I'm running a 76mm or 2.99" pulley on my car with 42's. I just got my tune done buy a vendor lets just say there performance is over the top. My old cobalt was on a GM stage 2 pulley and tune only boosted to about 14.5 maybe 15psi. I did a couple pulls with the Redline and I'm almost hitting 17psi. I'm running K&N Intake, stock manifold, a 3" catless DP, and GMPP exhaust. I would have thought being catless would reduce the boost a tad but this thing boost like crazy. Anyone got any ideas of why Id be hitting these number. I thought a 3.0 would get you around 15psi or so.

YouTube - 04 Redline 3.0" pulley

wow i had a 2.8 and wasnt getting that.:banana_hi

 

its cold out more air more boost

 

Still seems high. That's what i get on a 2.7, unported head, Slp header, Vibrant cat back, in the winter.

 

It was 65 degrees I don't think it would made that much difference. I did put a new M62 on it and it's different than the one I took off. By different I mean the sensor hole and bracket mount on the top of the charger is different than any M62 iv seen. And my bypass says prototype on it lol.

 

broken boost gauge

 

i have a full 3.0" catless exhaust with no resonator, yes it's loud, with a gm stage 2 set up and i'm still hitting around 13ish peak. This is without any tweaking so i am believing the numbers, maybe not 17 but around 15 i would believe.

 

I have a 3" header back exhaust (cat is roughly 2 months old) 2.9" pulley and 60# injectors and I'm around 16-17psi. I don't that much boost as fast as you did though. Clogged cat maybe?

 

thought clogged cat as soon as i started reading, then he said it's catless lol.
3.0 i boost like 13 14 if its dense

 

You might have your self a H62. Look for four blades on each rotor. And if this is so find yourself a wideband quick.

 

Head doesn't flow as good.

 

The H62 still has 3 Lobes just more of an aggressive curve to them. I couldn't tell much of a difference when I looked at my stock one. But then again I didn't really look that close or pay much attention. I plan on getting a wideband soon but when we tuned the car everything looked fine my IDC were good and it ran smooth as can be. The car hauls pretty good I went from a 45 against my buddies LS6 CTS-V and was at his back door. He had an 04 GTO before with LTs full exhaust and a tune. He put down 338HP and 339TQ. When I raced his GTO from a 45 in my Cobalt he pulled on me a car. He said his CTS-V is faster than his Cobalt and his gearing is better. So I know my Redlines faster. When I get a Header and more cooling mods Id like to hit a Dyno and see what she does. As far as my heads not flowing as good when I was on a stock Pulley id hit 11 maybe 12, 12.5 if it was cold enough. That's normal boost for a stock pulley so if that was the case then I should have been boosting more stock. Correct me if I'm wrong on that.

 

I think the stock tune limits your boost to 12.5 no matter what. I might be wrong I have never looked at a stock tune. No where in the tune can you make it boost more.

 

Stock pulley is capable of 13psi but at 6000rpm it bleeds boost. Thats what the by pass mod does.

 

Where did you get that supercharger from?

 

Also you should measure the pulley to make sure they didnt put the wrong size on it. Its a long shot but it is possible.

 

If its a H62 its a POS. You should throw it away or send it to me so I can throw it away for you.

 

Hey no cutting in line to destroy it I want to do it first so send here instead.