Alright, i was reading today and i finally figured out what you guys meant by 5th and 6th ports, when i first read about them i was thinking something totally different, i was thinking it was in the throttle body itself, something to do with the butterflies. But, now that i found them and figured out i was way off, i just realized that they arent opening. I put a dab of grease on the actuator shafts after seeing them stay perfectly still while revin motor and watching them, and after i put the grease on i took it for a test drive (almost redlined it to make sure) at WOT in 2nd gear, and i took a look after and grease was intact. I then took the rear actuator off (closest to firewall) and i noticed that its impossible to move the, well thing its supposed to move, i guess its the lobe kind of on the end of the port butterfly. I dont know how else to describe it. I got a few questions.

1. Are both ports (butterflies?) connected to each other mechanically (ie a rod connecting the 2, making sure they open simultaneously.)?

2. The actuator i took off moves quite freely when i press it (im pretty sure its working properly), it makes an air wooshing as it goes in and out. It provides a little resistance when going in and out. Is that normal function?

3. The gasket looked a little beat up on the actuator (stuck to surface as well), could that be my problem right there?

4. If the butterflies or ports or w/e are stuck closed, how hard is it to take the intake manifold off to get inside there? I only saw a cpl bolts, holding it on, but then again there is a crapload of stuff on it.

Im thinking the gaskets started to leak on both and then they froze up from no movement. Where i read the info from also states about a 25hp reduction because of this? Is that right?

I do have a fair bit of mechanical experience, working for 2 years in shop class at school, i have done a little bit of everything. This is just my first serious repair to my car. Thanks in advance.

PS: I also searched around for this but came up empty. Would be appreciated if pointed to a how-to guide or something, prefferably with pictures.

 

Keep searching, its covered weekly. Don't know much about 5th/6th, as I have a 4 port (t2). Good luck. As I understand what kind of exhaust are you running? Stock with stock cats? Also (if youa re so inclined,) is it a s4 or s5. AFAIK S4s open due to exhaust back pressure, and S5s run solely on the air pump/ACV. So if its an S4, if you have hollowed out cats, or upgraded exhaust this may be the problem. S5, possibly the air pump has been removed. Don't really know, because youu haven't specified if its 100% stock, S4/S5, etc.

 

Hmm, S4 No cats, straight pipe from stock manifold to stock mufflers. Could this be the problem? Is there any way i can get them working without relying on exhaust backpressure?

 

aux ports only work under load, so rev'ng the motor will never activate them.

Also if you have been in shop class for two years and you still don't know that exhaust back pressue is a bad thing... well..

The aux ports on a 84-88 are controlled by exhaust volocity, not back pressure. So if you have a straight pipe in place of the cat, you probably don't even have the split air pipe hooked up to activate the aux ports.

And your bump has been deleted. Bumps are fobidden here in the 2nd Gen RX-7 technical section.

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Probably not helped by the fact that that's nobody seems to know what they're really called, so they invent little kiddy names instead. The correct name for the system is Six-Port Induction (6PI), the two extra ports are called auxiliary ports, and they're opened and closed by the auxiliary port valves. There's info on the system in the FSM Fuel System chapter, page 4A-60 onwards. If you don't have the FSM, click here and download it in PDF format for free.

No they're mechanically independant, but the same pressure source is teed off to the two actuators.

It's not too hard, but it's not a small job. There's no other way to fix the valves anyway. Instructions are on FSM page 4A-61. Read everything thoroughly before starting, and make sure you get new manifold gaskets.

I've never seem anyone do proper testing with the valves both open and closed, but anything from 15-25hp is probably a reasonable estimate.

 

Yea i suspected they wouldnt open just by reving, so i did take it for a "thorough" test drive.

I do know that backpressure is a bad thing, but in the first reply to my first post unW7WZ stated that they operate on exhaust backpressure. I dont see how this would really work, but i know that having no cats reduces backpressure, therefore could possibly be the cause of actuators not functioning.

I will search for this "split air pipe" you speak of, i assume its not hooked up and that is my problem, because i have been under the car and there is nothing hooked up to exhaust, other than the o2 sensor on the manifold. Now that i think about it on most cars that i have seen there is always something hooked up to the cat. Thanks for pointing that out.

NZConvertible:

Thank you for the FSM link, and the other answers you provided.

Props to you both!

Will reply/edit if i need more help.

THANKS!

 

backpressure is not always a bad thing, piston engines work with a little backpressure. But if you think there broke and have straight pipe then you probably dont even have it hooked up and might as well pull the sleeves out so there alwyas open.

 

Well is pulling the sleeves out going to affect my mileage too severely? Thats the only thing im really worried about. Also, do i still just leave the actuators and rods in place?

