Type IV plenum intake manifold questions..., Why single and not double like the 911 motor? Options

[Mueller]

Has anyone made a dual plenum like used on the 911 engines for a Type IV?

[Jake Raby]

When I've gone this way the result was an even more difficult to tune engine that was much more picky about cam specs than any other way. I've always had better luck with twin ITBs over a central plenum or a pair of localized plenums.

Only once has this made more power here and that was a 2.6L engine for a square back where I was able to get 80% of the engine's displacement into a pair of plenums. It wasn't worth the 6Hp that it made.

This post has been edited by Jake Raby: Mar 14 2015, 10:29 PM

[Mark Henry]

When I've gone this way the result was an even more difficult to tune engine that was much more picky about cam specs than any other way. I've always had better luck with twin ITBs over a central plenum or a pair of localized plenums.

Only once has this made more power here and that was a 2.6L engine for a square back where I was able to get 80% of the engine's displacement into a pair of plenums. It wasn't worth the 6Hp that it made.

Your statement doesn't explain much.... (IMG:style_emoticons/default/dry.gif)
As far as the plenums being 80% that would be about the size of a connecting tube and two 1-quart (1 litre) oil bottles (or for a single plenum one 2-litre bottle).

Here's what it takes to fab a single plenum intake
http://www.sdsefi.com/air12.html

Simple search may give you some ideas
https://www.google.ca/search?q=EG33+intake+...anifold+project