As posted here & featured in issue #125 of Y-Block magazine, I'm very impressed with the design of the single plain intake for the racing Falcon project, that the Mummert's & associates put together.  Pulling 535 H.P out of approx 331 cu. in. thru a 4 Bbl, without power adders, is over the top!. Anyway, it got me to musing about it. If I understand correctly (?) single plain intakes are often effected by reversion issues, which is one of the reasons they are not usually street suitable . So, after kicking it around for a while, I've come up with a question, but first, we've never seen a birdseye view of the intake interior, so my question may be irrelevant. However, what if the plenum had a "divider" in it like a dual plain intake? Would that work & would it possibly be of any benefit? Just an idea..


Paul

The only issue with running a single plane intake manifold on the street is the lack of low rpm vacuum signal and velocity. The single plane high rise intake is made for higher rpm use in marine and racing applications. The main difference is the runner design and length. A longer and more narrow runner creates more velocity at lower rpm levels where as the open lower velocity design of a single plane allows for much more air/fuel flow at a higher rpm range where you don't require the velocity. Basically the power band is higher and therefore should be properly matched with camshaft, heads and compression levels in order to operate properly. Hope this helps...

PF
  From what I have read on the www.jalopyjournal.com Jeff Mummert has been studying about manifold design and this is his design for the race y-block. Without looking inside, he would be the one with the answers. He post on the site as OHV4D, so you could ask him.

Gary Ryan San Antonio.TX.

babor: Interesting info on single plane intakes, however, my main interest was the possibility or not, of of using a plenum divider. Thanks anyway.
girbird; Thanks, but I couldn't figure a way to do a specific search on the jalopy journal site, so I never found Geoff Mummert.   


Paul

Why would you want to divide a single plane intake manifold? Some of your higher end pieces have either sort of a short separator, but not usually more than about 1/2" to 3/4" past the runner in the plenum opening and others use a ribbed bottom plate in the plenum for air/fuel atomization. I don't understand why you would want to separate the runners. This I think would just cause you problems, especially if you had a carburetor issue with a clogged jet or air bleed that could cause the carb to act in an un-predictable manner such as a lean out. Where this would just normally lean out the entire mixture a little bit if you  separated the runners you could entirely melt down cylinders in this scenario. What exactly are you trying to accomplish? Not being cocky, just curious...

So to clarify
A single plane has a common chamber shared by all runners
A dual plane has a divided chamber to seperate left and right banks.
I guess dividing the chamber would increase manifold vacuum. However I'm sure John put a lot of though into this particular manifold to suit the application. Runner length, diameter, etc.
Additional to the subject of dual or single plane. I have recently read about valve angles and the effects they can have on flow. In this it was noted that they had found by applying certain angles in sequence a reduction of reversion can be achieved. It can be manipulated to allow flow better in one direction or another, inlet or exhaust.
i thought this was interesting and fitting to share.

http://www.jalopyjournal.com/forum/threads/y-block-dyno-day.938305/  Here you go paul.


Gary Ryan San Antonio.TX.

Awesome.
Wonder if it would perform on the street due to the long equal runner length?
Maybe the runners would need to be smaller dia.

If you get the Yblock magazine you can read all about it. It was not designed for low end power. Geoff Mummert is an extremely talented young man. People send him cylinder heads from all over for his porting expertise. Dad's no dummy either.

Frank/Rebop

Bristol, In ( by Elkhart) 

Those longer runner lengths helps to make Geoff’s intake a good street manifold.  From personal experience, using shorter intake runner lengths brings any reversion issues to the forefront with cylinders #1 and #2 being at the top of the list.  An intake design that makes another 20HP over the best ported aluminum dual plane intakes is definitely a step in the right direction.  I’m ready for the cast aluminum version of this intake.

Lorena, Texas (South of Waco)