Rotary Engine Porting Vs Drivability - What Makes a Big Port Unbearable on the Street

[@orbitstrid3r]

So glad I discovered your channel just as I bought my first gen. Picking it up this weekend and I'm already loaded up with rotary/Rx-7 goodness!

[@sjhart14]

This video was super helpful. The "stabilization of airflow" concept is the piece I was missing about why cammed/ported engines surge and buck.

[@RADPotential]

I think im going to do a video on airflow for next week. Going deeper into that topic and the hardships it has on tuning

[@88Frank]

So informative. This is the video I've been looking for for months!

[@6ixbanger]

Thought I was very knowledgeable about rotary. I learned something new. Thank you for breaking down. Easy to understand.

[@RichardPope-b3y]

What's causes the loping idle is exhaust gas dilution of the intake mixture. The mixture misfires. Because it did misfire the next intake phase or stroke is not diluted. So it ignites normally. Fire, musfire, fire, misfire. Brap, brap, brap. At higher rpm the exhaust gases flowing out of the port helps to drag more mixture into the engine. More power.

[@rafaelmontanez1667]

Dude if you organized a video over the course of a week and did a white board behind your camera to stay on track. I think you would have the best rotary channel on the planet. I must say I can follow you just fine but, I'm sure there are people that struggle to keep up. As far as content and knowledge imo your 10/10 but I'm only going by what I've read on forums and books. Thank you so much for posting these. Feel free to reach out if you don't understand what I'm trying to say. Shit reach out to me if you need a padawan 🤣😂🤣 I think it be great to learn this hands on!

[@franco4182]

Recently purchased my first rotary, 1987 Rx-7 GXL, your channel is incredibly detailed and informative definitely had to subscribe. Thank you so much!

[@ottolohr]

Nice description of the port differences. The stud reference point detail really showed how port size is difference between irons. And white board worked very well to explain how removing material in difference direction impacts intake cycle.

[@iLuv4Play]

Bridging just the 5th and 6th ports is exactly what I was planning on doing with my '84 SE 13B. Pairing with a 48 DCOE Weber. Also I was hoping you'd cover exhaust port timing, and how they differ between turbo vs NA.

[@RADPotential]

It's just a lot to cover in one video. I can make another one for that

[@nobullshiit5682]

Yo man love your show , its great to hear all the knowledge about rotary engines. I use to have a gen2 turbo it was a great car loved it and im thinking about getting back into rotary engines so keep them coming and ill keep watching . could you talk about or even do a build on bolting two 1.3l engines together to make a 4 rotor engine that would be awesome , thanks again man take care

[@miatalife94]

Subscribed!, All Mazda sport vehicles are underrated thanks for getting deep into something that's pretty niche haha

[@AvoiidTheVoiid]

I definitely needed this video, thanks man it up!

[@jasonskinner1652]

Awesome man. Thanks for the vid. I was wondering if you were gonna get into exhaust timing too. Especially with the low duration rx8 exhaust. But then come up with the idea to adapt rx7 housing to a renesis and somehow maintain side ports too. Anyway, cool channel. Hope your ad revenue picks up!

[@tommygibson9515]

Got a 12a extended port, your making me second guess, buying an ida, also love the channel could here about rotors all day

[@rockyhernandez5978]

This is awesome. Keep up the good work! One day I would like to street port my FD.

[@stlchevy95]

one day, i would like to own an fd

[@BobNew-n5i]

I drove a 13B FULL Bridgeport on the street for years. Copper clutch with lightened steel flywheel. Never a problem, no overheating.

[@whitenite007]

Excellent video. I knew half bridge was a thing but didn't understand primary and secondary intakes.

[@kaizousha5531]

Have you ever done a compression test on an engine with 0 miles, particularly on used housings? I just rebuilt my renisis with what I thought were great condition with all new hard and soft seals and a half bridge. It started well and sounded great, it even hot starts relatively well which is crazy because it only have 70 psi in each rotor!!!! I plan on doing another test very soon however each rotor was within 3psi of each other which is perhaps the only good sign.

