RX8 Renesis Porting, Good or Bad? Mazda Rotary Street Porting KMR tech talk

Porting templates, videos, and tools available from KMR
www.kylemohanracing.com
Porting is a good way to help the motor breathe which can prolong the life of you build.
Helps with power and TQ gains. Also helps reduce exhaust gas heat build up and warpage to the iron plates.
Average power gains seen in dyno testing.
7 hp Street port
8 to 14 Half Bridge

[@sonoragingerdoodles]

Like a magician giving away the secret to his tricks!

[@NateRist]

I'd like to see you go more in depth with how porting affects the entire power band in the renesis as it's very common for ported rx8 motors to see loss of low and midrange performance for minimal top end gains. I'm all for porting older motors as my SA has a 76-78 based high compression large streetport 4 port 13B with fantastic results and considerable low end torque and HP gains. IMO I see zero point in porting renesis irons with exception to mazda's poor casting of the exhaust port where carbon builds up which is why I smoothed them out in mine, but left the intake side stock and all port shapes left stock as well. Also with the typical cooling mods my running temps usually stay pretty low (this was with both the previous bone stock motor and current one), so not really seeing the benefit for exhaust porting in that aspect. For a turbo build maybe, but for NA my understanding as far as older motors go is that porting down leads to HP loss and if it affects the renesis in the same way then even more reason to avoid it. I look forward to your response.

[@KyleMohanRacing]

Dyno charts, race results, and tests have shown gains for Porting a Renesis if your goal is performance driving ( Minimal yes but its there ) . Yes, Both intake and exhaust should be cleaned up at a minimum to reduce carbon build up, its a bigger problem in the exhaust like you mention. Porting will increase performance and lifespan if done properly. Who drives a ported rotary at low RPM?... The heat im talking about is the heat not expelled or absorbed properly. Exhaust porting helps remove some of the heat build up in the cast iron housings at the exhaust port. Ported housings don't shrink as much as oem. I hear you but my ported rx8 beats my friends without porting and he has more mods. Thats not really a quantifiable test but dyno tests are. I will dig some charts up. Also alot of dyno readings are false on OEM cars because of the CAN system. I will try to do a video about what we have learned. In the end. Everyone can build what they want to achieve their own goals. I'm just showing what we have learned. Thats the joy of cars.

[@danc5963]

@@KyleMohanRacing would like to see this my rx8 needs a rebuild and im looking into staying na and street port

[@stevecarlisle3323]

Would you consider making a vid on your career using Mazda Wankels, together with your association with MazdaTrix, and their history !

[@KyleMohanRacing]

That would be awesome

[@alexlevy4581]

Hey Kyle, is there any worth of bridge porting the RX8 irons. I have heard many who have bridged renesis motors see very little to no gain with this porting, even with street porting them as well. How much power is there on the table with ported RX8 irons, both boosted and naturally aspirated?

[@KyleMohanRacing]

I will do another talk about the gains and reasons people struggle with the RX8 but yes. Both Street porting and Bridge porting options have gains on the table.

[@stevecarlisle3323]

QUESTION, What are your concerns in regard to the corrosion in the water seal area ?

[@KyleMohanRacing]

Shrinkage and corrosion leads to pre mature water seal failure. Lapping flat give a like new or much better seal.

[@THE-GO-BRO]

Nice vid... thanks

[@patriotagainstcpsabuse1296]

Is there a cooling benifit with the exhaust? Asking cuz I got a 2011 gt that I just picked up and I’m use to my old 88 fc. I’m not too fond of the new OMP setup as I like the Sohn option for the 04-08 models.

[@GeenIdee2]

What's your idea on porting a 4-port renesis? couldn't find a template or I'm looking over it

[@marcusmazdaboy]

Check out ARC rotaries on youtube

[@jasonskinner1652]

Hey Kyle, what porting do you recommend when using gsl se housings in a renesis rebuild?

[@KyleMohanRacing]

Have youvseen this video kzbin.info/www/bejne/b6ipgnaJmrSimqM

[@aydankraemer377]

I bought your half bridge port street template for my 8 I’m currently building, first question, do I use the half bridge on the center housing? I assume not but first ever Dorito build and ya never know. And second if im not going to bridge the center iron should I flip the apex’s so the second smaller apex corner rides on the center and not the bridge? Just paranoid of one of the pieces from the apex being able to clip or fall into the bridge??? Love you vids and you’ve helped a ton already so thanks!!!!

