I am a newb to the rx7 website and the rotary motor as well. My cousin just got an 86 n/a for his birthday, and was thinking of mods to do without going turbo. I've done some searching and I just can't find exactly what the types of porting there are, and what are you porting. Please don't flame me if this is repetative, but I just can't seem to find the answer i'm looking for. I'm familiar with porting and polishing when it comes to conventional motors and heads, but the porting on the rotary motor keeps me wondering Thanks, -Dave-

 

it helps to know what the ports look like. have you pics of anything??

 

well, what do you know? understanding how an engine works helps. understanding how air works maximizes that. creating new and innovative ways to move air helps further.
but we're just talking about the engine.. if you understand the ports, than you'll understand the "porting" process.
http://www.rotaryengineillustrated.com/
http://www.monito.com/wankel/
http://www.iluvmyrx7.com/index.htm

basically, street porting just involves increasing the intake ports where they need to be extended. also, smoothing out the runner.
a magazine just recently covered the process. i want to say it was Modified Mag, but i could be wrong.
maybe someone will post pics. i dont have any on me.

casio

not to mention that porting also requires a rebuild. you have to tear down the engine to do so, and it would not be wise to use all the same pieces over again, though some are salvageable.

 

I do understand the engine, I guess I didn't understand what you ported if there was no conventional "head" Those links helped out, thanks. I do understand that to port the engine is to open up the intake and runner, you helped me find the answers thanks again.

 

http://fc3spro.com/TECH/PORT/porting.html


-Ted

 

and i would suggest NOT "opening" the port sooner in the intake phase, only widening and extending. also, you can buy templates. they only act as a guide for the face of the housing's surface. its a 3d object, so the rest is up to your (hopefully intelligent and creative) imagination.

 

Uh, widening the intake port does open the port sooner.



-Ted

 

It can make it open earlier, it just depends how wide you make it

 

i want to ask "how so?," but its hard to ask without a picture. trying to make sure we're on the same page.

 

Look at a typical intake port in the side iron...
It's an upside-down teardrop shape.
You cannot port inward toward the center of the iron, as this will cut into the oil control ring path; cutting inward will cause oil smoking due to excessive blow-by.
A lot of people port outward, opposite of the center - and THIS increases the opening timing or opens the intake port EARLIER.  You need to get a solid idea of the relation of the rotor position versus the port position to understand this.
Increasing the duration (i.e. delaying the closing) of the port is done by porting "upward".



-Ted

 

Also, don't port to big using a stock ecu..You tend to see alot of overlap and the ecu stubbles so to speak... I guess that pertains to BP for the most part.. The standard RB templates are a good place to start for an N/A....my point is that the stock ecu is limiting