that will account for my large coolers.

[ajm55]

Originally Posted by M6Roar

What is your opinion on BPM tune? since you run one? I changed my charge coolers to a larger one and I'm short 2 PSIs and I got them back using JB4 but the logging on JB4 isnt that great. Not looking for custom just a tune that will account for my large coolers.

I'm happy with the BPM tune. AFRs and timing are in check. It is a custom tune that limits the torque beneath 5,000 rpm which is what I asked Mike to do. Boost doesn't keep up with target after 6,000 rpm but that's because of altitude and is not tune related. I don't know if there is a way to tune the car to hold boost longer at high altitude but unless you're at high altitude, this is not something that will trouble you. I also installed the CSF intercoolers after loading the tune and I'm seeing about 1 psi drop. I may ask Mike at BPM to fix this for me