I took my 1989 GTA to Superior Automotive for a dyno test and the results are not what I expected. I did most of these modifications in 1990. I have not done much with the car since and my daughters have used it at college etc. I now have it back and I'am going to work on it again. Here are the modifications. Brodix street heads(67CC), SLP exhaust system with Tri-Y headers, dual cats, SLP cat back exaust and muffler. SLP cold air package with K&N filter, SLP runners, Edelbrock TPI manifold, 52 MM throttle body. Chet Herbert reground the stock cam. I don't remember the numbers but not drastic somewhere around the 215/215 range. MSD6 ignition and 8MM wires. I dont' remember where I'am at on the eprom.
Here are some of the readouts from the data sheet supplied by Superior Automotive that may lead to the problem. Idle 775 with the A/C on and the Fan Request on. I think they ran the dyno test with the A/C on??? I called but could not get confirmation. The torque at the rear wheels is probably higher as the graph line slope appears to be comming down when the chart starts at 4200 rpm.

MAF g/s = 10.0
Airflow = 10.0
LV8 counts = 66
I don't know how to add the graph but will I will do it this way. The readout is only from 4200 RPM to about 5150 RPM and of course from the rear wheels.

TORQUE Horse Power
4200 = 310 247
4400 = 305 255
4600 = 288 252
4800 = 278 252
5000 = 264 250
5150 = 250 250
Maybe a fuel problem?? Need new eprom?? Help??? How much HP is lost by the A/C being on??? Thank You for any help. Allen

 

a/c probably eats more power than anything except an auto tranny.