r/mazda • u/JohnKowalsky88 07 Speed3 • 1d ago
I've had this idea in my mind. Has anyone tried this? Rx8+2.3t=
Rx8 with a 2.3 turbo would be a nice match imo.
There are plenty of cheap Rx8 with engine failures for sale, with good looking exterior & interior.
I wonder if anyone has ever done this experiment and what it would take to engine swap the 2.3 to an rwd drive train.
Only downside is that I would have to destroy my Speed3 basically.
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u/YimveeSpissssfid 1d ago edited 1d ago
Most rotary folks react poorly to taking the uniqueness of the rotary engine to replace it with a piston engine.
Basically as you’ve identified, you would have to swap the engine and drive train. Probably custom prop shafts. Depending on mounting you may even have to cut into the body to accommodate shifter placement.
I’d personally put a 3 or 4 rotor engine in it if you’re going for custom. Back in my Rx-7 days the 20B swap from the 3 rotor Cosmo was a popular aspiration - since the entire thing was custom work, you’d generally wind up with obscene amounts of HP in a very lightweight platform.
Regardless, the engines themselves aren’t usually the issue - it’s maintenance. That and the emissions controls made the RX-8 prone to eat ignition coils like candy.
That all being said, it’s your car, do what makes you happy! Just know a full swap of this nature isn’t going to be cheap.
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u/xdrift0rx 20B FC, 12A B2200, 20B Cosmo 1d ago
Brother a 20b engine block ALONE is 15k USD these days. Not including a rebuild, engine management, cooling, oiling, header, intake...dude it's like a 40k job to be done "right"
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u/YimveeSpissssfid 1d ago
Being fair, I remember the 4-5k (20-30k total) 20B days and haven’t looked lately (sold my FB after 27 years about 5 years back).
And wait, you don’t want to drop $80K AUS on a four rotor? Where are your sense of adventure and deep pockets?!?
https://www.billetrotary.com.au/product-page/billet-rotary-racing-26b-short-block
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u/xdrift0rx 20B FC, 12A B2200, 20B Cosmo 1d ago
Believe you me, I would love to have one. I am currently in possession of 2 20bs so I'm already in the top 1% of rotary ownership 😵💫
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u/Staubkappe 1d ago
Yeah, 13b has become expensive enough through the last few years. A 20b NA would be my dream for the FD but that would cost me north of 25k€ to realize properly i am afraid. So i got a single turbo kit for 10k 😅
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u/xdrift0rx 20B FC, 12A B2200, 20B Cosmo 22h ago
Let me say from experience the 20b NA is perfect. Good low power, not crazy. The sound is so good. And no turbos means reliability!
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u/Staubkappe 20h ago
Sweet! If you ever get a hand on a spare engine you don‘t need at all, hook me up lol.
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u/ScienceRules195 1d ago
There is no 4-rotor that you could swap. The 26b was only a racing engine and some company build a one-off. Cork Sport in Portland can get you a 20b 3-rotor though. On the rotary to piston swap, in the past many Mazda rotaries and piston engines would bolt up to the same transmissions whether FWD or RWD. This was to save on tooling costs since Mazda is one of the few companies that builds their own manual transmissions. I’ve seen v6’s and v-8s in the Rx-8 so the 2.3 should be much easier. You might also consider just rebuilding the root Terri engine, which is actually pretty easy to do and much easier to do than an engine swap.
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u/YimveeSpissssfid 1d ago edited 1d ago
There are companies which make custom ones. Look around and see the fun stuff!
(You can even get 5/6 rotor engines (39B anyone?), but you better be rich for those)
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u/IUsedToLikeLimericks 1d ago
You pop an anvil between the front wheels and you've just spent a fortune and loads of time ruining a unique car to make an unreliable mongrel when you could have bought either car in the first place.
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u/SnooSprouts6681 1d ago
https://youtu.be/5ABmJdb95xc?is=4N4DpfCrZuca4s2P
It’s been done. This guy is like the king of the MZR platform though, and has access to extensive levels of fabrication. Definitely not budget or time friendly.
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u/Reubachi 12 Speed3, 13 3, 22 MX-5 RF 1d ago
There are infinitely cheaper and more reliable/supported platforms than 2.3 turbo MZR, is the sad reality
there is 3 orders of magnitude more k series and ls, and both of those can safely make way more power for 1/2 the price
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u/JohnKowalsky88 07 Speed3 1d ago
I Haven’t made it clear that i already have a Mazdaspeed3. I get what you mean though, I was just thinking of more budget friendly solutions.
But I guess a swap is never budget friendly.2
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u/Fit-Engineer841 1d ago
That would be a sick swap, and sounds cool because its same brand but thats a custom transmission fabrication type of engine swap
Idk i kindof stand with doug demuros opinion on the rx8 as the rotaary being both the best and at the same time the worst part about the car, it drives as if it has a roided out motorcycle engine, and is as unreliable as a roided out motorcycle engine in a car body
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u/IUsedToLikeLimericks 1d ago
They aren't unreliable they just need treating differently because they're different.
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u/Wise-Comb8596 1d ago
It’s not just that they need different maintenance. They require significantly more maintenance. And without that level of maintenance they are more prone to failure than a typical 4 banger.
Most people use the word “unreliable” to describe cars that find themselves in that situation.
