Re: Getting power out of small motors.

[Todd Phenneger <phen9461@uidaho.edu>]

>that and the fact that turbocharging is far superior supercharging.
>Turbos are more reliable, last longer, dont take any power from the
>engine to produce some, can handle more boost, and contrary to popular
>belief, superchargers dont produce all that much torque down low..

	Well, yes and no.  Keep in mind that technically a turbo is just
an exhaust driven supercharger so by definition a turbo is a type of
supercharger.  Now there are three types of superchargers and I suspect
Dinan was comparing the two most common.  Turbo's  vs  Centrifugal
Superchargers.
	1) Turbo:  Efficiant.  Can produce VERY high boost levels.  
		Disadvantage: Turbo Lag and HEAT, as it sits by exhaust.

	2) Centrifugal Supercharger:  This is the type that has a
compressor turbine just like a supercharger and is usually belt driven and
sits off to the side of the motor like a hydraulic pump or something.
This is what the VW G-60 Supercharger would be I spose as well as most of
the new age kits by Vortech, etc...   These can produce boost levels like
a turbo (ie...HIGH), are better for heat as they are belt driven.  Lag is
BETTER but not great.  THere is no lag from waiting for exhaust gasses to
compress compress and turn the turbine faster as it is instantaneaous BUT
it is still a turbine and needs RPMs to turn fast enough to compress the
air.  AND its less efficient since its belt driven.  Nice thing for
aftermarket tuners is that its MUCH easier to install than a turbo since
you dont have to do custom exhaust plumbing.  You still need an
Intercooler but heat isn't as much of a problem since the air never comes
close to a Red Hot exhaust turbine like a turbo does.
	3) Positive Displacement Supercharger.  (Did I say that right?)
This is the type that Top Fuel Dragsters use and that you see on tricked
out Hot Rods that sticks off the top of a V8 about 8" to a foot and is
driven by a MASSIVE 2-4" wide drive belt.  These are the type that are
heraleded as having no LAG.  They work right off Idle because what they do
as besically work like a Paddle Wheel simply stuffing the intake with air.
Every revolution moves a given amount of air so as soon as it starts
moving it is making boost or positive pressure in the motor.  The boost is
adjusted by way of different size pulleys to underdrive or overdirve it so
you can run 3psi in your stock Chevy 454 powered boat or 12psi in your
custom built Cigarette Boat or Dragster.  Bit disadvantage is heat since
you cant cool that air AND efficiency I believe.  
	I'm taking this info from a TURBo magazine where they went in
depth into the different ways to BOOST your engine.  
	The FINAL way is a type of Hydraulically driven Turbo that Garret
is designing for Turck use and eventually for car use.  Very efficient as
its run off of a hydraulic pump.  Boost is controlled by varying
hydraulic pressure.  Instant response if you want it.  BUt, Alas, we cant
buy it yet so we can only dream.  I just hope that Audi's TEAM HYDRAULIC'S
never gets their hands on it. :-)

>This info:  From Steve Dinan himself....i went to a presentation of his
>and he stated:  I dont do turbo kits anymore because people think that
>turbos are unreliable, they dont sell, so i make supercharger kits.

	I spose he's right.  Turbos do have a bad rap among many people.
Its a shame really because they have gotten so advanced and Lag problems
have almost disapeared for street use.  Oh well.  WE all know the
advantages. :-)
        And of course if you find a discrepancy in this please feel free
to correct me.  I could of messed up on part of it but I'm Mostly right.
As was Michael in his diagnosis of the differences.  I was just expanding
on it and adding the info on the Positive Displacement Superchargers.
	L8R
                          
	Todd Phenneger
	1985 4000 quattro / silver / daily driver
	1983 ur-q / black / fixing it up
	1984 4000 quattro / modified/ awaiting Turbo Transplant.
	1987 4000 quattro / Saphire Metallic Blue/ Girlfriend's
	1996 A6q / Volcano / Dads Car
   *****1985 5kt / PARTING OUT!