The Super Charger
The Super Charger
The Different Types
Roots -positive displacement units, which means every rev of the blower pumps out a fixed volume of air, regardless of the blower's rpm. Result is that boost comes on instantly. Most applications will produce full boost at 2000-2500rpm. Boost can be increased or lowered by changing pulley size. Best to under drive larger unit than to overdrive smaller one.
Centrifugal- Most popular type for fuel injected engines. Provides airflow proportional to blower rpm, thus full boost comes as high rpm.
Twin-screw- positive displacement, similar to roots. The difference is that this type uses twin screws instead of lobed rotors to compress air, works best when overdriven.
Properly Sized Intercooler Piping
Each Supercharger and intercooler use a certain amount of air, you should always
try to set up a close ratio of each. One way you have to do this is to have piping that runs from
the intercooler, if chosen to use is properly sized. If your pipes are too large, The smaller piping will mass flow, and
increase velocity. The problem with smaller piping is that it can choke the engine. You must
research this and find a nice medium. The size of the piping a Supercharger uses is not
as delicate as that of the turbocharger, but the velocity must more finely tuned with a
Super Charger. The largest concern with the piping is the length.
A one by one inch pipe will flow thousands of cfm, but if it's 12 inches long it will only flow
a few hundred at most. For the intercooler piping, in general most people use piping that’s 25% larger than
your compressor output. The largest limitations is the throttle body, make sure the
throttle body can keep up with amount of air flowing into the engine.
Picking the right Super Charger
When considering your Supercharger, you must first decide which of the types you would like to have. This will alter the
set up of the unit. Don't pick a Supercharger that is too small or too large. But it is better to under stain a larger unit
that it is to overstrain a smaller unit. Also look at how much boost each of the different units creates on a low, and on
a high boost pulley. The larger and the heavier the pulley is, the slower it spins, which in turn creates less boost.
Information on Super Charger Parts
Waste gate-The waste gate is a valve basically, it senses the boost level and if it is too high, the waste gate will open
and allow some of the excess air through and bypass the compressor, which in turn will slow the blades down. If it senses
it does not have proper boost the waste gate stays closed and no air is bypassed. The waste gate can be either an internal
or external. You must make sure the waste gate is large enough to support any extra air that may be bypassed.
The Intercooler-The intercooler is there for one real reason. To cool down the air that goes through the Supercharger.
The colder the air is, the denser it is. The denser the air is, the more oxygen there is. An intercooler, like a Supercharger
, must be properly sized. When looking into which intercooler to use, try to find out how much air flows through that intercooler so you can achieve
a nice ratio between that and the air flow of the supercharger. Also consider how much pressure is lost by each intercooler.
One advantage with a supercharger is there is instant boost, so the intercooler does not create boost lag since there is none.
The thicker the core, the less air flow to the cooling system. There are also two basic types, the air to water
and the air
to air. Air to Water intercoolers are more common at tracks because they
are more efficient until the water
they use hits ambient temperate, then they drastically loose efficiency. Air to air is far more common, and stays just about as
effective throughout most of the time. If you really want to drag race, spray your intercooler with a fire extinguisher
right before you line up at the track. If you have an air to water, you can put ice in your water reservoir.
Porting-Porting a Supercharger will help beautifully with the performance of your car. By porting the Supercharger,
the air flows more freely and achieves a higher velocity. It also allows more air to pass through the piping at the same time.
Polishing-Do you have that much money? Expect to spend a a few grand more by doing this apparel mod. Not my style.
The Blow Off Valve-The infamous blow off valve, this works by releasing the air the compressor just compressed, so that
it doesn't push against the spinning blades, when you let off the gas. You must tune your blow off valve properly to achieve
that lovely whistle. This basically works the same way as a bypass valve. And yes you can have one on a Supercharger.
To hear some of the bypass and blow off valves on the market: Sounds
