Originally posted by Rara:
oh, one question, in a generic situation, why would a twin have to run a higher boost pressure to make the same power as a single?
I'm really not trying to be argumentative
I just love discussing this stuff
[/QB]
It depends on where you take the boost measurement and the comparitive sizes of the plumbing. One could run 35psi thru a straw, but what does that get you?
(Pulling out the equation book..)
Take for example:
(1) 4" diameter pipe can flow 2 x the amount of air that (2) 2" diameters can at a given pressure (staying in the laminar flow).
Therefore, in order for it move as much air as a larger turbo, the smaller one would have to develop more psi (move the air faster), unless as stated below.
But, (2) 3" pipes can flow about 12% more air than a single 4" pipe. In this case, the smaller turbos can run at a lower psi and make the same air as a larger turbo.
So, to answer the question. Yes and no. It depends on the geometry of the pipes as to how much psi the turbo needs to develop to achieve a certain amount of air flow.
This was the "simplistic approach." There are a lot of things that can change, as to the location of the psi measurement to the whether you want the engine to be "presurized" or have an ample supply of air. It all has to do with volume and air flow.
