Twin down pipes?

[shortsport]

Is there any difference other than design in using two 2" downpipes side by side instead of one 4" down pipe? Just thinking because of clearance issues.

[Acidburn]

I'd probably say some turbulance etc from the part where it seperates after the turbo and splits.

Same sort of thing that happens at the end of the downpipe and splits into the pipe for the two cats.

[markrs2]

Without even considering any other factor 2*2inch pipes have only half the flow capacity of a single 4inch pipe

[Rusty]

Area is half as pointed out and flow is completely different too. So in answer to your question, no 2 2" pipes would not give the same flow as one 4" pipe.

Two 3" pipes are close in terms of area but packaging will be a nightmare!

I seem to remember that Doug is using a DP larger than 3" in his S2 and some use 4" and then taper it to 3".

[Jamo]

Without even considering any other factor 2*2inch pipes have only half the flow capacity of a single 4inch pipe

Not according to Animal Mother

To be honest 3" will flow up to 600 bhp, The less change in diameter in the exhaust the better.

Single 3" from tip to tale is great.

Doug and Mark H have massive 4" exhaust systems.