Originally posted by E55 KEV
RennTech now has the following for the 2003 SL500:

5.5 Renntech/AMG supercharger and
displacement conversion (477 HP)

The impressive power development in the eight-cylinder engine is largely down to a newly developed belt-driven supercharger that generates about 30 percent more charge pressure than other comparable belt-driven
supercharging systems. Rotating at over 25,000 rpm, the compressor's aluminium rotors press some 1600 kilograms of air per hour into the combustion chambers. The screw-type compressor is connected to
the crankshaft by means of an electromagnetic clutch and a separate poly-V-belt, thus enabling it to spontaneously react when the driver presses the accelerator and provide powerful thrust at engine speeds
barely above idling speed.

Originally posted by KLEEMANN


30% more charge pressure? What I think they mean is a screw type has a 30% mass airflow advantage compared to a Roots at the same pressure.

Kilograms per hour is simply a mass measurement of airflow- what you need to know to make ANY sense of this is at what engine speed? One would imagine its at max engine speed so you can quote big numbers. Hows this: the AMG engine makes 469hp @ 1600 kg/hr the KLEEMANN system makes 530hp @ 1120 kg/hr!! Whats more impressive?

Electromagnetic clutch?? be cause there is no bypass!! In "clutch off" mode the engine has to spin the dead weight of the rotors to ingest the air required to run- this is nothing to brag about in my book. The clutch is just one more control system and part to wear out and fail. The super secret reason MBZ does this is to abate SC noise at idle- when there is no road noise tomask the SC noise. There is no "performance" reason to do this. Nice spin eh?

The SC MBZ uses is an IHI (Japan) unit that uses Lysholm rotor profiles- screw kompressors are largely identical in efficiencies, adiabatic and otherwise. 25,000 RPM is VERY misleading. Screw kompressors have a male and female rotor, one turning at 1.5 times the speed of the other (typically). They must be talking about the "fast" rotor. If they are talking about the drive ratio to the crank Im scared for all the about to be AMG owners. Most screw kompressors are rated at 16,000 RPM max sustained RPM. KLEEMANN systems spin 13,000 RPMs at max engine speed- slow speed = long life.

They dont even mention their intercooler- cant say I blame them as it has one of the worst efficiencies Ive ever seen. Charge temp is where its at- 8 psi at 280F will make less power than 6 psi at 150F. Big boost numbers and huge quantifications of mass flow are BS with out the power to back it up. KLEEMANN makes 60 MORE HP at 2.5 psi LESS pressure.