SC-12 Max boost

[Volodkovich]

Hi Everyone,

I was just wondering how a SC-12's coating on the rotors melt at around 10,000 rpm. Is this due to the heat of the boost its creating, or due to the supercharger spinning too fast?
What im actually trying to say is would this 10,000rpm limit apply for a smaller capacity engine running more boost? Or is the 10,000rpm blower rpm 'limit' set at the amount of boost it makes on a 4agze?
i.e. is it boost or blower rpm dependant?

Thanks, Rob

[Alex B]

why would you want it to run at 10k they are more restritive than good at that level of revs anyway.

[Volodkovich]

This isn't on a 4age, so it doesnt really apply like it would on one. I would like a high-ish redline without having to worry about melting the coatings on the rotors, while still having quite of boost throughout the rev range..

[matt dunn]

I think the spinning speed causes heat,

and the boost makes heat too.

At lower boost levels you may get it to spin faster ok but there will still be a limit.

Matt

[ants_ae92]

Hes not talking about engine rpm pyro_sniper2002.

Hes talking about rpm at the supercharger. The supercharger runs at 1.25 times the crank speed, So at 7k its actually spinning at 8750. And with a larger crank pulley, you are spinning it faster again.

I've heard more like 12000 rpm, but you would have to check, I think I saw that on a post here, try searching.

Alot of the guys recommend a front mount intercooler if you are upping the boost.

[Lanius]

The charger becomes inefficient due to the heat it produces. It still provides boost throughout the rev range, but the heat of the intake charge negates any benefits of the boost. A supercharger is not the best option for power at high revs, no matter what CC rating your engine is. Fitting a front mount is an option to help combat the high temperatures, but you also suffer a "follow on" effect as the throttle is before the intercooler. This means airflow through the cooler keeps the engine running for a brief moment after you take your foot off the accelerator, which wouldn't be a problem if you've declutched, but its something to be aware of anyway.

Remember SC12s are more than 10 years old now ...

[EDIT: if you could find a way of cooling the entire SC12 unit (including the "vanes" inside), you may find a way to get the SC12 to be useable for the application you've described, but then you'll be looking at a more and more complex system. Keep it simple for reliability]

[Volodkovich]

i would have thought a waterspray on the intake to the SC would work well...help cool the vanes of the SC.

Was just looking at the HPC site, and apparently they make a coating for blower rotors, i thought it might be a good replacement for the fluorine resin coatings on SC-12's? Anyone tried this out? If they use it on blowers for V8's im sure it wouldnt melt at 14psi like the coating on sc12's do...

[Lanius]

Not sure of the size ratio between crank and charger pulleys on a V8, but I doubt they would spin as fast as an SC12.

Find a way of injecting NOS straight onto the vanes ... bet that would have some interesting results

[Adamal]

A supercharger is not the best option for power at high revs

*COUGHCOUGHCOUGH*

Should say:

A ROOTS type supercharger is not the best option for power at high revs

[Volodkovich]

What does the coating on the vanes do anyway? The vanes don't actually touch, so what is the point in coating them in teflon?

[Lanius]

A supercharger is not the best option for power at high revs

*COUGHCOUGHCOUGH*

Should say:

A ROOTS type supercharger is not the best option for power at high revs

LOL ... the only "economically viable" model is the roots type. If I could make a cheap screw type, I'd be rich by now

[Adamal]

Hmm... True. Screw tyes do cost arm and leg

[Lanius]

Reckon ... would have stuck to my 4AGZEs instead of moving up to 3SGTEs if the screw types were cheap. I miss my instant boost

[vvega]

centrivicals arnt to expensive
and as for a roots
nothing wrong with them ethier you just need to size them right...as with everthin

[Lanius]

centrivicals arnt to expensive
and as for a roots
nothing wrong with them ethier you just need to size them right...as with everthin

I remember being told aaaages ago that the screw types were preferable as the boost was "constant" as opposed to coming in "pulses" as caused by the vanes on the charger.

I'd love to see the engine bay arrangement for fitting one of those archimedes screw types in ... imagine they'd take up a fair bit of room ...

[Adamal]

Actually, twin screw types are, a majority of the time, the most compact S/C's on the market.

Have a look at the measurements of the Whipple ones:
Heres the 3.3L displacer version


Heres the 1.2L displacer, which they use in the PT Cruiser kit (2L engine):

[Lanius]

Fark ... well there you go! To the original poster ... get yourself one of those puppies

[Adamal]

HAH! You're talking some serious bling there! The 1.2L version would set you back about $2000 JUST for the S/C, and then you'd have to get the bypass valve system.
They're excellent superchargers though

[vvega]

the millar cycle engine that mazda? produces has a good one on it
maybe you could look into that...i.e talk to some wreckers

v

[Lanius]

HAH! You're talking some serious bling there! The 1.2L version would set you back about $2000 JUST for the S/C, and then you'd have to get the bypass valve system.
They're excellent superchargers though

lol, I knew it would be either 1) too expensive, or 2) impossible to do