FAQ's

What about bypass valves? During non boost driving, bypass valves reduce NOX emissions and allow the supercharger to operate at a cooler temperature by circulating compressed air (boost) back to the inlet. If the supercharger is located in front of the throttle body (blow through) as in the case of centrifugals, and the throttle body closes at high rpm, the compressed air has no place to go. The resulting back pressure and surge can destroy the supercharger. Since the centrifugal is driven by the engine crankshaft, the higher the rpm the greater the air flow and more severe the problem. Assuming the inlet air temperature into the engine is 100°, the boost temp must be added making 170° the temperature the engine sees under 7 psi boost conditions (7 psi X 10° = 70° + 100° ambient = 170°). In some cases the elevated air charge may not be desirable. For example, NOX emission increase with temperature. Since the bypass valve eliminates most of the work of compressing air, the supercharger's parasitic losses are also reduced under normal non boost driving conditions. During idling or part throttle non boost operation, the bypass valve is held "open" by engine vacuum (10"-22"Hg). This allows the compressed air in the supercharger to re-circulate or bypass to the inlet thereby lowering the temperature. When the throttle is opened and the supercharger is called on to produce boost, the bypass valve closes off the re-circulating air thereby forcing all the boosted air into the engine. Positive displacement superchargers (Twin Screw and Roots) are positioned downstream of the throttle body (suck through). If the throttle body is closed at high rpm, there is no surge problem as with centrifugals (blow through). Centrifugals react against the closed throttle blade(s). This deceleration won't harm the supercharger in any way. However, when coupled to an "idiot underhood filter" that sucks in 200° air (the equivalent to another 20 psi boost), the heat may be a problem for any supercharger - centrifugal, Roots or Twin Screw. We've said it before . . avoid exposed underhood filters in supercharged and non supercharged engines - unless you think that your engine likes all that hot air.

If I add up all the HP claims in the ads I can end up with as much HP with bolt ons. Why Supercharge? Yes, and there is a tooth fairy. Any time, on our dyno, with a magazine writer in attendance. We'll even install the parts for free. Headers 25HP + Exhaust 25HP + Throttle Body 25HP + Meter 25HP + Ram Air 25HP = 125HP - and we haven't covered all of the bolt ons. Let's be serious. Think about it. It's ridiculous to assume that any OEM engineer(s) were brain dead enough to leave 125HP in any modern day vehicle. You would need a block under the gas pedal, a rag in the throttle body and a pickle in the exhaust pipe to kill 125HP! Isn't the lack of HP potential precisely why the OEM's are turning to supercharging? Of course it is.

If my engine has a lot of miles on it, is it safe to install a supercharger kit? Mileage is not much of a concern. There is relatively little wear in modern day engines. The mandated unleaded fuel and improved lubricants have contributed significantly to improving longevity. Since 1978, there has been numerous supercharged and turbocharged engines offered by the OEM. They carry the same mileage warranty as their naturally aspirated engine counterparts. We have many customers installing our kits on engines with 50,000, 75,000 and 100,000+ miles.

Can you give me a simple overview of engine performance as related to boost? All the information below is based on an engine with a volumetric efficiency of 100% so we can discount the benefits of cams, ignition timing, heads etc. as the goal of these products is to increase the VE - let's say from 75% to 100%. Other factors also enter into the equation but for discussion purposes it will suffice. God's atmosphere weighs 14.7 psi. It is this pressure that forces air into an engine when the pistons create a vacuum. Every one (1) psi of this pressure amounts to approximately 6.8% The atmosphere weighs less at higher altitudes (approx. .5 psi per 1000') as it's mass is less. Lose 1 psi from 2000' elevation and power drops 6.8%. If the inlet system loss through friction and restriction is 1 psi (2" Hg) the power loss is 6.8%. If the exhaust restriction is 1 psi, there is also a power loss. If the boost is raised 1 psi with a supercharger, the power increase can be 6.8%. If you bolt on a product that does not reduce inlet or exhaust restriction, there will be no power increase even though the engine noise is higher.

I'm confused about cfm and HP. Can you clarify? Try this. 1HP=1.5 cfm. Air capacity or cubic feet per minute (cfm) is a product of 1. rpm and 2. engine displacement (cubic inches). Theoretical max engine CFM at 100% VE = (rpm x displacement) / 3456
Example (5000 x 350) / 3456 *If your engine is 75% VE (75% X 506 = 379 cfm) it uses 379 cfm and produces 252 HP. Now let's increase the rpm potential with a cam, inlet manifold, headers, exhaust etc. to 6000 rpm (20%). 607/1.5 cfm = 405HP 75% x 405HP = 303HP. You've made 51 more "peak" HP (20%), killed some low end and mid range with the cam etc. and because of the higher rpm inertia loads, your crank, bearings, rods, pistons etc. 40%! With the supercharger, you enjoy 40% more HP and torque everywhere, not just at peak rpm, without over stressing the engine components. The supercharger doesn't require the engine rpm be increased. Instead, the boost makes the engine think it's 40% bigger. Therein is the advantage of supercharging.

If I buy a "9 psi kit," will it develop a full 9 psi boost under all conditions? Some will and some won't. Ours will. There's only one reason you buy a supercharger kit - for the boost. Here's how you test it. Floor the throttle from a dead stop and look at the boost gauge. If it reads 9 psi you should be happy (9 psi X 7% = 63% more HP and torque). You've got what you paid for. If the boost only reads 1-2 psi (2 X 7% = 14% more HP and torque) are you happy with that particular 9 psi kit? This lack of boost is commonly referred to as "boost lag." That is the basic difference between positive displacement (Twin Screw) and centrifugal supercharger kits.

What is "boost lag?" As the name implies, the supercharger or turbocharger does not produce the advertised or rated boost until the engine revs into a higher rpm range, usually the maximum or peak rpm.

How much HP and torque can I expect from a supercharger kit? This is answered in more detail elsewhere but typically 6-8% per psi boost depending on the engine and inlet component size.

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