[longhornchris04]

Originally Posted by ja78911sc

Bill,

I feel this is the most overlooked aspect of a motor upgrade on a track car. I have a friend with a 3.6 conversion on a track dedicated car mated to a 915. He has broke gears on two different occasions.

That being said. What HP do you feel is the max on a track car with a 915? (DE only not racing). I don't feel this is off topic and actually a very important equation when considering a motor upgrade with a 915.

I am also considering a motor upgrade (track use) to mate with my 915. If I remember correctly the 3.2 euro's with a 915 had a tranny cooler. Rough HP I believe was in the 230 range. Maybe a 3.2 with 964 cams, headers, chip & a tranny cooler?

Thanks,
Jim

Parroting what's been posted in the engine forum...

The 915 with proper mods (cooling, retainer plate, diff cover if magnesium) should handle 250Hp... but you are pushing it. Having a limited slip is also a good idea, as it will minimize having the transmission load and unload as the traction hits the limit.

Breaking gears is more a question of torque than horsepower. For the sake of example, an engine producing 250Hp at 7000rpm is less likely to break a gear than 250Hp at 5000rpm (numbers from the processes of rectal extraction, don't take literally). So the same 3.2SS with the same Hp as a 3.6 may not be as hard on the transmission. That 250Hp number may have been based on a high revving engine.

I've also read some stuff on people mating a 915 to a turboed VW Type-4 motor. Despite having the same power as a 3.0L, the larger ripple torque of the 4 cylinder had a bad habit of breaking stuff.

Regardless of how you make the power, cooling will be a major issue. If you are going much above 250 I'd consider options for beefier internals. And up goes the cost