DANMAS@aol.com wrote:
>
> Joe:
>
> For reasons too involved to go into here (I don't want to get into another
> long, involved, discussion - I took enough heat for the last few I was in),
> what you said is not quite true. A turbocharger does not spin on free energy.
> It takes power to spin it, just as it does to spin the supercharger, and this
> power comes from the engine. There are relative advantages and disadvantages
> to both, lag on the low end is a disadvantage for a turbocharger, for
> example, but free energy is not one of its advantages.
>
> IMHO, for the applications we are talking about here, a supercharger is by
> far the best way to go - barring a V8, of course :)
>
> A few years ago, turbochargers were the rage - how many cars come from the
> factory with them today, compared to then? When they were the hot ticket,
> superchargers were rare, but now there are several makes available in the
> aftermarket.
>
> Dan Masters,
> Alcoa, TN
>
Dan,
In principle, you are right. According to the law of conservation of
matter
and energy, you can't get something for nothing. However, with the
turbo,
the low end sacrifice is realized because boost does not develop until
the turbocharger spins up to optimum speed (and Temp). Until this
happens,
your 4-banger operates like a normally aspirated engine with a little
lost
power due to the flow restriction of the turbocharger itself.
After that, boost increases, power increases, speed increases, and
unfortunally
sometimes your tickets increase.
With the Supercharger being turned by the crankshaft of the engine (by
some
means-usually a belt), you are using some to the engines output at all
times
to service the Supercharger, thereby reducing the HP available to drive
the
wheels.
That said, as a rule several things can be stated:
1. Turbos are more fuel efficient than superchargers.
2. Superchargers are probably more reliable than toubos (due to the
heat)
3. Because of the number of units built, turbos are less expensive than
SC's
4. Because of how they are attached, Turbos are easier to install than
SC's
5. Because of the nature of the installation, Clearance is usually less
of a
problem than with SC's.
6. Superchargers do not have to be insullated from critical parts the
way
turbos do.
In Short, one must analyze what it is he wants to accomplish and see
which
option with its own set of pros and cons fits the application.
Joe Curry '63 Spit
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