So going by this dyno pull and the screen shot you posted, it looks like your power curve flattens out after 7000 rpm. If so that's definitely indicating your have a restriction in your set up.

More then likely your exhaust manifold/down pipe combo is the culprit. Just means the whole set up is capable of more.

 

Moarrrr!!

 

you might have hit 300 if you cleaned the MAF,TB and seafoamed. Try it one time and check it on HPtuners, you will be happy with the results.

 

Looking at the torque curve, it's a pretty steady curve down from the peak around 5300 rpms, if you change parts to get it to hold out up top, the car will lose some lower end power. Even with his H62, there's just only so much airflow it can manage, and it's falling off it's efficiency map at high rpms. A more open exhaust may help a little, but so would a better blower.

For me, i'd suggest porting the intake manifold, specifically where it meets the head. The stock ports aren't matched well, and there is a gain there, I saw the before/after differences on mine and other cars. It would be enough to get him over 300 and really shouldn't have any negative effects.

 

^that, and squaring off the slots between the laminovas, which is beyond what most would want to do haha

 

The MAF was cleaned, the throttle body cleaned, and air filter cleaned, and oil changed all a day or so before the pull. I'm very **** when it comes to my car's maintenance and up keep.

The car is running perfectly. I'm just maxed with the current pulley setup.

It was a very warm morning as well.



I wouldn't say that is flattening after 7k... It is still building power. Maybe not as steep as it could be, but for my setup its fine.

I'll have to snap a better shot of the graph, because the angle the pic was taken doesn't match how the graph looks when looking at it in person.

Peak power is between 7600 & 7700 rpm.

Def not the downpipe. 3" catless. Manifold maybe, but it was tested by GMR back in the day to support 350hp.

The 2.99 pulley is flowing at it's max. I have a fix for that coming soon.

Not getting into that man....

I have an original GMR test pulley coming my way to help add a little extra flow. The car made 299.45 whp last year w/o reving her out. She has at least 305 in her as she sits now.

Also, I'm kicking myself for not running my usual Sunoco 110 blend. Tried VP race gas... My calculated octane wasn't quite 100, so I might not have been getting full race gas timing.

Minimal gains for a whole bunch of work removing and reinstalling everything. Meh.

I'm not messing with anything major on this car anymore.

It runs perfectly and never has any issues like I see so many on here have when they mess with their cars.

 

Another rare oddity to add to my GMR setup.... An original GMR 74.25mm test pulley.

This is the ticket to putting me over 300whp. I'm going to clean it up, clear it, and install it later this week.

Thanks again Trevor.

 

nice! what other rare gmr parts are out there that you don't have? you missed out on those cams a few years back right?

 

Didn't miss out... I didn't want them... They are a bitch to setup correctly, and I already had cams, so I let those pass.

I'm sure there are some other GMR parts out their that I don't even know about, but for the stuff I do know about... I own, lol.

I actually almost purchased this pulley back in 2010, but let it go, because I just purchased the H62. It found it's way back to me 5 years later, haha.

Here's a picture of it I saved from the for sale thread:



I wish I could get my hands on all the size pulley's GM tested, but I'm sure they are long gone.

 

That is funny! You're like a hawk!
Random observation, i think your car is the only one ive seen tha tpulls off those wheels

 

Thanks man!

 

So your saying my car doesn't pull them

 

Not at all

 

 

GMR 74.25mm test pulley cleaned up & installed

 

Nice man I hope you get the gains your looking for

 

Thanks!

Judging from the test drive the other day... I should def. be over the 300 threshold.

I'm going to log it tomorrow on my day off.

 

very nice

 

Thank buddy

 

Nicely done Jeff! .... I know this is an old thread but did you ever get to dyno with the GMR 74.25mm test pulley?

 

Not sure he comes on here anymore. If you message him he may see it.

 

Yeah he kinda dissapeared after he sold his balt

 

Yeah, kinda figured after he traded in his car. Thanks for the info guys. Wonder who got his his H62 blower?

 

Holy OG, do you still have your cobalt?

I forget if he pulled the H62 blower or not, hopefully he has jumped back on here from time to time

 

Im not sure if thats the one that Al had and sold to a friend.