MazdaManGTU

I here all this talk bt 5th and6th ports?? what does that mean and how do i do it people sayto get them working??? another thing what are the pb sleeves? info can help thanks

rotarygod

iTrader: (1)

The 6-port engines are all 13B n/a engines from 1984-1991. The 12A's (except for a couple of years in Japan) and all 13B turbo engines are 4-ports. This refers to the number of intake ports per engine. The 4 port engines have 2 intake ports per rotor: 1 in the intermediate housing and 1 in the end housing. the 6-port engines have 3 ports per rotor: 1 in the intermediate housing and 2 in the end housing. The 2 outer ports are small. The upper most one has a rotating sleeve which opens through positive pressure at either a set rpm or load depending on which year car it was on. This upper port sleeve stays closed below about 3800 rpm to promote higher intake velocity through the lower port as well as less port timing for better low end power. Above about 3800 rpm when the port opens it adds its volume to the existing ports for greater airflow. Since it is open later in the cycle it is also in essence a variable timing system allowing greater high rpm power due to the increased port timing duration. Think variable timing was a Honda idea? Mazda had it on the rotary as early as 1981!These sleeves are of a poor aerodynamic design. They are a brick wall flat shape at the end that the incoming air has to hit as it enters the engine. Many people install Pineapple sleeves. Pineapple is a company that makes new sleeves with a gentle radius to smoothen airflow and increase power. Since these sleeves rotate either based on exhaust back pressure or the airpump, there are some problems which occur when the airpump is removed or when a really good exhaust system is used which may lead them to not open. There are various mods to remedy this including electric activation which is a sticky thread here. Others just simply remove them altogether leaving them open at all times. This reduces low end horsepower but also leaves nothing to fail. There is so much more info that pertains to these ports and ways to increase flow but that should have answered the question.

MazdaManGTU

Thanks for the info but any info on removing them or seeing if they are working??

eljefe62

Hey Rotarygod, i posted earlier in another thread about buying a gslse engine and someone posted (seemed very confident) that the 13b from 84-85 was 4-port.
I posted that I thought was 6-port, they denied it, it is 6-port correct?

rotarygod

iTrader: (1)

My 2 best friends have had GSL-SE's and I currently have one which I just built the engine in a few months ago. Trust me it's a 6 port. I used to have a spare one as well. All 13B 6-port engines that have the intake manifold that says RE-EGI (rotary engine-electronic gas injection) are from the GSL-SE. If they don't have a manifold on them you can also identify them by the fact that the GSL-SE also does not have any exhaust diffusers in the exhaust sleeves where as the 2nd gens do. If one of those guys say they have a GSL-SE or have seen one with a 4-port then it didn't come that way.

eljefe62

Thats what I thought.
I had a gslse before I knew as much about cars
was a fun car tho

rotarygod

iTrader: (1)

MazdaManGTU: There is tons of info about how to make sure they are working or not. If they are stuck closed then the car just seems like it no longer has any power above 4000 rpm. You can manually check them by hooking up a small hand held pump to the vacuum lines going to them and see if they open with a little pressure. The factory service manual actually tells how to do this. Another way is to take the vacuum actuators themselves off of the lower manifold (only 2 nuts per) and wire them in the open position to see if the car is faster on the top end then it is with the actuators installed. If it is then they aren't working. It is a very noticable difference between them opening and not. There is an overall top end performance gain to be had by completely removing them altogether. Remove the actuators and the rods that go to the sleeves. The corresponding holes have to be filled in after doing this. Install some Pineapple or other radiused form of sleeve in the engine glued in the open position. Now there are no rods in the way blocking airflow. Top end power is improved. Some people just wire them open and claim performance gains. They are only fooling themselves and really actually losing performance below 3800 rpm. There would still be actuator rods in the airstream in this instance so no gain could be had. If his is a litle confusing to you then I suggest that you study some detailed pictures of the engine layout or actually just take a manifold off of one and study it. It makes sense once you see it.

MazdaManGTU

Thanks man