jeff_oner

i want to hook up a more free-flowing exhaust system, but i read about the sixport actuation and that it is turned on by exhaust back pressure. so im wondering if anyone has moded it to start by rpm, and if so what would be the easiest way.

1.3liter_of_power

What year model is your 7? What exhaust are you going to get, there are some headers that come with a little plat in the header that keeps enough back pressure to open your 5/6th ports. Racing beat sells them. hope this helps


91na
intake,exhaust,S-AFC

Ryde _Or_Die

If you have an 86-88 and need the backpressure for the 6 port actuation, look at the topic "headers" in the 2nd gen spefic right now.

jeff_oner

i have a 91 and i dont know what exhaust i want, im thinking about some headers and mufflers and getting custom 2.5 inch piping.

Ryde _Or_Die

Ok, well lucky for you you don't have to worry about the 6 port acuation. Your 91 has the 5th & 6th ports actuated by the air pump. Are you trying to get the very best performance or best bang for the buck? Let me know what you are going for and I can help you out. Trying to look stock? Are you worried about how loud? Just let me know.

KNONFS

iTrader: (14)

RB headers must be used with a Pre-silencer, the silencer has a small tube that provides the needed back pressure, or you can build a custom spacer in order to fit the cat with the RB header.

hope this help

jeff_oner

how do i get the ports to acuate at a certain rpm? can i?

Ryde _Or_Die

With the 89+ the 6 ports are opened by the airpump, what you are saying applies to the 86-88. He can do whatever he wants with his 91.

TheTwinTurboRX-7

Ok, cause I had the same question. I am gonna get the header and pre-silencer so as long as I hook up the pre-silencer pipe to the air pup I should be ok, is that the case or am I just really confused??

Ryde _Or_Die

All I know is that the 86-88s 5th & 6th ports are actuated by the back pressure. The 89+'s 5th & 6th ports are opened by the airpump. Why would you need to hook up the airpump tube to the presilencer then? The airpump opens the ports already by itself. Why not just call the company you are buying the product from, they will know for sure.

1.3liter_of_power

On 89-91 RX-7's, the 5/6th port are opened by the ecu sending a signal to the 5/6th port soleniod valve at 3,000rpm, when it opens it lets the air from the air pump open the 5/6th ports. Alot of time this soleniod goes bad, like mine on my Rx-7, it went bad right after I put my header on. All I did was just took the soleniod off and, hooked the two vacuum lines to a valve with a pressure gauge on it and, had the valve open up all the way at 2psi, or 3psi. The 5/6th port soleniod valve has abrown sticker on it , it's right by the VDI soleniod valve witch as a white sticker on it. The valve's are on the drivers side right by the alternator.
hope this helps


91na
intake,exhaust,S-AFC

jeff_oner

should i feel some sort of "boost" at 3000.

i think i feel some sort of boost at about 6,000. would this be from anything normal?

HAILERS

jEFF OWNER.......I have the car rigged where I can open the aux at just about any speed I want, and frankly I can't feel squat when they open. The one thing I can feel without a shadow of a doubt, is when they are closed and never opening compared to when they open and I have the pedal to the metal b/t 6-8000 rpm. There is a vey, very big difference on the top end. But the transition, sad to say, I cannot feel. Others are sensitive enough to tell when they open. Not I. Signed: Insensitive in Texas

1.3liter_of_power

What your feeling at 6,000 rpm is the variable dynamic effect intake (VDI). What it does is force additional air in to each combustion chamber by generating pressure wave in the intake tracts. Your not going to feel your 5/6th ports open up, are sure they are opening up right now? To check them, detach the air hose from the acturator and, using a tee (three way) fitting, hook up a pressure gauge and apply low- pressure compressed air, just to make use there not stuck shut, 3psi should open then easy. Next, you might want to check the 5/6th ports solenoid valve, detach the vacuum hose that goes down to the metal pipe but, keep it on the soleniod valve. now, detach the other vacuum hose off the soleniod valve, blow throw the vacuum hose and veify air pass through the valve and out the air filter. Next, detach the soleniod valve electrical connector, apply battery voltage to soleniod valve terminals, blow through the vacuum hose and, air should come out the hole were you took off the the other vacuum hose off, if not the soleniod is bad. Before you do all this, just have someone rev the engine to about 4,000 rpm and, you should see the rods move, if they don't then there stuck or the soleniod doesn't work.


91na
intake,exhaust,S-AFC:p