ok i got a few questions about ways to get the boost. Dont laugh at me please lol. Ok i know that turbos are put on our cars and they do great but i have never seen a supercharger in any four banger motor. is it because you have to drop the compresion to put a good sized supercharger on the motor? why is the reason no one had been able to answer this question for me. Just wondering why it has not been done yet.

 

The new Chevy Cobalt puts a supercharger right inside of the intake plenum.

Also new Saturn.

The Mini 1.5 (?) supercharges.

These are all 4 bangers.

Dt

 

ok but what i am saying is why do people turbo cars like ours and not supercharge them? Is there some kinda downfall?

 

Well a supercharger unlike a turbo has no ways of making more boost, you simply cant tell your boost controller more boost. You can bend the fins on the inducer wheels though, good for 1 or 2 psi more maybe. You could also try different pull sizes too.

 

The biggest reason that most 4 cylinders have turbos instead of superchargers is becasue turbos generate a lot more heat, and more heat is harder to controll if your engine compartment is small, but you can always put a supercharger in a eclipse (if you have the space). There is also a lot more wear and tear on the engine with superchargers.

 

alright supercargers do have a way of making more boost with most charger i see on trucks you can put a smaller pulley and get +25hp than you can put a bigger pulley and get +150hp. it is a pain but it can be adjusted.
I would dissagree with that because a supercharger is made for a lower compression motor and as we all know the lower the compression the less wear is on the motor.
also if they a turbo generates so much more heat why are they the dominate source? superchargers have no lag and they are alwase boosting the motor so why do people not use them?

 

According to Merriam-Webster's dictionary, a supercharger is defined as:
"a device (as a blower or compressor) for pressurizing the cabin of an airplane or for increasing the volume air charge of an internal combustion engine over that which would normally be drawn in through the pumping action of the pistons".
A turbocharger is defined as:
"a centrifugal blower driven by exhaust gas turbines and used to supercharge an engine".


According to Webster's, a turbocharger is included in the definition for superchargers - it is in fact a very specific type of supercharger - one that is driven by exhaust gasses. Other superchargers that do not fall into this category - the kind that we are all used to hearing about - are normally driven directly from the engine's crankshaft via a crank pulley. So in reality, it is not fair to compare all superchargers to turbochargers, because all turbochargers are also superchargers. For the purpose of this discussion, however, a supercharger will be considered all superchargers that are are not driven directly by the engine, while turbochargers will be considered all superchargers that are driven by engine exhaust gasses.

Similarities



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Both superchargers and turbochargers are forced induction systems and thus have the same objective - to compress air and force more air molecules into the engine's combustion chambers than would normally be allowed at atmospheric pressure here on Earth (14.7 psi at sea level). The benefit of forcing more air molecules into the combustion chambers is that it allows your engine to burn more fuel per power stroke. With an internal combustion engine, burning more fuel means that you convert more fuel into energy and power. For this reason, supercharged and turbocharged engines normally produce 40% to 100%+ more power (depending on the amount of boost - check out our horespower calculator) than normally aspirated engines.

How They Work


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A supercharger is mounted to the engine and is driven by a pulley that is inline with the crank (or accessory) belt. Air is drawn into the supercharger and compressed by either an impeller (centrifugal-style supercharger), twin rotating screws (screw-type supercharger), or counter-rotating rotors (roots-type supercharger). The air is then discharged into the engine's intake. Faster crank speed (more engine rpm) spins the supercharger faster and allows the supercharger to produce more boost (normally 6 to 9 psi for a street vehicle). Typical peak operating speeds for a supercharger are around 15,000 rpm (screw-type and roots style superchargers) and 40,000 rpm (centrifugal-style superchargers).

A turbocharger operates in much the same way as a centrifugal (internal impeller) supercharger, except it is not driven by pulleys and belts attached to the engine's crank. A turbo is instead driven by exhaust gasses that have been expelled by the engine and are travelling through the exhaust manifold. The exhaust gas flows through one half of the turbocharger's turbine, which drives the impeller that compresses the air. Typical operating speeds of a turbocharger are between 75,000 and 150,000 rpm.

Head to Head Comparison


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Now it's time to evaluate the turbocharger versus the supercharger according to several important factors.

