prime

So yeah, my 88 GXL's 6th ports aren't being triggered to open. I assume there isn't enough exhaust pressure to operate them, since the pickup is hooked into the second cat, and the second cat is punched. Does anyone have a short term suggestion to get em online? I'd like my top end back.

And also, does anyone know if the Racingbeat Headers with 6port pickup operates the ports without cats, since it'd normally go onto a presilencer system?

DeMoe Aurelius

iTrader: (4)

What I did when I was N/A and was straight pipe with a 3" single can and R&B S5 header on mt S4 Vert was, Wire the ports open via Zip Ties. You lose bottom end true but top end was nice as long as you have other supporting mods to help you breath...

Derekcat

iTrader: (8)

The easy solution: get a T, valve [like for a garden faucet] and adaptors all the way down to vacuum tube size. Take the output of the air pump and put it into the middle of the T. Put the valve on one side and adaptors down to vacuum on the other - attach the vacuum hose that normally goes to the split air pipe to this.

Adjust the valve until the ports open at ~3600RPM.

Enjoy [This is how my car is setup - search for picts and a more through writeup - "airpump activation"]

Not worth it to ziptie when you can just do this ^_^

DeMoe Aurelius

iTrader: (4)

Yea that would be the best way to do it. I went JDM S5 swap and blew lack of fuel cut defender and now I'm with a built Ported S4 TII engine. Just trying to get it back up and running having a stupid fuel or ECU issue...

prime

Yeah, you aren't the first to suggest this, one of my friends did as well. I'm curious how much horsepower I'm losing by having the airpump on there, but I suppose less than I would be without my 6th ports aye?

Does anyone know if the racing beat headers with 6 port actuators overcomes this issue? I'd be incredibly happy if they did, it'd save me some trouble in favor of a simple order that I'd like to make anyways.... Just gives me a better excuse.

Zero10

This is probably a stupid question, but how can you tell exactly when the ports open if you are driving the car at the time...?

funkjaw

iTrader: (3)

You can always mark the little rods with something and take it out for a spin then pop the hood and see if they moved by looking at your marks for distortion or something. Just a thought.

Zero10

So you would what, drive it only up to say 3600RPM, then check, then 3800RPM then check, stepping your way up?

RotaryRocket88

iTrader: (7)

Aux. ports activation: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/. A simple solution for only ~$60.

Derekcat

iTrader: (8)

With the method I described, the car doesn't have to be under load for the ports to open, you just get a friend to hold the engine at ~3600RPM and you adjust the valve so it dumps enough air for them to open at that speed.

This method is pretty crude, but it seems to be reliable and super cheap.. [~$20 at Home Depot, make sure to bring a piece of vacuum hose and an airpump hose so you get the correct barbs - I had to use a nylon barb for the airpump hose since the metal ones didn't go up that high, it's holding up nicely]

Oh for note: I couldn't get enough pressure by tapping into the side of the ACV-Airpump hose, I had to direct the whole output through my plumbing. Putting a new nipple on the airpump ala RotaryRocket would solve that issue [if you want to retain the ACV for some reason..]

If you have the money to spend on an RPM switch, use his method. There's a reason he linked it ^_-
$45+SH[?] for the switch via summit right now.

Zero10

Thanks for the answers

The reason I am asking is because I replaced my cats with a RB presilencer then installed a custom made (for a turbo....) cat back exhaust on my 87 N/A. The presilencer has the air pipe to actuate the 5th/6th ports however I strongly doubt the rest of the exhaust can produce enough backpressure to open them as-is. Before I go installing an alternate way of actuating the ports I wanted to verify if maybe they are okay as-is.

I was thinking I would insert a T into the vacuum/pressure line that operates them and run a line into the cabin to a small mechanical vacuum/pressure gauge to verify the pressure at certain engine speeds under load. I don't want to completely side-track this thread, but do you know what pressure it takes to open the actuators? Obviously I can check what it takes to open mine, but for all I know they are a bit gummed up and don't open as easily as they should.

Zero10

After reading the other thread I think I answered my own question... looks like the number is 2psi. I'd edit my last post if I could

FC_fan

iTrader: (2)

great info. if not already done, both derekcat's method and rotaryrockets method should be archived and sticky'd in 2nd gen section as well. a lot of people don't go into the archive for some reason.lol (s4 noobs will be grateful for this, I know I am). well done guys.

Derekcat

iTrader: (8)

lol.... I was careful not to call it "my method" because it's just a small twist on one airpump method that's already in the archive [it says you can just tap into the side of the ACV-Airpump hose, which didn't work for me, hence the note] ^_^