My buddy and I scanned my car today on my lunch break.

The GM tune has the car tuned for nothing but knock retard.

between 3500-4500 i was showing up to 5 degrees of knock! And after that all the way to redline i had between 1 & 2 degrees of knock.

All that knock with a super-rich tune... Good ****** Job GM!

We're gonna retune it and get rid of the knock later today, lean the tune out a bit and hopefully make more HP!

 

Could we all just agree to always say nice things about GM? Because after paying all the money I have paid for their products and service, I would prefer to be completely in the dark as to the shitty workings of their crap bag mechanics.

 

Stage 2 on my 05 and no knock, 93 octane. What octane are you running, and seeing that you are knocking more on the lower side, and less on the top end...are you in too high of a gear when you floor it? I mean if I'm in 4th gear at 40mph and gun it it's gonna knock a little, where as if I was in 2nd at 40 I'm fine.

EDIT: I was thinking of something else. While I have no personal experience in tuning these cars I have done others. What I'm thinking is that these cars probably have some sort of torque management that would probably retard the timing. I'm not sure if this would turn up as KR or just as a decrease in total timing. This is all speculation as like I said I've never looked into what programming is in our cars (yet), so if anyone knows for sure please step in. I don't see how gm could be giving these things warranties with them knocking so much on hyper pistons.

 

it was a 2nd gear pull from 3500 rpms. about 36-38mph. AZ uses 91 octane which is what i use which may be 1 reason it knocks, but keep in mind, the stage 2 tune for the 07's is actually different from the 05 stage 2 tune. Today was the first time i've ever actually "heard" my knock... only cause my buddy pointed it out to me.

GM makes good products as far as aftermarket goes. the dual pass plate/ GMPP exhaust manifold/ Cat back exhaust are good quality parts. The problem is, each cobalt's motor isn't exactly alike, yet they have the same tune thrown all all of them of that same year. But if i were GM, i would't sit there and dyno-tune every car they make anyway, so it's really not their fault in general.

I'd also like to add that there was a lot of knock in the tune, even under part throttle. There were some far out numbers in it, but for the most part the Car had 3-4 degrees of knock

 

From what I'm gathering around the board people running 91 w/stage 2 are knocking. Especially in az where you guys gotta be getting hot about now A lot of places in PA are switching to 92 instead of 93. I hope we don't get all 92 around here, or I'll have to be adding some touline w/fill ups. Good luck with your tuning. Hope you get it straightened out.

 

Yep, thanks for the input. we'll get it figured out. this guy's like the aim-bot wall hacker of tuning

 

umm your problem is you are running 91 octane, the stage 2 requires 93. You are gonna have to tune it yourself for 91 Good Luck man! I hope it works for ya

 

so 93 is a must

we only have 87-89-91-94

 

Premium is required with Stage 2... I would definately suggest 93... or even 94 if you can get it.

Try adding a little octane booster next time you fill up.... just a little... enough to get the octane up there the rest of the way.

 

did you not read the information about stg 2! It requires 93

 

I wish we had 94 here. Its 93 octane every time for me

 

all i can get is 91......