I lurk around the forums and spend hours digging up old threads with tons of great info. I'm also a quick learner, so bear with me for a moment. I was reading a thread and one of the guys wrote: "During my engine rebuild I didn't reinstall my 5/6th ports i just left them open and blocked off the outside connections, tubines, etc. I left the VDI still connected."

I want to learn more about what that means exactly because I have no clue what blocking ports does. All of the posts regarding 4 port or 6 port etc. are too technical and I have no idea what the OP's are talking about. Is there some place I can go to learn the fundamentals of what the advantages/disadvantages are to blocking ports? I didn't see anything about this is the FAQ. Thanks.

 

The auxiliary ports (commonly called 5/6th ports) are ports that can be either close or open. When closed they help low end torque and once they open they allow full flow into the engine for maximum peak hp. They are the rotary equivalent of variable valve timing (Vtech, VANOS, etc).

Hope this helps.

 

There's noting but Disadvantages to deleting the aux/six ports on the non turbo engine. He didn't actually block the ports off themselves, he removed the auxillary port sleeves and actuators and blocked off the places where the actuators bolt to the intake manifold.

I guess downloading the Factory Service Manual from this site would help. At least the ENGINE section and the Fuel and Emissions section. And somewhere there is a Training Manual that can be downloaded. Both the engine and fuel and emissons section of it downloaded would help.

Actually, page 4-15 of that training manual, FUEL AND EMISSIONS section, shows about as good a description as you will get.

 

See my signature below (second link has training manual). Don't loose the 6PI system (6-port system, which the turbo's don't have), or VDI system (S5's NA's only, variable length intake runner system), because they mazimize airflow characteristics going into the engine, essentially.

Give us more info on your car and any mods. - highly related to this discussion.

 

mine's an 86 or 87 NA, the kid I bought it from had removed the smog pump. I was reading around yesterday about smog pump removal because I want to reinstall mine and found out some interesting things about the aux ports on S4's. Apparently exhaust backpressure regulates the ports opening on S4's. Now, if you remove your smog pump and melt your stock cats, that backpressure goes away and the aux ports dont open. I hope this information is incorrect otherwise this is going to be a PITA.

I went to How Stuff Works yesterday and got a crash course on the rotary engine hoping to gain more insight. I am going to check out the sources mentioned above now.

 

I have a t2. Im curious when these ports open on a stock computer? Is it more based on rpm or load?