Macfreak007

in order to create serious torque gains, the runner lengths would have to be dynamically adjustable... anything is possible. I would think that shorter runners would give a better lower end?

ferrari already has a dynamic adjustable intake runner length setup, using multiple throttle bodies at varying distances inside the intake.

944CS

the cayenne was introduced with variable length runners
http://content2.eu.porsche.com/prod/..._intake_system

Macfreak007

awesome, what other companies have implemented variable runner lengths on their cars?
looking for more info...

inactiveuser92616

it is possible to have intake runners that are infinitely variable between a max and minimum length; the biggest problem is getting an appropriate control algorithm to have them at their resonance frequency at all loads. Doing so would require the equivalent of a programmable fuel management, with at the least a 2d load/RPM lookup table. Effectively you have to compensate for the varying speed of sound in air as pressure, velocity, and temperature all vary; and then coordinate that with engine RPM.

bleucamaro

Ford Motorsport has an available intake manifold for the 4.6's that is cast magnesium and has dual length runners with butterfly valves to go to the shorter runners at high RPMs

DanG

BMW has scrolling intake runners. I can't find any good links, but its on the new V8, along with their spiffy "throttless" Valvetronic valve timing.

I work in an air induction department. We have active variable resonators, for noise cancellation purposes. Unforunately we don't do much performance enhancing stuff.

Here's a cool pair of pages on VLIMs...

http://www.autozine.org/technical_sc...h_engine_2.htm

http://en.wikipedia.org/wiki/Variabl...ntake_Manifold

Rich Sandor

Lance Hayward did the head on my 951 when it was out. I asked him about that ITB setup photo. He said it was a mockup that he tried, iirc, toyota supra TB's, but the problem is that the 951 market is so small that there is no money to be made. The Domestic and Japanese import scene is so much stronger that he would rather focus on that.

Matt H

There is money to be made...they aint selling for 6K in the import world either.
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Rich Sandor

I think Lance is just more interested in sales volume. The Domestic and Honda guys seem to line up at his door and pay top dollar, whereas the 944 guys are few and far between, and generally are penny pinchers.

IIRC, John at Vitesse tried to get Lance to make some... if John can't convince Lance that there's at least a little money to be made in 944's, then no one can.

ehall

good point. BTW if there is a guy under your hood, then perhaps you should check under your bed Rich.