So how dumb is my rotary engine swap idea?

So a while ago I bought an '84 RX-7 GSL-SE off a buddy. Apparently it somehow sucked some water in the intake and a crack appeared on the rear cover near the oil filler tube and started pissing oil when it ran. The car has now been sitting about 2 years and ive decided to write off the engine. What I would like to try is swapping in a renesis from an RX-8. There is a local Mazda/Toyota boneyard that I can source a renesis for about $1500, plus it runs cleaner, quieter, and the extra 100hp should make the lightweight 7 quite fun. My main concerns are 1. Do i need to fab up engine and tranny mounts even though they are both technically 13B engines. 2. What transmission do I use? I would like to keep the stock gauge cluster w/ its speedo, which I believe is cable driven off the tranny, while i think the RX-8 speedo pulls its signal off an ABS sensor. 3. What the hell am I gonna control the engine with? I assume the stock RX-7 ecu wont cut it, splicing in a RX-8 ecu will be a wiring nightmare, so I was thinking megasquirt or do i need to spend the cash on AEM or Motec. I just want it to be a fun weekend car, with near stock reliability.

I don't know a lot about rotaries but I do know that if you want the Renesis to run like it does in the RX8 you'll need the harness, ECU and all the sensors that go with it. Many modern cars also won't run without the instrument cluster from the donor car and maybe a security device in the ignition barrel. If you find out from the RX8 crowd just exactly what you need and are patient in the junkyard, it will be the cheapest/easiest way by far to get where you're going. Somebody point him to the appropriate rotary website please!

Someone on Rx7club/Rx8club did this. I can't remember the particulars. It'll be fun, but I imagine that the fun/$ contest would be won by an LSx.

There will be a RX7 at the challenge with the Renesis swap.He can show and tell you all you want to know.

how in the world did someone buy a roller and a renesis swap on challenge money!?!

^^Yeah^^

^^And here.^^ I can't even find Renesis housings for less than Challenge monies.

We're in redneck country. If it doesn't have 8 pistons, people get afraid.

I don't see how someone could honestly fit a Renesis-powered anything into a challenge budget.

I do... just depends if you can find one in a yard or not.

I can get any rotary that comes through my yard for $150.

BTW, to answer a couple of the OP's questions: AFAIK you can use any rotary transmission 12A and up. Megasquirt can be used but you will need to either run premix or convert the front cover to a mechanical oil metering pump. I think the front cover from the13B in your GSL-SE can be bolted to a Renesis, if so you have just solved the OMP and engine mount problems at the same time. Beware, though: from what I understand Mazda had to cut the oil consumption way down, otherwise the side exhaust ports that are the Renesis' big advantage over the earlier motors can clog with carbon very quickly. But it sounds like a fun project!

Hmmm...how dumb?...rotary...You're new around here, aren't you?

92CelicaHalfTrac wrote: I do... just depends if you can find one in a yard or not. I can get any rotary that comes through my yard for $150.

I'm sorry, but I just don't see it happening.

Curmudgeon wrote: BTW, to answer a couple of the OP's questions: AFAIK you can use any rotary transmission 12A and up. Megasquirt can be used but you will need to either run premix or convert the front cover to a mechanical oil metering pump. I *think* the front cover from the13B in your GSL-SE can be bolted to a Renesis, if so you have just solved the OMP and engine mount problems at the same time. Beware, though: from what I understand Mazda had to cut the oil consumption way down, otherwise the side exhaust ports that are the Renesis' big advantage over the earlier motors can clog with carbon very quickly. But it sounds like a fun project!

A couple other MS-specific Renesis notes. A stock Renesis would have a drive by wire throttle body; your best approach for dealing with that would be to swap on a cable operated unit. And the stock crank trigger is supported in MS2/Extra and MS3, but not MS1. One of the code gurus on the Extra code is a big rotary fan.

rotard wrote:

92CelicaHalfTrac wrote: I do... just depends if you can find one in a yard or not. I can get any rotary that comes through my yard for $150.

I'm sorry, but I just don't see it happening.

I've seen MR2 Turbos and MKiv Supras come through... why not an RX8 that's barely worth more than the MR2, and way less than the MKiv?

OR you can cut that crap all off weld a 4 barrel intake on it.Change the front housing put a holley 650 on it and bring it to the challenge

rotard wrote: Someone on Rx7club/Rx8club did this. I can't remember the particulars. It'll be fun, but I imagine that the fun/$ contest would be won by an LSx.

An LSx may be cheaper overall, but this is a GSL-SE, and I believe she deserves to have a high revvin, NA rotary. :-)

speedbiu wrote: There will be a RX7 at the challenge with the Renesis swap.He can show and tell you all you want to know.

The challenge is in florida, right? Im in Portland, OR... so its unlikely I will be attending.

So it sounds like I should source an RX-8 engine, wiring harness, ecu, and gauge cluster at the minimum. Then find out if I need an ignition barrel, gas pedal, OMP unit, and driveshaft depending on if I use the stock tranny, or source a RX-8 one. My main goals are reliability and making the swap as easy as possible, I dont mind spending a few extra bucks to do that, it'll just take longer to save up my pennies. :-)

Not dumb at all

http://www.rx7club.com/showthread.php?t=361916&highlight=renesis

speedbiu wrote: OR you can cut that crap all off weld a 4 barrel intake on it.Change the front housing put a holley 650 on it and bring it to the challenge

this^
my goal for the 2012 challenge (hopefully that soon) is to find a carbed l28 (which isnt gonna happen) or a carbed rotary. so much easier to tune!