going rotary?

[stangant]

I figure it's a Mazda it should have a rotary... any else attempt this? I have google searched and only seen chatter of people say they are stupid but seriously someone should have tried this by now. I have my project car mustang right now but who knows I may try to do a rotary mx one day if it's possible.

[Ryan]

..... Yay, another rotary thread.

People say they are stupid, because they are.

Bang for buck factor is not there. Time, and money. People who own MX-3's occasionally have time, but never money.

[Savin]

I think stangant would be able to pull it off. I don't know the depths of his fabrication skills, but he's done some pretty nice stuff with his mustang. And Ryan, I have a feeling "bang for your buck" won't really bother him. He turbo'd, then later supercharged his V6 mustang just 'cause:

I like the kit it's fun, looks cool but just idk don't feel "right" for me. We will see how it goes.

(quoted from v6power.net)

V6 ponies aren't exactly as easy as the V8's to up power on the cheap.
Best of luck if you decide to do it!

[stangant]

^^ haha.. nice... yea I tend to do something that is not common.. the mustang was similar in that some people said it wouldn't get done, but I asked for an apology when it was. lol. I know someone out there has to have at least started this. I may pick up a mx-3 with a blown engine one day to attempt this and build a tubular front k member set up. I live next to Orlando so rotary engines and parts are not hard to get for cheap. I almost bought an rx7 with a blown engine for 500$ but the guy couldn't find the title and I moved on.

[Savin]

There was a person selling a rotary RWD MX-3 on ebay a loooong time ago. It was a complete abomination. Unfinished, too. I can't find any pics of it.

[Ryan]

Alright, it seems you want a serious answer.

Lets say you have the money, skills, and time.

The first issue is the drivetrain. Which one to use? RX7? Miata? The Miata one is more similar, but both require fabrication of new suspension mounts. If you use the miata one, you need to, at some point, interface with the rotatary which requires some custom fab or adapter plates.

You need to hack a huge hole in the floor to fit both the driveline and the exhaust (unless you race-car it out the side)

you need to hack out most of the firewall to fit the transmission, you'll likely also have to remove most of the HVAC stuff, back to racecar.

Once you mount the rotary in the bay, there is an innate issue with RWD swapping FWD cars. The motor sits basically over the front wheels, if not ahead in some cases. This will lead to a poor weight distribution and handling. Its not something you can correct with a set of coilovers either, its just never going to drive right.

You're also going to have to figure out something with the front subframe and steering rack, because it currently exists in the location where you'd want to be putting your transmission.

Once you start messing with steering rack location, you need to know a bit about suspension dynamics and how tie rod length affects it, or you're going to wind up with nasty side effects like bump steer.

More money, unless you're real lucky, the driveshaft won't be the right length, fab there. Axles will be different too, money there.

Thats a little, I could go on. If you're still interested I could bring up more points....

[stangant]

A rear wheel drive converstion on similar vehicles for example a civic does not consist of the mutalation of the vehicle.. epic tuning converted a civic hatch to rear wheel drive using wago van parts.... so a valid doner is a rx7 or miata in this case. to keep the weight even I have reaserched and it would be as light as or lighter then the 4 banger option... thus the weight stays at or closer to 50/50.. I of course will not be a simple kit/swap as advertised at granny speed shop to put a v8 in an rx7. I can't however go about doing this anytime soon so I will of course keep the project at research. If i did do the swap I already have the engine picked out, I would build the engine and it would be a custom 4 rotor turbocharched engine with a smaller trans along the lines of the tremic T5 with the adaptor plate, custom drive shaft and the rear out of an rx7 or miata. The miata of course will be the closer of the 2 in that its wheel base is closer. Not sure what has the IRS exactly but I would prefer that for the street/track use. The recipe that I would need is deffintly located about 45min away from me in Orlando were RX7 are popular and miatas are not hard to find at all. As you can see from my other car I don't do the hack job that some may do to cut corners, it has taken me quite some time to get the mustang were I want it and all I have left is the tune pretty much. I definitely don't post questions to have stupid answers.. I am always looking for serious answers. Thanks, I know with some group prep in this matter I'm sure we can figure this beast out.

[Ryan]

I apologize. I don't know you, and made a poor assumption about your character.

Most rotary threads we get are started by people who don't have the means (tangible and/or intellectual) to tackle such a project.

You should look more in depth for the differences in the rear suspension. The MX has a rather tall, basically vertical strut. I don't know what the donors look like, but I imagine they're a similar setup (Trailing arm, lateral links, strut), but the geometry may still be very different. Building a custom subframe, I think is the route to go, perhaps with custom trailing arms to use our stock location. Mounting the strut is clearly very important, may require fabbing something entirely custom.

I don't know how much you know about vehicle dynamics, but for sure don't just go welding random s--- together, make the geometry with a purpose, or the result will likely produce undesired effects.


The fitment of the transmission does concern me. To avoid laying the engine on the ground to fit the transmission beneath the front subframe... I have no suggestion. I don't know how you'd tackle this. You could move the whole shebang further forward, so you'd have to lower it less, perhaps point it downward so the lowest point in the system is directly beneath the subframe.

If you wind up moving it, that is a lot of work. If you don't... then a lot of stuff can stay, like the firewall and the HVAC.


Aside from that, it should be a cakewalk.

[RS_OBD'oh_2]

4 rotor?
So this is going to be a 20B swap, not just a 13B?

[Carnuck]

You mean 3 rotor like my Cosmo coupe and RX2 racecar was? Wish I had a rotary motor to put in my friend's MX3. I'd swap her car for my B2000 pickup (or one of my Comanches). I did one in an AMC Pacer years ago. Put the 232/904 into a Chev van. (no sense wasting it)

[stangant]

no it will be a custom 4 rotor setup.

[TOP SPEED LABS MX-3]

like the idea.


was looking to put a V8 in my infiniti here soon.

[Carnuck]

A 4 chamber rotary (done right) would be like a V16

[Mi|<E]

It will be like this minus the hilarious japanese guys:

http://www.youtube.com/watch?v=fvPfi-ZeQRM

[Josh]

So after months of research the parts for a four rotor alone can cost close to and more than 16K and you need to have machining done to make it all work. most spend an average of 16 to 25K building a 4 rotor. so I hope you have deep pockets for this. There is a place to get an eccentric shaft and most parts needed for like 8K, but you still have to buy and source parts and they still need machining work.

I am not saying you cant do it at all, as I am the last one to say you couldn't. It is totally doable, it is just going to cost a lot of money.

IMO it would be cheaper and far easier to do a FWD converted 13B. There are several Toyota guys in Portugal who have done it with just a bell housing adapter. I think that would be killer good luck I look forward to seeing progress on this build. Nothing beats the sound of a rotary especially a 2.6L