Changin Runners length on intake mani ?

[Jase EK]

hey there

ok.. question..
changin runners length on the intake manifold
shorter..coz new intake wont fit,

[Weq]

cut and weld.

runners are tuned length for ur application though.

[ekslut]

Does anyone have any good info or sites about designing runner lengths? And what happens if you make them shorter/longer?

[EfiOz]

I found a pretty good discussion the other day here

http://fsae.com/groupee/forums/a/tpc/f/125607348/m/16210118231

The short story is, the shorter the ram, the higher the torque peak, the longer the ram, the lower the torque peak. Hence the big long manifolds on production cars and the short ram tubes on racing engines.

We've done a bit of work with variable intake rams on quad inductions. The difference it makes to the torque curve is awesome.

[Slow96GSR]

Cliff notes: The changing the runner size will mess with the mixing of the a/f. The longer runners are there for higher power at high rpm's. The shorter runners are made more for 7k rpm+ on boosted/na race motors.

Read this (http://www.strathlan.com/CMS/docs/Intakemanidesign.doc)!

[iamhappy46]

Also, for all of those people fitting longer intake pipes so they can mount their pod filter in the inner guard, take note...

Short intake pipe = hi rpm torque/power
longer intake pipe = low rpm torque/throttle response

[BiGANG]

Also, for all of those people fitting longer intake pipes so they can mount their pod filter in the inner guard, take note...

Short intake pipe = hi rpm torque/power
longer intake pipe = low rpm torque/throttle response


think u got em backwards buddy..

[honda_b_blastn]

hey there

ok.. question..
changin runners length on the intake manifold
shorter..coz new intake wont fit,

Hitting the firewall are we Jase?lol moving the propertional valve didnt give you enough hey?
You really only have 4 choices
1/ use your standard manifold
2/ get the skunk2 cut and shortened(professionally)
3/ Use a different mounting kit
4/ ITB's

ahh dont you just love the modifying game...:)

[iamhappy46]

Def not backwards!

A short wide pipe, will flow high velocity air/fluid but has very poor manifold vacuum at low rpm.

A long narrow pipe, will straighten the air for low rpm but restrict airflow at hi rpm.

That is also why ITB's often have short, wide ram tubes fitted for maximum power production.

Consider why a LOT of people fit a larger bore TB for higher air flow.

Also, have a read of the article posted by Slowgsr ;)

[Slow96GSR]

Ya, that's what it's there for! Lol!