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Kennedy's Dynotune
3165 Niagara Falls Blvd. |
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"Kenne Bell Frequently Asked Questions"
Tech Tips and Frequently Asked Questions Can I change pulleys to increase boost? Are other upgrades needed when I install a supercharger? Why the "big switch" to Kenne Bell? Will a Kenne Bell supercharger decrease my fuel mileage? What kind of performance increase will I get? Why is a Kenne Bell supercharger better than other performance modifications? How much boost can I run on pump gas? How can Kenne Bell use a six-rib belt when other manufacturers use an eight-rib? Do I need an adjustable fuel pressure regulator? What is the most ridiculous aftermarket product? Why is "knock protection" so important and how does Kenne Bell handle this? What about a larger mass-air meter?
We offer the exclusive Kennedy Advantage. When you buy from us we provide free technical support! The support is from a knowledgeable racer/installer and is only a phone call away. In addition, for our supercharger installs we offer free "before and after" Dyno testing. We verify proper operation of your new supercharger system and assure you of a proper air:fuel ratio. This is the best way to get the "performance you want and the reliability you deserve" - a Kennedy exclusive!
A supercharger is the most versatile form of power adder. The power is available "on-demand" at all times, unlike systems such as nitrous oxide. Under light load conditions when the supercharger is not making boost it takes only minimal power to spin the blower. As a result in normal driving gas mileage does NOT decrease. This common myth is just that, a myth. In fact, some of our customers report a slight IMPROVEMENT in fuel economy under highway conditions after a blower installation.
There are two basic types of compressor. The positive displacement type is illustrated by the Kenne Bell "twin screw" supercharger. With this type of compressor a fixed volume of air is delivered per revolution of the supercharger. The main advantage over other types is that full boost is available from just off-idle all the way to the redline. This makes a Kenne Bell (or other positive displacement blower) ideal for street performance cars or trucks/SUV's. Vehicles used for towing really come alive with this type of supercharger. The added torque makes accelerating, passing, and hill-climbing effortless and expands the safe operating envelope, especially at high altitude. We have also been very successful using this type of blower in the drag racing environment. To read about one of our shop cars utilizing a Kenne Bell supercharger follow the link to Joe Zito's Water Injected Wonder. To learn more about the theory and application of supercharging, see our Superchargers page.
Can I Change Pulleys to Increase Boost? Yes, of course you can. A smaller supercharger pulley (or a larger crank pulley) will increase the speed of the screws which will generate more boost. Typically, each 1/8" decrease in pulley size will increase boost by approximately one pound. Use caution if you have a stock motor - while the supercharger is capable of providing more boost, the motor may not be able to handle the increased power. Various systems may need to be upgraded (see below). We can provide the components you need to handle higher boost, just ask.
What Other Upgrades are needed to Install a Supercharger? Our kits come complete with all of the parts you need to successfully use your new supercharger. If you want even more power you may need to upgrade various components. The Kenne Bell Boost-a-Pump is an extremely effective method for increasing the capacity of your fuel system. To see the details visit the Boost-a-Pump page. The Kenne Bell Boost-a-Spark does the same thing for the ignition system. One of our custom Kennedy's Water Injection Systems is another upgrade that can add even more power to the impressive gains from one of our supercharger kits.
Can I Use "Pump" Gas With My Supercharger? Our kits are designed to run on widely available commercial premium unleaded fuels. If you have increased boost or have made other modifications that increase horsepower you may need higher octane fuel and/or retarded timing to avoid detonation. This is especially true on motors that have been modified for a higher compression ratio. Please call us to discuss your needs and we will advise you. We know superchargers and can help!
Why the "big switch" to Kenne Bell? Kenne Bell believes that a well designed centrifugal supercharger can be a good, reliable product that deliver the peak boost they advertise. The philosophy at Kenne Bell is not to knock their competitors but to talk about the benefits of the twin-screw supercharger. As a prominent Kenne Bell distributor has said "if everyone could test drive a centrifugal and then a Kenne Bell, the decision would be hands down......Kenne Bell!" As stated by Motor Trend "...everyone loves to quote peak horsepower and torque numbers, but the true measurement of an engine's output is how much power it produces across its' operating range..."
Does the supercharger decrease my fuel mileage? Not under normal driving conditions. However, if you use the boost it will, of course, use more fuel. You can't make power without fuel.
What kind of performance increase can I expect from my Kenne Bell Supercharger Kit? Approximately 30-50%. Check out the individual catalog listings.
Why is a supercharger better than other performance modifications? A Kenne Bell Supercharger is by far the best performance value of all. You can spend more money on exhaust, headers, cool air, chip, cam etc. and not get anywhere near the performance you would from the supercharger kit. Besides, the OEM's aren't leaving much HP - if any - in the above mentioned products. That is precisely why they are now resorting to supercharging for big performance gains. See our "Bolt on parts vs. supercharger" comparison that Super Ford Magazine did on a Mustang. Pay particular attention to the low and mid range gains with the supercharger.
What parameters determine how much boost my engine can run on 92 octane? Good question. One of the top 3 most commonly asked. Variables include the following. COMPRESSION RATIO - Lowering the compression ratio allows the engine to run more boost with the same octane. For example, 8.0:1 vs. 9.5:1 can tolerate another 3psi. 3psi gives 38HP. The 1.5 lower CR loses 3% (2% per point) or around 9HP in a 300HP engine. That nets 29HP (38-9=29). Now you know why OEM's use low compression ratios on supercharged engines.
