How To Streetport A Rotary Engine Part One

[jesusjcrrotary]

Thanks for sharing. I've been porting for a very long time and have found most of the power and response in the bowl and back cutting inside the opening edge. As for the measurements to the edge of the side seal, there is additional space between the rotor housing and the edge of the rotor. I determined this by assembling a rotor/stationary/housing and iron so I could see its assembled clearances. I like to keep the guess work to a minimum. Additionally, most of the squaring of the port between the opening and closing edge is meant to protect the closing end of the side seal which is equally important. Again, thanks for sharing!
JCR Rotary

[Thehairyhippie]

i love these videos, im a mechanic by trade but never been in an engine in this depth. I own a 91 FD, and was thinking of street porting as it requires a low compression rebuild. what i would love to see is what tools you are using, also, please assume i dont know what your engine slang means. Explain everything.

[UpdogGolf]

If you havent already, you should make a video on technique with mat removal, youre absolutely text book no scribbling just right to left layers. Thats one of the most easy ways to ruin the port/iron by just trying to remove as much as possible as quickly as possible. I think youve got the skills and knowledge to give a good tutorial video on that. Beautiful chamfering bud.

[mecab]

Wich Dremel is this ? And what carbides did ya use ? 1/4 1/8 Awesome work guys 👍

[DartzIRL]

Stupid question time, but a thought I had while watching.

Polishing the exhaust port runners on a renesis?

Seems like there'd be a benefit to preventing carbon buildup by smoothing the surface - and to reducing heat trransfer to the cooling system/iron from the exhaust, along with the reduced surface area.

[josega]

What about an RX-8 housing, with a PP added, rectangular or square, controlled with the twin peak Ford Canada patent Reed-Valve, closing the side intake ports, and keeping the side exhaust ports?
Would this keep the best of 2 worlds? Salut +

[AlikaSEOULROK]

Now i'm very certain I don't want to do this myself.

[rudyvargas]

what's better Bridgeport or streetport.... want lots of HP but also drive it here and debating on which one to go with. what do you suggest?

[Drunken_Hamster]

How much further up past the template and in towards the crankshaft could you mill these? Basically, is there any MORE that you can port it without doing Bridge, Peripheral, or anything that would severely lower MPG, reliability, and low end power?

EDIT:: Just heard the part about porting the runner and the intake. What're the effects of those? Can it be combined with the street port for improved performance without the negative effects of PP and BP and whatnot?

[deeremeyer]

Agreed that the bridge porting is the stupidest "power modification" ever for a rotary, which is already low-speed/high-load challenged and doesn't need any more problems getting a good clean air/fuel mixture into the engine. It MIGHT have some "value" in turbocharged engines, but only because its using boost and fuel/air to help overcome exhaust backpressure and maybe burn the air and fuel in the exhaust ahead of the turbo to increase exhaust gas heat and energy to "spool" the turbo better. But you're just making more boost and bypassing more of it as that happens.

I'd also say that your porting is probably mainly a waste of time. You're basically opening up an area of the port that unless the rest of the port all the way back to the intake plenum is opened up similar to support and feed it, really isn't increasing flow. There might be a slight benefit by making "port closing" more gradual and controlled rather than sudden so reversion is decreased and "swirl" is increased, but other than that, what you're doing is like adding a little valve lift or duration to a stock engine that's really already limited by the INTAKE SYSTEM AHEAD OF THE VALVE.

You claim the port is "much bigger" but you're not enlarging the actual "port". What you're doing is more like creating a larger valve seat and changing nothing else. Getting rid of the sharp edge might reduce the tendency of the engine to detonate and it might make seals dragged across it last longer, but otherwise its really not gaining you much.

As you said, no two irons will be cast the same, and I'm guessing that template is one someone came up with using the largest factory port they came across in a factory iron and maybe from a "special" high-output factory engine or maybe a "high altitude" engine. Its also worth mentioning that ACTUALLY increasing port "size" (actual porting increases VOLUME) tends to make the fuel-air mixture "lazier". Given the design of the engine, that might benefit low-end power, but every "improvement" comes with a drawback. That's just how engines are.

[deanphillips]

Thanks for the vid. Am I right in thinking the old 12A (R2?) side housing has the biggest port to start with?

[darianistead]

I have a 2002 S8 RX7 and I've gone extend port and a little further down with overlap as you said not to but it goes alright. It made 509rwhp @18psi and boost comes on around 4200 to redline. I know overlap in boosted applications isn't ideal except oddly in antilag situations as evident in my big cam/turbo evo that's responsive af.. I was looking to go to a half cut Bridgeport to keep it drivable instead of a full cut bridgey but still have that pulse

[MM-opti]

What are the power gains with stock parts? And with full exhaust/ intake/carb?

[DMSBrian]

How much is the average engine life expectancy reduced when doing this street port? On either turbo or non-turbo FC

[jamesannis]

How much port until a new ecu is needed?

[robertmontgomery]

Any ideas where a new RX-7 owner can go in the Southeastern Wisconsin area for engine and tuning work???

[fnestmemes]

hey i'm new at rotarys but i want to own a rx8 soon and want to learn much about it. for what are these ports? hp? turbo build? fueĺ safe? can you explain it in easy english :D much love from germany! :)

[twcaldwell]

lengthening the port causes it stay open longer, allowing less time for compression to build. isn't that going to reduce torque?

[wildchild]

some of the things are right but i have to dissagree with alot you have done. what your saying about side seal isnt right. you can open up intake porting from the side a few mm from stock. and the edge where opening and closing is has to be acute angle to prevent the closing side seal not the opening.

[MinhDangcraft]

Is anyone still selling 12a housings? Isn't it not produced anymore?