Q Cobbler

Listen im wanting a rx7 later on down the road which I know could be a huge financial decision so I was looking to see which rotary engine was more reliable I’m not looking to heavily mod a rx7 I’m more towards on enjoying the driving experience of one so I’ve seen well mostly heard the 12a rotary engine is more reliable than the 13b? soo Have anyone done a swap on the Fc body cause I like the style points I would get if I did a Fc rx7 with a 12a vs the Fb

WondrousBread

You don't often get "style points" for swapping a smaller displacement, less powerful engine into a car. Plus the 12A is harder to find good parts for.

FB ('81) : 114 hp, 2300lbs (at lightest) > 0.050 hp/lbs

FC ('86 NA): 146hp, 2700lbs (at lightest) > 0.054 hp/lbs

Your suggestion: 114hp, 2700lbs (at lighest) > 0.042 hp/lbs

Considering a good condition, maintained (or rebuilt) NA 13B is pretty reliable, you're swapping in an older engine with less power and more expensive parts that need replacing when they fail (eg. 12A housings have weaker chrome, and are harder to find). This is a recipe for a more expensive and slower car. Also consider that FBs are often swapped with FC engines due to the extra power and greater availability.

I don't know if a 12A FC has ever been done, but I doubt it.

I don't want to discourage you from doing something unique, but consider that most people generally do the exact opposite of your plan and for good reason. If you decide you want to do it, all the power to you. Just consider that you will likely be decreasing overall reliability and power output whilst increasing expense.

DR_Knight

iTrader: (23)

I do think the 12a would last longer than a 13b n/a, but we’re talking like 200k vs 150k. Does it really matter.....?


how are you going to mount the 12a? More work than just putting in a 13b from a fc.

how are you going to wire up the 12a? More work than just plugging in the stock 13b harness.


what transmission are you going to use? 12a tranny is more work. Will a fc trans even bolt to a 12a? Using a 12a tranny will probably require a custom driveshaft.


13b is reliable. It all depends on what you put into it..... literally. Inspect all your rotors, irons, housings. Use a reputable fuel system, ecu, sensors, ignition and you reduce chances of failures.

In the end, it’s your money and your car so do whatever you want. I don’t like when people hate on ideas.... they’re not paying for your car, so do whatever you want.

rowtareh?

iTrader: (1)

Okay I am all for swaps, it is just a car, but this would be a massive pain in the *** with zero gains.

Just save your money, buy a great condition S4/S5 NA, and just enjoy it. These cars are very rare, with almost no support for NOS parts.

j9fd3s

iTrader: (3)

in my experience the 12A being more reliable is a myth. besides finding a good one is not easy, rebuild parts are NLA. REW swap is the future

Q Cobbler

thanks I’m just new to this so I decided to talk about it here I had seen in a video someone had said the 12a was more reliable than the 13b which in my standing I’m not sure I want to get a fc rx7 later down the road I’m not too sure about getting a fb rx7 even though I like them as well I just want to make a good choice when it’s time to do so it’ll practically be a project car for me but I’m not looking to do much , maybe customize the car a little and maybe a couple of light mods I’m not looking to make big horsepower I’m just wanting to enjoy the driving experience while keeping the car reliable

j9fd3s

iTrader: (3)

the Rx7 is actually really good at that. the stock car an be a little bland, but a couple tweaks (alignment, a little more power; exhaust) and they become really fun. plus there are all kinds of wheels that look great

Dak

This.^^ Not the cheapest route but probably the best as far as parts availability and power potential are concerned would be a 13B-REW setup to run N/A. It has the best ports and can make good power non-turbo on a standalone ecu. The mounting issues have already been solved for the most part. Someone with more old school knowledge can correct me but I see no reason it can't be as reliable as 12A. 2nd choice would be the S5 TII engine setup n/a with modified N/A intake manifolds, as from what I understand the 4 ports have better power potential once street ported. At least it can use REW rotor housings if the S5 ones become NLA.

j9fd3s

iTrader: (3)

for me the REW does a couple of things, first its easier to find parts, and second it makes more power and is emissions legal. third, the stock FD ecu is a huge upgrade, it is so much better.

the S5 t2 with NA intakes could actually smog here too, but the only S5 T2 engine parts that are good are in Mazda's warehouse $$$

DR_Knight

iTrader: (23)

Just throwing this out there...

what I did was: bought a s4 n/a running from a friend. Upgraded the suspension and replaced worn items. I then built up a s5 t2 motor over a couple years, finding deals here and there. Once I had everything, I just did a swap to the s5 t2 over a two week span.

go to some meets, talk to some guys, ride in their cars.