Side entry or Centre entry intakemanifold

[goodall]

Which type of intake manifold is more efficient at getting equal flow?
I ask as I am currentaly designing a intake for my 7A and am not going with ITBs so have been researching various intakes.

heres two pics showing each style, on ferraris since they are both every well engineered engines

Center entry


Side entry

[terrybullwon]

I think if you look at orginal ones already in production by companys like Pro Mo, Wagner and furans you will see how it should be done. A dual pendulum is the way to go. Also look at the Audi sport cars.

[lind4hl]

if you´re building an high powered 7a, why NOT ITB´s?

[speeding-g60]

dual plenum? Lehman design? i guess it really is going to depend on internal design. my own thought was center entry for mine, and it made use of the space i had. Derek went side inlet, with a dual plenum design he came up with. both of our manifolds feature a radius port inlet to the runners, CNC machined into the back plate, helps with flow alleviating sharp edges which would disrupt flow.

here are the ones we just built.... Derek built his (it is for himself) and i had it finish-welded out as my welding machine did not have the NUTS to weld the flange and plenum backplate..... and mine (bottom one for 4cyl) my welder buddy and i design/built for me.






































but my own design for my car is side inlet.... lots of people said it would blow up or break, not work, etc. it made 592 AWHP @ 6krpm only in 3rd gear on the initial dyno tuning, and its only a measly 4cyl 20v setup. but it handles 45psi like nobodies business, and the head lifts before the manifold ruptures...

[quattro84]

I designed and flowtested some different designs in CAD software.
My experience is that both type of designs can be altered to accieve an equal flow.
Dual plenums are better because they are more consistant (as in: balance in air speed) troughout the entire rev range of the engine.
If you are looking for maximum performance a single plenum is better because of the lower restriction.

[goodall]

I don't want ITBs two reasons one simply cost. The other is more important and that is part throttle driveability/control from what I have read seems ITBs to on-off where as a plenum and signal throttle the approrote size is just as powerful yet have more part throttle control. However I can find very much info on how get equal flow besides what might look right. Which isn't always correct. I have solidworks and might see about the floworks ad-on however would be no good with out an idea of what's good and bad.

Dual plenum is no good for NA applicateions as plenum gets to large and makes throttle attenuated