Question on Performance of 8psi

Arctic_White_WS6
04-13-2003, 04:30 PM
I finally got my 8psi procharger tuned on my 97 Trans am this weekend. The car is a 6 speed with 3.42 gears and street tires.

I'm subtracting 1.5 degrees of timing per pound of boost from within the PCM. AFR is between 11.8 and 12:1 from 1500rpm to 6000rpm, WOT. No knock is reported for WOT run in 4th from 1500 to 6000rpm. I'm seeing 7psi at 5800rpm (I'm at 1800ft elevation).

After all this, the peformance really isn't what I was expecting. Should I have traction problems in 2nd gear??? I spin like crazy in first, but the car did that stock. 2nd will not break loose by just punching it at any rpm. The tires may be slipping some above 5000rpm.

The car runs well and hits 100mph very quickly, pulling a lot harder than stock, but with around 500crank HP, I would have thought it would spin the tires silly in 2nd gear. Car has 42# injectors, MSD, headers, no cats, and a borla. Engine internals are stock.

Does this sound right for performance (I won't be able to get to a track for a month or so, and there are no dyno's around)??? I'm going to have to get the 383 stroker a lot quicker, because as it stands, this is defintely not enough HP for the $$ invested so far.

rwb
04-13-2003, 07:39 PM
You should be able to smoke your tires in second. Unless you are running big slicks. Take it to a dyno and have a wide band put on it. With 440 hp my car could smoke the tires in second from 2500 rpms on.

rskrause
04-13-2003, 08:09 PM
When I had a stock 350 with the Vortech S-trim and 6-7psi it was noticibly stronger than stock, but not god-awful fast. Sounds about like yours. On a good road there wasn't wheelspin in second unless the temps were cool (more hp with denser air).

Headers helped considerably, but on the chassis dyno and by SOTP testing. The hp is misleading. Peak hp obtained from a centrifugal does not make the car as fast as NA hp or especially nitrous hp. The gains are concentrated up at the top of the rev range.

Now, once you hit the 600rwhp range, it will feel real fast ;)

Rich Krause

MSM69Z28
04-16-2003, 06:16 AM
may be pulling out too much timing. a few degrees on the bottom end and the torque will really pick up. obviously you are monitoring detonation. its a fine line you have to walk. the lean and more timing the stronger a blown motor gets (obviously to a point), but it can be a dangerous thing to toy with. creep up on some additional timing slowly and see if that gives it a little more.

the car probably wont go silly spinning in 2nd on dry, but should get a little sideways on the shifts, IMO

mike