FB II

ok ok, i'm very torn in a motor decision right now. my 84 gs is about to get a swap. i was very set on doing a tII motor swap but it's going to be a daily driver and i want reliablity. er go, N/A right? well today i came upon a guy thru a friend of mine that is selling his 91 6-port 13b n/a motor that has only 4,000 miles on the rebuild. 3mm apex seals too. nice if i get that i want to slap a carb on it, good exhaust setup, and be done. i am wanting a nice, reliable, fun, daily driven street car that i can do the occassional race or two and autocross every now and then. if i do this then i can build a monster tII for another car, just curious as to who has done an N/A swap in to the FB and what their results are. HORNBM, chime in please hahaha. thanks guys.

Icemark

off to first gen

Jeff20B

iTrader: (13)

Get the 6 port engine. Put an FB or SA front cover on it. Get Racing Beat's 6 port Holley intake manifold or get a Weber DCOE with the appropriate upper manifold to go on your stock 6 port lower intake manifold (LIM). Get the Mazdatrix exhaust for the GSL-SE so it'll come with the the 6 port sensing tube. It's the RB unit, but the backpressure sensing tube is in a better spot so it'll open the secondaries (5th and 6th ports) sooner. That is, with the stock LIM and a two barrel carb. If you go with the Holley, don't worry about the exhaust. Just get the 13B in a 1st gen version.

ioTus

iTrader: (5)

My turbo 2 setup will be daily driven. I hear TII's are very reliable cars when propperly cared for.

Jeff20B

iTrader: (13)

Here's a link to the 6 port Holley kit. http://www.racingbeat.com/resultset....rtNumber=18045

FB II

jeff20b, so you're saying i won't have to keep the 5th/6th ports open all the time? it'll actually have the full spectrum of power like it's supposed to? 1337!!! the only thing is that i'm pretty sure i want to go holley most likely because of streetability. the whole 2bbl weber no low-end response thing doesn't appeal to me. but i dunno. i have never ridden in a car with a weber. rotary should i say. either or, it'll be QUITE A STEP over my modded 12a! muhuhahahaahaaaa! oh yea, so why do i need the 12a front cover? so i can use the stock motor mount? thanks for your help!

Jeff20B

iTrader: (13)

Yep, stock motor mount.

Yeah, I think the Racing Beat Holley kit for 6 port engines will take care of the power band for you.

FB II

fug yes! i plan on using my 12a tranny. it will bolt up right?

Jeff20B

iTrader: (13)

To the engine, yes! I also know that the '86 6 port stock flywheel takes a 225mm clutch and pressure plate. So does your '84. It also has a lighter flywheel than your '84. Go for it!!! Or if you want a light flywheel, just get the rear counterweight from Mzdatrix, but it'll cost like $140 or something. It's gotta match the rotors in your engine.

Oh wait, I just read your sig. It looks like it's a '91 6 port. Same difference. Different rotors. You'll figure it out.

1984special

Yes the 12A tranny bolts on IIRC but I still wouldn't recommend it. 12A was 101hp at the flywheel while T2s and S5 N/A motors were 200hp and 160hp respectively. But of course it's torque that kills trannies. I don't remember the numbers off the top of my head but they're like 50% more than what the 12A tranny was built for.
Bottom line... your 12A tranny shold work. But it won't LAST!

Best of luck on your automotive motor-swapping and wrenching.

Wankelguy

Good point about the trannies. I'd suggest using a GSL-SE unit at least. And Jeff, I like the way you think regarding going with carburetion. But in all fairness, a properly tuned Weber shouldn't have a "no low-end" response by any means.

Jeff20B

iTrader: (13)

Hey thanks.