[hesh]

hi all .....i was sat musing about stuff for the car, and wondered if anyone knows how to calculate the optimum header length for the rb25de. (or any engine for that matter?..i assume is just some form of equation?)

i know each tube needs to be the same length, and that the reasons for this are to do with pressure wave flow to aid exhaust gass removal from the combustion chanber. As i understand it getting it right effectivly "sucks" the spent gasses out via a relative negative pressure in the tubes.

but! where does it all start...?

ive heard each engine has an "optimum" header length ...so what is it for the rb?

 

[2thepoint]

I'd doubt that anyone has ever had the need to work this out when there is a turbo version. Unless there was a demand for them.

Anyway the process takes a lot of R&D with an engine dyno, a lot of experience in this field and a bit of time.