i like the RX-8 a lot, the styling is cool and the doors are handy as is the useable back seat. but i'm not thrilled about the rotary. i'm a fan of torque. if i owned one i don't think i'd be happy with the mileage and oil consumption either. but there isn't really anything that fits the mold i'm looking for, lightweight, RWD, independant rear suspension and fun to drive. and the aforementioned torque and good mileage.

my '95 240sx is great but it's not getting any younger and there's nothing new on the market i want.

so i've been thinking about a swap for the RX-8 but i wanted to stick to the cars character and roots. the best engine i can think of is the engine out of the new mazdaspeed6, the 2.3l turbo. you'd get more power, a heck of a lot more torque, and all the cool technology like direct injection and a turbo. with a front mount and new exhaust bits the engine should even be close to 300 chp/lb-ft.

it's very close to the new miata 2.0, which is also closely related to the RX-8 (the miata i mean). so the swap should be somewhat straight forward, and the wiring shouldn't be too hard since they are both mazdas. it should mount up to a miata transmission, but could it handle the power?

so what do you think? i know some rotary guys will tell me to go to hell, but that's fine, it's bound to happen with any swap. the biggest problems are getting a car that needs a new engine already (or spending more on one with a good engine) and getting an engine from a brand new, rare car.

my other thought is a V6 from a 6 or LS, but i haven't put much thought into that.

 

I think that would be very difficult to do because the Mazda6 is a front wheel drive car. The Engine in transverse mounted in the Mazda6. The RX-8 is Rear wheel drive. You would have to change the transmission, motor mount points, pretty much everything. I think you would have better luck installing a Miata engine...the Miate is Rear Wheel drive already.

 

If you want to do a swap just put a LS1 motor in it and have all the power and torque you want. Youd have to come up with motor mounts and probally heavier springs in the front due to the wieght difference in the the motors. But it would go like stink and have a v8.

 

so why are you even interested in an rx-8? we aren't salesmen, and we'll be the first to tell you that if you want torque, better mileage, and rwd go buy a Z. the 8, and the renesis, isn't for everyone.

aside from being next to impossible and EXTREMELY expensive (we are talking about a brand new motor here, that's likely to have more ECu quirks than even the rx-8 does), it is a complete violation of the car's roots. the R in RX-8 is for rotary.

if you're hooked on a RWD Mazda, i think you should consider a turbocharged RX-8 or an MX-5.

 

turbo RX-8 would be much cheaper and give you all the torque you can handle.

 

according to sport compact car (not the greatest source, but it will do, and this article is what got me started on this anyway)...

"Mazda’s 2.0- and 2.3-liter engine blocks are, for all practical purposes, perfectly interchangeable. The 2.3 is 12.5mm taller, but all the engine and accessory mounting bosses are the same—even between the front- and rear-wheel-drive versions."

so a miata engine and the MS6 engine should be about the same difficulty. but with that being said, they said this later in the same article... i assume it will be hard the other way too.

"So there you have it—a do-it-yourself 2.3-liter MX-5. What? You want a Renesis-powered MX-5? So do we, but as far as we can tell, it’s not nearly as easy. Although the MX-5 uses RX-8 underpinnings, the engine mounts are in very different locations and the oil pan will have a territorial dispute with the subframe."

 

not much of a V8 guy, but i'm sure someone will do it eventually. an LS1 only adds about 60 lbs to the front end, there's more weight shift from an empty tank to a full tank.

it's in the first paragraph you quoted, the engine isn't the only important part of the car. and i want a back seat. yes, the G35 coupe is on a short list, but light and simple is more up my alley.

 

honestly then, why not go turbo? or even 3 rotor?

you'll keep the true heart of any rx-* car (trust us, the oil consumption on the renesis or any later model rotary is not really that big of a deal), you'll maintain the low weight and low cg of the car, it will cost less (a t/c renesis definately, a 3 rotor swap has been done for $7500 but it takes ***** to DIY) and the whole package will be much more oem-like than putting a 4 banger in there.

edit: the 3 rotor i was talking about put down 567whp and ran a 10.4 on slicks...just food for thought

 

are you saying i'm wrong for liking the RX-8? i like the FD a lot but i'll never buy one because there are similar cars without the rotary. the RX-8 is unique in ways that i like.

i have a car with over 100K (my previous one had 163k i think), both have slight leaks and i still never need to add oil.

do you check your tire pressure at every fill up? you should do that too. do you wash your windshield at every fill up? you should do that too. do you call your girlfriend at every fill up? you should do that too. see what i'm getting at? i've got other stuff to worry about than how much oil my engine has used up in the last 1000 miles.

 

i didn't mean to get everybody all riled up, i just wanted to know what you thought of my idea. i've mentioned it to some friends but i usually have to back up and explain how a rotary works and then back up some more to explain how a piston engine works. not so much a discussion as it is a class.

rather than give me reasons why my opinion is wrong, could we discuss whether it would work or not, and if so, how well? i guess i started it with all the back story, i should have just posted the topic

"a MS6 2.3l turbo in an RX-8....Discuss..."

 

What about the transmission bolt pattern? The article you quote doesn't say anything about that, and that would be a hard problem to overcome. Also, is there truely enough room in the engine compartment (rotaries are fairly shallow) without getting into extensive firewall redesign? Either way I think you'd be getting into a huge amount of time, money, and hassle for very little return, but if it's what you want I'd go for it.

 

A bit more basic, does the engine even rotate in the proper direction to mount to an 8/miata tranny for rear wheel drive?

 

well, the article did say the 2.0 and 2.3 were basically interchangable so the miata transmission should bolt up. my main concern is if it can handle over 100 more horsepower. any body got any hard numbers on how high of an engine you can fit in the bay? moving the intercooler from the top of the engine to the front will gains some space.

as for the engine rotation, isn't that pretty much a company standard? isn't honda the only oddball? never thought of that, but good point.

 

you'd be better off just buying/trading for a MS6 if you're that dissatisfied

 

In all seriousness, if you're going to go through all the trouble and expense of an engine swap, just buy a GM Performance V8 and jam in there. Many of them get better gas mileage, and many can be built up to 400+ or 500+ hp w/o FI. I know there are GM V8 RX-7's out there and I've even seen Miata's with 5.7L V8's so I'm sure with some work, clever design, and a C-130 filled with money, you can put one in an RX-8.

However, I'd imagine that even with some proper suspension changes, the swap will destroy the nimble handling we all love our RX-8's for. Don't forget that one of the biggest advantages of the rotary is not just it's low weight, but it's compact size, allowing for low, rear-ward placement that gives the car a far better center of gravity, very crucial to good handling. Even the 2.3 turbo is not going to be able to be placed nearly as well as the Renesis is.

Still, I love GM V8's. I have one. '02 Z28 that runs about 400hp with just some bolt-ons and a handheld tuner. I'd love to have an RX-8 with a nasty V8 under the hood. Although... I'd have to buy a second, b/c I'm not destroying my baby to do it, lol.

 

Here, check out some of the GM engines:

http://www.gmgoodwrench.com/perfpart...on=ce&cat=9274

May I point out the bottom few engines. 572cu in, about 9.4L and 620hp on pump gas. That's a bad *** engine. I've also read the the two variations of the 572 have been dynoed at far greater HP numbers than GM claims. (GM V8's often underated) That's one thing you can't shake a stick at when talking about GM. You'll never be disappointed at the dyno.