Looking for feedback in regards to a 20b PP exhuast manifold design.

As some of you know, Im installing a PP20B into a radical 914. I have quite a bit of room for the exhaust.

Over on the pcar forums they were telling me of the crazy runner length that the PP guys use. One guy said 96 inches! the collector was mounted next to the rear end of the car.

Id like to understand PP rotary exhaust theory. what are the differances in the optimal design of a 2 rotor exhaust vs a 3 rotor?

From what i understand the right exhaust design can make a HUGE differance over the entire range of the power band.

David

 

from the pcar forum:
" Header primaries and secondaries are very important. I am talking 30hp important through out the rev range. Our car has 96in long primaries. The collector is under the rear axle. You should talk with Downing about how long or short the primaries should be."

He gave me Jim DOwning's contact info, and will be calling him soon. Just wanted to get educated first.

 

calling rotarygod. . .

 

Ill call Downing as recommended, and report back. Another thing ive been thinking is using a transition to enhance scavaging
http://spdexhaust.com/TransitionsB.html