[Beaverboy]

with enough $$ anything is possible... but there's no good reason to go to all the trouble with a 4 cylinder.

I know, I know.. Subaru uses a bi-turbo setup (two differently sized turbos, one for low rev and quick spool, and one for high rev high boost power) on their EJ20 in the Legacy B4, but if you read any of the road tests of that car you'll see that the powerband is disapointing. Powerful.. sure, but there's a flat spot in the powerband where one turbo is running out of boost while the other is still spooling.

As for a twin turbo.. (two turbos, of the same size), there's really no reason when there are plenty of modern turbos that spool fast and make boost all the way to the top.

 

[Beaverboy]

Nahh.. B4 uses an EJ20, only a 2.0L, which is part of the reason for the bi-turbo setup.

It wouldn't be hard to fit twin turbos.. there's plenty of room left to right.. and the turbos would be smaller in diameter than a single turbo, so block to radiator fitment shouldn't be a problem. The thing is, a twin turbo system isn't going to net you much of an improvement... Sure, the turbos are smaller and should therefore spool faster, but you're only using half of the exhaust energy to spool each of them.

 

[Beaverboy]

subaru legacy
s didnt come w/ a 2 turbo system. My friend andy has 2 turbo legacy's and a non turbo. The legacy has 2 heads, but not 2 turbos.

Correction.. Subaru Legacys didn't come w/ a 2 turbo system in North America. That's why I specified the B4 Legacy.. I don't suppose your friend has one of those :wink:



Supercharging is great for making a 4 cylinder more driveable.. ups the power all the way across, making for a torquey 6 cylinder feel.

I'm suprised that the Trans Am would only have one turbo, considering most multiple banked engines (V6, V8, V10, V12.. etc) have turbos on each side.

Your uncle may want to look into nitrous to get him off the line.. the turbos will spool in no time once the nitrous hits... Otherwise, he may want to work on his launch technique.. big turbos work great at the drag strip.. they just take a lot of practice.