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Miata engine in a FB?

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Old 08-16-14, 02:50 PM
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Miata engine in a FB?

Okay didn't know I where to post this so I posted it here.
Would it be possible to use a 2.0/1.6 liter miata engine in a FB?
My 85 GS has a 12a in it. But it hasn't run in years. I'm hoping to put a 13BT in it at some point. But if I can't go Dorito, I Might consider going to a piston engine.
I don't really want to do a V8 (considered it)
I would like to run a 4G63 but it's a little too custom.
K20 is too expensive.
So that brings me to they miata motor. How hard would it be to put one in a RX7, and has it been done?

Please no scorn. Just brainstorming.
Old 08-16-14, 03:40 PM
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premix, for f's sake

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It'll be as hard as any other custom RWD swap. nothing about a miata swap will really be any harder or easier than a v8 or s2k swap
Old 08-16-14, 03:53 PM
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^ agree with Sgt. Stinkfist's post.

i guess it's early enough in the thread, so i'll say it and move on. your best, most cost-effective bet would probably be to go with a 13B from now - especially since you expressed some desire for a 13B-T at some point - the 6 ports are pretty easy to find and while prices are rising a bit, you can still find them pretty affordable. no custom mounting, no crazy tranny adaptations, not even any wiring (if you go the carburetor route).

that said, if you still want the Miata lump, search the race car section, (if memory serves me) Abeomid's race car is Miata-powered. maybe you can check it out. it's an honest-to-God race car, so just keep the ideas that you need, and ignore the rest.
Old 08-16-14, 04:02 PM
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i think the miata swap is a little easier than most, you put the FB tailhousing on the miata trans and it bolts right up.

it is an inferior power plant though, it costs twice the money to get the same hp as even a 12A, and while you can turbo the miata, the kits are quite expensive, and power and reliability aren't as good as the rotary. plus the miata block is iron, so its a porker.

basically you'd end up with an MGB-GT
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Old 08-16-14, 04:44 PM
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Thanks for all the responses. Main reason I am asking is because I live in Texas and 13b's seem to be non existent. And when I find one they are 2000 bucks (and iffy). Whereas I can find a miata in picknpull and get the engine out for 150 bucks. My car is already really rough, I am mostly just trying 275hp relatively cheap, plus I'm gonna be pounding the hell out of this car so I really don't want to blow up a rotary.
Old 08-16-14, 05:11 PM
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Originally Posted by FB_road-machine
Thanks for all the responses. Main reason I am asking is because I live in Texas and 13b's seem to be non existent. And when I find one they are 2000 bucks (and iffy). Whereas I can find a miata in picknpull and get the engine out for 150 bucks. My car is already really rough, I am mostly just trying 275hp relatively cheap, plus I'm gonna be pounding the hell out of this car so I really don't want to blow up a rotary.
to get 275hp out of a miata engine is like a 5k build...
Old 08-16-14, 05:40 PM
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Originally Posted by FB_road-machine
... I live in Texas and 13b's seem to be non existent. And when I find one they are 2000 bucks (and iffy).


Whereas I can find a miata in picknpull and get the engine out for 150 bucks. My car is already really rough, I am mostly just trying 275hp relatively cheap, plus I'm gonna be pounding the hell out of this car so I really don't want to blow up a rotary.
whichever way you slice it, 275 HP is going to take money and it doesn't sound like you have it right now. what exactly went wrong with the 12A?
Old 08-16-14, 07:26 PM
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Won't be too bad since my brother already has a turbo kit that fits it that he doesn't want.

From what I read I can pull 265 from a 14 psi blow dryer, and a mild cam change.
Old 08-16-14, 07:31 PM
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Originally Posted by diabolical1




whichever way you slice it, 275 HP is going to take money and it doesn't sound like you have it right now. what exactly went wrong with the 12A?
No idea what went wrong.

I'm just as confused as you on the availability of the 13b's. people around here treat those things like gold. I found a couple for 1200 that supposedly ran, but they sat in a barn for like 8 years without being covered so they were full of dirt daubers.
Old 08-16-14, 07:35 PM
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Originally Posted by j9fd3s
to get 275hp out of a miata engine is like a 5k build...
I understand it can be expensive. Not trying to argue with you.
Old 08-16-14, 08:02 PM
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Old 08-16-14, 08:03 PM
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Okay I got some bad info. Please forgive me for that. A more realistic number is 200.
Let's say I want 200 horsepower, that shouldn't be a problem with a good turbo and some intake/exhaust mods.