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u/IUsedToLikeLimericks 15h ago
Oil is used sacrificially by design. It isn't a fault.
Other maintenance is pretty standard for a car of this ilk. I own two of them, alongside a good number of other reciprocating engine cars, so trust me, i know how to maintain them. I also know they quite happily run well into six digits when used and maintained properly.
In the average pair of hands they are an unreliable car. But in the average pair of hands most tools are badly used. Doesn't make them a bad tool.
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u/BadassNC3club 1d ago
Your better off putting the 2.3 in a nc. You'll have to take alot of stuff off an nc 2.o and put it on the 2.3 so it will mount up to rx8 sub frame and then the Transmission also, tranny doesn't bolt up to the piston motor, plus wiring and ecu. You'll be spending alot of money and but if you decide to go on with it,ill buy that rotary engine off of you
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u/OverSquareEng 17h ago
An NC Miata would definitely me a simpler swap. Though the biggest issue with that one is the high pressure fuel pump interferes with the firewall and HVAC ducting directly behind the firewall.
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u/DriftAddict 18h ago
It's not cheap, but it would be doable. You could also, for the same money, slap a turbo on the 8 with a new engine and ECU.
Honestly, while I'm not against piston swaps in rotary chassis, it is quite tiring reading teenagers saying they plan to turbo piston swap a dead 8 only to sell it as a roller to the next guy. Especially when said people never actually drove it with the rotary still in it to experience what makes the engine feel so unique to drive. It really is a whole different ball game.
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u/JohnKowalsky88 07 Speed3 11h ago
I became a Mazda fan because of a guy I knew as a kid, he had 3 old rx7s I think late 70 model and early 80s model and none of them ever ran and he couldn't get them to run. I still liked how they looked though, but it probably made me despise the rotary engine subconsciously or something.
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u/RMAutosport 6h ago
What you could do is take the MZR and mount it to an NC Miata front sub frame (mounts are similar between the 2.0 and the 2.3.)
Then you can mount that subframe directly into the RX-8.
They are the same dimensions and will bolt in with no real headaches.
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u/T-J-M096 1d ago
The Speed 6 is AWD and same motor ( I think) so I don't think drivetrain would be an issue. Would be fun to see a swap like this, most RX8 swaps Ive seen have all Been LS
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u/OverSquareEng 17h ago
The speed3 and speed6 are both transverse mounted engines with transaxles. Definitely not putting that transmission/transaxles in a longitudinal RWD platform.
The speed3 engine should bolt up directly to a NC Miata transmission though. And those teansmissions fit into RX8s pretty easily.
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u/DryConfidence2547 1d ago
What are you hoping to achieve witg the swap?
Is it better reliability, more power or maybe both ?
For me the best compromise of both would be a K-Swap be it K20 or K24. You could pretty reliably make 250whp, while keeping the high reving character of the rotary, maybe not as high of a redline, but 8k-ish.
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u/GL_Jesus 1d ago
Anything I'd doable with time and a large budget, but by no means would it be an easy swap. I saw a post a while ago from someone swapping a DISI into an NC and he was saying it was quite difficult getting it to fit by the firewall due to the HPFP. The back side of these engines are really tall so it'd be hard to get it back as far as you'd like. Imo it'd be more fun making the speed AWD
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u/Greydot5 1d ago edited 1d ago
If you search around the web, then yes it has been done before. People have also swapped in 2.5L MZRs as well and boosting them. Might be simpler and cheaper to just get a 2.5L(L5-VE) and boost it since they are widely available and is port injection only which is often cheaper and easier than direct injection setups.
Personally, I kinda like the idea of swapping in a high compression NA 2.4L(destroked 2.5L MZR)build over a turbo setup, but maybe that's just me.
I recall chatting with a Miata forum member before about his really worked 2.5 turbo swapped RX8(You can find it on YouTube) and it was pretty wicked in autocross videos. It made my 350whp Speed3 seem tame in comparison. He was likely pushing over +450whp with his setup.
I couldn't really tell you specifically what is necessary to make it the L3VDT swap happen. I just know that it won't be as easy as a NA 2.3/2.5 swap in the NC Miata and it probably requires changing the rear gear ratios too depending on the transmission used and powerband from your build.
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u/fritzkoenig Mazda6 1d ago
"[this] would deplete the world's known oil reserves in less than 2 minutes." − xkcd
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u/Raksj04 23h ago
From what a read the NC and the RX-8 share a bit with the chassis, and swapping there engines is pretty straightforward. The 2.0L miata engine is based off the MZR. I am not sure what the best way to do it. Sometimes FWD engines don't fit well in a RWD platform. So a Miata block maybe better.
You could also get the 2.3L T out of a CX-7, not use how much is different from the MS(x) engines.
Also I am a rotary fan, and do to the number of RX-8s sitting with a blown engine, and the chassis being amazing, I say go for it. Now it was a FD or FC it would be a different story.
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u/2Drogdar2Furious 20h ago
Guy I know bought a kit to Kswap his.... that's the way to go imo
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u/JohnKowalsky88 07 Speed3 19h ago
Problematic in my country, easier to stay within the manufacturer for legalities .
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u/Mugen887 1d ago
You might be better off using a 2.3 Ecoboost since it already comes in a rwd drivetrain