[@RADPotential]

Yes. Go back and check out the video on the overheated 12a rebuild. Specifically the corner seals and compression loss topic

[@kaizousha5531]

@@RADPotential i had some noticeable step wear on the irons too..... I think that might be the underlying issue. The housings seemed to be in such great condition I don't think that would cause my numbers. Thank you a million bro!

[@RADPotential]

You won't see amazing compression with used housings until the apex seals have time to settle in.

[@kaizousha5531]

@@RADPotential I figured, just didn't expect it to be this low, we'll see after 1000 miles or so haha

[@ChErRyaVe20pK]

@Kaizousha I know its been a whole year. But any updates?

[@daviddetweiler7658]

Doesnt the "brap" happen because the engine is literally misfiring multiple passes until it gets a strong pulsed fire? especially a peripheral port. You only hear the "brap brap brap" because its idling at 2000+ RPM and is missing all those other revolutions due to an improper mixture.

[@nottobay6768]

The improper mixture is because of the overlap so yah kinda.

[@MrMyshed]

the best rotary port vid on ytube awesome

[@efaracing4000]

Cracking video mate! So much radformation to gain from you thanks

[@RADPotential]

Thank you sir!!!!

[@grantlister]

What about running Twin Weber’s?

[@ChristianGonzalez-xk1nr]

Where are you located ?

[@jfqp21]

My dude thank you for all the hard work, appreciate it the information

[@theredwedge9446]

So does bridge porting just allow more airflow but doesnt cause exhaust scavenging due to the rotary design ?

[@marakihiakita5336]

you need some monster bridge port templates knon as a j port in some country's like here in new Zealand

[@RADPotential]

Yes sir!!!! I would love to have a bigger port to replace the bridgeport 12a I have

[@benvlassoff6378]

Full Bridgeport is the minimum in New Zealand

[@abdulwaseer6054]

Sorry for asking this again. Hey Eric! I hope you are doing great. I have a question. I don’t know why but the fc just speaks to me. I am saving up my money but here is the thing. Nice fcs go for 10k up to 15k and the ones that don’t run and have been sitting out in Mother Nature go for like 2k to 3k. As a newbie which is me I WOULD LOVE AN FC. Should I buy a cheap up and enjoy the process to rebuilding it myself? Btw if I do this will be my first car!! Please I’ve been stuck with this question and people talk down on me for loving the fc. I would love your answer. Thank you ;)

[@michaelgarrison4281]

Very good channel. What in your opinion is the best set up for the most power retaining idle using a 4-barrel Holley?

[@Pheo0811]

Why didnt mazda just close all sideports and just do one (semi) periphal port per rotor?

[@frankwhite2072]

Would you liken a half bridge port to a rotary version of V-tech?

[@rip_biggie4202]

What is the best intake set up for a gsl se motor? Originally I thought some 12a irons, 4 port intake and along with a healthy amount of porting. With the lack of availability on 12a irons I’m starting to wonder if a couple racing beat p-port housings would about as economical plus part availability. Just looking for direction in my build, anybody with experience on could chime in, I’d appreciate it

[@VictorMPR]

So half bride porting is the Wankel equivalent to… VTEC!! Best of both worlds, in a way. This was a really cool, informative video. Thank you!

[@mitraramsaroop6275]

Very bless best channel for information keep up the good work bro

[@Jmhrx7]

great vid erich hope this video takes off for ya love the content

[@theredwedge9446]

I found it so cool that porting a rotary is just like a changing a cam inside an engine.

[@CapMC47]

Extremely aggressive "raceport" on a 4 port NA ecu, will it run??

[@davebruce88]

Thanks for this. I am considering porting.

[@jasondayberry9906]

Great video as usual. 1 port I have not heard alot about is the J port! Especially how u cut coolant seals ect.. any idea if you will make a video? Would be badass..

[@RADPotential]

I haven't ever been around a jport. I'll see what I can do

[@jasondayberry9906]

If u need a junk plate I can send one 😃

[@anyau]

Question, I have a completely stock NA s4(6 port) and a half-bridge port sounds good from how you described it,. Would anything need to be upgraded/changed when porting the engine? or can I just get the engine ported and drive it straight away with nothing to worry about?

