Ever since I got the engine back in, I have this niggly little window where there is KR, generally anywhere between 3500 and 4500 (usually close to 4000 RPMs).
Other than the "apparent" loss of power for a split second due to the decrease in timing, I detected no adverse effects.

It usually only happens when I take off in 1st gear. It rarely occurs in 2nd or 3rd.

It does not disappear if I decrease timing or add or remove fuel. This happened before I had methanol injection and used Racegas additive to boost it above 100 octane. It happens now with the methanol + 93 Octane and cooler IAT's. (The methanol injection has kept KR at zero in all other RPM ranges. My IAT's used to rise about 10 degrees or more. With the Meth, it does not rise, or maybe will rise 1 degree.) If I get to target RPMs of about 6300, I'm at 11 to 12 PSI of boost and mid-11's AFR.

Is this likely a noise transient at a particular harmonic? Is it something I can live with since it's brief? The car is pulling so hard, I don't see where the slight timing decrease for a split second is hurting my overall power.

Any suggestions?

Procharger D1SC, LS7 (Darton mid-sleeves), all forged, performance heads, Brian Tooley Stage 2 cam.


Log with brief WOT

 

I would definitely ramp in your fueling enrichment earlier. It looks like you are getting into boost while still near stoich. If that does not get rid of the KR, then I would consider the possibility that it is just noise. However, I suspect that it is fueling related based on the data you posted.

 

Thank you... I'll try that

 

What do the plugs look like?