Thanks Tracy!1  Real Good Info.
You'r 20 inch runner manifold sounds like what I am wanting hopping for.

We're all waiting for the RV-8 to get airborne.  It really should be a ROCKET!

Dennis H.

Tracy Crook wrote:

Dennis,
Yes, it used a dynamic chamber to direct the pulses from opposing rotors into each other, hopefully at the right time.  I currently use an open plenum on the Renesis with short 13.5" (but very clean) runners.  I'll never know what the old manifold was really tuned for without a good dyno run but it was better at takeoff & climb (about 6200 - 6300 rpm) than my current manifold.  New one can only manage 5800 - 6000 at takeoff   At 7200 - 7400 the new one takes the lead.  You can actually feel the engine get stronger as it accelerates through 7200.  Unfortunately, there are almost no occasions to actually use the engine in that range with a fixed pitch prop.  It sure would be a rocket on takeoff if I had a variable pitch prop though.

ROC on old manifold was 2650 fpm, solo, 12 gal fuel on board, standard day conditions.  New one can only manage 2300.

Just finished plumbing the fuel system in the RV-8 with only a few fairings and position lights left to install before first flight.  Hoping for about 4000 fpm ROC. 

Tracy Crook