COT multiplier

[Mike H.]

Hello everyone.

Just got back from the dyno, all last week I was street tuning a friends Camaro. The Camaro is stock save for catback, aftermarket y-pipe with cats, slp maf and slp lid. I was pleased with what power it made and so was the owner. At the end of the day it was 331rwhp and 358rwtq (t56 car).

The only problem was that I had to command a richer AFR to get the AFR that I wanted. I knew that this could be caused by not getting the airflow numbers right, but both VE and MAF seem to be dialed in. All of my stft's are dialed in to where they need to be.

What I now just realized is that I had accidentally left COT protection enabled. It was on during the street tuning and during the dyno pulls.

Could this be the reason that I have to command PE to be 1.275 to get 13.0:1 AFR? Was it possible that COT was kicking in while I was dialing in the VE table and MAF table? What say you guys, thanks.

[Mike H.]

At first I figured it was because the car had cats on it and we were using a tailpipe sniffer on the dyno but the car made more power every time I gave it more fuel so that doesn't add up.