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Old September 7th 2006, 12:29
beetle1303 beetle1303 is offline
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Join Date: Sep 2003
Location: Athens Greece
Posts: 303
as oicdn said, a supercharger is brutal on the bottom end (bearings mostly and bearing seats on the case),
and takes power to make power, that's why the relatively low power gain.

Now if properly designed and mostly calculated, both systems can perform similarly.
That said, IMO(from a longevity point view) a supercharger will be best suited to easy but fast
(linear kind of driving) around town, while the turbo for more spirited driving
(more racy, with many and sudden throttle changes etc)

Both systems can produce high hp and torque numbers. The limiting factor of the turbo will be the flow of the
compressor side
Example:the vag 1.8t when revved hard, above specific rpm the engine losses power before
reaching the limited rpm range. this means that the compressor cannot flow more air (which is produced on the
exhaust side due to higher rpm)

While the limiting factor on the supercharger while be the Continuous Variable Gearbox of the belt.
Because in this kind of application, boost is produced from very low rpm, just over idle when the throttle is
opened. If the gearing of the belt was static (constant), the boost level would rise and blow the engine apart.
There is this smart device called the CVG that reduces the gearing on the charger side of the belt.
The thing is what is the higher and lower gearing achieved and what is the rate of descent ("lowering rate").

If major tuning is going on both systems will require a suitable intercooler (air-air/air-water)
to keep intake charge temps down.

Gearing plays a major role in satisfactory driving performance and if done properly will complement any engine
(NA/Turbo/Supercharger), although the two later systems will need a little wider gearing to properly utilise
their increased torque output. On the other hand if this is overdone a turboed car's performance will suffer
from severe "turbo lag".

Both systems are boost-wise fully customizable, while the turbo offers more versatility in the mounting/routing
aspect of the modification.

My ideal config would be a fully forged 2.0L t4 with a t04 garret ball bearing turbo, custom header, custom manifold, charge cooler (air-water)2 twin throttle bodies, 2 intake plenums and standalone efi system with ignition control
Gearbox...dunno yet something to be able to hold 400hp and 45-50 kg/m
Just my 2 cents...

Aircooled 4ever

1973 1303 going towards GL
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