Tonight I decided I would head to th track one last time before I take the drag radials off for winter. besides spinning like mad and unable to cut anything better than a 2.3 60' ft midway through the higher gears the car would stumble/hesitate/ break up for a split second.

It was 45f and on the way home I did a WOT pull in 3rd and had an Oh shit moment. the AFRS where high 13s, even 14s, but I'm not sure how accurate it is since I have been running race gas for last few months. I checked the logs and didn't see any detonation so what do you guys think is going on?

I switched to Iridium plugs a month ago and pretty much had one solid run, then my TPS went to shit. This was the first time out with the new TPS (it's reading fine, I checked)

Any ideas? The data logs don't show anything abnormal

 

Did you retune with the race gas? My guess would be the different plugs and fuel making it act funny.

 

It's tuned for race gas, can just switching to Iridiums make a difference? I remember a few years ago I tried iridium and the same type of thing happened, but I have a hard time rationalizing how a better plug can make the car run worse?

 

If you have the ecu set to adjust fuel trim per the o2 sensor, it may be the o2 sensor going out and not reading fast enough. This could cause the ecu to freak out and not run correct A/F, which may be why you're seeing a really lean condition per the o2, but the ecu is doing other things to compensate when it's not really the condition it thinks it is. The lead in race fuel will greatly reduce the life of the o2 btw.

 

Plug change + breaking up = not gapped low enough. Try lowering it

 

Not sure whats wrong, but what did you times did you run??

 

I don't think Evans set it up that way. Either way,mim going back to copper. This isn't the first time my car ran like shit on these, not sure why it would though

 

It sounds like a plug issue . I would try and drop the gap down a bit and give it a go . If that still doesnt help then i would try a cheap set of copper plugs . What gap are you running anyway ?

 

The Iridiums are .25, the copper plugs which never gave me any problems are like .22. I do have the Kenne Bell boost a spark But rather than just turn that all the way up I'll just go back to the copper plugs that have never failed me

Running 25psi

 

+1 try running copper plugs gapped lower. I've owned two high boost cars booth which did not like platinum or iridium plugs or large gaps. My theory is the boost diminishes the sparks ability to reach stochemetry in the combustion chamber and causes misfires with bad AFR readings. Monitoring EGT and AFR will help diagnose this condition.