fatboy7

yes, and yes.....

Yes, it comes with a factory turbo, and yes its a completely different engine. Still a 13B, but with the newer housings, and 4 ports instead of 6. Lower compression rotors, beefed up oil pump, etc.

The_7

why did they get rid of 2 ports?

jutny

becuase the 6 port 13b was just an effort to extract a little more power from an NA motor. Something that is completely unnecessary on a Turbo motor.

*dreams about getting his TII motor in a few weeks.

The_7

even tho they didnt need the extra 2 ports if they left them there wouldnt you have even more power from the turbo engine?

Manntis

the extra ports were a way for a normally aspirated engine to be able to draw in more air at higher RPMs.

With a turbo, the air is rammed in under pressure, making two extra ports completely unneccessary. Why add moving parts you don't need?

The_7

but think of it like this...2 extra ports will let in more air than the lack of 2 extra ports regardless of whether the air is pressurized or not. i could be wrong but that is the way i see it.

Manntis

If you have 2 cubic litres of air being crammed into the engine through 4 large ports or 6 smaller ports, two of which rely on mechanical actuation, there is no benefit to going with the extra ports. It's just more parts, more weight, and one more system of moving bits to break down.

Given a fixed quantity of air being shoved into the engine via a turbo, the aux ports just don't make any sense.

The_7

wait a minute...the port area of the TII's 4 ports equals the 6 ports of the 13B?

jutny

ding ding ding... tell him what he's won

The_7

could it be a TII engine?

rotary emotions

Ok, here we go...
1st gen turbo's were Japan only (some were exported later on, but non-official) 1st gen GSL-SE were America only (same applies about export).
TII are the second (turbo) Turbo rotary from mazda, hence the name. NOT all TII turbo's are twin scroll by the way.
And about 6 ports: the reason is not more power at high RPM, it's less pollution at low RPM...
BTW: there is at least one 12AT GSL-SE (LHD) built by the factory! This car was built by Mazda Japan as a gift too Dr Felix Wankel. It spent most of it's days in the collection of the Felix Wankel Foundation, but is now in private hands, and registered in Germany, where I saw it. It's a GSL-SE spec car, but with a 12AT instead of 13B NA. Here's a pic:


For those wndering, no this is not a conversion. And yes, all (?) other 12AT where RHD...

hornbm

****, do you have any idea hpw much that thing would be worth?

fatboy7

6 ports allowed more low-end torque to be generated when only 4 of the six are open, while not sacrificing top end power. The Turbo'd 4 ports due to the innovations that madza put on the turbos (variable area to radius turbine for S4, and twin scroll on S5) made a ton more low end (46% more at 2000 rpm IIRC on the S4), so the 6 port design was unnessisary.

rotary emotions

If you're talking about the 12AT: about 160hp (flywheel).
The 12AT engine was used in the FB, and before in the Cosmo HB (for info on that one see: www.3rotor.com )
At that moment the Cosmo HB was the fastest production saloon in Japan.

And ideed 6 ports allowed variable torque/HP. At low rpm the bigger ports would give the rotary rather poor torque, at high rpm the smaller ports would give little HP. So they made a combination, and ended up with a sic port system: small area at low rpm, big area at high rpm. Since a turbo will add more torque anyway, the system could be deleted on TII engines and FD.
But it's back on the Renisis, although not in the same way. This engine will use variable intake, which comes down to the same.

MikeLMR

Bart,the renesis intake uses a very similar system to the 2nd gen 6 port engine (well the US version anyway)

check out the sleeves on the 5th and 6th ports

The_7

will t2 housings fit on a normal 13B?

fatboy7

Any post-85 13B, yes. In 86 they moved the water seals from the side housings to the rotor housings.

REVHED

No, the 4 ports have more port area than the 6 port.