I'm not trying to be an *** here. Just trying to figure out how hard this would be to up this in a FB. Like I said, I want somehing I don't feel bad about blowing up.
Old 08-16-14, 10:50 PM
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I have a rotary addiction

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The only reason I can think of doing the BP swap is the 32 MPG and easier to pass emissions.
Old 08-17-14, 12:18 PM
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Originally Posted by FB_road-machine
No idea what went wrong.

I'm just as confused as you on the availability of the 13b's. people around here treat those things like gold. I found a couple for 1200 that supposedly ran, but they sat in a barn for like 8 years without being covered so they were full of dirt daubers.
I've put in two "used" 13b's, both supposedly "good". Both were turds with issues. I agree with either rebuilding or swapping in a Miata motor. Any used engines out there are likely shot after nearly 30 years anyways. The only engine that truly fits is an 84 or 85. Good luck. If you go the Miata route, please document and start a thread about it. I'd be really interested to see how it comes out.
Old 08-17-14, 01:05 PM
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Originally Posted by andernamen
I've put in two "used" 13b's, both supposedly "good". Both were turds with issues. I agree with either rebuilding or swapping in a Miata motor. Any used engines out there are likely shot after nearly 30 years anyways. The only engine that truly fits is an 84 or 85. Good luck. If you go the Miata route, please document and start a thread about it. I'd be really interested to see how it comes out.
Well the picknpull has a low mile 99 near me. So I think I'll pull that and use it.
I'll make sure to document it.
Old 08-17-14, 01:07 PM
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Most likely will end up using a stock motor and running a 15PSI turbo on it. While this is going on I'll be saving up for a race lower end for it. If I blow the stock one... Oh well...
Old 08-17-14, 01:21 PM
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Originally Posted by FB_road-machine
Most likely will end up using a stock motor and running a 15PSI turbo on it. While this is going on I'll be saving up for a race lower end for it. If I blow the stock one... Oh well...
the miata engines don't really blow, but you can expect it to wear out really fast @200hp.

although with a 99, you probably want to change the thrust bearings before you put it in, Mazda had problems with those, even the "good" ones are weak.
Old 08-17-14, 05:40 PM
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Originally Posted by j9fd3s
the miata engines don't really blow, but you can expect it to wear out really fast @200hp.

although with a 99, you probably want to change the thrust bearings before you put it in, Mazda had problems with those, even the "good" ones are weak.
Alright. Thanks for the tip.
Old 10-24-14, 10:03 AM
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Im planning on doing this in the near future. I used to have an 85 I sold when I went off to college. Have been searching for last 2 years to find it and buy it back. But when I had it I went thru 3 engines. I have a daily Mazdaspeed Miata now with about 220hp and it is a blast!! So my next build after I get so other things out the garage is going to be a FB and do a BP3W swap. That I will eventually turbo and possibly fabricate the IRS into the FB so that I can go away with the solid axle rear end.
Then I drift and auto-x that baby like a queen!! Nothing beats an FB!
Old 10-24-14, 10:27 AM
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Originally Posted by FB_road-machine
13b's seem to be non existent. And when I find one they are 2000 bucks (and iffy). Whereas I can find a miata in picknpull and get the engine out for 150 bucks.
There's a reason for that, if you think about it for a minute.

Things that are cheap are usually... cheap.
Old 10-24-14, 03:25 PM
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Originally Posted by DivinDriver
There's a reason for that, if you think about it for a minute.

Things that are cheap are usually... cheap.
there is always the fact that the 13B's are a quarter century old
Old 10-24-14, 05:43 PM
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Originally Posted by j9fd3s
there is always the fact that the 13B's are a quarter century old
well ... when you say it like that ....
Old 10-24-14, 07:21 PM
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I think putting a miata engine in an FB is a good idea. Please post pics.
Old 10-24-14, 08:42 PM
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Vtec s2000 and call it RV-7
Old 10-24-14, 09:37 PM
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Why not do a beams 3sge? 200hp, 6 speed and around 1500 to your door.


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