Fins on back of Valve & Fins pre TB

[immortality]

It probably suits high RPM more where there is lots of air speed. Non the less, it would be cool.

There are a lot of arguments about where it's best to inject fuel. for many years people always said that EFI although more economical didn't really make the same peak power as a carburated engine.

[Holden202T]

yeah but how many EFI manifolds are designed for peak power ? is it really comparing apples to apples ?

i reckon if you got for example, a 304 V8, fitted a torque power dual plane manifold with injectors and a 750cfm throttle body and then replaced it with a 750cfm carby you'd get very similar results, and then add to that all the extra niceness at part throttle and such that you get from EFI .....

anyways

[The1]

yeh my idea with the angle is then each port is away from the other like in the group A manifolds, you also get slightly longer runners, where as straight trumpets just make it longer and don't help air distribution. The plenum isn't setup for a group A angled fluted port the pipe would have to be bent. Anyway that's just my murmurings im def not good at the math to workout all of it in theory.

[yoda69]

Do a search on Helmholtz Theory and intake manifolds, if you can get your head around he maths it's rather interesting. Below Is one I've found particularly good from a quick google search, there are heaps more:
http://www.stealth316.com/misc/grapeape ... ystems.pdf

There are some v8 Supercars that have the trumpet pointing perpendicular to the lid of the plenum, I think the idea is the wave coming out of the intake runner hits the plenum and bounces straight back down the intake.

The same basic principle is used for tuned length extractors.

[delcowizzid]

Green foam once apon a time devided a plenum in half down the middle to make a plenum for each side you soon learn about sound waves it made such bad sounds was funny as

[The1]

that would prob be good with a dual throttle body setup

[Gareth]

I've seen photos of that somewhere....

[Gareth]

this it?

[immortality]

That was a Walker V6 manifold. I don't think they made many as it was rather costly.

Nahh, it was a standard V6 manifold cut through the middle and then had a piece of alloy sheet/plate welded through it.

I remember that experiment.

[The1]

i think i remember reading about that walker one, bolt on stock engine got 20rwkw gain, something like that. Im guessing the torque on the bottom end would be better with smaller tubes and longer runs