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Why has
supercharging become so popular? |
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There are a number of reasons. First, an
efficient supercharger system can produce
yesterday's musclecar performance using today's
low-octane gasoline, with exceptional
reliability and minimal impact upon fuel
economy. Second, superchargers have developed to
the point that they are easy to install and
simple to maintain, especially when compared to
pulling, rebuilding and fine-tuning an engine.
Finally, unlike nitrous oxide, which requires
frequent repurchase of fuel, once a supercharger
is installed there is no more expense or hassle
associated with performance. In short,
supercharging delivers exceptional performance
with little of the hassles traditionally
associated with high performance. Centrifugal
supercharging is the only way to make a reliable
500, 600, 700+ horsepower on otherwise stock,
daily driven V-8's. |
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How does
supercharging increase engine performance? |
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Superchargers achieve performance gains by
increasing the density of the air/fuel charge
within the combustion chambers of an engine.
This increase in density is achieved by forcing
additional amounts of air (beyond the amount of
air that normal atmospheric pressure would force
into the engine) at the lowest temperature
possible. CFM measures the volume of air that an
engine is flowing, while MAF (mass air flow)
also factors in the temperature of the air
charge, since a cooler charge is more dense and
therefore more powerful. So in more technical
terms, supercharging increases both the
volumetric efficiency of the engine and the mass
air flow through the engine to produce gains in
both horsepower and torque. |
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How much
horsepower will a supercharger add to my engine? |
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Although some manufacturers claim a specific
horsepower increase, superchargers actually add
horsepower as a percentage gain (percentage of
an atmosphere). Assuming an engine with a
compression ratio of around 9:1 running pump
gas,if a supercharger gives your engine 14.7 psi
of boost (another atmosphere) that will
essentially double the output of your engine,
everything else being equal. After adjusting for
thermal and mechanical energy transfer, if an
efficient centrifugal supercharger is generating
7.5 psi (approx. 1/2 an atmosphere), you will
see around a 35-40% gain in horsepower and
torque at your non-supercharged maximum
horsepower rpm. If detonation forces you to use
an ignition/timing retard system, you will of
course see less of a gain because backing off
several degrees of timing will greatly reduce an
engine's power output. At higher boost levels,
the heat generated by compressing air will
produce diminishing returns as the boost is
increased, although the use of intercooling or
racing fuel can avoid this scenario of
diminishing returns. Assuming the use of
intercooling to run higher boost levels while
maintaining reliability, a 100% increase can
generally be achieved at around 17 psi on an
engine with 9:1 compression running pump gas.
The gains in horsepower and torque delivered by
each ProCharger system can be found on the price
list as well as on the "ProCharger
Systems" page
within this site |
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Are ProCharger
systems 50 state legal? |
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Most ProCharger systems are 50 state legal. For
information on the regulatory status of a
specific ProCharger system, please consult the
price list which is supplied with every product
literature mailing. |
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What type of
fuel do I need with a supercharged automotive or
truck engine? |
The primary issues that determine the type of
fuel needed are whether the engine is
fuel-injected or carbureted, the compression
ratio of the engine, and whether or not the
supercharger system is intercooled.
For Intercooled ProCharger EFI/TPI applications
with compression ratios less than 9.5:1, boost
levels of 14-17 psi can be safely run with full
timing on pump gas, and will produce horsepower
gains of 75-100% (depending upon the boost level
and the motor specifications). For 9.5:1 EFI/TPI
applications running without an intercooler,
boost levels above 5 psi will require the use of
ignition/timing retard on pump gas, and will
produce horsepower gains of 35-45%. Boost levels
above 12 psi should generally be avoided even
with racing fuel on a 9.5:1 motor. Of course,
lower compression motors will be able to run
more boost, and higher compression motors should
run less boost, everything else being equal. All
Intercooled ProCharger systems for street
applications are designed to allow the use of
pump gas with full timing and will not affect
daily drivability.
For carbureted motors, the rules are slightly
different. Carburetors deliver the vast majority
of fuel in a liquid state, and as this raw fuel
atomizes from liquid to gas, a chemical state
change actually occurs. Due to this endothermic
reaction, which draws heat and cools the
incoming air, a carbureted motor can safely
handle more boost than a comparable EFI/TPI
motor. For carbureted engines with compression
ratios of 9:1 or less and boost levels in the
8-14 psi range, pump gasoline works very well.
