Patrick1694

so i put my 87 RX-7 on jack stands and went under the car to take a look and found this under the car. and i honestly dont know what it is i think it might be a part of the ac line but i am not sure there was also a rubber hose attached that it was danggling by that i had to remove to take it off, if anyone can tell me what it is that would be great =]

RotaryRocket88

iTrader: (7)

That is the split air pipe that runs to the main cat. If you have a cat in the car, you're damaging it without the additional air that usually comes down that line. If your car is an S4 NA, you'll also have non-functional aux. ports (loss of top end power) because the actuators tap into that line as a pressure source.

Patrick1694

would i just need to buy a new split air pipe, like is this an east fix? and if i run straight pipe to the muffler would i still need the split air pipe?

whoknows

Ive done alot of reading on here and have gotten numerous replies on help for my actuators as well for my s5. If you look at all the threads, there have been a few, regarding the 5th and 6th port actuators, you should get all the answers you need. I believe i read for your s4 that you can tap your own line of which needs to be alittle smaller for the extra pressure you would need for tapping the line off straight pipe back up to the actuators. But if your line was never hooked up and just dangling, you might wanna check 1st to see if the actuator system was removed with block off plates installed, and/or if your actuator valves are simply wired open. I read alot of mixed reviews on this as in some folks believe with them wired open all the time gives them more power, which is does but only on the top end, but it kills your low end power cause all it does is substitute power. Im trying to get familiar with this car my own self so thats im just going off of what ive learned on the subject so far. But these guys should beable to tell you otherwise if im wrong and those recent threads should really help you out.

Patrick1694

Hey man I really appricaite your help, altough I do now a lot about cars this whole concept is new to me, basically what your saying is if I run straight pipes I don't need that split air pipe but that I should use block off plates to stop flow from the acctuators and should not wire them closed? And where would the actuator be found because the split air pipe was just dangling under the car by the tube that's connected to it

whoknows

Lol, no, what i was trying to say was to look to see if your actuators are blocked off and wired open and if they were then to get the actuators back on there and plumb you a new line off your straight pipe back to them so your car runs more efficiently and your not trading low end power for top end power. Sorry if i confused you. I confuse myself sometimes. Your s4 actuators are triggered, open, by the exhaust pressure, via that line that you have thats all bent up. The s5's work off the air pump in the car so they dont have that line like yours. But really, look into those threads that have been posted on the 5th and 6th port actuators, theres alot of them. I swear i saw an answer on how to do what you need to do in one of them. Theres a moderator here who helped me imensly on mine, Aaron cake. You could click on his name and check out his posts as alot of them are answers to your questions and will bring up those threads im telling you about. Also go to the frequently asked 2nd gen questions thread in this section and click and look up the manual for your car. You should beable to find everything there. But your actuators will be on the passenger side, lower part of your motor. 2 can looking deals with vacuum lines that come off the bottom and rods that come out the top of them that are hooked to the actuator valves that go through the side of your intake.

RotaryRocket88

iTrader: (7)

http://mazdarx7.iougs.com/intakeair.shtml

^ Scroll to the bottom of the page for info on how the split air pipe and aux. port actuators relate. It's a system that is activated by exhaust back pressure, so the additional intake ports will open around 3800 RPM. It's similar to variable valve timing found in most modern piston engines.

If you have the cats removed, chances are you probably won't have enough back pressure to activate the actuators anyway (~2 psi needed). In this case, you have a couple main options:

1) RPM switches with solenoids to mimic the S5 method. See my writeup here: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/

2) A small diameter pick up tube welded into your exhaust piping may supply enough pressure. I've seen some tapped into headers, and it apparently worked.

Patrick1694

Alright doesn't sound too complicated thank you both for your help, I'm gunna do what I can and look into this problem a littile bit more and if I run into any other problems ill ask. Once again thank you both very much