While the OP didn't make it terribly clear what he meant, I never tied the two together. It seemed like many in this thread had skimmed it.

Paul do you mean when cruising @ 30MPH then going WOT, as the engine revs up through the rev range for the downshift you see KR while it'* reving through 2500-3500 RPM?

A data log would be great. As mentioned above, KR is just the rate of spark retard, and TM can show up there in most GM PCM setups. Actual knock obviously shows up in KR, but also in knock counts by the sensor. Compare those two points of data and either fix the noise causing the knock, or the TM issue (if you want to..)

Paul, you should be running a larger pulley than the 3.3 on the GenV if you ran a 3.2 on the Gen3.

The GenV is more efficient, and can produce the same power with a larger pulley, producing less heat because it'* not spinning as fast, and robbing less power from the crank in the process.

It'* not more powerful.

Thanks for the clarfication.. The order of the items, doing 30..punch it. Right there you should be higher in RPM. Which is where I was wondering. As Jason asked about the split second as you punch it.

I've found in the past that I would get part throttle KR when I had too small of a pulley. Pulley up and it went away. It would be easy for you to test this.

No, I mean medium to heavy throttle downshift. An instantaneous event. Just enough to get the revs to climb very quickly from 1500 to 2500-3000. Then the KR falls from 7 to 0 as the revs climb.

I was running with a 3.1" before with the Gen 3, so figured the 3.3" would perform similarly with the Gen 5.....particularly if polished and ported.
Maybe all that polishing didn't have much effect. :?

......or could it be, it hasn't had enough time to learn yet :?:

I will pop the 3.4" back on to test again.........as soon as it stops raining.

Paul, it'* possible the GenV won't benefit as much as the Gen3 from the porting and polishing, simply because the V flows more efficiently to begin with. It'* an untested theory. I'd assume it HAS to benefit you. How much remains to be seen.

According to our air flow gurus that port our blower housings the Gen V is extremely efficient already (duh) and at most you MAY be able to gain 7-10 percent by porting it.

So Todd. Tell me. Based on the mods, I have now, and with engine temp of 160 F and IAT of 50 F, don't you think I should have no KR with a 3.3"?
Blower outlet temp was 140 F

Why does it not get KR at higher than 3 psi but spike to 7 at lower than a few psi?

No, I don't think you can run a 3.3 on a ported Gen V moving that much air freely on stock injectors. What is your IPW'*? What is your injector duty cycle?


Have you pulleyed up to see if the condition clears?

Just a thought, but if he has no KR at higher rpm'*, how'* it possible for him to be outflowing his injectors at a lower rpm?