Jawnathin

Slight dupe of another thread but a different question.

I added an intake to my already tuned C6 Z06 (tuned for manifold, TB, and headers, but no intake)

Intake Manufacturer (Halltech) says it should be ok. The MAF will compensate for increased air.

Tuner suggests a re-tune. Unknown if MAF tables were touched, trying to find that out now.

I did a few quick pulls the other day and the car seems ok.

So well, so far so good, but to be certain, how can I check for myself?

I've got a code scanner which I assume can read an AFR. Should I just do a pull and read the AFR? I understand 14.7 is 'perfect', but something a little richer would be better for safety. What should the car be running at before it would be wise swapping back to stock?

Thanks!

TARANTULA

In closed loop 99% of the time you would see 14.7 because the o2 sensors will correct the fuel delivery to obtain that. The problem is open loop because the car uses PE if the maf table is off your car will run rich or lean. BTW the scanner probably only reads fuel trims and that only tells you half of the story. I think you should get the car retune

Jawnathin

Thanks Tarantula, appreciate the input. I will definitely get a retune down the line to maximize my gains, but from a safety standpoint, do you think the car is at risk with the new intake?

And maybe I'm missing something, but could you also explain closed vs open loop? Not sure I understand the difference here.

I also could have sworn I saw another post last night that isn't here anymore, talking about how the fuel trims would adjust for increased airflow. Not sure why it isn't here anymore.

Does anyone else have a recommendation on how to check for a lean condition? Trying to get this all sorted out by Friday as I have an Autocross event on Saturday.

realcanuk

You need to hook up a wideband to really check the air fuel ratios. If you had a way to log stuff, you could check through trims and O2's. Without any software to log it or an air fuel ratio gauge there is no way to know for sure. Personally I wouldnt run the car hard unless I knew for sure things were right.

Jawnathin

Thanks. Just to be safe, I'll swap out to the OE intake later today and just wait for a tune before I drive the car hard. Thanks again.

jon6.0

I run a Callaway CAI and a ported LS3 intake manifold. My air fuel never went leaner than 12.3 on the dyno yesterday. Stock GM tune.

Jawnathin

I think under a stock tune I'd be okay (the CAI manufacturer is very clear about this). But with another tune, I guess it opens up a few questions.

I honestly think the car would likely be ok, but since its possible a lean condition could occur, I guess 'better safe than sorry' applies here.

Not really worried about the power gains, I can wait for that, just didn't wanna have to swap intakes back, just to do it again later if I didn't have to.

TRBOKEV

True but your car was probably running in the 10's with the stock intake and stock tune as most of our cars do. Do you see where this is going??

Jawnathin

FWIW, I asked my Tuner about some info...

The tuner adjusts the MAF tables and for a NA car he likes to see 12.2-12.5.. though a little leaner is okay too.