targeted a/f on boosted c7

[michaelcox5150]

went to the track last night with my newly installed aem a/f meter, ive been having past power issues with my 2014 stingray, ran a 11.8 at 120 1.9 60' time at a density altitude of 3300'.....my car seems to to lacking on top in power, my a/f readings under wot where at 11.5 all the way thru the 1/4 .. could this be my issue being so rich..i order a new pulley that adds 2 more lbs of boost with me running this rich do u think it be safe to add the pully with current tune? my data logs look good other than being rich in fuel

[5FDP]

For most turbo/supercharged vehicles shooting for 11.5 is perfect, 12.5 for N/A motors.

Do some vehicles like 11.8-12.0 yes, but others do not.

I like to keep it on the safe side just because blowing an engine doesnt always agree with your wallet.

[gmtech16450yz]

A C7 doesn't have an engine like "most" cars. It's Direct Injected. READ ABOUT THEM BEFORE TUNING. Direct Injection tuning is NOTHING like tuning a port injected engine. Direct Injected Turbo 4's running 30psi boost do fine at .88/.89 Lambda or 13.0/1 AFR. Running a Direct Injected engine too rich can actually be more dangerous than running it too lean.

[MarkTucker]

I agree with what 5FDP said ^. It depends on how much boost you are running? And then also are you stock motor(compression ratio)? But yes 11.5:1 is not to to rich. You can make some more power by leaning it out some. Just depends on your boost level. And also you stated you ordered a new pulley to up the boost 2psi. Even tho it is 2 psi. You will need to be tuned for that. Don't want to risk not tuning for it, and it run lean on you. It will also change the airflow table when not in boost from the blower spinning fast, so for best performance and efficiency you will want a tune.

[MarkTucker]

gmtech, I am glad you chimed in. I was thinking that he should be able to run a lot leaner mixture since being direct injection(like the LNFs). But from the factory they run a pretty rich mixture from 12:1-11.8:1. So is there a reason for that?

[gmtech16450yz]

gmtech, I am glad you chimed in. I was thinking that he should be able to run a lot leaner mixture since being direct injection(like the LNFs). But from the factory they run a pretty rich mixture from 12:1-11.8:1. So is there a reason for that?

Emissions.

[MarkTucker]

So like the Direct Injection I4's, we should be able to run them at that much leaner mixture with boost? So you say a safe AFR to set for at WOT with 12psi would be around 12.7-13.0:1?

[5FDP]

Emissions and because they want that car to be driven by anyone at anytime anywhere on the planet really. They want it to be "safe" in any condition.

[MarkTucker]

So to answer Michaels question, then his car is running to rich.

[michaelcox5150]

My commanded a/f is 14.1 my power enrichment is a 1.128 on the top end. im running 8lbs of boost right now, at the track my new aem meter read 11.5... and it is on a stock compression

[mowton]

Boosted C7's --- 12.2-12.5 PE (4500 and up) and at max torque (4800 rpm or so) 11-12 degrees and no more than say 14 out the door.

Ed M

[michaelcox5150]

im commanding 12.5 in pe but getting 11.5 on my a/f meter, do ineed to adjust the maf now to achive my 12.5 on my meter? Thanks in advance guys

[Ben Charles]

I already answered your question on the corvette forum. shoot for 12.4 to 12.6 on a boosted DI injection. Don't listen to the guys above saying 11.5 on a DI, that's Port INjection
IF your PE is correct then your MAF is too high and needs to be scaled back in the correct Hz levels.

[michaelcox5150]

I already answered your question on the corvette forum. shoot for 12.4 to 12.6 on a boosted DI injection. Don't listen to the guys above saying 11.5 on a DI, that's Port INjection
IF your PE is correct then your MAF is too high and needs to be scaled back in the correct Hz levels.

Thanks ben thats what ill shoot for..

[SultanHassanMasTuning]

especially if you are running a higher knock resistant fuel, DI motors are completely different

[michaelcox5150]

Ill get my a/f to 12.5 im in process of wireing up methonal alky kit do i try to go for same a/f or let it run rich on the meth? Also 50/50 or 100% meth do u guys recommend