This is a Port I recently did for a customer. It's a pretty wild ported secondary side housings and a mild port on the center housing. I posted this pic to keep giving people an idea into porting. Remember that besides changing port shape you also need to change port volume inside the tunnel of the port.



First a pic of the stock port.

Large streetport more then 30% larger towards the intake opening.

different view part II

How much of the corner seal is supported still? I'm trying to compare this to a bridge in my head and it seems you've removed most of the material you would normally leave for the bridge itself.... https://www.nopistons.com/forums/pub...IR#>/wacko.png



Can you post a comparison pic?

1/4's of the corner seal is supported by what is left of the port wall. I've done this type of port for another customer.(I won't say anynames https://www.nopistons.com/forums/pub...DIR ) but this port makes nice power throught the low,mid and high RPM range. This type of port has landed 700rwhp on 32lbs of boost with a 150 nitrous shot. to Xtreme of a wild port..

Beautiful https://www.nopistons.com/forums/pub...IR#>/bigok.gif



Does it make good low/mid range power due to the "mild" porting on the center plate and huge top end due to the size of the secondaries?

Yes Mr. Justin. I like to call it the best of both worlds. Mild and wild street ports.

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!!

Strange. This is the only pic I could find showing the beggining of the port runner. Ill take a pic tomorrow and post it.

You do mean that 3/4's is unsupported right? I have a port that I did down at the shop that only supports 2.5 mm of the corner seal. I was scared shitless when I ran it. It was fine though and eventually I decided to try something different. Everytime I build a motor for myself I try something different as far as porting. I like being able to see the differences for myself.



Very nice port by the way. Now I want to pull mine apart and try something else.

Corner seal has about 1/4 of its body supported. I love this type of large streetport only on secondary side housings for street cars.

I wanted to let other members know that this type of port while it works lovely and makes awesome power it could only be used with 2 piece 2mm apex seals or 3mm apex seals. The port is so large that it will swallow a 3 piece 2 mm apex seal. The 3 piece 2 mm apex seal is divided in half and the inner half of the seal will not be supported by the large port. Did I say wild?

To give you more of a professional answer, I installed the rotor housing and Rotor with the corner seal on and measured. I see half of the corner seal being supported by what is left of the port wall. Surely Xtreme porting. I will be using solid corner seals and a 2 piece apex seal. I remeber making this type of port for a 12A engine I use to run in my street car back in 1988 and when does secondary ports kicked in I was like WHAT!!!!!!!!!!!! felt awesome power and nice G-force. I have another engine running this type of port. I build the engine in 1997 and the engine is still running strong(has not been taking apart since 1997) car made 327 rwhp on 10lbs of boost on a 1988 turbo II using the factory Rx7 computer with bigger secondary injectors, stock intercooler stock fuel system and To4-e turbo we bought for 100.00 bucks. This turbo II ran a best time of 12.2 @117 mph at 10lbs of boost. Xtreme porting But yes nice power indeed.

holy ****. Thats awesome! So basically you put the rotor in the housing, marked off where half the corner seal was still supported and then ported it out? Wouldnt that put an extreme amount of pressure on the apex seal? Im very interested in this port, since im going to be spooling a big turbo, i want as much gas flowing as possible.

I would say, because only the ends of the apex seal is expoxed to the opening of the port there is no concern. Besides that, the ends of the apex seals are being exposed to the coldest part of any engine cycle that the seal is involved with. No worries about pressure. Remember apex seal could withstand some serious combustion pressures. They just don't like detonation.

You doing your homework and being able to understand what your getting yourself involved with is purely intelligent. I would advise to anybody to do as much homework as possible before taking on a job like rebuilding an engine. Basically you want to take away all the guessing and work with facts that have proven performance and reliability. what type of 3mm clearance are you asking me about? there a few of them.

To give you more of a professional answer, I installed the rotor housing and Rotor with the corner seal on and measured. I see half of the corner seal being supported by what is left of the port wall. Surely Xtreme porting. I will be using solid corner seals and a 2 piece apex seal. I remeber making this type of port for a 12A engine I use to run in my street car back in 1988 and when does secondary ports kicked in I was like WHAT!!!!!!!!!!!! felt awesome power and nice G-force. I have another engine running this type of port. I build the engine in 1997 and the engine is still running strong(has not been taking apart since 1997) car made 327 rwhp on 10lbs of boost on a 1988 turbo II using the factory Rx7 computer with bigger secondary injectors, stock intercooler stock fuel system and To4-e turbo we bought for 100.00 bucks. This turbo II ran a best time of 12.2 @117 mph at 10lbs of boost. Xtreme porting But yes nice power indeed. [/quote]

Cool, I guess I judged the pics wrong.

