This is dumb the only reason cars would have two turbos stock is because they are v6's (or rotary) and have two exhaust manifolds so they put one small turbo on each eg. 300zx, 3000gt, stealth r/t 6spd, supra, rx-7. And I guess the v8 engine in the saleen s7 TT but i couldnt think of another v8 but its the same concept as the v6's. Tell me where you would put 2 turbos on a I4?

 

I'm surprised no one mentioned the famous Twin Turbo Callaway Corvette and Lingenfelter Vette..they pioneered twin turbo technology back in the mid 80's. I used to love reading about those cars when I was a kid.

 

First, not all twin turbos use two small turbos. On higher displacement engines then yes, you would use two large turbos because the torquiness of the V8-V12 would be enough to drive around town waiting for the higher RPM spooltime.

Secondly, On smaller applications such as the RX7, etc. they use a smaller turbo to spool up fast for quicker low RPM driving, and a larger turbo that kicks in @ higher RPMs to take over the load of the small one. The smaller one @ 2000RPM and the larger one @5000RPM more specifically. This is called a "sequential" turbo setup.

Thirdly, it is very easy to run two turbos on an I4. I don't see why you don't think it wouldn't work. Granted its not practical on an I4, but having two turbos in the exhaust path would cause nothing but aggrivation and a single turbo would be better, but its just as simple as running another turbo.

 

Volvo is another manufacturer that has experience with Twin Turbos setups. They did use TT on their 750R Wagon, and it was an in line 6 cylinder. Later they launched another SW, I think it was the CrossCountry which had a l5 engine again with TT setup; I drove both of them and they were really fast cars with plenty of power from the lower band.
I don't know if it is the most efficient setup or not, probably not, but I think when a manufacturer wants to build "state of the art" techno impĀ“ressive setups, mostly for image, it works.

 

another famous (or infamous) TT user was Maserati with their wonderfully quick and fragile BiTubros. The Engines and drivetrains were robust.. it was the electrics that hindered the car.

 

yup. i own one also. notice my new Sig? yea. thats my car tongue.gif: wink1.gif fing02.gif