NoPistons -Mazda Rx7 & Rx8 Rotary Forum - Judge Ito's porting school thread

NoPistons -Mazda Rx7 & Rx8 Rotary Forum (https://www.nopistons.com/)

- Rotary Engine Building and Porting FAQ Section (https://www.nopistons.com/rotary-engine-building-porting-faq-section-85/)

- - Judge Ito's porting school thread (https://www.nopistons.com/rotary-engine-building-porting-faq-section-85/judge-itos-porting-school-thread-29264/)

Quote:

Originally Posted by GTUs' date='Nov 26 2003, 12:31 AM

excellent!

https://www.nopistons.com/forums/pub...1047683894.gif

Judge, do you have picture of the runner of that port. like you said, the shape of port open matters, but the shape of the tunnel/port matter a lot too.

My understanding is that the tunnel/port runner suppose to shape like air nozzle which has throw/choke point and discharge/divergence. the area of throw/choke point determines the max amount of CFM(Velocity x Area - Losses) before it choke.

the way you shaped the port opening or should I said the way you shaped the discharge section matchs to my ideal port shape for discharge, that I had in mind. It will be nice to see how the master shape the tunnel!!

Inside runners. When the inside runner is being ported your looking for a NO resistance port. The idea is port in a way that will allow the air fuel to flow right into the rotor chamber with minimal resistance, from the upper and side edges of the factory port. Factory ports have a ventury to increase air flow and low rpm torque. Is good to port some of this ventury away but still keeping a slight lip of the factory ventury to keep aiding in air speed. Overall port size needs to be increased to allow more cfm to flow. Bigger is not always better it all depends for the type of Power band your looking for.

I have a 2 step type of finish I give my ports. First I blend all the rough cut left by the high speed grinder with a slow speed grinder, then I blend a smooth port with a slower speed on the grinder. I don't like a glass finish on the ports. Not many people do. Personal experiences has landed me a better tunning ability with a smooth finish but not a glass finish.

More pixs. notice the upper flow. its flowing right into the closing edge of the port.

This is the upper part of the plate. upside down. Here I left a visual line so you could see the way it needs to be ported from the outside of the port to the inside of the port. A nice path from one point to the other then blended together. This line was blended later on.

when you say the stock ports have a venturi built in, are you talking about the slight narrowing of the port a few mill's from the manifold side entrance?

Quote:

Originally Posted by Drago86' date='Dec 11 2003, 12:11 AM

when you say the stock ports have a venturi built in, are you talking about the slight narrowing of the port a few mill's from the manifold side entrance?

Yes... The outer edge of the port by the lower intake manifold side has a ventury.

Those are beautifull and very clean, what I'm interested in knowing is wheather or not there's any chance passing emissions with those ports making about 450rwhp. I really want a car that can kill the 1/4 and drive me to school plus the occasinal (yeah right, I meant frequent) highway pull.

Awsome work Ito

Ah, now I see what you mean by making it a smooth but not glass-like finish. Awesome pics!

Possibly slightly off topic, but I have heared tell of cases where builders have chamfered the rotor edges to increase timing when regs don't allow a bridge.

Looking at the shaping of the closing edge of the port, shaping the rotor at that point could be beneficial over that last 10-15 degrees of inlet duration. May also have some benefit at inlet opening as you are channeling the air down towards the exhaust.

Means you then have to get the whole thing balanced, but wondering if anyone here had seen this done?

Bill