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Old 09-12-2009, 08:45 AM
scottj scottj is offline
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Join Date: Oct 2000
Location: Crystal Lake, IL
Cobra Make, Engine: Everett-Morrison, 434 cid
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Quote:
Originally Posted by Dcmgt View Post
Thanks Scott. If you can benefit (ie; more HP) from generating a vacuum even on your street engines with the higher tension ring packs, then why not keep the crankcase sealed on those engines too?
Good question... we didn't see significant gains on the dyno with the street combo and that was on the same dyno with the dyno drysump system. On the other hand, the dirt LM engines that were built to run sealed, I think we picked up about 15hp @ 10" making 800+ hp.

I know the new Z06 Vette drysumped LS7 motors are running lower tension rings for a street application, probably to increase fuel economy, but they also have oil control issues. The track guys are going to vacuum pumps or a Dailey system on these. I've also gone to a modified LS7 in the Cobra.

For my Cobra I just wanted a low maintenance, reliable, street/track motor. I didn't want to send the pump out all the time to insure it was in the condition required to pull vacuum. In fact, being that is was a SCP 4-stage pump, it wasn't a good enough pump to pull vacuum (for a sealed application) when it was new.
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