Possibly a dumb question, but did the 13b change drastically between 85 and 86 (or any time within the 2ndGen time period)?

I've been thinking about a carburated 13b setup, and I was looking at parts on the racing beat site, and I'm not sure if there'd be a different header for an 88 13b than for an 85 13b.

Anyone?

 

Well... the part numbers differ...

 

Big change from '85 to '86. I'd be here all night trying to list the differences. The header would be the same. The intake manifolds are not interchangeable since the bolt pattern changed. The older rotors are heavier. The pre 86 engines had 3mm apex seals vs the 2mm of the newer ones. The engine mount location was changed from the front cover to the intermediate housing. There are a ton more other changes like that. You can get some good carb setups for each style. Just don't get them mixed up.

 

How did the intake manifold bolt pattern change?

Intake manifold difference pics

I'm planning on putting a S4 intake on a GSL-SE 13b in my friends car. Other than maybe needing to fill some egr passages what needs to be changed?

 

The bolt pattern of the GSL-SE is the exception. It is the same bolt pattern as every other rotary through '91. You can put an S4 or S5 manifold on it. I have an S5 on mine. The primary intake runners (the middle ones) either have to be filled in slightly with epoxy or the engine side needs to be hogged out a little due to the difference in size. No a big deal though.

 

Compression ratio and rotor wieghts... the OLD SCHOOL 13b's pre 80 had some wierd cornor seals on them... had a different kind of oil pressure reg.... I beleve some of them had twin distributor front covers... I heard that the 84 se was a 4 port I heard the 85 se motor was a 6 port... ALL pre 84 13b's were 4 port all post 86 13b's were 6 port except for the turbo motors which all were 4 ports... All the se motors I have delt with were 4 port to the best of my memory but some people swear on there life there all 6 ports... heres a hint the 91 vert rotors were 9.7:1 the highest that came factory in 13b engines... the series 5 motors had a different machining process done to the rotors and had harden stationary gears... The j spec 3rd gen motors had a different port desighn... and thats all I can rant about right now I am shure I have forgott a few things...

 

All gsl-se's had 13B 6-port motors.

 

I noticed that the primary port runners were a bit different. Not a problem....


Another point of confusion is where the o-ring grooves are in the GSL-SE 13b 6-port. Are they in the rotor housings or on the irons? This is another critical question to my friend's project. (but primarily my responsibility to get this right)

I need to know so we can source either a 79 REPU intermediate housing or an S5 turbo one. (biggest primary ports) And then the intake will line up quite nicely too.

 

ALL of the GSL-SE's are 6-port. If you worked on one that was a 4 port it didn't come that way.

ALL '89-'91 S5 2nd gen rotors are 9.7:1 compression ratio (n/a's). The T-II's were 9:1.

ALL '86-'88 S4 2nd gen rotors are 9.4:1 compression ratio (n/a's). The T-II's were 8.5:1

ALL rotaries between 1985 and 2002 have the water seal grooves on the rotor housings. Pre-86 engines (GSL-SE included) have the water seals on the side housings. The Renesis also has the water seal on the side housings.

If you are building a pre-86 engine and want the largest intermediate housing ports you can get then use the early 12A housings. If it is after 85 then you will need the T-II which can't get near as large as the 12A or the Cosmo 13B intermediate housing. This one can get as large. The downside to this is that the 3rd gen and Cosmo 13B intake ports enter the engine housings from higher up meaning that you will either need all parts of these engines or a custom built intake manifold. The last option if it is a post 85 engine is to have a 12A intermediate housing machined so that the water grooves are cut into it. I am currently talking to a machine shop about this.

 

you meant from 1986-2002 the water seals are in the side housings. from 1967-1985 and 2003+ the water seals are in the rotor housing

mike

 

Oops you're right, my bad. Damn, now I've been wrong twice in my life

 

Since you guys seem to know your poop on the gsl-se's... How much power will the stock ecu support?

As mentioned the intake will be the long runner S4 with the afm being replaced with an S4 unit as well.

Thanks for the clarification on the housings. Now we can finally source parts for his engine. I basically want to build him another one of mine. (if you've seen anything on it in the second gen forum)

 

my gsl-se runs out of fuel at the top of third, or i should say leans out enough to detonate/ping. it has a rb header and muffler. so i would estimate about 150rwhp.
it is possible my fuel pump is weak (230k miles), or there is something else going on, but i seem to be at the limit of the afm/injectors

mike

 

Mines fine and I have an RB Header and presilencer to a free flowing muffler, but the car never goes lean (have an A/F ratio meter in the car too). I'd check your pump and injectors out.

 

The car I'm working on currently has the RB header and a straight pipe and pacesetter muffler. (supposedly high flowing unit. I'm sceptical of it myself as the car is far too quiet to be making any power) It's also got a solid hub 6 puck clutch and 22lb rims on the car.

With myself driving, and its owner in the passenger seat, I would have difficulty spilling coffee in this car. Even with our combined weight being close to 500lbs this vehicle should accellerate far better than it does.

I keep telling the owner (my good friend) to ditch the wheels and he will not. (purchased them before knowing me) I want to throw some light rims on it to show him his handicap in using those things.

Anyways... I want to build another engine capable of 175@ the ground with beat on it all day long reliablilty. I want to then put this engine in his car. Will I need to scrap the stock fuel management to make this happen?

Another point of confusion is to which apex seals are used in the gsl-se's. 2 mm or 3 mm?

Thanks for the help so far!

 

stock gsl-se is the 3mm seal

mike