12a vs 13B???

[43975]

So I have my mind wondering about doing a Rotary transplant into my Suzuki samurai. I've seen it done dozens of times on my Suzuki forums. What i'm trying to figure out is much is the better motor to turbo, and if the Transmissions behind them are the same or at least interchangeable? I found both an 84- 13b and 83 12a for the same price with similar miles close by but neither come with a Tranny or wiring. I do have an extra t25 turbo here that I plan to use on the motor. I know that out of the box the 13b has 30 more horses but is it the prefered motor for turbo swaps? I guess my main issue at the moment in the Tranny though.
In addition. If the Tannies are different, which is the shorter one?

 

[GiJoe]

I am subbin to this due to the fact that I am planning a rotary transplant into the Miata.

 

[NCZ13]

The only 13b that is easy and worth turboing with the last amount of work would be the s5 turbo engine. The NA engines are to high compression, and turboing the NA engines are more work then your looking for.

The 13b from the GSL-SE FB i believe is the same NA 6 port motor from the s4 rx7, which cant be turboed easily.

 

[43975]

Thank you for that response. My initial plan was suzuki 1.3 DOHC out of a suzuki swift GT. It's a direct bolt on to the samurai tranny and motor mounts and good for 100 HP. It also has forged internals stock so it can handle boost quite nicely and a moderate build with a T25 can net me 175 HP without opening up the motor. The quickest samurais I have seen all have Rotarys so I figured I'd look that route as well. Now NA how much power can be expected with a moderate 13b or 12a? If I can get 175+ HP without having to open the motor I still may be better off going Rotary

 

[NCZ13]

In order to make that kind of power NA youll need to open it up for porting.

Full exhaust, and a AFC might net you the drivetrain HP loss back, but without opening up the ports its going to be hard to make 175+

 

[43975]

Once again thanks for that info

 

[NCZ13]

No problem.

 

[Shadow102]

The 13b and 12a NA trans are interchangable. However the 12a trans is weaker than the 13b s4/5 na trans. Gear sets between all na rx7's, b2200, miata, and rwd 626 are interchangable with slight modifications as well. The 13b turbo transmissions are different though and are beefier, they require different flywheels, clutches, slave cylinder, counter weight and driveshaft. They are all generally the same length with the rx7 trans.

You can infact turbo the na motors the gsl-se 13b your looking at is the older model has has lower compresion, you can even turbo the s5 na motor but with the higher compresion you have less margin for error in the tuning. You may want to keep an eye out for a turbo motor if going that route.

A s5 na motor will put out 175whp on a stock port though just need your basic bolt ons, a safc, and assoctiated drivetrain modifications...much past that you are looking into porting.

 

[Austerror]

everyone I talk to also says the 12a is more robust. I would go the 12a route.