89IrocZ350TPI

So I got all my cars dynoed and tuned. I was wondering what the crack hp was. Mainly because I am bored right now haha.

98 Trans Am WS6-magnaflow catback and k&n's plus tune--337rwh
89 Iroc Z L98 Full bolt ons--252rwh
86 Iroc Z LG4 Full exhaust/Intake/Dual snorkle--185rwh

1. LS1--337/.85=398 Seems high
2. L98 252/.80= 315 Seems high
3. LG4 185/.85= 218 Seems correct

Anyone have any different methods for calculating fly wheel power. Or any input.

stealtht/a

iTrader: (1)

does your LG4 have any mods to the carb?

do gear ratios effect final rwh vs crank?

Orr89RocZ

iTrader: (20)

300-315 hp is about right estimate for 252whp. Mine was 254whp and i figured it was 310 hp

337 is good numbers for a strong exhaust modded LS1. 400 crank is reasonable.

89IrocZ350TPI

Yeah I really like the LS1. I still cannot believe I am getting almost 20mpg with a high 12 second ride. Never took it to the track but id assume it can get in the 12's with radials.

tpi90rs

iTrader: (2)

what bolt ons for the L98?

89IrocZ350TPI

The L98 has cat back, headers, 1.6 rockers, intake and runners, ported plenum, chip, tb bypass, msd ignition, cai, k&n's, injectors, afpr, air foil with 3.45's.

Atilla the Fun

your LG4 results impress me. As for the LS1, you should be on www.ls1tech.com

89IrocZ350TPI

really? what would the avg one dyno w/intake/exhaust

Atilla the Fun

My late-'83 L69, installed in my '71 Camaro, dynoed 179.4 rwhp through a TH350, 2.73:1 8.5" axle, 235/60R15 tires, with an Edelbrock intake and a Hooker dual exhaust system. I suppose you have a T5?

89IrocZ350TPI

T5 Yes. My guess is the dyno is wrong. An L69 has a better cam than an lg4. My lg4 probably should be around 160rwh and 200 at the motor sounds more accurate. It really is extremely slow.

doc

I would use 0.85 for the 3rd gen cars. For the LS1 car, 0.88 is more accurate in approximating the drivetrain loss.

89IrocZ350TPI

I used .80 for the l98 auto and .85 for the others. why would .88 be better for ls1?

doc

I got it straight for Scott S. aka godfather of the F-body. With advancements within the drivetrain to lower resistance (friction) and increase fuel mileage, the LS1 cars are much better at putting the Hp to the drive wheels. I think that you are correct in assigning different values for the auto vs manual 3rd gen cars, but I would lean toward 0.825 for the auto.

89IrocZ350TPI

I always felt ls1's were better at putting power to the wheels but I could never find an explanation to prove my theory.

Atilla the Fun

A 7.625 is a 7.625, and GM didn't install synthetic lube, SLP may have, but from GM, NO improvement there. Any improvement would be if the T56 had a lesser-angle helical cut on the gears, which I doubt, because it would be noisier. And it didn't need it because it was stronger by mass and materials. Otherwise, the T56 has more internal mass to accelerate, making it slightly less efficient. It has been well established by the Mustang crowd that a T5 and an 8.8, with synthetics in both, together eat right at 13 percent. The 7.625 has the same relative pinion height in relation to the center of the ring gear, so I use 13% for all m/t combos.
As for the 4L60E, it's still just a 700R-4 for everything except the valve body, and still eats the same amount of power. A stock-line-pressure 700R-4 with stock GM converter and stock 7.625 eats right at 22%.