I know that the S4's are opened by back pressure from the exhaust but from what I understand the S5's work differently. The reason I'm concerned is because I have a '89 N/A that I'm putting a race pipe into and I don't want to mess with the ports. So how exactly are the 5th and 6th ports controlled on the S5? And also will replacing the cats with a straight pipe w/ resonator cause any negative effects?

 

It is in the archive, but I'm thinking they're pump operated.

 

the air pump controlls them i think.

 

The S5 6PI and VDI systems are operated by pressure from the air pump, via ECU-switched solenoid valves. The exhaust has nothing to do with them, so exhaust changes have no effect on their operation. I figure that's what you wanted to hear.

 

86-88 cars: Back pressure from the exaust.
89-91 cars: Airpump, ECU controlled. Both the VDI and 6 ports are controlled by the ECU through 2 different solenoid valves in the "rat's nest"

 

Well damn NZ.... beat me to it.

 

so theres two thingg, the 2 ports opening after 3800 and the VDI thing?
My friend felt something at 5500s last night, i don't really pay attention.

So i guess thats working, but i put grease on the 5th and 6th ports to see if they worked (i THINK they grease moved) and i'm kinda paranoid that theyre not working, is there anyother way to test em?

 

VDI opens at roughly (stock tach is usually off a bit) around 5600-5800rpm. I can feel mine open in lower gears. Theres a video I have somewhere of the ports opening...

Video link in here: https://www.rx7club.com/showthread.p...ight=aux+video

 

that video link is badd ***.. i got my hooked up to my air-pump.. got mine to open up at 2 grand.. im not sure why but it just opens at that range..

 

Wow thats good I didn't want any issues with installing this race pipe.

 

If you want to check the auxillary ports for being stuck or not, thats not a big deal. Screw grease on a series five. Got to the solenoid. Pull its plug off. Jumper a ground to one blade on the solenoid and 12v to the other with the car running. The aux ports should open. If not, check for air pressure at the ports inlet pipe.

OR.....remove the two vac hose at the solenoid and jumper them together with a plastic vacuum pipe that can be bought at the auto store. Start the engine and the aux ports should operate.

OR leave the plug on the solenoid and backprobe the wire in the connector that IS NOT COLORED BLACK/WHITE, and ground that wire. The aux ports should operate with the engine running. Life is easy, life is good today.

EDIT: The words *screw grease* in the first paragraph could be misconstrued. I did not mean to say screw some grease on the series five. I meant ***** on using grease on a series five*.

 

you know s5s have one large spine and a bunch of little spines ont he steering rack knuckles so you can't misalign the steering column. S5 has just a bunch of small spines with no set spine = steering wheel cocked off to the side... since you're pissing on s5s and all...

 

Series four have REAL ball joints, not those plastic or whatever they are made of ball joints. Meaning....series four car owners are not always replacing the ball joints and having to readjust their steering. We also don't have that piece of plastic afm that the series five have that does not work nearly as well as the series four afm.

Series four is the coveted series. If you have a series five...trade it in asap before it loses all its value. As you might have noticed, us series four owners have pride in our series car. It's hard for us series four owners to soar like eagles when we're surrounded by a bunch of turkeys. (humor, please)