For everyone who has had their car dynoed, Did the horsepower drop after 5600 like this?? If so what does everyone think it is. Cams, heads, i've even heard belt slip. idk i'm confused and i dont like it. HELP!!!!

 

What are your modifications? Do you have a custom tune?

 

take it to a different dyno.

 

that looks nasty, here



actually, after seeing your mods, I bet its belt slip...I'd try a smaller belt and a larger idler pulley

 

IDK but the two AFRs I see on that graph are suspect - one is PIG rich, and then the other goes off the chart towards lean territory...can you determine which one goes with which power lines?

also -- why aren't you running to 7k rpm?

 

Looks like the AF Shoots off the scale lean when that happens in one case. The Knock sensor likely detected a lot of detonation and threw timing to compensate (Power Loss)

(Yellow Line at 5200 RPM)

This is not a happy car..

 

take a look at mine:
https://www.cobaltss.net/forums/dyno-results-170/my-gmpp-catback-dyno-results-32554/

 

Wow that chart is a mess. Can you take a picture of the actual chart and maybe everyone will know what they're looking at?

 

so is it belt slip or just a bad tune??

 

i would put on the stage 2 belt cause it is slipping if you dont have a smaller belt or a larger idler pulley.

 

It's the tune. You're way too fat up top. You should be at 11.4 all the way to redline for AFR. At 5700RPM when it starts dropping into the low 10's and then the 9's, your power is going right with it...

 

got the same problem you just have a horrible tune. my power drops at 5800 rpms and at the same time the a/f drops to 10.0

 

Yeah, the tune is definately robbing him of power. Eventually, he'd wash out the cylinders and possibly screw up his cat. Pull some fuel out and watch that graph climb until redline...

 

so does anyone have a pic of a dyno sheet from one with similar mods as me. (in the sig) so that i can show the people to compare.

 

Keep in mind too that the smaller pullies tend to lose more steam in the top end comparted to stock, due to all the extra heat generated. Compare that curve to some other 2.6" dynos and it won't be as far off. (although I do agree that car can definitely use some TLC)