difference between turbo and supercharger

n00b on demand · #1 03-16-2006, 07:55 AM

Whats the difference? I know turbo's have lag whereas superchargers dont but what are the main differences. My cousin has a chrysler crossfire and wanted to know.

Ricochet · #2 03-16-2006, 08:08 AM

Turboes are exhaust gas driven, meaning the gasses pushed out through your header pushes a turbine on one side of the turbo. On the other side is another turbine that sucks in and compresses the air going into your intake. There is lag because there isn't much exhaust pressure at low rpms.

Superchargers are belt-driven. The crank belt spins the turbines which compress the air into the intake. There is no lag with superchargers because the turbine spins directly proportional to your crank shaft.

Think of turbo lag like blowing on a fan, it would take a second to get it moving, especially with larger turboes. Now think of supercharger lag like having a little motor hooked up to that fan, it gets right up and moving.. but won't have much of a top end.

A wastegate on a turbo "opens up" at a certain psi to leak the rest of the boost out. A boost controller tells the wastegate when to open up.. earlier for low boost, later for high boost. A smaller pulley on a supercharger spins faster making it suck in more air, which is more boost. Superchargers are more reliable because turboes get very hot (the exhaust gasses passing through them).

There is much more to it but that's pretty much the gist of it.

n00b on demand · #3 03-16-2006, 08:40 AM

Wow i learned alot from that post. Thanks!

So then why don't more people go the supercharger route instead of going turbo? I know people can go twin turbo...can you go twin supercharged? And my cousin said his crossfire has dual intakes....i dont know if thats true since i dont have the car in front of me...would that mean he would have to go twin turbo? Thanks for the input.

Ricochet · #4 03-17-2006, 05:53 AM

Quote:

Originally Posted by n00b on demand

Wow i learned alot from that post. Thanks!

So then why don't more people go the supercharger route instead of going turbo? I know people can go twin turbo...can you go twin supercharged? And my cousin said his crossfire has dual intakes....i dont know if thats true since i dont have the car in front of me...would that mean he would have to go twin turbo? Thanks for the input.

Superchargers aren't as upgradable as turbos, you can only go so small with aftermarket pulleys, but it depends on what kind of blower it is.. and no there aren't any twin superchargers. Pretty much every car only has one intake and superchargers themselves can be pretty large physically. As for the dual-intaked Crossfire I think he means heads.. Every V6 and V8 has two heads but are fed through a single intake/throttle body on top of the engine.

On a V6 yes you can go twin turbo, but each turbo would have to be small because each one is only feeding 3 cylinders. You could also have one huge turbo to feed all 6 though. There would be some lag, but at mid/high rpms there would be a lot more power potential where two smaller turbos would reach peak psi earlier. It really depends widely on how the car is setup and what it's going to be used for.. I've seen twin turbo V8's with two big turbos each feeding 4 cylinders, but the engines were totally built.

n00b on demand · #5 03-17-2006, 06:29 AM

Thanks Brian. This is a pic of his engine bay taken off of a dodge site....

SilverSpear · #6 03-17-2006, 07:10 AM

But there is a concept between the two that I am not getting straight. You all know that when the A/C pump is ON, you feel the engine less responsive, like if you are pushing gas while overloading the car with 4 passengers. When you turn the A/C OFF, the car is in "relief" with better responsiveness. This happens because the A/C pump is activated with the engine rotation power. The supercharger uses the same concept, it takes power from the engine through the belt but on the other hand it pumps air back into the engine, hence providing power. But still the engine is stressed from that additional pump he has to activate even though it is providing more compression.

As for the Turbo, it is getting its power from the exhaust, so there is no stress on the engine except for that additional compression that the turbo is providing over the pistons.

Is my statement about the Supercharger above, correct? Then the engine will be "USED" more than the turbo engine.

And what are the Pros and Cons of each one? Let me be the first to state them:

Supercharger:
Pros: No lag at low rpms, and quick responsiveness.
Does not need continuous maintenance as the turbo does

Cons: higher fuel consumption from being continuously turned on with the engine
Power vanishes at high rpms.
Consumes engine life more than a turbo engine.
Belt driven, so it is gaining power and loosing power also in the same time.