[@allanwenzke749]

what about peripheral port?

[@smiththers2]

im super excited to street + half bridge my 6 port after seeing this. i already love the way the car drives, more power would make it so much better!

[@richardgiddens14]

How do I get a contact with him to see if he can rebuild my engine?

[@andrewblank5731]

Does bridge porting affect your choice of seals ? Read some say that bridge porting will cook cheap seals faster and possibly even Oe ones and say they would go ceramic with bridge ports ?

[@tendaibrown375]

Hi am looking for seals O ring seals for rx8 13 B engine

[@thaddeusothello2021]

What's your thought of a 48mm Del'Orto Carb on a 12A 1983 GSL?

[@HotGritz910]

What if you cut through the aux port on a 6 port to make one port?

[@cmudgesickl3]

Wish you could build/sell some engines for other rotary enthusiast like myself. You could make some money. But your content is awesome.

[@RADPotential]

I am going to make a video about something like that here soon. Might be a controversial topic

[@mohamedalibachar1744]

Insane video man! Keep it up!

[@jonathanduplessis4351]

What porting would u recommend for oval track racing? Im from South-Africa bro

[@ggggg-kc4hl]

Would it be possible to port the primaries but just downwards only? Or just port the exhaust upwards to get the noise? How would it affect the idle rpm and driveability?

[@c.b.6350]

Could you do a video on the auxiliary ports. Mainly the rx8 6 port. I would like to delete the sleeves. But what would be the downside?

[@RADPotential]

Downside would be huge ports open all the time. Less low and midrange power. But more top end

[@stlchevy95]

how do you polish the plates?

[@rotary13bturbo70]

Wonderful video loving it keep up the great work….. rotary 4 life

[@soloracer1]

Great info , I understand it better.

[@rx8tom]

If I’m building a hybrid renesis with plans to turbo, can I use 13bt irons that are ported to have the same performance as a 13b rew? Would it be cheaper? Thanks for the vid btw, awesome learning about rotaries!

[@MK-go7vg]

Helpful information for those learning. Your explanation would have been better illustrated if you showed an end plate, housing, shaft and rotor assembly being spun over the different port types to show the differing opening and closing/timing associated with the different port types.

[@RADPotential]

Its super hard to see. I have a model of it but it's just too small. I need to figure out a way to visually show it in the computer

[@DanielSanchez-xt9zv]

So can a large street port make your motor brap almost like a bridge port? And does the bridge port add extra hp or its just for a louder and nicer brap??

[@RADPotential]

Yes you can get a good brap with a street port. It will rival a full bridge, but not quite as nasty. Bridgeport will add more HP. Maybe 10% more than a big street port

[@BrycenKauai]

Hey, Great video per usual. Love the channel! Curious if you can give me some insight on an issue I've been trying to hunt down on my GSL-SE swapped GS. The car has a slight vibration that's barely noticeable at idle but build to be pretty noticeable at ~2500rpm then quickly goes away at about 3000rpm. Above 3000 she's buttery smooth and pulls hard. At first I thought maybe the fan clutch was out of balance or worn out but no. Then thought maybe a vacuum leak in the ignition advancing circuit but not that either. A previous owner installed an aftermarket flywheel and clutch but it is an OE style full disc so maybe something to do there. Cant find anyone with a similar issue on the forums and since I'm new to rotaries I'm hesitant to drive it like this. I know your probably super busy with the crazy amount of content you put out, but any tip or insight would be greatly appreciated.

[@RADPotential]

If it has an aftermarket flywheel of any sort the balance of the counterweight could be wrong. Did it just start doing the vibration? If it just started and hasn't been like that the whole time, you could also have the flywheel to counterweight bolts be backing out causing the vibration.

