dyno day

[big_G]

Last Thursday blew 4 hours tuning my 'Vette. Was hoping to hit 600 rwhp. Fell short at 555. I think my set-up is capable. Re-cap on my current set-up:
383, 8.3 scr
Vic. Jr heads and EFI intake
FAST EFI, 1200 cfm throttle body
Comp. cams solid roller 230/236/114*
ProCharger, D1SC 15-18 lbs. boost (inter-cooled)

Here is a dyno graph...Thinking maybe a bigger cam. 4 cam vendors all had different recommendations...lol. Open to any suggestions.

[RSX302]

What A/F Ratio and timing were you running?

You're not far off on the cam. I'm running a 234/238/114* (224/230)
You do not want any overlap at .050. My runs -1*. About as close as it gets.

[big_G]

A/F was 11.0 above 5 psi boost. Timing was 30.0*. No detonation evident by reading plugs. IAT was 130* after the intercooler. What kind of power numbers do you make? Thanks, Gary

[RSX302]

A/F was 11.0 above 5 psi boost. Timing was 30.0*. No detonation evident by reading plugs. IAT was 130* after the intercooler. What kind of power numbers do you make? Thanks, Gary

11:1 is too fat...I'm running 11.7 at WOT on a 9.7:1 motor. (ceramic coatings on piston top and partial head chamber)

I always thought that you wanted to increase timing to gain hp. Not always the case with boosted motors---I reduced timing to 25* and gained hp.

My little 302's last dyno pull netted 653rwhp at 7200rpm. This was on a 93 deg day. I think it's a little more now that I spent some time tuning on it. It really loves the colder weather!

Here's some approx's of what I use:

15-15.5 at 15-18" vac (off throttle cruising)
14.7 at Idle (16" vac)
14-14.5 at mild loads (5-10" vac)
13.5 at 0 psi
13.0 at 2 psi
12.5 at 5-8 psi
11.7 at WOT 10-13psi

[big_G]

On the last run I bumped the timing to 31* and picked up a few horses at 6k+, but lost a little torque down low. I assumed since I picked up a little, I was not too high on timing. I assume you run turbos? Nice numbers.

[RSX302]

Every engine combo will like a certain spot for timing. I don't argue with it---I just move it around until its happy. You may be at the timing it likes.

Lean out the mix first...Leaning out should give you a bump, but be carefull, with 30+* timing you might start getting into detonation. If so, start backing out timing. When I was at a lower compression ratio, it didn't detonate at 30-40*, it just kept lossing power.

Excess fuel will cool the cylinder reducing the chance of detonation as well as reducing hp. Someone correct me if I'm wrong on this, but I think the faster burning heads of today typically use less timing.

Yes...I'm running Turbo's..
On a mid hp street engine, this will typically gain around 50hp at the same boost pressure due to the lack of a belt. 100hp on a race motor.

[RSX302]

You're not far off on the cam. I'm running a 234/238/114* (224/230)
You do not want any overlap at .050. My runs -1*. About as close as it gets.

Boy did I screw up my cam numbers...here are the real numbers

224/230 at .050
284/290 Adv Dur
114LC