Running vaccum to crankcase on street car?

[Tommy]

I've read a lot about vacuum pumps pulling crankcase vacuum to add horsepower in race engines. I've heard the theory, but I'm interested in hearing from people with actual experience. Has anyone here used an electric pump to pull crankcase vacuum on a street driven car? If so, what has been your experience?

[Hotfingrs]

I've used vacuum pumps before. To see any benefit, you'll need to run low tension oil rings, and the vacuum is needed to seal the ring to the land, otherwise you'll burn oil like crazy. Don't see any real benefit for a street car....IMHO

[scottj]

Tommy,
The less pressure you have in the crankcase the lower the ring tension you can run = more power.

My race motors are built to pull vacuum based on the ring package. The motor is sealed air-tight, using double-lipped seals for this application and a 5-stage drysump pump provides the negative pressure. The ring package in these motors use low tension .043 second and a 3mm oil rings and MUST have negative pressure to seal properly. There was a 14hp gain on a 775hp motor from the neg. pressure and the low tension rings.

My Cobra motor is built very much the same as the race motors but with rings suited for a street application. Without the ring package I didn't feel pulling vacuum was warranted, especially considering the small gain percentage-wise.

[Steve R]

Tommy,
Check out this link. This guy designed his system to stop oil leaks. I think it is a very interesting and informative read.
http://www.teglerizer.com/triumphstu...ns_system5.htm