Plenum Chambers

[ahk068]

Is there any science around the size/shape of plenum chambers. I'm seriously considering efi for this turbo BBC and have a idea in mind for a back yard manifold set up but I need to know how big the plenum should be.

Also would 2 x V6 commy throttle bodies cut the mustard or would stock ls1 one's be better. I've done no research on this but they must be getting cheap by now.

[Billzilla]

Is there any science around the size/shape of plenum chambers.

Um just a LITTLE bit. Probably a hundred books and engineering papers or more.

Simple rules - It have to be at last the volume of the engine so if your engine is, say, six litres then the plenum should be at least six litres as well.
On the inner surface facing the inlet runners, face that surface at an angle so that the reflected inlet pulse doesn't go back down the inlet runners. Sometimes it can help if you work really hard to get that right, often not.]

Edit - that doesn't read very well - I mean that you can get the reflection from the far plenum wall to be useful when aimed back at the inlet runners, but it's hard to get right and so you're better off making them bounce the waves away from the inlets a bit instead.

[JZK25]

Your piece of string seems to be of an undetermined length due to lack of info.

[ahk068]

Ok, idea was to use a tunnel ram bottom half, drilled for injectors with basically an alloy box sitting on top with two throttle bodies bolted to the front. Ideally i'd love to get away with 8 injectors but I also am aiming at 1000hp so I may have to plumb some extras in somewhere.

Now wondering how high an 8 litre box on high manifold on a big motor will end up.

[morerevsm3]

Now wondering how high an 8 litre box on high manifold on a big motor will end up.

so you need someone to photoshop Paris Hilton naked, doing a handstand on your bonnet?