Turbo:
Pros: Lower fuel consumption than the supercharger.
Power increase at high rpms.
Consumes engine life less than the supercharger.
Gains power from exhaust gas and not directly from the engine, hence the engine is gaining without a loss.

Cons: no power at low rpms, in other words, a lag.
Needs turbo maintenance each 30K miles (I think)

What is the best alternative? Am I correct above? and what about the electric blower, it can consume energy from the battery and still provide the desired output somewhere between the turbo and and the belt driven supercharger?

SilverSpear · #7 03-17-2006, 07:12 AM

I bet that the engine you posted is a mercedes V8 engine inserted inside a dodge shell...

Ricochet · #8 03-17-2006, 09:02 AM

Quote:

Originally Posted by SilverSpear

What is the best alternative? Am I correct above?

What you're talking about is irrelivent. You'll lose maybe 5 crank horsepower in parasitic loss to gain 70-100 horsepower from a blower. Do the math. And no, power doesn't "vanish" at high rpms, it just flatlines at wot at low rpms and boost stays the same the entire rpm curve.

Quote:

Originally Posted by SilverSpear

and what about the electric blower, it can consume energy from the battery and still provide the desired output somewhere between the turbo and and the belt driven supercharger?

Don't even bring up that piece of ****. It's expensive, has to charge up to use, gives minimal gains, and our cars already have electrical load problems..

oab_au · #9 03-20-2006, 05:43 PM

Quote:

Originally Posted by SilverSpear

But there is a concept between the two that I am not getting straight. You all know that when the A/C pump is ON, you feel the engine less responsive, like if you are pushing gas while overloading the car with 4 passengers. When you turn the A/C OFF, the car is in "relief" with better responsiveness. This happens because the A/C pump is activated with the engine rotation power. The supercharger uses the same concept, it takes power from the engine through the belt but on the other hand it pumps air back into the engine, hence providing power. But still the engine is stressed from that additional pump he has to activate even though it is providing more compression.

As for the Turbo, it is getting its power from the exhaust, so there is no stress on the engine except for that additional compression that the turbo is providing over the pistons.

Is my statement about the Supercharger above, correct? Then the engine will be "USED" more than the turbo engine.

And what are the Pros and Cons of each one? Let me be the first to state them:

Supercharger:
Pros: No lag at low rpms, and quick responsiveness.
Does not need continuous maintenance as the turbo does

Cons: higher fuel consumption from being continuously turned on with the engine
Power vanishes at high rpms.
Consumes engine life more than a turbo engine.
Belt driven, so it is gaining power and loosing power also in the same time.

Turbo:
Pros: Lower fuel consumption than the supercharger.
Power increase at high rpms.
Consumes engine life less than the supercharger.
Gains power from exhaust gas and not directly from the engine, hence the engine is gaining without a loss.

Cons: no power at low rpms, in other words, a lag.
Needs turbo maintenance each 30K miles (I think)

The supercharger takes power from the engine when pumping boost. When cruising the blower is spinning in a partial vacuum, so it consumes very little power. In fact I have had blower belts break, due to a backfire, and the blower just kept spinning, due to the engine pulling air through it.

The fuel consumption is the same for both, as long as they are driven the same.

Quote
"Gains power from exhaust gas and not directly from the engine, hence the engine is gaining without a loss." Quote.

The old saying " you get nothing for nothing". The turbo does consume power from the engine. To fit the turbo, the existing exhaust system has to be removed and replaced with a short system to power the turbo. So the power that the factory exhaust provided is now lost. The low speed Inertia is not there, or the high speed resonate system is not there. So this must be considered as power taken to drive the turbo.

The other differences are the supercharger has a cooler air output than the turbo, that suffers from heat transference from the turbine side to the compressor side.

The supercharger provides boost at low rpms, but is inefficient above 1.5 atmos boost. The turbo provides little boost below 2500/3000, but can produce boosts in excess of 1.5 atmos.

Harvey.