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Porschefile Porschefile is offline
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Join Date: Jun 2004
Location: Austin, TX
Posts: 150
700 flywheel or wheel horsepower? There's a pretty big difference between the two. Making 700whp is not impossible and will not necessarily make it unreliable, however that will considerably shorten the lifespan of the motor to the point where you'd probably be rebuilding it often. Also, sustaining 700fwhp or whp on the track will put a TON of stress on the motor, drivetrain and chassis to the point where you'll be rebuilding it after a certain number of operational hours as opposed to miles. In a light car, 700fwhp or whp is a bit overkill unless you are planning on racing in some unrestricted class and taking on some serious competitors. For the occasional burst on the street though, 700whp wouldn't put nearly as much stress on the motor so, if done right, it could be made to last.

What displacement would you be using? 700whp on a 3.6 or 3.8l actually wouldn't be that unresponsive. I guess response is really a subjective term that's a matter of individual preference. Personally, full boost at ~4-4.5k rpm isn't bad IMO. Some of you guys might be surprised with some of the new-tech turbos that are on the market now. Garrett's GT series are excellent, and there are plenty of custom turbo companies like ITS making responsive ball bearing turbos. Either way, 700whp is getting into the 70mm+ compressor size range, which is a fairly substantial size of turbo. You can acheive that much power with smaller turbos, however I don't see too many aircooled guys running high boost pressure like 30+psi, and I'm not sure if there are any issues such as head lifting at these higher pressures so a smaller turbo might not be feasible.

IMO, as light as pre '89 911's tend to be, anywhere around 400-500whp is fun enough and fast enough for most people. 400+whp in a 2800# or less 911 is usually good for ~high 11's in the 1/4 and mid 120's which makes for a very quick car overall. At those power levels the motor would be considerably less stressed, more responsive, cheaper to build and would last longer. I'd highly suggest riding in a high hp car if you haven't already. Lots of people get the idea in their heads that they need one million hp or something, but honestly 400-500whp in a sub 3000# car is a hell of a lot of fun, and already past some driver's skill level to handle. If you really just want to make lots of horsepower, more power to you! There's nothing wrong with that, though I think you should really be sure that it is what you want to do. I do like the "Tim the Toolman" approach too, though personally I've tried to set my sights a bit lower to take it easy on the wallet.
Old 01-09-2007, 05:05 PM
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