Common plenum or individual runners???, for gas milage and drivability Options

[Mueller]

for my 2316 it seems that the stock plenum might be reaching it's limits as far as volume goes.....so, I either fabricate a larger common plenum, or go with individual throttle bodies such as TWM or Jenvey*

single plenum would be easiest, but the individual throttle bodies look better (IMG:style_emoticons/default/smile.gif)

has anyone switched from one to the other on the same motor with everything else being the same???



*Jake Raby is the U.S. distributor of these....

[914efi]

This is what I built for my 2.2E engine. It seems to work well (nothing to compare to). The runners are sized to match the port dia. I have had lots of problems with low speed driveability, but have now traced it to factors other than the manifold. I am using SDS, and it does not do a good job with engines like this that have low vac at idle. The megasquirt system will work better where you can program MP settings at specific rpms rather than just relying on MP signal. This was not out there when I did this, or at least I was not aware of it.

I think I might make the runners a bit smaller in hindsight, since the restriction from the heads is the limitation, and the smaller runners might help the low speed a bit. The TB is from a 3.0L Nissan, and I reduced its dia a while ago to try to get more progressive tip-in. I don't know the actual size, but I can measure if anyone needs it. If you watch your MP at WOT full load, and as long as it stays at atmospheric, you know the TB is not too small.

BTW I have moved the injectors to the ports since this photo was taken. once again for better low speed work. I am using injectors from a 3.2, and this also presents a few problems as the duty cycle is so low at low speeds, that the output can double very quickly.