I have a 96 Z28.Mileage:98k Current mods: Jet hot LT's, straight pipe exhaust, CAI, OBDI w/tune by MADZ28. Had car dyno tuned today, and end result was 216 whp and 230 wtq. I'm running out of money and patience. I've been told it's possible that I'm not running on 8 cylinders. Tech told me he usually sees 260whp on stock LT1s. So something is way wrong. After the tune the power drops off when I approach 4k rpm in every gear. This didn't happen before the tune. Any help would be greatly appreciated. I'm located in Jacksonville, Florida
Thanks

 

something is definately wrong. you are low for an lt1 with no mods. with the power dropping off id think its a spark or fuel issue. maybe opti of fuel pump

 

well, I asked about that and the tech showed me the ignition performance screen on the test equipment. He explained each part of the graph and said everything looked good. How else can I test it?

 

If ya are a tech ya should be able to listen and tell if a car is missing/not running on all cyls. Damn
Ya need to take it to someone that knows WTF they are doing.

 

So they checked the ignition system and everything looks okay. Did they check the fuel system to see if that is up to par? Maybe you have a struggling fuel pump that can't keep up to the demand in the higher rpms.

 

No, did not have that checked. I'm still new to all this. How is that tested? Is it something I can do myself, with a limited selection of tools?
Thanks

 

You gotta use some kind of pressure gauge, someone else should chime in. You woud know right away if it wasnt running on all 8 cylinders and wouldnt have even taken it to get tuned. It could also be that your timing chain jumped some teeth and the timing is retarted, or you Knock module is picking up some false knock maby from your straight pipes. Tho I dont know if it would dock that much hp from just a Knock Module.

EDIT: Also if the car feels powerful on the street. Does it? That Dyno could just be ****edup.

 

Can you post up your dyno graph? If not what was the end result for Air fuel ratio?

 

You might want to do a compression/leakdown test on your engine.