I was reading about Audi's twin turbo engines, one per cylinder bank, and got to hypothesizing (who knows why) about trying something similar to a B21 or 23, i.e. modifying/fabricating a split intake to accommodate the same sort of configuration. It would have two intercoolers, two turbos and I guess two throttle body’s--but one TB control--each feeding two cylinders via a split intake manifold/plenum. Anyone have thoughts and/or suggestions as to feasibility and performance and ideas in general?

If you are a fabricator (i.e., do your own welding, have a machine shop or cheap access to one), then it could be an interesting project. Also, if you have a very large budget for this project, feed free to go ahead. If economics or simplicity are important, stick with a single turbo. Each turbo would get only 2 cylinders worth of exhaust energy so they would have to be pretty small turbos. A non US available Subaru did use two turbos on a four cylinder but the Subaru I think is a flat four with opposing cylinders so this may be easier to do in that case than on the Volvo in line. Unless you have very particular needs, you will probably be happy with a turbo selected and sized for your goals and accompanied by appropriate other bolt on modifications.

Philip Bradley

If you can weld stainless steel and aluminum, and you're good with the electrical part of an engine, it shouldn't be too hard to build it. Tuning might be another problem.

It's not feasible unless you just want to build something that no one else has done. With the money you'd spend designing, building, designing, and building again the twin turbo setup, you could put it towards a 16V single turbo 4cyl. and probably make a lot more power.

Which Audi twin turbo were you reading about? 2.7L V6 Bi-turbo? You could build something similar using the B280F engine. Replace some parts with Eagle Premier engine parts and get 3L from the V6. Then turbo it. There's a guy who sometimes writes at the turbobricks board who has that setup in a 262 rally car. It makes lots of power and torque (500ft-lbs? I'm not certain), but it also costs many thousands of dollars for a project like that.

If you post at the t-bricks board, the first things they'll ask is what's your budget and how much power would you like to have.
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wow... you really have this figured out... the only twin turbo 4 cylinder setup that i have ever seen was on an 8 second Honda civic drag car... they had the header coming off the block and then a y-pipe where the downpipe would be and then two turbos off of there and then another y-pipe on the intake side that went to the intake manifold... i would think that you would have a big problem with the turbos spooling up and also the backpressure.. i think that the B21/23 would have to be cranking out quite a bit of horsepower naturally aspirated... the volvo six cylinders would be really cool to twin turbo, but i have a displacement to big displacement engines... if you have the money and resources to do it, i say go for it... then you can race something a little better than old grannies... something more like a toyota supra or a mazda RX-7.. could you imagine the looks on their faces being pulled on by a Volvo??? I think that it would be great... good luck!

JD

Try www.turbobricks - if anyone has tried this, they have...