[@BrycenKauai]

@@RADPotential Good to know! That may very well be part of it! I tried to find a brand name on it when it was out but no luck. Looked like a quality piece though. I dont remember the vibration in the donor car, but i didnt drive it a whole lot before the swap. I just replaced the vacuum T-Joint on the advance cicuit and that seems to have helped some. looks like someone used an irrigation fitting in a pinch. With that in mide have you ever heard of those advancing pots going bad? Im thinking about swapping the pair from my low mileage 12A to test? The car is also running no cat and the o2 sensor had been removed. Ive got a sensor coming now but figured more info couldnt hurt. Thanks again, really appreciate it.

[@RADPotential]

I have never seen an advancing pot quit. But I usually don't run them. So my sample size is small lol. I wouldnt think a vibration would be the effect from thT cause. If they aren't working, you would see a power loss on the top end as it's not advancing the timing. Not a vibration down low. If you havea timing light I'd check what your base timing is

[@BrycenKauai]

@@RADPotential Good to know! My base timing is good, checked it last week. Just found my Air temp sensor on my intake manifold had its leads broken. not sure thats too blame but it makes me think that its probablya combination of things and not just one thing. Have new coils and wires coming also as the ones on the car are the ones that came with the donor. yikes i know.

[@stattack5855]

can u use a weber on a stock port car? i want to eventually bridgeport it

[@RADPotential]

Yep. That red rx7 I put a weber on is stock port 12a

[@Rekluse22]

Awesome video man

[@erwinhauquier2414]

About the port timing: porting down does not change the port timing, only more volume. Porting more outwards towards the water jacket opens the port sooner. Im Building a 13b REW engine myself with an extended streetport , so a little earlier opening towards the water jacket, going upward for late closing , and downwards for more volume.

[@RADPotential]

That makes sense. I think it will come across with the same effect in the video. I'll add your comment to the description.

[@KmcOffroad]

I'm running a bridgeport turbo. I wish I could get a stock port engine and build a street port. It makes driving the car a job. The heat is almost unbearable, mpg sucks ass, tuning is a pain in the dick. But it braps.

[@RADPotential]

Hell yea!!! My 12a bridge is an experience to drive. Let's just leave it at that haha. It has its pros and cons like yours as well!

[@KmcOffroad]

@@RADPotential I can't seem to get the tune leaner they love 12.0 to 13.2 afrs just pigs in the mpg world but fun.

[@ryderrankin4670]

Great video

[@tonytorres4239]

I thought the bridge was the one that makes the brap

[@cucosauto7409]

Bridge Sports affect your frequency and you Intec the manifold and that's what you got the rum rum rum rum so when your match the frequency of the Bridgeport Sunny moon is when you get there more intake

[@mflbikes1870]

So if you don't port the primary ports you won't get a nice brap at idle?

[@RADPotential]

You will see some effect from the secondaries being ported as that will still allow more air at idle. But not as pronounced

[@mflbikes1870]

@@RADPotential what rpm do the secondary ports actually have an impact

[@RADPotential]

Secondary ports will open based on throttle position not rpm unless you have a carb with vacuum secondaries. So if you go 100 percent throttle at 2k rpm they are open

[@drkhancock14]

@@RADPotential You said a half bridgeport is done on the secondaries, but most people do a half bridge for the braps. Wouldn't that be on the primaries? The half bridge you just put in that FD, was it on the secondaries or primaries?

[@mflbikes1870]

@@RADPotential what about at idle when you want the overlap will they be open

[@RAFAELRODRIGUEZ-mz3lu]

Megusta por que ya se entienden los videos..

[@theaussienurseflipper.8113]

You don't have a rotary for it be quiet you have a rotary so when you pull up at the lights everybody knows around, that you're going to kick their ass. Cheers Graham

[@DStead2239]

Brap is life...

[@ClwnJuNkY]

Grab a stock 6port 12A and chuck Extractors and a 38mm IDA on it and presto !!!

[@floridamangonwild]

its just like porting a 2 stroke engine

[@sasukekonoxa]

Comment to support !)

[@sbarnett6720]

Well explained 🤙/o\\

[@SLYDIT]

Everybody wants the brap

[@mflbikes1870]

Third

[@Cassaknova]

Second lol