Inlet plenum design

[hmmmmm]

I dont see many custom inlet plenum's on the interweb thingie. Is this because the OEM plenum is good enough, even when using a supercharger. Or is there room for improvement?

And a more specific question for paul;
Ive been looking at the 3.1L inlet plenum you made for Johnnys 5VZ, but there isnt much info in the build thread. Whas that design researched of where you just winging it?
I dont suppose you did any flow test's on it, and i dont want to go mental with it like this guy (http://forums.hybridz.org/index.php?/topic/61549-turbo-intake-plenum/), but does fabbing a bigger plenum without any test's actually flow better? I realize you needed a bigger one because of the massive engine and charger but would you consider this for a lower level build like woozy''s for example?

Any tips are mich appreciated, im still in doubt as to what to do with the plenum. I like the idea of feeding the plenum on the center, and taking it straight from the turbos in the boot to the plenum without any big corners but i just dont know if its worth it creating a new plenum..

[jayray]

The best plenum design I've seen on a V6 is WTFauto's 1MZFE turbo. I'm not sure if he's posted it on here, but I'm guessing it would definitely be on mr2.com or mr2oc.com.

[Paul Woods]

On Johnnys build we calculated the volume needed for that manifold based on the engine size/flow rate but the plenum was never flow tested or anything, it made superb power though.

If you notice on Johnnys plenum it extends further past number 1 cylinder than it needed to, that was because we didn't quite have enough volume terminating it at the cylinder port.

[jayray]

Thank you so much for posting up that link earlier on. :thumbsup:
I'm only part of the way through that thread, but already mindblown. Love seeing that level of engineering work being available for the world to see
:brill:

[Goldy]

On forced induction engines the plenum design is not so critical as the air is getting rammed in there. On an N/A its more important to ensure even velocities and flows to each cylinder. My supercharger book suggests that centre inlet is generally the better and simpler to design to get a balanced airflow.