Lean @ WOT
Posted: July 30th, 2018, 8:01 am
Hello and welcome to another episode of WTF. I hope someone can help shed some light on this. Yes, I have searched and tried reading up on this problem, but have yet to come across any solution.
No matter hoe much I calibrate/scale the MAF, I keep missing AFR targets (on the lean side) when going WOT. By a lot. I'm at this point 99.99999% sure it's not hardware related. Had a tiny exhaust leak on the external wastegate - fixed that. No boost leaks. Certainly no vacuum leaks.
So what am I missing? Map and a log attached for reference. The map is a work in progress and farfrom perfect, as I need to get MAF and target AFR down before I can continue with tuning.
Some history:
Car previously had a built motor with a Holset HX40 turbo and Cobb custom map (tuned by myself) - no issues. Life was peachy until the motor shit the bed (long story).
Sold the AP while the car was down. Eventuallyu got to building it again last year, and decided to give VT a go. Had the lean WOT problem back then already. But there were so many small issues to sort out, that I never got to tuning it properly.
The built motor eventually ran bearings to such an extent that the mtor had to be scrapped (even longer story). Replaced that with a stock mk2 motor, and a smaller T3/T4 turbo. And lo....still the same problem. The interesting thing is, I get next to no KR while it's running this lean. And by lean, I mean 12.7+ AFR when it should be 11.4.
The other interesting thing is a friend of mine is having the exact same issue on his BT Mk2. Never had sw before - went straight VT. Installed a custom BT kit after his k04 decided to grenade itself. Also running lean at WOT. Increasing MAF values has little to no impact in honing in on AFR targets.
What are we "doing wrong"?
My mods list:
Custom twin scroll manifold.
T3/T4 china charger
Turbosmart External Wastegate, with screamer pipe
Custom 4" intake
Custom FMIC
El cheapo (but good) BOV, set to VTA
VTCS delete
Custom 3" Exhaust from turbo to tailpipe
Any advice, thoughts, suggestions - even questions - will be greatly appreciated.
No matter hoe much I calibrate/scale the MAF, I keep missing AFR targets (on the lean side) when going WOT. By a lot. I'm at this point 99.99999% sure it's not hardware related. Had a tiny exhaust leak on the external wastegate - fixed that. No boost leaks. Certainly no vacuum leaks.
So what am I missing? Map and a log attached for reference. The map is a work in progress and farfrom perfect, as I need to get MAF and target AFR down before I can continue with tuning.
Some history:
Car previously had a built motor with a Holset HX40 turbo and Cobb custom map (tuned by myself) - no issues. Life was peachy until the motor shit the bed (long story).
Sold the AP while the car was down. Eventuallyu got to building it again last year, and decided to give VT a go. Had the lean WOT problem back then already. But there were so many small issues to sort out, that I never got to tuning it properly.
The built motor eventually ran bearings to such an extent that the mtor had to be scrapped (even longer story). Replaced that with a stock mk2 motor, and a smaller T3/T4 turbo. And lo....still the same problem. The interesting thing is, I get next to no KR while it's running this lean. And by lean, I mean 12.7+ AFR when it should be 11.4.
The other interesting thing is a friend of mine is having the exact same issue on his BT Mk2. Never had sw before - went straight VT. Installed a custom BT kit after his k04 decided to grenade itself. Also running lean at WOT. Increasing MAF values has little to no impact in honing in on AFR targets.
What are we "doing wrong"?
My mods list:
Custom twin scroll manifold.
T3/T4 china charger
Turbosmart External Wastegate, with screamer pipe
Custom 4" intake
Custom FMIC
El cheapo (but good) BOV, set to VTA
VTCS delete
Custom 3" Exhaust from turbo to tailpipe
Any advice, thoughts, suggestions - even questions - will be greatly appreciated.