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.



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...