Thread: Can valvetrain noise cause KR?

Trying to tune, and I'm just getting obscene amounts of KR for the mods that I have (I think, at least). So I'm wondering if the ticking that I seem to have from my rockers is loud enough to make my knock sensor think that I have knock. It only happens under load with the s/c belt on and it really doesn't change whether I'm on a 3.6 or a 3.4 (I've been on the 3.6 for a while now). I'm actually getting a VS cam installed next week and will be going back to my stock rockers, so I'll probably find out then. Just wondering if there's anything else I should have them look for while the engine is torn apart. It just really seems that my KR is mechanical and not just fueling or something tunable.

rockers wouldnt set of your knock sensors.

it REALLY depends on how your tune looks for anyone to tell anything.

It's actually a pretty conservative tune. Mainly stock since I got the 04. Started with the basic Webracin tune to eliminate some of the TQ management stuff. Couple tweaks to PE/AFR/RPM/Time as well as a few MAF tunes. I had 42# injectors in there, but went back to stock, along with bringing the IFR table back to stock. I don't have a WB (I know, I know), but my NB O2s have always seemed to stay in the 930-940 range. And it's not burst KR or shift KR either. It's consistent and only when I hit a higher TPS% (i.e. I can run at 60% TPS in boost without KR, but if I get over 90% then it's all over the place).

it sounds like you havent pushed the thresholds of the torque limits as far as they need to be. once i pushed them past what my car was making (to save the transmission) my knock was down to 1* from 10* when we started.

That could very well be. With different gearing in the 04 than in my old 97 and whatnot, I'm not sure exactly what's different. A lot of what I've been setting things to came from my 97 bins just as a starting point.

ooh, nice. didnt know you got a new car. good luck with that one.

I havent heard valvetrain noise being a promblem on the 3800. IIR LS1s have this promblem sometimes. what type of tuner do you have?

Powrtuner. I actually had my 97 tuned pretty well. There's just some differences in tables and views in the 04 bin that I'm not exactly sure if they work the same way (with support tables I can't see, etc). Like I said, I'm not really doing much more in the way of tuning until I get my cam installed next Monday, so we'll see what happens to the noise when the stock rockers go back in. I'm really kind of hoping that I can go back to the 3.4 and maybe even the 3.2 if it's tunable once that cam is in there. We'll see...with winter coming, I'll probably leave things conservative for now.