joeandcarol2

Two interesting threads going on right now. Can anyone talk about the pluses and minuses of the two approaches? I know they both boost the charge in the combustion chamber.

1killercls

Supercharger compresses ambient air...Turbocharger utilizes the exaust to compresses ambient air...THINK. Heat is VERY HARD on engines. Also turbos are driven by this exaust air and become very hot...this also produces a "Lag" prior to Turbo Spool up...Superchargers are driven on a belt hooked to the crankshaft...the power tends to be delivered in a more"Linear" manner. For an everyday driver...keeping dependability in mind..I think the Supercharger is the way to go. If massive HP and rocket performance is more your style...Turbos...will do the trick.

Edited...DUH>

allmotor_2000

The BOTH compress ambient air... except that a turbocharged system usually intercools the ambient air, hence dropping the temperature down significantly.

A supercharger uses the engine's power (via a pulley attached to the crank) to start things churning... a turbo uses the car's exhaust to start things churning. There are arguments about turbo lag on a turbo-system... but a well-chosen turbo will prevent that completely. Heat is very hard on the motor... hence intercooling the intake charge always helps. Honestly I think Supercharging is probably better for a daily-driven street upgrade... while turbo probably has more available power if harnessed properly.

Both need the proper fuel, ignition tuning etc. to work well.

Doc.Booty

Neither is the choice for me - i'm broke and i've yet to see a turbo or SC designed for an auto CLS.

1killercls

Dude...the Compech S/C will go on an auto.

Doc.Booty

Really? The site says it's for the 6 speed. This is most intriuging...

Red Rider

The latest info has the SC for the 5AT avaiable in mid Feb.

SiGGy

Only thing I would add is the air really gets hot from being compressed. 1killercls response is incorrect. Good you corrected it. As everyone has said, simply put, both are air compressors, supercharger is powered from crank shaft. Turbo is powered from wasted exhuast gas. I assume 1killercls also didn't know that most turbos are water cooled to help fight the heat.

Boyle's gas law will give a good explanation of why the air gets hot when it's compressed.

http://members.aol.com/profchm/boyle.html
http://dbhs.wvusd.k12.ca.us/GasLaw/Gas-Boyle.html

EDIT:

I see 1killercls fixed his post

Doc.Booty

Ooh... daddy want...

Wires

There are two types of superchargers (roots, centrifugal). Roots, like the Comptech unit, produces boost from idle to redline. This gives you nice linear power, and you really don't notice the difference from stock (other than the extra kick in the pants).

Centrifugal is the boost side of a turbo, driven off crank. The power tends to be higher up the RPM range, since it requires a bit of RPM to start making boost (i.e. Vortech Superchargers).

Turbo uses exhaust gases to drive the boost blower.

SCC had a really awesome comparison (9 issues long I believe) comparing the pros/cons of each.

If you want predictable, linear power, roots superchargers are the way to go (gives you extra torque down below). Like it was said above, better street driveability.

The turbo can be tuned more than a blower. By changing the size of the turbo, you can change where in the RPM range the boost happens. The larger the turbo, the greater the turbo lag (time it takes for the heavy unit to spin up). The turbo is more tuneable. The reason you can't pick one turbo for everything is the turbo spins upwards of 40,000 RPM. Around that point the vanes reach the speed of sound, and stop pumping air. That's why you would see twin turbos on some street cars. Newer materials are making turbo lag less (lighter impellers).

Personally, I like the roots blower in a vehicle that has the traction to handle the lower RPM torque. The SCC article leaned towards the turbo. Mind you, in the CL's case, I'm surprised Comptech went for a roots blower since the CL-S has issues hooking up stock.....

Another final note:
Apparently turbos may be replaced by superchargers in more and more new vehicles. The turbo slows the heating of the catallatic converter, and thus the car pukes out more emissions until it's warmed up.