| Why has supercharging become so popular? |
| 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. |
| How does supercharging increase engine performance? |
| 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. |
| How much
horsepower will a supercharger add to my engine? |
| 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 |
| Are ProCharger systems 50 state legal? |
| 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. |
| 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. |
| 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. |
| How will a supercharger affect my fuel economy? |
| 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. |
| What type of warranty is provided with ProCharger systems? |
| 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. |
| How long
does it take to install a ProCharger system? |
| 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. |
| 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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