runner length importance before and after the throttle

[ArsenicPants]

I know that adding more runner length to the intake manifold after the throttles will increase low end torque at the expense of maybe a little bit of throttle response
but how does runner length effect power when they are longer before the throttles?
I'm running ITBs on CIS and it has a short little manifold at the head, then the throttles, then a plenum, then a long hose that connects to the CIS air metering plate, then the air filter
how will this long winding track effect the powerband? the same way as long intake runners?

[bmwquick]

Free bump. Im interested in this too. I was thinking of how to experiment with runner length tuning by not having to modifiy my already-completed custom intake manifold for my R1 carb'ed 16V. Instead of just slapping on 4 filters on the carb intakes, I could fabricate various size runner tubes that I could place in between the filters and carbs.

But I dont know if that would have the same effect as actually changing the intake manifold's runner length.

[need_a_VR6]

On carbs and itbs the length of the runner even before the throttle plate is *very* important. As long as your power is below the choke point of the head you can see the different torque peaks that the resonance frequencies cause in a dyno chart.

I have seen small/short intakes on plenum manifolds cause power loss, but they are usually very undersized before you'd see an effect.

[bmwquick]

Thanks, I'm going to have to try my idea now.

[ArsenicPants]

On carbs and itbs the length of the runner even before the throttle plate is *very* important. As long as your power is below the choke point of the head you can see the different torque peaks that the resonance frequencies cause in a dyno chart.

I have seen small/short intakes on plenum manifolds cause power loss, but they are usually very undersized before you'd see an effect.

that's funny, I wasn't thinking of the long tube as being part of the plenum, but I guess it is
the air doesn't know they're two separate pieces

well that's perfect then, because I was thinking the "plenum" i'm using was a little too small anyways

thanks for the help