hi guys,

as in sig, 12a has crapped out, i was wondering if anyone has done a 12a carbed to a -se 13b efi? i was wondering how hard it is to do the switch and what the results are. i mainly want to do this b/c i want to stay in my scca class, and search revealed nothing about this

thanks
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Physically installing the engine is the easy part, you can spend $80ish for a special motor mount plate from Mazdatrix/Racing Beat or you can modify your old one. Essentially, the 13B is 20mm longer and so the front of the engine needs to sit 20mm further forwards, so you need to do some creative ovalling of holes. After you get that squared away it falls right in.

Keeping the EFI is the *fun* part. What SCCA class are you running in? I was under the assumption that the -SE was in a different class and any updating/backdating for a 12A car could only use parts from another 12A car. But the class you are running in dictates just how much OE stuff you need... if worse comes to worse and you have to use all OEM parts, that is doable of course, since after all your car had the 13B as an option.

 

In CSP, he would be able to use the engine from any NA RX-7 as they are listed on the same line. Even one from a 91.

Of course, by the time you go through that much work, wouldn't a turbo II motor have been more fun? There is nothing wrong with running in SM2 or EM.

On a side note, PJ, does that mean that using the mount from the SE will not locate the holes on the motor mounts correctly? I had assumed that if you kept the original pieces from the SE, then you didn't have to oval holes. Are the mount points on the subframe farther forward then?

 

The mount for the SE is the same as the mount for the 12A The crossmember is the difference. Now, you *could* acquire an -SE crossmember, if you wanted, but it's More Work. And while you're changing crossmembers, you might get the impulse to repaint it before it goes on. Then you won't want to bolt those rusty looking control arms to it, and before long you are doing over your entire car with a case of Q-tips every night.

CSP? Intake is free, I'd just throw a 45DCOE Weber on it and call it done. Or, if you have the money, a nice purty 48IDA Weber and intake manifold. Get the manifold from Mazdatrix, but Racing Beat has the scoop on the 48IDA pricing...

 

ya in csp, i think that it has to be from that model year thou. but i need to keep the emissions because its also my daily driver, how hard is the wiring switch from 13b from 12a? i figured that it might take some work with all those cables from the carb that wouldnt be used anymore

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It's not all the cables from the carb, it's all the wiring to the new engine. And the other things you need that don't come with the engine. (fuel pump, "maybe" a fuel tank if the car stalls in hard lefts, air flow meter, computer)

 

you do need the SE fuel tank. The SE tank has a much bigger fuel outlet than the 12a models do, even the 84-85. Its one of the things I had to do on my 13b swap.

 

8mm fuel line can flow enough for 450hp. 12A's have 8mm fuel line.

 

DAMN

 

i did the swap! the cars awesome!

 

k, so the total list then to get for the swap:

rb bracket
13b engine
ecu
wiring harness
fuel pump
efi for intake (intake cone and that whole thing, injectors, the metal piece)
im assuming a 13b header of some sort?

oh, and one last questing, could i just be lazy for the moment and just bolt the nikki on until i get all of the efi equment in?

thanks for all the help so far

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The Nikki won't fit. The manifolds are totallt different. You can get a 6 port to 4 port adapter plate and then a 13b to 12a adapter plate but it wouldn't be the best route. If you don't want FI you can always get a Nolley carb and manifold for 6 ports.

 

i would suggest the carb, the wiring sucked!

 

nah, i want to go fi, but i was wondering if i could do that as a "till i get the rest" fix

anything im missing from the list?

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i did the work, the efi is really nice, but im not sure it was worth the work, a heathy carb would prolly work as well and have more hp at wide open throtle