What is the best, Turbo or Blower??

[graywolf624]

"Turbo cars tend to kinda lose that "pull" in the way-high rpm range"

Some superchargers do this as well(particularlly roots blowers).

[coloradosilver]

Mine's a centrifugal(spelling?) SC. It pulls like a MoFo all the way to red line. I think the reason that some roots blowers lose some power is because they're sucking the air in from inside the manifold (on FI cars) while the Centrifugal typs blow it in from the outside. Not sure if that makes sense, but thats my best guess.

[graywolf624]

" I think the reason that some roots blowers lose some power is because they're sucking the air in from inside the manifold (on FI cars) while the Centrifugal typs blow it in from the outside. Not sure if that makes sense, but thats my best guess."

Partially (they dont suck all the air from inside the manifold. They do suck some) and partially because they do not compress the air internally like centrifigual.

Thus you have heat inefficiency.

[Wutputt]

Originally Posted by veilsidebr I just say one more thing: For turbochargered engines, use a wastgate valve or pop-off. This will helps you and will give the famous tschhhhhhhhhhhh...

The "tschhhhhhhhhhhhh"-sound when lifting off isn't caused by the waste gate, but by a blow off valve or dump valve.

The waste gate is a tool to limit the turbo pressure and turbo revs. Otherwise turbo pressure would run away to high and the turbo would overrev. Most turbocharged cars have waste gates. Modern turbodiesel with VGT (Variable Geometry Turbine) mostly don't have a waste gate any more.

A BOV (Blow Off Valve) is used to keep the turbo spinning while lifting of your foot. Without BOV the turbo will be decelerated by the air in the intake between turbo and engine. So a BOV reduces turbo lag.
You have two types of BOV: a VTA (Vent to Atmosphere) and a recirculating. The VTA gives that nice hissing sound, because air in the intake is vented to the atmosphere. A recirculating BOV circulates the air between turbo and engine to the intake pipes before the compressor of the turbo.


Here some pics:

Wastegate (7):



BOV:

[zevolv]

A traditional supercharger like a roots system can actually make more power due to the size of the supercharger itself, with a roots setup the air is usually drawn in from the rear or in the case of older cars it could be through the top. these can actually draw more air than a centrifugal but the can cause way more heat because of the friction from the two "screws" forcing the air around in the housing. Centrifugal superchargers are good for compact setups where there isn't alot of room to install a roots supercharger like in Corvettes and S2000s unless you modify the hood. An advantage of centrifugals is that you can intercool them much easier than you can a roots blower. So in traditional setups a Roots can be better if you like to go big. There really isn't any performance difference between the two that would be significant enough to sway your choice, it's mostly about ease of install and the room available roots can be difficult to install.

[graywolf624]

"There really isn't any performance difference between the two that would be significant enough to sway your choice, it's mostly about ease of install and the room available roots can be difficult to install."

Wrong. A centrifigual supercharger gives non linear boost based on rpm. A roots gives linear boost based on rpm.

A turbo charger is often refered to as a centrifigual supercharger driven by exhaust. The reason is associated directly with the turbo lag (or lack of boost at lower rpms).

Furthermore the way they work is different so the performance at higher rpms differs. A roots does not compress air internally as a centrifigual or screw supercharger does. Thus it has more thermal problems.
A roots also does not allow for the air to flow backwards as a centrifigual setup does. Thus it is more subject to air leak.

Basically roots are commonly used on passenger cars because they are less expensive and due to room.

[coloradosilver]

On the LS-1 engine. The Centrifugal superchargers are making more power than the roots type in EVERY case (all other aspects of the car being equal).

[RC45]

Originally Posted by coloradosilver On the LS-1 engine. The Centrifugal superchargers are making more power than the roots type in EVERY case (all other aspects of the car being equal).

Are you still running stock internals with yours?

[coloradosilver]

Yep. I've got Stainless Works Headers, Corsa Pace Car exhaust, LPE manifold (in avatar), 42lb injectors, B&M ripper. All the internals are stock until this spring. I'm having my tuner do a full-blown race set up head&cam package. I'll also be going with a single front mount intercooler and 10lbs boost. we're aiming for 650rwhp

[graywolf624]

"On the LS-1 engine. The Centrifugal superchargers are making more power than the roots type in EVERY case (all other aspects of the car being equal). "

Not suprising. There are very few supercharged ls1s out there. Id imagine the thermal issue for the roots isn't optimal for the layout of a vette engine bay. Then obviously you can design the centrifigual charger to work earlier (just like you can a turbo). I'd bet you at low rpms the roots would provide a larger burst of power. That being said roots is by no means the most efficient system because of the external compression of the air. You get a roots generally if your trying to save money and ensure reliability. You more generally see them on lower displacement engines.

[spicymustard]

TURBO

[blah]

Originally Posted by SFDMALEX It does depened on the engine I guess. If your car only revs up to 5000rpm then I dont think you'll get much boost from a turbo. so a blower is this case. If your car can rev up to 8000rpm then the turbo will have enough room to spool up completly and stay like that since you'll not get below 3500rpm....on a track..... Anyway Im not expert, just my own little "theory"

not neccesarily, because ones its spooled up, the turbo is will be there, the problem with the turbo is the spooling time, some people defeat this by using a smaller turbo, and a larger one, the small one goes first, while the large one spools. There are hundreds of vids, and pictures of turbo stangs, maros, corvettes (lingenfilter), vipers, and other cars.

[TeflonTron]

Originally Posted by zevolv The idea of using both types of forced induction is workable but electromagnetic clutch plates switching them on and off is rediculess using them both is the best idea you can use a Centrifugal supercharger forcing air into the turbo forcing the turbo to spool up that way and then sending it through an Intercooler since the heat created would be obsurdly high and the amount of room required to plumb all of it would be high and the engine would have to be bullet proof to be able to handle the amount of PSI going into it. The arguements for both are good but using them together just isn't efficient in any way. I use both in different cars of course and they are both usefull.

Actually, I can think of many applications where a SC + TC setup would work well, and Koenig used this perfectly in their "Competition" to make 850+BHP. They also used an electromagnetic clutch plate, if my memory serves me right.

[SilverPhoenix]

I like turbo, as long as it is set up right.

[TeflonTron]

I've never been in a Supercharged car, so I can't comment. I've never even sat in m uncle's XKR *sniff*