Cost
The cost of supercharger and a turbocharger systems for the same engine are approximately the same, so cost is generally not a factor.

Lag
This is perhaps the biggest advantage that the supercharger enjoys over the tubo. Because a turbocharger is driven by exhaust gasses, the turbocharger's turbine must first spool up before it even begins to turn the compressor's impeller. This results in lag time which is the time needed for the turbine to reach its full throttle from an intermediate rotational speed state. During this lag time, the turbocharger is creating little to no boost, which means little to no power gains during this time. Smaller turbos spool up quicker, which eliminates some of this lag. Turbochargers thus utilize a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses boost pressure, and if it gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down..
A Supercharger, on the other hand, is connected directly to the crank, so there is no "lag". Superchargers are able to produce boost at a very low rpm, especially screw-type and roots type blowers.

Efficiency
This is the turbo's biggest advantage. The turbocharger is generally more economical to operate as it as it is driven primarily by potential energy in the exhaust gasses that would otherwise be lost out the exhaust, whereas a supercharger draws power from the crank, which can be used to turn the wheels. The turbocharger's impeller is also powered only under boost conditions, so there is less parasitic drag while the impeller is not spinning. The turbocharger, however, is not free of inefficiency as it does create additional exhaust backpressure and exhaust flow interruption.

Heat
Because the turbocharger is mounted to the exhaust manifold (which is very hot), turbocharger boost is subject to additional heating via the turbo's hot casing. Because hot air expands (the opposite goal of a turbo or supercharger), an intercooler becomes necessary on almost all turbocharged applications to cool the air charge before it is released into the engine. This increases the complexity of the installation. A centrifugal supercharger on the other hand creates a cooler air discharge, so an intercooler is often not necessary at boost levels below 10psi. That said, some superchargers (especially roots-type superchargers) create hotter discharge temperatures, which also make an intecooler necessary even on fairly low-boost applications.

Surge
Because a turbocharger first spools up before the boost is delivered to the engine, there is a surge of power that is delivered immediately when the wastegate opens (around 3000 rpm). This surge can be damaging to the engine and drivetrain, and can make the vehicle difficult to drive or lose traction.

Back Pressure
Because the supercharger eliminates the need to deal with the exhaust gas interruption created by inserting a turbocharger turbine into the exhaust flow, the supercharger creates no additional exhaust backpressure. The amount of power that is lost by a turbo's turbine reduces it's overall efficiency.

Noise
The turbocharger is generally quiter than the supercharger. Because the turbo's turbine is in the exhaust, the turbo can substantially reduce exhaust noise, making the engine run quieter. Some centrifugal superchargers are known to be noisy and whistley which, annoys some drivers (we, however, love it!)

Reliability
In general, superchargers enjoy a substantial reliability advantage over the turbocharger. When a a turbo is shut off (i.e. when the engine is turned off), residual oil inside the turbo's bearings can be baked by stored engine heat. This, combined with the turbo's extremely high rpms (up to 150,000rpm) can cause problems with the turbo's internal bearings and can shorten the life of the turbocharger. In addition, many turbos require aftermarket exhaust manifolds, which are often far less reliable than stock manifolds.

Ease of Installation
Superchargers are substantially easier to install than a turbos because they have far fewer components and simpl

 

Holy crap get435...that's like a freakin book...
I honestly thought you wrote all that until i read the end... oh well..

Anyways, the 87-89 mr2 came supercharged also. So did the Previa minivan. Just thought i'd throw those into the mix....being a toy fan and all...

 

turbos more fun and has more potential. you can easily supercharge something but look at all the fastest cars out there, from muscle cars to imports, what will you find? turbo...

 

Also, a lot of early enthusiasts saw the turbocharger as providing "free" power, being that they operate from expelled exhaust gasses. The supercharger will always have parasitic loss, no matter what type or how large/small they are.

Reason's why you would put a supercharger on a car then? Well, instant power and they are a bit more stable than a turbo(think boost creep and boost spike situations). Although there are electronics to control that, if the electronics fail, then the tubocharged engine might have some serious problems. The only way to increase boost in any way on an SC engine is to change the pulley. If the pulley is damaged, the SC just doesn't work, a rather simple insurance.