twin charging ?>

[97greensnake]

i was haveing a conversation with the roomate today and this came up...twin chargeing...from what i understand its both a supercharger and turbo system...so pretty much the s/c is spolling (sp?) up the turbo, he told me its rare but its been done ...anyone know much more bout this ? is it even worth it ?> sounds crazy!

 

[65StangBoy]

I know that I've read about a twin turbo, twin supercharged car in a magazine sometime. Probably not the most efficient way to make power but it works.

 

[buckleupkiddies]

in the january 02 issue of sport compact car they had the ultimate street car challenge. there is a 1985 toyota mr2 that has the twincharger setup......it says in the paragraph "the basic theory behind a twincharger set-up is simple. at low speeds the positive displacement supercharger makes the engine breath like a larger engine, spooling a large turbo faster than it otherwise would. the supercharger is bypassed once the turbo gets moving. thus, the engin combines the responsiveness of a roots blower with the top end power of a big-turbo engine." the car also had nitrous on it. there was also a twin engine, methonal fueled, twin turbocharged hyundai tiburon that ran 10.6. i would sell my truck if i lost to a tiburon.

 

[97greensnake]

yeah i remem,ber that tiburon...it had 2 v6's ..i remember they sayied "how do you do an AWD burnout?> put one tranny in reverse and the other in drive..."

 

[MINI_ME]

ive heard about it being done also. sounds cool i guess but why not just TT it and be done

 

[HrslessCarriage]

I'm not sure I get it.
I'm assuming a centrifugal is used. So the supercharger feeds the compresser on the turbo? I guess that would eliminate the heat problems because you arent using the exhaust to drive the turbo. It also eliminates the need to fabricate a turbo manifold. None of you are going to try this, are you? I guess it MIGHT rank high as a coolness factor but there are more efficient ways to make big power. Spooling isn't even much of a problem for 350+ cubic inch guys because they move so much air. Getting rid of (well, some of) the spooling and heat are the only factors I could see it benefiting from and even then there are better ways to eliminate these things.

 

[kb97]

What about putting a cent in front of a kenne bell and hangin a turbo on the exhaust?

 

[HrslessCarriage]

Originally posted by kb97
What about putting a cent in front of a kenne bell and hangin a turbo on the exhaust?

What is a "cent"?
I think it would have to be a big turbo to be able to keep up to the roots charger. There also will probably be airflow problems due to the roots wanting to make power at low rpm...the turbo won't be able to feed it the air it wants that early.

 

[4sdvenom]

The only theory that makes any sense with twin charging is to use a positive displacement supercharger, with a large turbo. The positive displacement would not have any problems sucking all the air it needs thru the compressor side of the turbo. In fact it would help spool it. Not to mention the low end boost created by the positive displacement blower will create a significantly higher amount of exhaust gases which in turn will spool the large turbo much quicker than the motor alone would be capable of. The design problems start when the large turbo is trying to force more air past the positive displacement supercharger than it is capable of moving thus creating more heat, and restriction than either would create alone. Some theories are that the air being forced thru the positive displacement supercharger by the turbo actually alleviates some of, if not all of the parasitic drag placed on the motor by the positive displacement supercharger by actually taking over the spinning of the rotors by a turbine effect. It is based on a lot of theory, and has been done in one car by Ferrari, and the above mentioned Toyota MR2 (read that article also). Not very practicle, or cost effective, and a tuners nightmare. A tuner would have a lot of variations in fuel, and timing curves in order to compensate for one power adder compensating, and over-riding the other, and vice versa. You would have varying degrees of horsepower loss (from max used by supercharger to none when turbo overspins the supercharger)due to parasitic drag, which means A/F would be all over the place. Then you are adding extra restrictions into all aspects of the airstream which in the end are going to ultimatly limit the amount of horsepower that can be produced.
In theory, and a perfect world it would be the ultimate set-up. In reality nothing more than a wow factor for looks. Even the Ferrari that had it had to use an elaborate set-up to bypass the positive displacement supercharger when the turbo took over. Would never be reliable for anything other than a show car.