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slow&rusty slow&rusty is online now
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Join Date: May 2005
Location: Houston
Posts: 3,742
Quote:
Originally Posted by raceman View Post
Well Dave,
this one has been hashed out to fistacuffs and you`ll find TONS of info on here if you search. A supercharger creates power with no lag,right from idle which is nice but it creates this power at great cost. lt might cost 50horsepower to make 100horsepower,the parasitical drag is enormous compared to a turbo system. Personally l feel superchargers wear out motors much faster then turbos providing the same boost.This is widely believed by some,denied by others and proven by many. There is a really good reason Supercharger kits are not as popular for Porsches as turbo conversions.
Having said all that, one day if given the right opportunities l`d love to build up a supercharged 3.2L Carrera or 964, the technology has improved quite a bit since the early days..
All the points made in this reply are excellent. The motor has to overcome another set of substantial pulleys (two at minimum) to even start building power, hence the parasitic drag or lag, 8 and 12 cylinder engines can overcome this quite easily, 6 cylinder engines are marginal and 4 cylinder engines forget it. I had a project a few years ago where I supercharged my N/A engine and I was *very* disappointed with the results, you can tell the engine was definitely making more HP and more torque but considering the cost, time, fabrication and effort, the results left me a little gasping and I kick myself that I just did not turbocharge the engine instead. I would have been ahead in terms of performance, effort (and time involved) and would have probably saved a few $$$ in the process.

I even went with a custom CNC crank pulley to spin the supercharger to a higher boost (12psi) in conjuction with a custom CNC pulley on the Supercharger as well. I also intercooled the motor with a large intercooler and custom flame bent aluminum piping (read "$$$$") with the most gentle bends to help flow, after it was said and done, the end result did not yield the results I was anticipating. I even rebuilt the SC (Roots style SC) thinking that it may been a problem with it, but it was perfect even when I took it apart (teflon blades with perfect seal) and made no difference to performance when I put it back together.

I wish I had dyno'd the car, but never made it to the dyno. The coolest part of the conversion was that I had the TPS set with the Supercharger relay, and at a certain throttle position, the SC relay would "click" and you could feel the SC kick in. Mid range throttle response was decent so long as you were in the power band. One frustration I could never figure out was that at wide open throttle the boost would hit 12psi for a second or two and then slowly creep back down to around 10psi, I could never figure out why I lost 2psi and that frustrated me to no avail (hence rebuilding the SC, the intercooler and the flame bent aluminum piping).

Turbo technology has become so impressive with the new type of turbos, wastegates, blow off valves etc available, that in my opinion there is no alternative, not even close.

Go out and drive a SC motor at 10psi and a turbo engine at 10psi and then report back in with which one left you (more) impressed.

No disrespect to JohnJL or any other members who are partial to Superchargers, but this is my view based on actual wrench time and experience.

Regards - Yasin
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Old 11-23-2008, 06:52 AM
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