 

as for power people really like it, some people say its not even noticable. I dont know about gas milage probably doesnt effect it to drastically like maybe 2-4mpg more.im sure someone knows the exact decrease in milage

 

Alright well i drive fast enough as it is, and i read that when they are closed it increases low end torque, which is low enough IMO so i want to try to get the ports operating properly. Now, i have just been searching for hours, and i need a picture of a S4 split air pipe, what it exactly consists of and where it goes to. Also, if i fab one up or buy one, can i just tap in to my exhaust with it? Thanks again.

 

did you buy the car with the straight pipe. or did you do that modifiation. the split pipe is a thin pipe that runs from the cat. you probably go ride of it with the cat, or who ever did the mod did. you can probably get one from a junk yard, alot of people remove there cats if you know someone who can weld and fab that in it should work.

 

Yea i bought the car with cats removed already, so i dont have a clue what it looks like or where it goes to. If someone could find me a picture (ive searched... lots) and points out where it goes to, that would be exponentially helpful. Welding/fabricating/installing it in is no prob, once i know what the hell im fab'ing and installing it to.

 

It'll be just as much effort to get the sleeves moving freely as it will to pull them out. Locking them open or removing them reduces low-rpm/low-load combustion efficiency, which means both less torque at low rpm (where a lot of street driving is done) and higher average fuel consumption.

Actually a 2-4mpg reduction in mileage is pretty drastic. If you were averaging 20mpg before that's a 10-20% drop, which is huge.

 

well again, since the actuators don't work on back pressure, they work on exhaust volocity.

I'll explain how that old wives /shade tree mechanic tale got started.

See many people replace the cat and cat back with the incorrect size pipe, figureing that it reduces back pressure. But too large of a pipe (say anything bigger than a 2.25"Dia. on a non turbo) and you loose exhaust volocity. Suddenly their aux ports stop working and they blame it on a loss of back pressure.

When all along its because the put the wrong exhaust for the engine on in the first place.

Without the split air pipe, unless the aux ports were hooked up to an alternative pressure source (like a switching solenoid and the air pump), they would not be working at all.

 

Just will rob you of low end power- it will be very gutless under 3800. Torque will be way down (and of course your 0-60 times will plummet.

If you are concerned about mileage then you want to leave them in a shift around 4000 rpm anyway.

 

Alright i think i have about all the info i need, other than a decent pic of the split air pipe. Thanks alot all for the great replies.

 

I have. Here's the dyno sheet. Now granted, my car was running like **** that day. I had fouled plugs and a very restrictive resonator in my exhaust, and i'm ported. But you can see that I gained almost exactly 20hp from opening them up. That third number there was a pull several months later that had some of the issues fixed and a more free-flowing exhaust.

Ports were wired open on the second and third pull. I've since gotten then running electronically.

 

Wow arghx thank you to that wicked dyno sheet. Helps me tons. Today i just wired them open with the actuators removed, and it feels exactly like you guys said. Definately noticed the boggy low end now but once 3500 rpm comes around, holy *****. Just nuts top end now. Wow couldnt believe it. My 180kmh-0 stop definately heated up my breaks ahaha. Took a lot less distance to get to 180 too. But anyways, i got too looking, and i thought this was just an emissions line or something at first, because i thought the split air pipe would actually be bigger, something like 1/4 inch. But this looks like it has been capped off somewhat recently, so i thought this might be it. Its more of a "line" or "hose", but i guess its metal so could be thought of as a pipe. So is this the "split air pipe" i ahve been wondering so much about? Thanks in advance.

#1-Split air pipe and cap im assuming?
#2-The rod/assembly the actuator rotates.

 

Never mind i just quickly found out that thats exactly what it is by testing it. I just took the cap off and blew in to the stem with a piece of long tubing i hooked up to it, and covered up the actuator holes. I will take it to an exhaust shop tomo to see how much it would cost for them to rig up a new piece from exhaust. THANKS ALL AGAIN!!!

 

well instead of spending money of you still have your air pump, you can tap off the dump line from the ACV and use that to activate the aux ports.

 

\
does that work properly? i was wondering about that.

 

Hmmm would it still engage at the proper rpm or would it be on all the time? I do still have the air pump so that seems like a better idea than tapping in to a brand new exhaust to me... Cuz i would rather bung up an easily replaceable rubber/plastic tube then patching my exhaust...

 

tap into the ACV dump line as close to the ACV as you can, at 3800 when the 2ndaries kick in, they (the aux ports) will open.

Requirements:
working ACV
Working air pump
Entire ACV dump line including muffler

 

so how would you do this exactly??

the dump line from the air pump directly into the air tube line that would normaly connected to to the CAT?

thanks

would you recomend connecting like stock or from the pump, is there a noticable diffrence?

 

Could i get a picture from icemark or whoever about what he is talking about. Even a diagram will help, because i cant find it in the fsm (maybe im looking in wrong place??) but i cant find anything about the "dump line".