Cobb Stage II AMS Map, AFR's 12+???
 

Update: Post 15

I had my car baselined yesterday with 93 octane fuel, off the shelf cobb stage II tune built for the AMS short ram intake, and 3" turbo back exhaust with high flow cat. I was very happy with the hp numbers but was surprised at my 12+ air flow ratios at WOT. This was all done on a mustang dyno.

Doesn't that seem too lean or is that a normal A/F reading on a X with a tune?

When I dyno'd the car with the cobb stage 1 off the shelf map the A/F's were in the low 10's.

Thanks for the help:beer:

Edit: The A/f device used was hooked up to the dyno operating station/computer (not installed in my car) and was clipped on the tailpipe.

Where was the wideband placed? Before or after your cat?

Yes the higher the ratio the leaner your running, 12's isn't something Id be to concerned about, it all really depends on the map its self as well. If it was way higher then that Id worry about cracking a piston. Just make sure you keep an eye on it.

12's is not good for a turbo car at WOT on pumpgas. However, if the wideband sensor was placed after the cat, then he's ok.

Yea but not everyone is running meth. If he pays enough attention and is tuned properly he should have no problems.

The wideband sensor was a "sniffer" type attached to the tailpipe. I will be installing a wideband precat before the protune.

So you all think the positioning of the wideband sensor caused these high readings?

The tailpipes typically read slightly leaner than having the wideband up front.. Just do a couple logs then contact AMS if youre still unsure. Posting online isn't going to help when youre dealing with guys that back their work and would have no problem ensuring things are 100%.

Cheers!

It depends, your gonna get a slighty different reading where ever you put it.

Good advice.

Just to clear things up this is not a map that AMS tuned. This is the off the shelf map you can download from Cobb's website if you are running the AMS short ram intake and turboback exhaust.

Dont kid yourself. 12's on pump gas at wide open is not a good thing. That is a grenade waiting to go off.

Now it's just a matter of finding out where the sensor is getting the signal. If after cat, might be ok.

If Iam not mistaken the the Cobb Ap only reads the front O2 sensor's so it isn't to accurate as well. hopefully he has it mounted after the cat as well, or on the DP.

We have seen the ignition timing used in many of these maps and add lean afr to the mix and it would not be something I would want to drive around with.

Thanks to all of the reply's. I am going to flash it to the ACN 91 stage II AMS intake map and still run 93-94 octane. I also plan on not flooring it until I get my tune in two weeks.

I defenitely don't want to grenade the engine. Thanks for the advice guys!

I dont think he got the afr numbers from the AP. And even if he did i would not trust that. But you are correct if the AP can read it, it would be the front O2.

Update:

I installed an AEM wideband this weekend and reinstalled the off the shelf stage II map for use with the AMS intake. In all gears the leanest the car ever got was 11.1. The shop I went to must need to recalibrate their wideband. Just thought everybody would like to know that the off the shelf map does appear to be safe.:beer: