FI Plenum Design, MS'ing my 2270 Options

[Tom Perso]

Hey Guys,

I am designing a MS system for my 2270 (163.86b cam, 48x38 valves, future Triad header). I am looking at running stock intake runners and possibly making a new plenum to run my Ford TB (probably from a 4.0L Exploder/Ranger).

Are there any "design guidelines" that should be followed when making a new plenum, such as a certian volume required for engine displacement?

Looking at space requirements, I see running the TB on top of the plenum is the only way to go. That, of course - begs the question... Is the stock 914 2.0L plenum a good starting point to modify to allow for the Ford TB?

Here are some pics for reference... I had a Bus 2.0L intake system to borrow, so I am basing my measurements and ideas off of that.

http://www.qtm.net/~persot/MS/

Any ideas, suggestions, etc, are appreciated!

Thanks,
Tom

[Jake Raby]

With the cam that I set Dave up with, his plenum has a better chance.

Something with more volume would always be better, but I won't know how much better till mine is done.

Tom, You need a cam change badly to run a common plenum system. The cam you have opens on a 104 center and is very difficult to tune at idle. It makes gobs of power but totally depletes that plenum with its early openings.

Been there and done that with the same cam. It is one power making bitch for carbs, but I'll never use it for FI again.. If you change it to a 110 center it comes to life though with FI and the loss of downlow power isn't there because FI makes more power at low revs than carbs..