AIR CHARGE TEMP - The supercharger itself determines how much boost the engine will accept. Some superchargers require an intercooler. Others, such as the Kenne Bell, don't need intercoolers because the discharge air temp is cooler. 1 psi boost increases supercharger air discharge temperature 10°-20°, depending on supercharger type. A 6 psi "rated" kit usually requires 8 psi "total" boost (+2psi to overcome inlet and outlet losses). Consider two 8 psi superchargers: 8x10=80°, 8x20°=160°. The 160° supercharger should use an intercooler. An air to water intercooler will lower that 160° to around 80° (160°-80°=80°) or the 80° temperature of a more efficient supercharger without an intercooler.
BOOST - Both higher compression ratios and boost increase cylinder pressure and demand higher octane fuels to eliminate detonation. Fuel octane determines the amount of boost an engine will accept. Kenne Bell runs 6-7 psi on all our Ford, GM, Chrysler and most other kits with our Twin Screw superchargers. One octane will support one psi of boost. Example: If fuel octane is 94 or you add a can of NOS Octane Booster you can typically run 8 psi.
IGNITION TIMING - Retarding ignition timing will allow the engine to run more boost but not without a penalty. 4° retard=16HP.
AIR FUEL RATIO - You can't make horsepower without fuel. Richer air fuel ratios reduce power but permit higher boost levels on a given fuel octane. Leaner ratios make more power but need lower boost so a lean mixture with high octane makes the most HP. We thoroughly understand all the parameters of supercharging. Supercharger kit tuning demands ignition timing, air fuel ratio, fuel octane, boost, compression ratio, discharge temperature and supercharger parasitic losses all be carefully considered in the design.
1 . Lean fuel mixture 2. low octane fuel 3. excess boost 4. lack of fuel 5. advanced ignition timing 6. vacuum leak 7. "hot" spark plugs 8. overheated engine 9. excessive inlet temperature (under hood filter).
Why does Kenne Bell use a 6 rib belt to drive the supercharger and others use an 8 rib belt? Because our Twin Screw supercharger has less parasitic loss than others and therefore requires less HP to drive - which means the engine develops more HP with a Kenne Bell.
Do I need an adjustable fuel pressure regulator? Unless you're playing with an '86-'93 Mustang, don't bother.
What is the most ridiculous aftermarket product? Hands down, it's the "little intake fans" and the "throttle body spacers" with the bore grooves. Right there on the list has to be those "underhood exposed filters" that suck in 200° underhood air instead of ambient (70°- 100° air from the fenderwell). 10° air temp rise is -1% HP. That's how dynos are calibrated for temperature changes. Does anyone really believe that all those OEM manufacturers designed expensive plastic inlet systems - for the last 20 years - that pull cool air from the fenderwell, hood or grill because they didn't have anything else to spend their money on? Then there's those "factory calibrated" mass air meters that do not use a chip or re-calibrated processor with oversize injectors. They unwittingly reduce the voltage signal to the mass air meter to compensate for the larger injectors at WOT but they neglect all the drivability issues. The result is over advancing timing, lean mixtures, detonation, surging, bucking etc.
Why is knock protection so important? Does Kenne Bell supply "knock protection" with their kits? Knock (detonation) can destroy your engine if it is not negated. Suppose your wife or a friend unknowingly fills your tank with 87, or you get a "bad batch" of gas, the engine overheats, someone installs a pulley that raises supercharger boost, the wrong spark plug heat range is installed (too hot) or a vacuum leak develops and the engine leans out. That's when an engine needs knock protection. No one in this industry has more experience than Kenne Bell with knock protection. We call it "detection/protection." There must first be "detection" and then automatic "protection" from detonation. Protection from potentially engine damaging detonation (knock, ping) is our #1 priority at Kenne Bell. We would NEVER sell a kit for a '96 and later Ford, GM or Chrysler application without knock protection. We've led the pack for years in this department. The turbocharged Buick V6 utilized knock protection way back in 1978! GM and Ford have used knock protection since the 90's. We modify and/or expand the OEM protection in our supercharged calibrations. Most Chrysler engines except for the late 3.7 Jeep V6 and PT Cruiser do not use knock detection. Kenne Bell engineered our own knock system for the 5.3, 5.9 and 4.7 Chrysler products. We are the only kit manufacturer to include this important feature with all our kits.
Does Kenne Bell sell a mass air meter? Yes, we offer only one - a 90mm for Mustangs and the 4.6/5.4 trucks and SUV's. They are sold only with a chip and will increase horsepower and torque on ANY Ford V8 or your money back. How much of an increase depends entirely on the HP (airflow) of the engine - or how much of a restriction the meter is creating. Expect 5-50HP. Always use at least 80mm.
By far our number one complaint. A larger mass air meter theoretically makes more HP if the one you have is too small for the engines air flow. If it isn't, the HP increase is "0." Factory engineers spend considerable time calibrating their engines to a specific computer. Then someone "just sticks on a new meter?" No, No, that's not the way it's done. The computer must be recalibrated and never, never, ever install a meter and larger injectors without re-calibrating the computer or installing the proper re-calibrated!
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