Compression ratios of 10:1 and higher require
lower boost levels, higher octane fuel,
intercooling, or some combination of the above.
Compression ratios in the 7or 8:1 range can
usually handle 12-20 psi on pump gasoline. |
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What is
detonation, and how can it be controlled? |
Detonation, or engine knock, occurs simply when
fuel pre-ignites before the piston reaches
scheduled spark ignition. This means that a
powerful explosion is trying to expand a
cylinder chamber that is shrinking in size,
attempting to reverse the direction of the
piston and the engine. When detonation occurs,
the internal pneumatic forces can actually
exceed 10x the normal forces acting upon a
properly operating high performance engine.
Detonation is generally caused by excessive
heat, excessive cylinder pressure, improper
ignition timing, inadequate fuel octane or a
combination of these. Of the previous, excessive
heat is usually the culprit. As an engine is
modified to generate more power, additional heat
is produced. Today's pump gas will only tolerate
a finite amount of heat before it pre-ignites
and causes detonation. Although forced induction
engines usually produce far less heat than
comparable naturally aspirated high compression
engines, the cylinder temperatures in
intercooled engines are radically cooler yet. It
is rarely boost that causes detonation, just
unnecessary heat. An intercooler is such a
natural solution for forced induction, that in
almost every sophisticated application,
intercooling is part of the package.
For engines that are experiencing detonation
problems, the primary options are the use of
ignition/timing retard systems, higher octane
fuel, or intercooling. While ignition retard
systems can be helpful in certain situations,
they can also greatly reduce the horsepower
output of an engine, as any reduction in timing
will reduce horsepower. And while a reduction in
timing can save a motor from detonation, the
excessive heat which was causing the detonation
is still present. Intercooling, on the other
hand, actually removes the heat which causes
detonation, and allows higher boost levels to be
safely run with full timing on pump gas. This
produces the maximum benefit in terms of both
horsepower gains and engine protection, without
any additional maintenance or hassle. |
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How will a
supercharger affect my fuel economy? |
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Although roots superchargers have significant
parasitic load and do dramatically decrease fuel
economy, centrifugal superchargers will yield
approximately the same fuel economy as normally
aspirated engines, under normal throttle
conditions. When racing, however, fuel enconomy
will decrease given the supercharged engine's
ability to consume additional fuel and produce
additional horsepower. |
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What type of
warranty is provided with ProCharger systems? |
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Most ProCharger systems are covered by a 1 year
warranty, although a 3 year extended coverage
policy is available for many automotive and
truck applications. For information on the
warranty coverage for a specific ProCharger
system, please consult the price list which is
supplied with every product literature mailing. |
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How long does
it take to install a ProCharger system? |
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Most ProCharger systems can be installed in 8-10
hours with simple hand tools. All ProCharger
street supercharger systems are engineered to
the highest quality standards, with no need for
cutting of body panels or alterations to stock
hardware. Race-only products and ProCharger
systems with certain higher-performance
upgrades/options may require some minor vehicle
modification. Please call to speak with a
technician if you have any questions about your
specific application. |
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Will a
supercharger shorten the life of my engine or
drivetrain? |
That is a very subjective question, as the
manner in which an automobile is driven directly
affects engine life. Assuming a properly tuned
system, proper oil change and engine
maintenance, and similar driving, supercharging
generally will not shorten the life of an
engine, just as is the case with OEM
turbocharging (with proper cooldown for
turbochargers. A cooldown period after driving
is not necessary with supercharging). This is
especially true of centrifugal supercharging,
which generates boost in line with engine rpm,
unlike roots and twin screw blowers, whose low
rpm boost can place additional strain on the
engine and drive train.
Superchargers can be used with automatic or
manual transmissions and will not increase
transmission wear under normal driving. When
racing, however, the additional torque provided
by supercharging will place additional load on
the transmission, especially when increased
traction is present, such as with slicks. This
impact is minimized when the boost increases
with engine rpm, as is the case with centrifugal
supercharging and turbocharging. |
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