turbo and super chargers

[gaara]

why is it not common with street performance cars to both turbo and super charge their engine?

 

Also, what are peoples opinions of electric turbo's?

[Cor80]

Are u referring to after market performance street cars. if so....

 

firstly, who owns street performance cars. It's generally the average Joe that's got the passion to build a performance street car. Turbo's is costly story. Superchargers is usually 4 times more in price. In short...its damn expensive.

 

Secondly, its not every tuner that got the balls to do a hybrid charge conversion cause its a tricky business. There is a only few people that attempted this and had success.

 

If ur talking about manufacturer's performance street cars...

 

vw is busy with super & turbo charger 1.4 engine which will go in production soon. Is called the 1.4 st or ts golf 5

[Rocket Man]

both turbo and supercharge? uh, yeah, good luck with that..

 

both have exactly the same function, compress the air before it enters the engine. that way you get more bang per cylinder. i think if you had a supercharger running and the engine idling, the exhaust gas would be insufficient to spin the turbo against the inlet pressure.

 

if they were in series, you might be onto something. but if you squeeze too much air in then inject fuel to match, most cars would start spitting crank arms. even the bigger, gruntier cars.

 

basically the only reason you don't see both on a car is because you can alter one to match the power of both unmodified.

a supercharger draws energy from the axle, a turbo applies back pressure on the exhaust. both, i think would the essence of redundacy.

[Cor80]

a super charger supply power at low rev range.

Turbo's supply power at a higher range. A reason for using both would be to

eliminate turbo lag. At low revs super/c is working and the turbo is just idling.

At mid revs super/c is topping out and turbo is starting boost (taking over). At high revs the super/c is just a fan spinning without effect and turbo can play fully.

 

This has been done by a selected few. It will become more popular once

manufacturers follow. And they have started.

It's like every new concept of improving power...must prove to work

before everyone will follow.

[Pangloss]

Yup, it is certainly possible to supercharge and turbocharge, and there have been a number of examples. It's all about getting the most power from the engine without making it larger.

 

The main reason why you don't see either approach more often is that both have an adverse impact on fuel efficiency, and require additional maintenance and engineering. They add cost to a vehicle that may simply not be necessary. Your typical buyer is looking for a specific performance envelope (whether they know it or not), and the car may be able to meet that envelope without the additional complications of super/turbo-charging. New engine technology is constantly improving power output per given displacement without the need for these "outside the block" approaches (such as variable valve timing, gasoline-direct injection, etc). And remember, most new cars come with long-term warranties these days.

 

But they're certainly still part of the modern automotive engineering repetoire. And both continue to be developed. The newest Corvettes have supercharged V8 engines, if memory serves. And the general just put out a new turbocharged 4-cylinder motor that uses an interesting twin-scroll design that reduces the notorious "turbo lag" to almost nothing (they're getting a whopping 130hp/liter out of that engine!).

 

This is interesting given that BMW just introduced a new twin-turbo engine (in the 335i) that uses the traditional approach of having a lower stage for low-end (stoplight) boost and an upper stage for high-end (highway) boost. That same engine also uses gasoline-direct injection and advanced computer control, yet they went with a more traditional turbo design. I haven't read enough yet to know if that was a matter of marketing or engineering.