Originally posted by Scorch:
<STRONG>Larry,
You are an engineer.. I have a hard time believing that you think an auto tranny is going to cause an extra 125 hp loss on the dyno.. thats a whole civic worth of power. That would demand a gear driven water pump and a "tranny cooler" the same size and thickness as a civic radiator. Personal experience.. a long long time ago I dyno'd a single on an otherwise stock car at 9 psi..I got 280 torque and 340 Hp.. this is no tuning, no fuel, no intercooler, no lockup switch. 340 * 1.33 = 450 hp at the motor.. thats pretty good for 9 psi. Maybe I am wrong, but 250 hp or so is a WHOLE lot of heat to be losing through a tranny, like enough to melt the bellhousing. Additionally, what is the flow rating for a turbo like the sp63? 667/.67=995 HP at the crank.. thats almost 100 lbs of air per hour.. I thought consesus was it would take something along the lines of a t100 or at least a t76 to run that kind of CFM. Again.. I could be wrong, but common sense, personal experience, and physics tell me I am not.
Dylan
[ June 18, 2001: Message edited by: Scorch ]</STRONG>
Dylan, I also had doubts about these losses until I talked to the engineer from B&M. Remember that Ethans car has a high stall converter that will not lock up, we are working on a fix for that. Also Ethans car has a 120 hp NOS kit that was used on that run.
Here are a few more examples.......
We dynoed two identical cars 2 years ago, both HKS twins, cams, etc.... 6 spd made 67X RWHP at 24 psi, auto made 540ish same boost.
Our SP63 on a 6 spd car typically dynos at 625-650 rwhp, but on an auto the best we have seen is 580.
On an auto car we see as much as a 60 rwhp difference on the dyno when we lock up a converter. This is on cars in the 500 RWHP range.
Two weeks ago we ran my partners car at the track with a converter that would not lock up. It had a lot of hard runs on it. The best trap speed was 125. With just a new converter that now locks up, the traps increased to 134 with NO other changes. Where did the HP go?? Do the math and see how much HP was lost.
Also note that on Jarretts 8 sec car, he dynoed it with a 6 spd in it...... wonder why???
Lar
SP