Ok guys, First time at dyno. Well, with my mods in my sig. 224WHP. Yes, I know, too low for my mods, should be at least 230-240WHP. Everything was setup and the tuner with EFI live gave me the start signal, he was by my side at passengers sit. After 3k (4th shift) I hit it,WOT, up to 7k. After finishing the pass He told me I got detonation problems. Suggestion by tuner, don't overdo it and come back friday for tuning. We are discussing and told me, well is either increase timing or inject more gasoline. I know there are several issues with 42's so I'm thinking to buy 60's from RC Fuel injectors. Also, should I change sparks? Any other changes other than tuning? I'll post logs as soon I receive them by email. Funny thing is no codes on the car have pop up.

Conclusion
In my opinion, gm tune file is not that good.

 

what octane fuel did you use during the dyno, and what was the outside temp? was it a dynojet or a mustang dyno?

 

if your getting knock then it's gonna kill your timing, and cut power.

 

IMO those numbers aren't that bad but to be expected with the exhaust mods you have on your car. Both exhaust pieces do not benefit you as much as a true dedicated header/catback would. Isn't the GMPP catback a 2.25" pipe?

 

thats way to low...man...whas it a mustang dyno?...

 

Texaco with techron 93 octane, outside temp I'll say 90, dynojet dyno.

 

Yeah it's 2.25

 

That's right. Its my current issue.

 

probably could of used an full exhaust...trying adding a d/p with an header ..maybe that would make a difference

 

ummm, ok.

if the tuner knew what they were doing, they could have worked through that issue.

 

2.25" I was expecting around 230-240WHP

 

I put down 257whp with stage 2, 2.8 pulley, AEM Intake, Octane boost (95-96Octane), super cool day around 40 degrees, with stock exhaust, I iced my supercharger to.

But yours seems low i would say that it should be around 245whp with those mods, but if its 90 degress than you will loose some

 

I will be tuning on friday, just went to obtain numbers.



I was hoping max 240 WHP, yesterday it was hot.

I would like to know which type of injectors our car uses:

1. Peak & Hold Fuel Injectors
2. Saturated Fuel Injectors

I'm thinking on getting 60's because probably I'll have too run a little bit rich to decrease temps when mixing occurs. Correct me If I'm wrong. Still I'll be friday tuning and we will see how it goes. I hope to post the logs tonight of yesterday's dyno.

 

You don't have bigger injectors and you're running a 2.8?

 

anyways.

have the "tuner" drop the timing table down to 18 degree's, and work up from there, after you get the afr finalized. remember kids, timing does affect the air fuel ratio to a degree

 

Yes I have been for a year or so with absoluatly 0 issues, I know that the 2.8" pulley is very much debated on here but I can tell you I have had no issues and has much better pull than the stock stage 2 pulley, I dyno'd and the AFR was alright, its the IDC that people are so concerned with. I will be getting one of Nates 2.9" to be sure, but I dont always take the car to 7k redline. I mostly still shift at 6500 WOT with that pulley just to be a little safer. I found that the exhuast mods helped alot when running that small of a pulley it pulls much better than it did with the stock exhaust.

JKennedy1612 did you notice any gains with the GMPP manifold? I want to put one on asap but wnat it to be worth it performance wise, was there any more noticable torque? I heard its only good for 4-5hop and 6-8 tq??

any thoughts?

 

The GMPP honed manifold is the biggest WASTE available. Why would you waste money on it when a header around the same price will give you double the gains?

 

why do you think you need 60's with a 3 inch pulley?

 

I got the manifold, exhaust, and stage 2 installed all at once lol. So I couldn't really tell you...but you are correct, it's good for about 5-6hp and 6-8 tq. My understanding is the manifolds are better for tq.

 

I dont want a header becuase my previous car was super loud and dont want that same sound with my cobalt, second I would rather have something worry free as far as leaks go and something that the dealership wont void my warranty over, I would rather sacrifice 5whp for a car I can live with sound wise and something that doesnt wake the neighbors up every time I drive by.

Dont get me wrong i know that performace/dollar a header is the way to go but would rather have a little more low-midrange pull with the manifold than the high end peak hp of the header with less sound.

To each there own, I am just asking for opinions at this point wont buy it if it doesnt provide at least modest power gains

 

you can get over 240 to the tire as it sits.
without having to get 60's or other things that are not needed.

 

1. Dealership can't void your warranty because of a header
2. All you need to do is add resonator's to your exhaust to quiet it down
3. You could make excuses all day. Anyone who buys a honed manifold over a header is an idiot.

 

I appreciate the input but its whats important to the person that drives/owns the car. I just dont want something crazy loud, thats why i am looking at the GMPP, I am just looking at this point and will decide from other members feedback that have it on if its worth it? If not I will save the money for something else like a dual pass plate or lowering springs.

 

Well it's actually a 2.99" pulley (stg3 pulley). It was a thought about getting the 60's since I'll be injecting more gasoline . Although I did calculate and its supposed to be "safe" using 42's. I'll tell you on friday if I need them or not.
BTW do you know the type of injectores our car uses?

1. Peak & Hold Fuel Injectors
2. Saturated Fuel Injectors

 

i can tell you right now, you don't need them.

i have no idea what the 42's are.