I agree haha i jsut want to hit low 13s m3 at 240hp. 6psi about 40-50 hp? i know it depends.....so im looking at almost 290 hp maybe more with mods of course

 

oh i know about the rpm band..thats why i like exhuast driven spool time...rather than a belt fuck waitin for RPMS to increase to get boost..i want full boost from time my foot htis the floor..haha (lil lagg never hurt)

but seriously...say you have k20 turbo k20 s/c.... both 10psi...what RPM does it take the s/c car to get 10psi?? ive always thought it had to be at max rpm...since it driven by a belt. unless they use a BOV type thing to regulate how much boost goes in so they dont have to wind all the way out to reach 10psi???

 

Going back to the original question... Whether or not an engine can handle boost safely has nothing to do with what RPM that boost is achieved or what RPM range it stays at that level of boost.

Superchargers can reach full boost at full RPM, but it depends on how they're sized for a particular application. A smaller supercharger will not be able to flow enough at high RPM, which is why twincharging is such a fun advantage (the turbo picks up when the super starts to drop the ball)..
You have to realize there are different types of superchargers also, centrifugal units (Vortech) don't come onto boost until higher RPM. They're essentially belt driven turbos and have similar RPM-based characteristics. Roots or Eaton superchargers generate boost all the time at lower RPM because their displacement ratio is fixed. Like I said, it's down to sizing.

 

Ah, i see. so in the end, i still love a turbo more. haha.

 

I'm going to re-iterate what on what Fabrik8 is saying. Its not necessarily about your compression ratio, rather its about the dynamic cylinder pressures. Its ALSO about reaching that limit in the most efficient way possible. For example, you might have a motor with an 8.0:1 that you can run say 20 lbs of boost. OR you can have the same motor with a 10:1 ratio and only run 12 lbs of boost. Now you need to consider ambiatic efficienies. On setup a (20psi) the turbo may be running at 62% efficiency, where as setup b (12psi) will be running at 76% efficieny. Superchargers (centrifugal style) usually max out around 80% efficiency peak. You're dealing with curves, NOT straight lines in forced induction. The goal is to match your needs/purpose, to that peak.

 

all things being = a turbo will allways make more hp then a supercharger will.

 

LoL - god you people are so ignorant.

 

i seeee...i understand what you are saying....thanks

 

This thread just made my understanding of forced induction alot better thanks, maybe when i find the M3 I want, I'll hit you guys up again

 

agreed.....