Let's talk intake manifold design

[z31maniac]

15 times? That seems a bit much, no?

That would mean a nearly 8L airbox volume for a 3.1L M20.

[moatilliatta]

When I was doing research on mine, I found that for the plenum size you want the internal volume to be at least as large or larger then the total engine displacement, My plenum ended up having a volume of 3.2 liters. Runner length all depends where you want peak power, look up Helmholtz frequencies. In my case I ended up using a runner 3 inches shorter then I calculated I needed, but it ended up working perfectly, I may of miss calculated or just got plain lucky

I herd also on a F.I. set up you would want the plenum volume to be 1.5 of the displacement. i thought that was interesting.

[tubby17s]

have a look at this thread. they seem to have done a lot of research/work into this
http://forums.hybridz.org/showthread...ghlight=plenum

[einstein57]

I was thinking of hacking up an intake manifold from a 750il for my set up. After all each one is designed for 2.5l displacement. My main concern is to keep the TB location or move it to the center like the m50 engines.