simmode1

Lately, I've been seeing youtube vids of 4-Rotor & 6-Rotor Renesis RX8's instead of boosted rotaries. Seems the Renesis doesn't do well with boost, so I'm guessing that staying N/A & keep stacking rotors is the way to go for serious power gains on the SE3P.

I have found that you need the correct Eccentric shafts to spin the rotors and the desired number of rotor housings for starters. But I can't find any real info on what goes into building one of these motors & the attached price tag.

Can somebody give me the basics? Google keeps sending me on wild goose chases and there's a very slight possibility I may pick on up since they're so cheap nowadays. I'll probably go SW20 turbo or another SR S13 instead, but I love how RX8's drive and their gimmicky suicide doors so I'm mildly curious how much something like this might cost/level of difficulty.

I mean, are we talking comparable to 1/2jz or LSx swaps or what?

lflkajfj12123

I don't think there are any 4 rotor renesis maybe a 3 rotor. Almost all 4 rotor engines are built from the 13b and it requires a custom eccentric shaft that needs to be balanced. Which is really hard to keep the port timing if you go that route on a renesis.

ITT: pipe dreams

LoneStarSilvia

Agreed. Unless you're growing money in your back yard, the juice definitely isn't worth the squeeze. Anything over a 3 rotor is going to take quite a few custom bits.

I'm sure a 20B would pull a premium a week before Race Wars though.

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simmode1

Alright guys, got it. I must have been mistaken in thinking the videos & pics I saw were Renesis units. Looks like the RX8 remains the evolutionary blackhole that it always was. I thought someone had been making some new breakthroughs or something. I guess I'll stick with turbo MR2 or another SR S13 for my next toy.

LoneStarSilvia

Techinically there have been some break throughs, last I checked a crazy shop was close to making a 6 rotor possible. The problems lies that they're all pretty much one-off frankenstein porjects.

Personally I've never been a fan of the Renesis. A step back from the 13B IMO.

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180sxmaniac

SR swap the Rx8

208s14.5

Give this a little look 4 rotor fc build

The only difference is that he is using 13b housings

lflkajfj12123

You make it sound like thats a small difference. The ports are completely different on the renesis. They're designated 13B-MSP (Multi Side Port) and in turn makes them much more of a pain in the ass to tune with less freedom.

PeaceOnesxWai

Anything past 3 rotors is custom.. The only 3 Rotor being from Mazda is a Cosmo motor. Even building those they would be extremely expensive with reliability issues

Like the 4 rotor build FC up there, that build took over 2 years and the person building has a background in engineering. Rotor housings are not just stacking lego pieces together (though it seems like it). If you are planning so, better have some knowledge in engineering, people do not just sell off their eccentric shaft or for a cheap price tag.

The power that rotorys make is unlimited and they sound amazing (+low weight) but the cost is x3+ of what you are going to put on a 2JZ/RB26/LSx as everything is mostly custom or low production made. If you do want Rotory, go 2 Rotor from Fc/FD.. there are still some supporting aftermarket items out there for this motor, but not for anything over that.

simmode1

Ugh... Okay. So rotaries are still every bit the nightmare to build as I thought they were. I thought something about the Renesis had made them better to work with, but I guess not. I guess the Renesis is just junk basically.

I'll stick with conventional piston, rod & turbo engines.

PeaceOnesxWai

Renesis motor is newer and more modern but doesnt mean its better, the age it was built in was aiming at gas mileage and emissions.. Also the gearbox from a Renesis does not handle well with mods. If you keep it stock they are reliable.

Stick with 90s motor, it was the best era

kingkilburn

If Mazda would commit to putting rotaries in everything there would be much more of an after market for them.

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zooopreme

Most mechanics are unwilling to touch a rotary engine because it's different from the norm of what's being taught at trade schools or from wherever they learned. Also, because of your typical generic warranty policies, it's hard to see companies trying to start up, create, and become eager to sell especially with the way the motorsport community/car community has become. Less time creating and more time purchasing and installing.

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S14DB

B series are not that bad. Renesis is just a whole new animal. Not many people want to invest the time to do the R&D on them that has been done on the Brew's. Now that they are no longer in production there really is no future money in development.

Do a 1MZ swap on the SW20.

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simmode1

If I were going to do a V6 swap on an SW20, I'd aim for the 2GR-FE. Why do you favor the 1MZ?

I'll most likely just grab a turbo version though. I'm so in love with the idea of factory turbo'd RWD cars at the moment. I wanna get one and go FRS/BRZ hunting...lol

S14DB

It can handle some boost stock. Weighs less than the 3SGTE.
The 3SGTE and the 1MZ have the same bolt pattern. You can bolt the 1MZ right upto a turbo trans and done. Bolt in swap. 5SFE is a different pattern.

The 2GR needs custom mounts, Gas pedal, Rav-4 Wiring Harness and ECU, Manifolds, mod the flywheel.
Basically a lot more money and custom work. But it is cheaper than an Evora.

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simmode1

Hmmm... Didn't know that about the 1MZ. Interesting. But I'm not chasing weight savings on such a mildly built streetcar. The 3S-GTE is relatively simple and more than adequate for my modest needs/goals. No need to reinvent the wheel.

Maybe if I ever blow up a 3SGTE, the 1MZ may become a more appealing option to me.

S14DB

So, FCD + MBC = Done?

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simmode1

^^^Well, I'm targeting ~300hp so maybe a little more than that. And in terms of aesthetics, I hate the 3SGTE's crossover style intake manifold. I would want to swap that with a sidefeed style like from the Caldina plus a topmount turbo manifold for ease of access.

But these are just some initial ideas. If they turn out to be prohitibitively expensive or complex, I'll pull back. I'm just hoping that MR2 parts aren't any more expensive than comparable SR stuff.

But someone can lock this thread since I got my Renesis questions answered and it's turned into an MR2 thread... lol

racepar1

The "renesis" engine is simply either a bridge or side-ported (can't remember which) 13b with fancier electronics. It even has "13b" cast into the rotor housings. The theory behind building it, the ability to hold boost, and the utter lack of reliability are the same as any other Mazda rotary engine...

kingkilburn

Sometimes I wish GM hadn't scrapped it's rotary project. I feel like most of the faults of these rotaries are on mazda not inherent flaws of the basic design.

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Matej

The thing to do with an RX-8 is to keep the motor stock and make sure to blow it up before the engine warranty expires, though chances are it will do that on its own. Then repeat the process after Mazda gives you a new engine with a new warranty.

BOROSUN

I've been reading these stock renesis can (are) live (ing) a long life.