fictionrx

why does everyone prefer the 12a over the 13? is there really potential for big horsepower? How is this accomplished?

hornbm

i dont perfer the 12a over the 13b.....

Lee Lyons

It depends on who you talk to as per the preference to the 12a over the 13b. Both have the potential for a turbo or a supercharger. I've seen a 12a with as much as 850 horsepower. There is something about it that makes it the perfect candidate for a huge *** port and turbo job...and of course all the extras that are needed to get big horsepower. ie manifolds, exhaust, even NOS. The 13b although somewhat of a bigger engine in its production phase was toned down in production...which I'm sure it could have been a beast engine. The 13b although can come with a turbo is no match for all the specialty parts built to make the 12a a horsepower machine!!

peejay

I do.

The only thing I like about the 13B is that the '86-up engines have 2mm apex seals, which are easier on housings and are more RPM-abuse tolerant.

I make 12As that would make you swear there was a 13B under the hood. But they still have that yingy 12A quality to them.

Such a shame that 10As are so horrendously rare and impossible to get parts for, I'd be championing those instead.

DJAngelicon

I heard the 12a could have potential for more horse power. Also I heard that is easier to deal with on your car. Other peoples say get a 13B because 12a parts are becoming harder to find. Other say stay with a 12a to make it cheaper for you to upgrade instead of buying a new engine 13B. Also if you get a 13B you will need to get more stuff than your engine for what I know. I think the Tranny, rear end etc.. This is just things that I learn but please feel free to correct me anyone about this.

I feel for my personal view, it is best to learn what you have and also to be a bit different in some ways. Everyone wants a 13B or 13BT, or TII etc... I would like to see peoples coming up with some massive crazy mods or invention for the 12A. Is not a bad motor and I think it could run and look just as good as a 13B. But that is just my opinion and personal view, however if you have the cash for a 13B and feel like taking a big project like that. Then go right ahead because if is speed that you want. You will get it for sure with a 13B over a stock 12a.

fictionrx

where can turbo parts be found to hook up the 12a

fictionrx

are their any sites or catalogues were i can order these parts other than racing beat or mazdatrix

peejay

13Bs that started life as turbo engines are more beefierful than a 12A (or N/A 13B for that matter) could ever hope to be. Especially the twin turbo versions (FD, Cosmo).

DJAngelicon

I got a nice catalog from them at www.VictoriaBritish.com

steve84GS TII

12A's just match the 1st gen's charactor better.
Light,nimble,responsive.The 12A has lighter components and a shorter distance between the bearings,both of which contribute to its RPM happy nature.
It made sense to put the 13B in the 2nd gen.Its a larger,heavier car.Plush torque is what they were shooting for with the 6 port N/A engines,rather than spastic revs like the carb'd 12A.

As far as durabilty,the shorter housings and 3MM seals lend themselves well to high HP/rev applications, and help offset the defeciencies of smaller displacement.The S5 N/A 13B is a close contender with the 12A for "fun to drive" pleasure,but the 12A has more history,primarily as the rotary workhorse for over 10 years in the 70s and 80s.

mcnannay

^ well with that logic with the seals, the 70's 13b should be better...but i know better than to jump to that conclusion. Honestly i love both engines, but lets not forget about our little bastard friend the 10a and monstrous 20b, id love to have all four
Personally i think its cooler to see a high performance 12a than a 13b, you see fc's and fd's with em all the time. But honestly the 13b has more potential, my next project is going to be a powerful 12a though, either a large streetport turbo, or bridgeport. Just work with what you have, hell they both have rotors and thats a big plus in my book

mortenf

The 13B definetivly has more potential for power. I prefer the 76-78 Cosmo 13B over any 12A. If you do the same mods to the 13B, you will get about 33% more power than the 12A, and a lot more tourqe.

Easy as that!

Directfreak

iTrader: (2)

13b>12a.

It's all about Torque.

Max7

20b

FB II

12a here baby! will probably always have one under the hood. next motor is in the works. definately a 1.1 ltr.... just a bigger turbo and bigger ports. MUHUHUUHHAAAAAAA i still say fork a 13b 1st gens and 12a's are like two peas in a pod. haha

peejay

Actually given the same porting the 12A can make the same power, just higher up in the rev range.

13B's are more thermally efficient, though, and for reasons I can't quite go into here they can make better use of a given port size.

perfect_circle

12a turbo!!!yay!!! seriously though, i just think 12a's and 1st gen go together.

fictionrx

every one says first gen turbo. were can i get the parts to make mine turbo?

seanrot

iTrader: (2)

Do a search. youll be pleasantly surprised in that function of the forum

cpa7man

iTrader: (2)

This is a little different slant on it: I've been trying to decide for my SCCA race car to go 12a or 13b. I can't do any kind of forced induction and can only do a street port to comply with the rules. I asked one of the most respected engine buildiers and racers in the country and this was his answer.

"The 13B is a larger displacement engine producing more torque and horsepower. You are required to run the 84-85 housings which are a little different from the second gen. 13B's. The water seals are in the rotor housings unlike the second gen's which are in the side housings. To run the 13B you have to weigh more than the 12A. Lots of people have over built their cars and cannot get their car down to weight to run the 12A. The 13B has a heavier rotating assembly and wears out quicker. Also, the 5th and 6th ports on the 13B make the engine hard to make power with the inefficiency of the porting, thus you have to rev the engine close to 10K rpm's.

I run a 12A and always will. I haven't had a first gen with a 13B in it beat me yet. The parts are cheaper, the motor's last longer, and peak power in my engines is around 8600 rpm's. I'm going to the runoffs this year again with the same motor I ran in the runoffs last year. They last very well and I can usually get at least 2 long season's out of a single rebuild. "

Keep in mind a 1st gen running the 13b in SCCA EP has a 140 pound weight penalty.
Anyway when the racers have a choice they run the 12a......

FB II

that really makes me happy. 12a's just rock!

hornbm

rotary emotions

A larger engine should be able to make more power and torque. There's no point in arguing about that. Since they are simulary build the 13B has all of the (dis)advantages of the 12A, it's just bigger. If the 12A "makes the same power higher up the rev-band", what would prevent you from taking the 13B there?
The larger engines (either larger rotor wide, or more rotors) will always be able to make more torque. If you'll push a 12A higher up the rev-band, that'll have negative effects on the torque-band.
I'd go for 12A in a ultra-light car (like Lotus Seven styled ones) but the 13B performs very well in a SA/FB. Just wish I could get mine to run.

karism

I like 12A,and allways will.

I have allways like them,because they came standard with the car,and they are more special.

Lets be honest,everyone goes 13b because there is loads of them to go around and the parts are easilly available.

The whole torque thing allso attracts people.

Its allmost the same as to ask why some like Turbo,and some love NA.

13B is easy,cheap HP.

I`ll allways have a ported 12A somewhere in my garage

Karis

12at

I stuck with the 12a mainly because people told me I would never get any decent power out of it. The common phrase was, "why dont you just get a 13b turbo?"

Now I have 480rwhp and people over here are starting to realise that you can make similar power to 13b's.