The 4 650cc injectors will tune the all motor set up then a 250 nitrous oxide shot https://www.nopistons.com/forums/pub...#>/biggrin.png will tune the rest of the engine.. landind me that 500hp Xtreme NA stuff but Im going for the record.

Wow! https://www.nopistons.com/forums/pub...1047683894.gif Does a port like that affect idle? Thats the most incredible port ive ever seen.

Idle tries to stabilize but every once in a while you'll get the lump in the idle. Something like this. ---------^-------------^----------------^---.

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.

more pics.

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?

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

Whom ever spoke of such things should be in the know.At the last resort call upon the engineers at Downing Atlanta. Send Rick Engman $50.00 bucks for his time and a check off list of numerical data that you must have answered in your quest

for the ultimate street rotary.( unless your in E prod then contact Darrell Drummond). These guys have in house dyno, Mazda support and have lead the racing world in every form of rotary racing. (except drag...Puerto Rico is light years ahead)This is were the experiments can be afforded as well as dyno numbers to support each endeavor.Best O Luck

P.S. I did.

generally the bigger the port the harder it is to get it past smog. the extra over lap hurts the idle smog numbers

Hey Judge! Have you ever used this style of porting on a 20b engine? How much power do you think a 20b would be able to put down with this style of porting(without NOS)?

I ported a 20B using this exact port. The car is a Mazda MX6 full tube that recently was showcased in an NHRA sport compact race. The engine made 930 rwhp on a huge thumper turbo with VP c16 race fuel no nitrous on 29lbs of boost, double throttle body intake manifold.

the reason for eyebrow shape on the closing edge of the port is for the effects of inertial supercharging right? Ito san? because the intake port closing has the greatest effect on VE of the intake cycle as it is trying to sqeezed the last/max of air charge in the chamber. right? it has to do with trying to increase the velocity of the intake air though a narrower passage?



thanks

You are correct. besides increasing power and torque. This you will notice in the effects of acceleration. It takes less effort to rev an engine with this style of closing the port in comparison to stock ports.

Thank you! Ito San. https://www.nopistons.com/forums/pub...1047683894.gif



This is great stuff, you have inspired me! I am very much appreciated!! This is like my long distance corresponds course on "Judge Ito's Rotary Porting School".



So, we had touched on the issues of port tunnel shaping and port eyebrow/closing.



Here is my some of my questions:



Does the eyebrow/closing technique ONLY apply to secondary and aux ports? What about the primary port, what can we do to enhance the efficiency of the primary port? Can we apply the eyebrow technique on the primary port? Or there is some difference technique for primary.



I am aware that, a primary port is part of the maximum CFM air-flow a rotary can digest; moreover, I am also aware that the main function of a primary port is generate a high velocity charge through a small channel/port to aid torque and improve air/fuel mixing, during low rpm operation.





After I have good understanding of how porting effect the performance of a rotary, I will ask more specific questions about how to attack a S5 N/A 13B to achieve maximum area under the curve, for a application of high performacne street driving with a chance to past smog test, autoX, track lapping day.

I am going to be porting my engine over the next week, using the information in this post, I am just wondering about the side seals, if the leading edge could fall into the port if you port outwards with only 2-3mm of coner seal supported?.



Thanks

Jason

Yes, the side seal crashing into the closing edge of the port is an issue. I will address it with pictures and my recommendation in how to fix the problem. Sideseal to port closing edge is another chapter in itself. Ill reply soon with detail pictures and explanations.

Ill throw in this picture of an extended port. I didn't want to make a new thread on a smaller port.. this port opens a bit later and closes a bit earlier then the wild streetport. I just wanted to keep showing some options in porting sizes. I would post a picture of a mild port but Ito doesn't do MILD. Porting size could be fitted to any application(meaning RPM range and horsepower through rpm range) once you have the intake manifold to match the port size...