I just now installed my 2.9" pulley on my stock GM Stage 2 tune and did a few runs down a secluded road to get some data. Well for the most part my interceptor gauge read 0.0 knock but on some runs it would read maybe .7 or so and go back to 0 and some would stay 0 and go to maybe 3-4 degrees of knock and then go back to 0. For the most part it was the mid-range RPMs mainly but not all the time. Really inconsistent results. I ask though, how much knock it too much? Also, after I get tuned with HPTuners will that get rid of the knock?

 

I'd be interested to see what the aeroforce said about your injector pulse width and how that adds up to your injector duty cycle too.

 

I briefly looked at the injector pulse width and I beleive it was around 14ms at 5k RPMs. I couldn't go any further for a curve and stop sign approaching.

 

Any knock is to much. Knock is the devil.

 

Yeah I know I want it to be zero all the time but if I gotta live with some until I can get tuned in a month, how much is damaging?

 

>0 is damaging...

 

Does tuning get rid of knock?

 

Yeah, it should.

 

^^ listen to the man^^

 

I am listening, and it's not every WOT run either...just seems like random times. I'm blaming the GM tune. I still had slight knock with the stage 2 pulley.

 

what are your a/f ratios at wide open throttle?

 

You are safe as long as you don't get more than 1 full degree on a regular basis. Its impossible to get 0 knock 100% of the time without running 10 degrees of timing on race gas.

 

Thats just as disturbing...near redline it's 10:1-10.5:1

 

Damn, that's pretty rich. Why are you so rich? What size injectors are you running? Are you running HP Tuners just yet?

 

Stage 2 tunes run uber rich, thats why stage 2 + 2.8" = 105% duty cycle

 

yeah its just plain ol stage 2 tune but I don't have the 2.8 I have the 2.9
I'll be getting HP Tuned at the end of March

 

Gotcha.

I don't know...that's crazy rich. Talk about safety lol

 

Just picked up my g/f and did a few more tests and I'm definately getting between 2 and 4 degrees of knock and I'm in the high 11s as far as a/f goes at 3k RPM and steady drops to about 10 flat at redline. Man HPTuners better get rid of this knock and ridiculously rich a/f ratio...

 

What other modifications have you done? What are your IATs?

 

No knock is good knock, but up to six is somewhat safe as long as it doesn't stay there. If it spikes six every once in a while its still bad but not damaging.

 

Knock owned me on my cobalt. I pretty much was knocking for about a year lol, did everything to fix it, I have hptuners and still get knock with a safe tune and 100 octane...but that's why my car is not in great running condition anymore

 

yeah i heard 6-7 is acceptable not the best though, what you should watch out for is how long it knocks and if the counts keep raising. that is when you are doing the damage

 

you will be ok with 3-4 being max, just dont go WOT all the time.

what kind of gas are you using?

 

what are you people smoking no knock is good! 6-7 degrees of knock? your motor should be shot already. get some octane booster until you get it hp tuned. Read my thread.
https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/how-get-rid-knock-without-tuning-48461/

 

I always run Shell V-Power 93 octane. I got the Stage 2 with 2.9 pulley, BKR7E plugs, k&n intake and corsa cat-back and my IAT2 temps where usually high 60s-low 70s during most runs but after coming out of the store I did one run with IAT2 temp of 120 some with same exact results.