Plenum/intake manifold questions.

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Plenum/intake manifold questions.

Postby RomanV » Thu May 25, 2006 2:41 pm

So I was thinking about plenums.
I was thinking that if you've got a single throttle body, then you're going to want a small plenum... To minimise the amount of air volume between the throttle body, and the head. (For better throttle response?)
However, what other criteria dictate plenum volume/size/etc?
Is smaller better at high RPM? or vice versa?
If you have throttles on the intake runners, would a large plenum be better than a small one?
Are they generally small, for the sake of engine compactness?

Also, with a side feed intake manifold, is the flow biased towards or away from one of the cylinders?
It seems to me as if the cylinder furthest from the throttle would get less air than the closer ones.
I have no scientific basis for this claim, it's just what seems instinctively logical to me, even though I know that it probably isnt true.
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Postby Ebola_One » Thu May 25, 2006 2:54 pm

I think, that for a properly design plenum/IM it has to have a volume around twice that of the engine capacity. so 4L for a 2L engine.
Maybe it's just for boosted applications, I'm not sure.
Dirty DA Duz 14.4's, 48's (Taupo) & 1:25's (Manfield)
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Postby craigt » Mon May 29, 2006 10:02 pm

I think you need a minimum of 1.5 times engine displacement.
Im going for 2 times, my plenum for my 4AGTE on the end of my quads
is 3.2 litres
If it doesn't fit, force it.
If it breaks it needed replacing anyway!

AE101 4AGZE
KP60 4AGTE project
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