R1 exhaust primary length

[7ishNZ]

I did not get the stock pipes when I bought my motor.. I am about to make a 4 into 1 header.
I believe the R1 has a primary length of 16" ..? Can anyone confirm that for me? Thanks.

[andrew7]

NZ, this may help. http://www.locostusa.com/forums/viewtopic.php?f=10&t=6064
The builders are over there.

[Ian7]

NZ, something else to consider is that exhaust primary length has an influence on power and torque output.
You might want to consult a few engine builders as well, and take advantage of their knowledge to better optimize the exhaust for your car application before committing to a pipe length.

[catracer]

Another suggestion is the Burns Stainless site (race exhaust specialists) have (or had) an application that would optimize exhaust system components based on your inputs. If you have a good handle on the specs of the engine, it's intended usage, it's a pretty good first step.

[7ishNZ]

Thanks.. I have seen the burns suggestion for a 4-2-1 system, though they don't specify which cylinders should be paired. I am guessing that 1+4, 2+3 are the correct pairings for the R1.
I was wondering what length Jeff Underwood used on his 4-1 system.. it looks pretty good!