rawr

I am running the cobb access port stage 2 settings with high flow cats. At idle he Air to fuel ratio is a consistent 14 and sometimes bumps up to 15....this seems rather high... At full throttle it dips a bit and keeps alternating between 12-14. I am not that affluently learned in this area and have heard from friends that these numbers seem high. Any input would be appreciated

bboysteele

You probably will need to wait for the Stage 2+ tunes which should be out in a week or so. Stage 2 I don't think is for HFCs but I am not sure. 15 is high IMO.

Sirhc7897

a high A/F at idle is not that big of a deal. The engine is under absolutely no load. Almost all vehicles have very high A/F's at idle.

Now high A/F's and a engine under load are very dangerous. I know N/A motors can be run a little leaner safely than F/I motors but the sweet spot on F/I motors is usually in the 12.0 to 12.5 range....I would think 13 would be fine N/A...IMO

juang37

14.5 to 15 in idle is fine.

Gamedog

iTrader: (9)

Just looked at my baseline run and saw that when stock I was at around 13.5 at idle and went down to about 12 at full throttle... So yeah, I think you're a little high IMO...

rossab

iTrader: (6)

wonder if anyone from cobb can chime in on this.

Buddy Revell

iTrader: (2)

Here are my A/F readings both before and after a Technosquare reflash. It's pretty normal to have high ratios at idle:

Gamedog

iTrader: (9)

Good stuff Buddy...

To the OP: I still think your "full throttle" A/F Ratio is too high when it hits 14... Do you have a graph? Maybe you might've misread

Skyline-LEXY

if you have HFC ur going to have high A/R no matter what

AZg37

iTrader: (17)

guys, the perfect A/F ratio is 14.7, so at idle running 15 is completely fine. Under load you want to be around a 12.5 to 13.5 from different sources I've read. Your numbers don't seem off at all.

AZg37

iTrader: (17)

stage 2 is for HFC. stage 2+ is supposed to include intakes. 15 is actually almost perfect at idle. if he was at 15 under load, he'd have serious issues.

bboysteele

I didn't read it closely enough. I assumed he was at 15 while accelerating.

SurgeLineTuning

Quote:

Originally Posted by rawr

I am running the cobb access port stage 2 settings with high flow cats. At idle he Air to fuel ratio is a consistent 14 and sometimes bumps up to 15....this seems rather high... At full throttle it dips a bit and keeps alternating between 12-14. I am not that affluently learned in this area and have heard from friends that these numbers seem high. Any input would be appreciated

12.6 to to 13.2 is acceptable for a high performance naturally aspirated car.

Two questions:
1) is the traction control on? If the car sees slip it will reduce power and go lean for a fraction of a second.

2) how and when are you measuring AF? At light load the car will always target ~14.7:1. Under load the AFs immediately get richer.

If you are running high flow cats AND are using an intake your calibration is likely not appropriate. Cobb's current calibrations will not take into account the exta airflow and maf scaling associated with both intake and high flow cats. If you are using both the performance will improve with the soon to be released stage 2+ calibrations.

Also, John Shafer at Cobb in salt lake city and SurgeLine Tuning in portland oregon are offering custom accessport mapping for unique configurations. This is a paid service that allows us to develop totally custom calibrations for virtually any combination of parts.

If you have specific questions feel free to email sales@surgelinetuning.com or call.

Regards
Tim Bailey - SurgeLine Tuning - A cobb premier calibration R&D facility