Grizzly

I am trying to find out as much Information as i can on peripheral porting a rotary.



Does anyone on hear have any good links or built one?



I would like to build one but dont know what exactly to expect? i have been told they can be made with less overlap than a Bridge port but i have never seen a P/P engine close up let alone driven one so a Pro Tuners input etc would be helpfull.



Thanks.

Node

The old NSU wankel powered cars had peripheral ports, but they were small. Made for lowend and midend I believe. One had a automatic and was FWD.

Dragon

Talk to Judge Ito or pinaple racing.. they are who you need to get your info from..

Grizzly

So it all depends on how its made?



I do have some options from a Masive D port that i would expect no low end power from so a small round port.



The guy who will be doing the Housings for me says he cuts the ports high up the housings to keep overlap down as much as possable whilst still giving it good gas flow.



The other thing i'm looking into is the manifold, how long to make the manifold before i fit the Throttle bodys etc?



So i'm doing lots of reading at the moment.

DJ Rotor

How long you make the manifold will depend on where you expect the powerband to be; the more top-end biased you want it, the shorter you should make the manifold.



J

Grizzly

Yeh it would make sence that the distance between the Inlet port and the Throttle body would change the power band .



So if i peripheral ported it (quite large) thus making 80% of its power high in the band i should make the distance between the port and Throttle as long as poss to bring the band down a bit?



Also i have been playing with a Bridge Primary and have noticed the port opens alot sooner than a peripheral, i relise this will help a bit with the over lap but how will cuting bigger (upwards) change the running of the Engine? Does it come down to the bigger the port the slower the Air/Fuel speed at idle and low speed?



Thanks.

Grizzly

Does anyone have pinaple racing's site address?

DJ Rotor

http://www.pineappleracing.com/index.html



Google is your friend



Regarding your other questions, my tendency (NOT having done this before) would be to use a short intake to maximise power, and to heck with the powerband. Your dyno chart is going to look like a cliff anyway so just make it go as high as you can.



The bigger the port, the more high-rpm biased it is as you correctly stated, because of the mixture velocity. Bigger port, better flow, but worse low-rpm performance because of lower mixture velocity. Cutting higher would also affect the timing, although I'm not quite sure how - where's Judge Ito when you need him?



J

Grizzly

So small is better for Low/Mid range.

j9fd3s

peripheral porting is kinda wierd. the only off the shelft parts are for racing so they are setup for peak power in the 9500-11,000rpm range (320hp in a 13b). since the racers didnt care about low rpm power the housing are not deigned for it. if you made your own housings you would have the freedom to move the port timing around and alter the power peak/torque curve.

the racers also tended to use short intake systems, but the 787's used a varible length one to broaden the power curve.

so pp has been well developed for road racing, but hasnt had much development for a street car since the nsu's



mike