Plenum Size for peripheral port.
 

Howdy all, thinking about intake side of things for my 'soon' (read: more than a month..) to be put together peripheral port motor.

It has ~50mm runners, was considering making these long (400mm or thereabouts) for a wider power band. More concerned about <8,500rpm efficiency here, so tell me if i'm going about this wrong (with regard to runner size/length).

Then connecting those runners to a plenum, this is where i'm stuck at, I would not have the foggiest idea how big it 'should' be for a PP motor. What would be the consequences of a large one opposed to a smaller one?
What are the tradeoffs invovled?

I was _thinking_ about a 4in or so sized section of pipe about 220mm long? would that be in a ballpark?

It will be dual throttle body setup with the throttles (50mm ones) mounted very close to the actual port, as in, as close as you can get. So i'm not doing this plenum to make it one TB only, just doing for efficiency's sake (if there is a decent ammount to be gained that is).

Anyone with any input?

The only suggestion I can offer is to look at a piston based page and use the info there. Check: http://www.grapeaperacing.com/GrapeA...tech/index.cfm Click on the induction link and read the section on Helholtz resonators. Treat your 13B as a 2.6 litre engine and you should be fine

Hope this helps,
-Trent