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Rx8 anyone?

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bryanwheat

DSM Wiseman
7,111
198
Aug 16, 2004
Columbia, Missouri
I've found a few pictures online of this swap, but not much info, wondering if any of the people that built them are on here by chance, or anyone on here. Seems like it would be more popular since they make a bellhousing adapter and flywheel to attach the 4g63 to the 5 and 6 speed rx8 transmission's.
 
Man I’ve been thinking about this one too! Rx-8s are all over for $1k. I drove one 10yrs ago and it was a blast. I loved the in-cabin feel.

I didn’t see the adapters tho. Who makes them?
Yeah, there are some clean ones out there for little to nothing and its a really good handling platform so i'm surprised more people aren't going this route. https://drifthq.com/products/pmc-motorsport-gearbox-adapter-mitsubishi-4g63-mazda-rx-8-f0rx8-4g . One of of those page has a flywheel as well to bolt to the 4g63 that will work with the rx8 clutch and trans. There are just a few that i can find though, but this one in this pic seems like it fits really well. It mainly just seems like it needs a rear sump pan and some mounts fabricated and it's pretty straight forward from there.

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Yeah, there are some clean ones out there for little to nothing and its a really good handling platform so i'm surprised more people aren't going this route. https://drifthq.com/products/pmc-motorsport-gearbox-adapter-mitsubishi-4g63-mazda-rx-8-f0rx8-4g . One of of those page has a flywheel as well to bolt to the 4g63 that will work with the rx8 clutch and trans. There are just a few that i can find though, but this one in this pic seems like it fits really well. It mainly just seems like it needs a rear sump pan and some mounts fabricated and it's pretty straight forward from there.

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I'm a big fan of the 4G63 - and I'm sure this would be a beast of a ride (in a good way) but I'm also a Purist. The rotary can be awesomely smooth with low center gravity, and really good power. It's almost a crime to toss that out of the RX8.
 
I'm a big fan of the 4G63 - and I'm sure this would be a beast of a ride (in a good way) but I'm also a Purist. The rotary can be awesomely smooth with low center gravity, and really good power. It's almost a crime to toss that out of the RX8.
They were funish, but not a lot of power and insanely expensive to rebuild when something goes wrong. A stock rebuild can be 5-7k pretty easily if the housings and plates are damaged and than you still have a bone stock motor. They are also super easy to damage when you start adding forced induction to them. One detonation event can destroy an apex seal which eats the rotor housing's and than it's back to spending another 5k plus. It's a fun platform for those with a lot of funds to dish out, but for a fun track car on a budget not so much.
 
I see some guys on YouTube saying that the apex seals are usually ok but it’s the coolant seals that go bad and then yeah if the rotor housing chrome is gone they are probably done, but they rebuilt one for under $1k. Idk. I used to hate the look of them but they’ve grown on me. It will be a rare car one day I think to see driving around.

I also thought about buying one and retaining the rotary engine and did some reading on the rx-8 forum and, while I think it’s cool engineering, the 4g is a much better platform, as stated.

I wonder how the transmissions hold up to power? And which is stronger? The 5 or 6 spd?
 
The 6 speed in the RX8 is made of glass, it’s not going to stand up to the torque of a 4G63. The 5 speed of the FD RX7 has awful ratios, so it’s out too. I’d want a Tremec TKX or T56 variant behind it instead of dicking with a bunch of dodgy old transmissions.
 
The 6 speed in the RX8 is made of glass, it’s not going to stand up to the torque of a 4G63. The 5 speed of the FD RX7 has awful ratios, so it’s out too. I’d want a Tremec TKX or T56 variant behind it instead of dicking with a bunch of dodgy old transmissions.
There are quite a few having a lot of luck with the 6 speed trans with the k series swap making under 500 hp with them the 09 and up is supposed to be a stronger than the early versions from what i've read.
 
I see some guys on YouTube saying that the apex seals are usually ok but it’s the coolant seals that go bad and then yeah if the rotor housing chrome is gone they are probably done, but they rebuilt one for under $1k. Idk. I used to hate the look of them but they’ve grown on me. It will be a rare car one day I think to see driving around.

I also thought about buying one and retaining the rotary engine and did some reading on the rx-8 forum and, while I think it’s cool engineering, the 4g is a much better platform, as stated.

I wonder how the transmissions hold up to power? And which is stronger? The 5 or 6 spd?
If the 13b rew from the fd's were available for an even semi decent price they are easy to fit in the rx8 with a few aftermarket swap parts and they are excellent engines, the na's from the 2nd gen's were really stout too but only around 140ish horsepower. I had an 87 sport model a long time ago and it was an incredibly fun car, not fast at all, but you could drive the absolute shit out of them, like redline from every stop light every day and they didn't mind at all, as long as they weren't detonating they just kept on going. It is a really fun engine to mess with if money isn't a problem though. I looked even into a low boost small turbo on e85 setup on a renesis and cant even really find a turbo header for one. There are some kits that are like 4-6 grand, but for whatever reason nobody is making a header for those. I am thinking they just know 10:1 compression on a rotary with boost is not a good combo so nobody really made them. Pretty much anything else a person can get a header for though, I just want like 300-350 hp at the crank, but it's like the limit on the high compression rotary, or a freshened up 6 bolt with some arp rod bolts and head studs to hold it togther with a stock evo8 manifold and turbo that points towards the front of the car to pretty easily get that kind of power. Other than oil pan, mounts and some kind of intake mainfiold with the opening on the timing side it seems pretty straight forward, i am basically just interested in how other's built their rwd oil pan's. Basically just wanting to put something together that i can take to the new road coarse track we have down the road that isn't stupid fast, but fast enough have a lot of fun and still be a little dangerous. I think even the evo 8 style intakes with the injector bosses welded up and than resurfaced with a little reshaping of the ports would be a perfect rwd intake for the 4g63 as well. Not a lot of stuff out there for rwd 4g stuff unless it is ultra expensive magnus part's, so a lot of it is trying to make other parts from other stuff work with a little fabrication.
 
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