Just my guess but I disagree that the "air rushing past the runner" caused the EGT imbalance.   I think you can blame that ( as well as the puddling of gas in the plenum) on those injectors pointing the wrong direction.

Tracy

Sent from my iPad

On Aug 8, 2011, at 1:01 PM, Ernest Christley <echristley@att.net> wrote:

> Ben Schneider wrote:
>> That is exactly what their intentions are. Crissi mentioned a couple of ideas they had about upper manifolds. One of which is a plenum on the end of those runners, coupled on with hose sections as mine is, then one large tube feeding the plenum up through the center (i.e. the large tube would lay parallel to the runners shown and couple to the manifold in the space between runners 2 and 3). The other would continue on across the engine to the other side, still another option would be to feed it from the front or rear based on cowl clearance and airframe.
>> Ben
>
> That last option has some hidden snakes lying in wait.  I did basically that, except with a composite plenum.  The EGT of the rotor feeding from the rear of the plenum was about 300* higher than the one feeding from the front.  I theorize that the air rushing past the front runners were creating a partial, albeit localized, vacuum.
>
> Heh, Cozy Girls, if you're monitoring the list, I can send you pictures of what I know WON'T work, and a picture or two of what made things better.
>
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