I had my 95 z28 at the dyno shop 2day. It is a m6 w/ basic bolt ons: edelbrock lt headers, K&N cai, Flowmaster exhaust, Cut out was open, 160 degree thermostat, hypercrap programmer, no cam or head work of any kind and it has 183,000 miles on it. It maxed out at 265 rwhp and i was jw if those numbers sound about right for what i have done 2 it. I know it's not runnin as good as it did a few years ago when it had around 100k miles on it b/c back then it ran b/t 13.8 and 14.00 in the 1/4 and now it has been runnin b/t a 14.8- 15.2. A few people have told me i should have the compression checked b/c that may be the problem but i just thought i'd get a few opinions on here also. Thanks

 

That sounds about on the low side of average. I'd expect anywhere from 260 - 280whp.

 

its largely dependent on what type of dyno you went to. On a Dynojet I would say thats low on a Mustang type dyno I would actually say thats about right or maybe slightly high. Any blowby that you can tell? If so a Compression test or leak down test would be good to perform

 

Something doesnt add up.
265rwhp should be way faster than 14.8-15.2 in the quarter, unless you have absolutly no traction, or missed a couple of shifts. You may have other powertrain issues.

 

Sounds like your motor is getting tired or you have other problems. It should run 14.2 stock, and mid 13's with that stuff. I was at 13.6 @ 105 with headers, catback, and cold air.

-Dustin-

 

You mention "Edelbrock lt" headers..... do you mean "long tube"? If so, what is the part #? I didn't know Edelbrock made long tubes for the LT1. What is the primary diameter?

What EXACTLY is the "Flowmaster exhaust"? Is it a full cat-back, or just a muffler? Which Flowmaster muffler is used in the system?

Are you running a cat? Is it possible its plugged up?

At 180K miles, when is the last time the plugs and wires were changed? Has the Opti ever been replaced?

The Hypertech programmer "power programming" has been shown to lose HP on the dyno. The only definite gain comes from the lower fan on/off temps to match the 160* t'stat.

On the dyno sheet....
-what RPM does the HP peak at?
-is the curve "smooth" or does it have major peaks and valleys?
-what was the A/F ratio at max power?
-what correction, if any, was used - SAE or STD
-what is the altitude for the dyno, and for the track you race at?

Could you post the dyno sheet?

 

It was on a dynojet. I dont have a scanner to show the dyno sheet where i am at right now but i should be able to scan it later on this week, either wed. or thurs. The edelbrock headers i just assumed they were long tube b/c they hang down much lower than the stock headers, I dont have a cat. converter, and i can't remember exactly which flowmaster muffler was put on b/c it was about 7 years ago and it was a full system not just a muffler. Ill find out what altitude the track is at, which is located in montgomery,alabama. traction wasn't an issue those nights at the track. and i also forgot to put that the difference in speed had dropped from 105mph when i ran the 13.8 a few years back and is now at 95mph at 14.8

 

Sorry i forgot to add that that the plugs, plug wires, and distributor were changed around 165000 miles

 

I was able 2 run down 2 my friends house and use his scanner. They printed off 2 sheets, one w/hp and mph and the other w/hp and rpm and i only got the one w/hp and mph. rookie mistake. They made the pull in 4th gear and the rev limiter was set at 6200 rpm and that was where it stopped at.

 

yea 4th gear is correct, it should be a 1:1 ratio with the motor.