600rwhp Turbo vs 600rwhp SC?
 

I'm wondering where the differences would show up most.

Anyone?

Torque will come much lower and more flat with a good turbo setup.

Clipped.
"Turbo systems use flow and exhaust pressure instead of a belt driven pulley and are therefore more efficient at generating horsepower and torque.

Boost is easily adjustable with an electronic switch to match your performance needs. No pulleys or belt changes are required.

Turbo systems are quieter when driving around town. Turbo noise isn't heard unless the boost is on.

Turbo systems can increase gas mileage because they make the engine more efficient and don't take power from the engine to make power.

Turbo systems are more reliable than belt-driven superchargers because there are fewer mechanical and moving parts.


Superchargers

Use belts driven by crank shaft to increase boost to the engine. It takes horsepower away from the engine to drive the supercharger.

To change the amount of boost you must change the size of pulley used by the supercharger.

Superchargers in general are noisy because the gear drive is always engaged, even at idle.

Superchargers generally decrease gas mileage because they are using the engine's power even when the supercharger is not producing boost.

Superchargers can throw belts causing damage to other components in your engine compartment. "

Don't forget to add :

"Turbos will generally cost 50% more than a supercharger at a given power level, are much more complex, require inventive plumbing on a C5 and generate much more heat"

I love turbos - I just can't afford them :D

EG :cheers:

I'm getting a little frustrated hearing people assert that there is parasitic loss with a blower (takes power to turn the belt that turns the blower) and that this doesn't exist with turbos. I know a lot of people say this, including people who are supposed to be experts and should know better, but it's just not true.

"01 2000 Z06", I don't mean to target you with this, 'cause I know you were just quoting.

Granted, a supercharger takes crankshaft horsepower to run. But a turbo does too. The power is just taken in a different way.
When you use a turbo, exhaust manifold pressure goes up. It's the compressed air in the exhaust system that drives the turbine.
So lets say you're under boost, and you have 10 pounds pressure in the section of exhaust before the turbo.
This means it is more difficult for the crank to push the piston up on the exhaust stroke.

We'll use the example of a 4 inch bore. This gives the piston top an area of about 12.56 square inches. With that ten pounds additional back pressure, that piston has to push up with an additional force of about 120 pounds to push the exhaust out. At 6000 rpm, your 8 pistons together are encountering this additional 120 pound force 400 times per second. Where does power to overcome this additonal force come from? The crankshaft. You're not running those turbos for free.

Now there's one other factor having to do with parasitic loss and efficiency that I hardly ever see mentioned:
Some of the energy used to drive the supercharger or turbo is fed back into the system.
When under boost, the piston doesn't have to work as hard on the intake stroke. Instead of having to work against a partial vacuum, there may even be pressure pushing the piston down. This is fed back into the crankshaft.

So both systems, turbos and belt-driven superchargers, take power and energy to drive. With a supercharger, the power is taken from a crank pulley. With a turbocharger, the power is taken from the piston compressing air on the exhaust stroke. If you calculate the horsepower required to run either compressor, that doesn't really give you the total picture, because some of it is recycled when compressed air pushes the piston down on the intake stoke.

For you engineers reading this, I know my explanation has been grossly over-simplified, but please understand that I was trying to keep it simple to illustrate the concept.

Thanks for listening.

:lurk: Great thread! I'm curious of this myself.

EDIT - Wow, WarpFactor, sounds like you know your stuff!

I will add just one point pertainant to this thread. He stated 600rwhp to 600rwhp. What weighs more a pound of lead or a pound of feathers :). Most points cut and pasted dont apply.

In general in most apps it will be a wash, yes the SC will have less area under the curve, but that that power level traction has a huge impact and SC's are generally easier to drive in most conditions.

Phil

Very well said. :thumbs:

What he said!

I've owned both a 600rwhp SC setup and 600rwhp TT setup -- the TT just has a different feel to it. Given the same amount of HP, my TT made about ~100 ft/lb more of torque which gave it more midrange oomph.

The power under the curve. For example at 3500 to 4000 RPM my TT setup produces WAY more power than a ProCharger. This translates to more fun on the street, IMO.

Mark

:iagree: :thumbs: :)

OK, so power under the curve is different, at least for belt-driven turbine style blowers. Seems like this would be easy to fix.

Why not put on a smaller pulley so boost comes in lower, and also incorporate a relief valve that bleeds off the excess pressure that this produces at high rpm? You'd lose a little efficiency when the relief valve was open, but who cares? What percentage of your driving time do you spend at maximum boost anyway?

Simple to make; just a hole covered by a plate, held shut with springs. Excess boost pressure overcomes the spring force, plate is unseated, and the hole leaks air.

Would allow you to easily adjust maximum boost too, by tightening the springs, or putting in weaker or stronger springs.

Wadaya think?

I approve of this message. My opinion, both systems have their places.

Warp Factor: I believe someone is working on this, but I'm not certain.

And that would probably help greatly. I think ECS either has something like this or is working on it.

Mark

I think you are referring to inlet restrictor plate that Paxton has used in the past.

Mike :cheers:

Good in theory but then you expose the issues with SC in terms of belt slip/wear by decreasing the belt contact surface area. This is compounded by now an increase parasitic drag form the head unit being spun higher. But, you can pulley down an SC and see much better midrange fill in general. An example wold be a D1SC pulley some vs an F1R as the same boost. The D1sc has less drag and better midrange than an under utilized F1R.

Phil, are you wasting all your time on the forum responding to me, or are you getting your other work wrapped up so you'll be ready for my supercharger install? :)

Looks like all your points about S/C's were CONS. :lol:

I'll also add another Con. Usually need a fat/ugly, unstealthy hood, at extra 2K expense. Good fitting hoods are not cheap and need repainting.

Right on -- another forum member tried this before, using a pop-off valve (basically a simple valve that will bleed off boost above a specific pressure). I think he gained some midrange power but lost a lot of top-end power to the point where it just wasn't worth it to bleed off the boost.

Not only are you losing power driving the blower itself, but you're also creating more heat in the intake charge... so without the benefit of more air going into the cylinders you end up losing a lot.