Ok, went out this morning to take advantage of the cool temps, since the local track cancelled last night at the last minuite. Made a few short full throttle blasts. Shifting right at 5900;56-58psi fuel pressure at wot; 10 pounds boost/w3.2 pulley; no kr; Amoco 93 in the tank, but still hear pinging right at the shift point. Unfortunately, I can't see my wideband readout at the same time as looking at all the other gauges, and the road. I noticed before that it's 11.9-12.0 at wot, should be right in the ballpark. Any ideas? I have 5 gal of 104 CAMII unleaded that I might just dump in to check. I really don't want to waste the good gas on the street if I don't have to.

 

whats your timing look like up there. I back mine down near the shifts for that reason.

 

I have just developed some KR and valve rattle with the colder air. Must be due to cyl pressure increasing. I'm going to try upsizing my meth nozzle.

 

I'm seeing a rock solid 17deg at wot, and thru the shifts. That's exactly where my timing table is set at, with no iat correction. Maybe it's just the cooler, denser air?

 

it doesnt sound like a timing issue, you could probably run more. It must be the air. Does anyone what mechanism causes that?? Does the cooler air throw off the AFR...... but when I went from nonintercooled to intercooled my AFR had to be leaned out.