Superchargers VS. Turbochargers

[Scaff]

Here you go from the BorgWarner turbo-facts info pages (turbo manufacturer).

The high-altitude performance of a turbocharged engine is significantly better. Because of the lower air pressure at high altitudes, the power loss of a naturally aspirated engine is considerable. In contrast, the performance of the turbine improves at altitude as a result of the greater pressure difference between the virtually constant pressure upstream of the turbine and the lower ambient pressure at outlet. The lower air density at the compressor inlet is largely equalized. Hence, the engine has barely any power loss.

Lots more info here

http://www.turbodriven.com/en/turbofacts/advantages.asp

Its a shame that Mopar 68 was an arrogant fool who got himself banned, for while he was strictly speaking right about the advantages of a supercharger in the lower rev range he was off the mark as far as motorsport applications go.

While Superchargers are more effective at the lower rev range than most turbochargers, and that it is a distinct advantage on the road, its almost totally irrelivent on the track. A race car lives on revs, the last thing you want to do with any racing engine is to let the revs drop, regardless of it being NA, Super or Turbo charged. As such the lack of boost at lower revs becomes far less of an issue on the track than on the road.

Another disadvantage of a supercharger on the track is that it is essentially a parasitic device, robbing some power to give you more, now again on the road this is not a big issue, biut on track any power losses can be a major issue. However thats not the biggest issue with superchargers, that fate is reserved for how they opperate, put simply they incure more frictional losses to the whole drive system than a turbo and in many cases have more moving parts than a turbo. More moving parts means more weight, more balancing that needs to be done and more chance of a componant failure. The increase in frictional power losses can also limit the maxmimum rpm the engine can reach, and with a lot of racing applications more revs = more power.

Now thats not to say that Superchargers can't work in motorsport, they have a strong showing in Drag Racing, which does have very specific needs.

The argument that they are not used because of bans is also a daft point to try and make. Put simply plenty of series have banned turbo's as well, only to have them re-introduced through manufacturer pressure. Superchargers are not commonly usedin motorsport because at present teams and manufacturers do not see them as a major advantage over turbos.

It should also be said (I don't have the book on me at present - will dig it out tonight to confirm the quote) that his argument over what would be defined as a turbo and a supercharger is also irrelivent. A turbo is a form of Supercharger and strictly speaking should be called a Turbo Supercharger.

Regards

Scaff

 

[Dave A]

Yep, I've read that about the Turbo supercharger name before and that the Turbo is really just another type of supercharger.

 

[NHRA Tech Wiz]

im just writting in regards to the enormous turbo picture a few pages back...seems fairly stupid to bring a turbine that large into the equasion...concidering mopar was obviously talking about road vehicles...a turbine that size most definately will not fit in a car...

and also...my personal preference would be a twin screw dual chamber superchager...i have one on my car..and it is much larger in capacity to any turbo charger available with in motor car restrictions...i seen as mopar stated in ealier posts that the cfm rate of superchargers is much more extended than turbines and its widely known that though turbo's perform well...superchargers and definately that of a twin screw s/c is much more exillerating for it as some 1 said earlier it doesnt only throw air through the engine it actually builds pressure to keep a constant high flow

 

[NHRA Tech Wiz]

Yep, I've read that about the Turbo supercharger name before and that the Turbo is really just another type of supercharger.

its plausible in some aspects but its certainly not the case s/c and t/c run on entirely different aspects...where as turbos run on rpm...s/c do also BUT they also rely on what pressure they gain to keep it building...even whilst you are idling your motorcar the supercharger will continue building pressure so when the accelerator is dropped an enourmous amount of air is dumped through the engine...and because of the constant pressure build it will continue to push the fuel/air mixture at quite a significant rate...most cars effectively match the fuel/air mixture but you will most definately find on a dyno run with near any s/c vehicle that it equals its air with fuel much more efficiently especially that of the twin screw s/c

 

[backspace]

From what I've read, a turbo sucks in more air than it pushes into the engine at ground level and wastes the rest or something like that.

Well, yeah. Thats how pressure occurs. The rest isn't "wasted" (unless your talking about exhaust flow being diverted or an atmospheric blow off valve) it just builds up and adds pressure.

...

you wouldnt happen to be mopar, i'm sure.

 

[Azuremen]

I was kinda wondering the same thing there MR2 avatar dude. The completely impossible to follow post works with Mopar... but he was banned so long ago.