[@SargTeaPot]

ive got a 13b almost stripped at the moment. looking through the exhaust i can see rotor 1 is chewed up. is that recoverable or should i cut my losses now?

[@KyleMohanRacing]

Keep the good parts. Throw away the bad.

[@yeahnah6468]

How do you store your spare parts? For example, spare irons that want to corrode. When I was slowly rebuilding my renesis I was coating everything in WD40 between working on it to try and prevent surface rust. But I'm not sure how long that would last if I had parts that might be left for a year or more.

[@KyleMohanRacing]

Yea. Use oil with rust inhibitor

[@stevecarlisle3323]

When I first bought a milling machine, I though WD40 would be a good rust preventative. WRONG. It attracted moisture in that application. I switched to Fluid Film, with good results.

[@travtech1]

Just wondering has anyone you know of ever tested doing a bridgeport on the exhaust ports?

[@EASTCAMDEN4LIFE]

Should I port and then get them lapped or lapped them first?

[@zavedali3246]

Do we need to port all the three iron plates when going for ports?

[@KyleMohanRacing]

all modifications are up the the owner. But generally yes, all 3 plates are ported.

[@zavedali3246]

@@KyleMohanRacing I am running a 4 port renesis in my 2004 rx8. I wanna go for a Bridgeport. Do I need to get it tuned or something too. Any necessary info will be appreciated thanks:)

[@thonythony4861]

therefore no full bridge or half bridge (with AUX and secondary ports) on rx8 renesis?

[@KyleMohanRacing]

Streep ports and the half bridge have power gains when properly setup.

[@thonythony4861]

@@KyleMohanRacing the half bridge, you mean only the AUX and secondary ports? because I know that in england, some use the renesis with the 6 bridged ports. rotary revs offers a full bridge for example.

[@pasteu]

Any chance to use some front cover like a 12a with a hole for dizz? I want to put a weber48 in my 13b 6port from rx8, I'm building a l200 single cab with this engine. @l200dunz

[@marcusmazdaboy]

Checkout ARC rotaries

[@1sinister80]

What kind of power gains can you get out of this? Can you get a 300hp NA?

[@scsnox]

No

[@jdmcarcollection73]

what about using fd housings with the rx8 end plates?

[@KyleMohanRacing]

To many water seals? .... Watch video kzbin.info/www/bejne/b6ipgnaJmrSimqM

[@infinitexsound6087]

Do u still nitride the plates after wpc treatment?

[@mrawesomelemons]

The hardening on the stock irons seems to be of varying thickness. The lapping process can get rid of the hardened layer leaving you with a soft side housing. Nitriding is highly recommended if not necessary.

[@dacollecta2000]

Do the street ports and bridge port pass smog?

[@PlayTrickshots]

Yes

[@alexlevy4581]

Also, I have heard claims of RX8 exhaust porting allowing flow to be increased by 30%, how much does it actually increase flow by? As well, doesn’t porting the exhaust reduce the rotors “stroke” before it evacuates the exhaust air? That would reduce torque and horsepower in that sense, is there a happy medium between increasing flow and reducing torque from the natural movement of the rotor?

[@KyleMohanRacing]

Depends on port design and shape. The RX8 has restricted exhaust from in its OEM trim. To big can effect TQ, but Restrictive flow will kill HP which also will bring TQ back up. SO generally TQ and HP come up for most of the RPM range until you get fairly big. This is not a big port....

[@tommygibson9515]

What do you think of using rx7 housing on the rx8 engine

[@KyleMohanRacing]

Watch our older video about it. kzbin.info/www/bejne/b6ipgnaJmrSimqM

[@euroe12]

The two Renesis motors I've seen ported were both losers. Maybe with the right intake and spun to 10k

[@TWENTYB]

Plates... not housings.

[@KyleMohanRacing]

I'll do a video on this topic. Lol

[@doppies2000]

when a Rotary Specialist calls Side and Centre Plates Housings...

[@KyleMohanRacing]

Go Google Mazda side Housings, Thats what the factory calls them. 😆 Ohh and nice to meet you. Lol.