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Rx-7 Rotary Swap Worth it?

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J

JohnnyB1275

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Since the winter hasn't let me touch the cars in a while, I've been thinking of things to do in the spring. I have a 74 midget shell that has been on a rotisserie for the past 4 years, and have been thinking about putting a 13b-turbo engine in it. /ubbthreads/images/graemlins/devilgrin.gif I'm going to college this coming fall and would like to do this before then(the restoration of the car has been going on all of my high school years, very very slowly). Am I crazy /ubbthreads/images/graemlins/crazyeyes.gif or do you guys think it's worth it /ubbthreads/images/graemlins/driving.gif ?
 
If only you could get your hands on a Renesis ... then it might be worth it. I wouldn't bother with the RX-7 motor (13B).

Matt
 
This is on my long term 'to do' list. I've seen writeups on naturally asperated 12A and 13B conversions and also seen track video of one and it looks like a BLAST. I've always been a fan of the RX line and enjoyed both the first and third generation cars I've driven. The idea of putting in a turbo 13B along with a new rear end seems like a killer car. Roughly equivalent weight distribution but suddenly you're running almost 200HP in a 1600lbs car!
 
I think it depends on how cheaply you can get your hands on a 13B and how much work (if any) the motor will need to be up to snuff...
 
I am doing a 13b swap right now in a 65 sprite. So far ir has not been to bad. I got a running 2 gen 13b for $150. The guy was puting a vet crate motor in it, so I got it cheap. I took off all the fi and put a race beat intake and a preditor carb. I did have to cut the heater box and battary shelf out to get the motor in. So far it has not been to bad but I still have the rear end to get changed out. I am hoping to have to running in a solo II by the 4th of July.
 
Thanks for the link Chris. My friends dad said he can get me the motor, wiring harness, trans, and ecu for less than a grand in perfect condition. Lucky for me the heaterbox and battery shelf rotted away due to a battery acid spill. I was going to replace it then thought about the swap.
dickc, do you have any pictures of your progress?
 
not to get off the topic of a rotary in a midget, because I think that is pretty cool. but I am currently planing to put a BMW 1.9L in my Midget. I'm trying to find a whole bimmer to use as the pig, and I'd like to get as close to the end of the 1.9Ls life cycle as possible, but some of those cars are still close to 10k. but high mileage onse I can get as little as $1000
 
I just helped a friend put a 1600 Ford and 5-speed Sierra trans in a 948 Turner. I really like the Ford Kent motor in these type of cars.

Another neat one to consider (if you like pistons) is a Miata engine/trans....cheap, plentiful and will fit with less effort than the rotary (according to what I've read anyway).

I'd like to fit the Rover "K" motor in mine at some point.....kind of keeps it "MG-ish".

The yellow Spridget below has a 13-B, one-piece glass body and IRS. Races in our club....beats "Vettes and 5.0 Mustangs.
80b.jpg
 
[ QUOTE ]

Another neat one to consider (if you like pistons) is a Miata engine/trans....cheap, plentiful and will fit with less effort than the rotary (according to what I've read anyway).

I'd like to fit the Rover "K" motor in mine at some point.....kind of keeps it "MG-ish".


[/ QUOTE ]

I have a hard time convincing myself the miata transplant is worth it, since at the end of the day, I start to wonder if I should just get a miata since I'd get a chassis and suspension upgrade in the process...I can justify the RX7 transplant since it's a bigger car and putting it in the midget has perceived added value to me. I'm not making much sense, but hopefully you get what I'm trying to say.

As for the rover engine, I'd love to do it if the parts weren't so expensive in the USA!
 
Honestly, I understand what you mean. I own a Miata and really like it....but putting a Miata motor in a Spridget seems wierd to me too.
The benefits of using a Miata powertrain is that they are one of the few small, front-engine, rear wheel-drive setups available (that are not too expensive).
The problem with the rotary engine (as I have heard it) is that it sort of an unusual shape that requires quite a bit of sheet metal surgery down low. I talked to a guy with a rotary MGB and he said it was a tough transplant....harder than a Rover V-8 in his view.
For now, I'm happy with the 1500 engine....but I look all the time on eBay for a reasonable "K" motor (plenty of expensive ones).
 
It needs a little surgery, but like all things it is possible. Take a look at https://the-mite.com/mite5.htm The transmission modification to get the shifter in the correct location was very ingenious.

Chris
 
[ QUOTE ]
The yellow Spridget below has a 13-B, one-piece glass body and IRS. Races in our club....beats "Vettes and 5.0 Mustangs.
80b.jpg


[/ QUOTE ]

Is that John Leary?

I've also considered the S2000 motor, mmm 9000rpm redline stock, but it was too tall.
 
My goodness the man is an artist. Can't wait to see the next stage. Supose he is going to put a Bugeye rear end on it.
 
d7_1_bsmall.jpg


This is the only pic I have of the girl. The day I picked her up.

The 13b fits well into the frame snug as a bug. Now you will not get the oil pan off but hey. Right now I am getting the 92 motor changed to a cap style ignishion. I hope to fire up by next weekend.

have chated with a guy in az. that put a turbo miata motor in an MG. He crashed it about two months after he was done.
From what I hear from the miata guys I race with it has quite a beefy bottom end and can handle a nice boost.
 
Nice hubcaps!

:smile:
 
The other side had "turbo" hub caps. I had to take them off becouse it make the car pull from the extra power all on one side. /ubbthreads/images/graemlins/tongue.gif
 
[ QUOTE ]
Is that John Leary?

I've also considered the S2000 motor, mmm 9000rpm redline stock, but it was too tall.

[/ QUOTE ]

Yes! He is now racing a Spec-Miata, but I think he still has this car. Last time I talked to him, he also had a street Spridget with a rotary.
 
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