Intake runner lenght

Hello,

we are building our own intake manifold for our 620cui race engine.
It´s going to be something like a stack injection but a bit different than the "normal" stuff.

Can anybody help me to determine the intake runner length? I´ve found different formulas, calculators, etc. but always with a different result.
It´s a struggle

Ashburner wrote:Hello,

we are building our own intake manifold for our 620cui race engine.
It´s going to be something like a stack injection but a bit different than the "normal" stuff.

Can anybody help me to determine the intake runner length? I´ve found different formulas, calculators, etc. but always with a different result.
It´s a struggle

I've used pipemax a few time and the results where real close.

I've never built one, but here is some info from people that do.

http://www.swartzracingmanifolds.com/tech/index.htm

Ashburner wrote:Hello,

we are building our own intake manifold for our 620cui race engine.
It´s going to be something like a stack injection but a bit different than the "normal" stuff.

Can anybody help me to determine the intake runner length? I´ve found different formulas, calculators, etc. but always with a different result.
It´s a struggle

Just be aware that entire runner length is usually measured from the back of the intake valve and this includes the length of the cylinder head intake port. Be aware that runner taper skews the actual intake runner length; more taper acts like a shorter runner.