rx7raca

hey guys, i just rebuilt my engine an im done breaking it in and everything, now the next step is to get my 5/6th ports working, since i have a s4, they dont open by the ecu, they go by back presure, but since i removed my cats an have custom stright pipes there is very lil back pressure to open them.

now ive heard about the elect. APs but, how will the air pump know when to open the ports. one of my friends tells me you can use the V-afc, an program it to the airpump an get them to work that way. is this true?

what other ways are there to opening the ports on a s4 with an elect pump?
plz help
thanks

Black13B

iTrader: (1)

An electric airpump is an idea. I was going to do this, and I may set it up soon, but I'm going to try something new over the winter.

After I got my door poppers, I inspected the actuators closely.

The very same actuators could be used to open the ports. You could use just one actuator even to open them both.

I would be removing the air diaphrams entirely, and going from there with a true electric auxiliary port activation.

The actuator is a small cable that retracts (pulls) when it has electricity.

An electric airpump can cause problems. renns said it best when you convert "work" from electrical to mechanical to air powered is going to cause alot of problems. The compressor can fail, and it's likely not rated for constant use, etc. etc.

silverrotor has the electric port activation via an electric air pump. It's working great for him as of late, as is why I'm going to do it for a while. However if my latest idea takes off, then I will convert.

Zach McAfee

You could run a line from the air pump to a solenoid then from the solenoid to the actuators. Buy an RPM switch for about $40 from Summit, have it ground out the solenoid sending pressure to the actuators at whatever RPM you set it to.

I got pretty deep into the true electric thing, but it's not worth the effort. I'm concerned with exceeding the duty cycle of a solenoid and engine bay heat destroying plastic servos.

Black13B: I don't know if this will help any. I worked more with servos than I did with solenoids.
http://www.zaxjax.com/electronicAPVS.htm
and
https://www.rx7club.com/forum/showth...hreadid=147853

Dougster

Interesting stuff. I just got a 88 GTU and while it runs good, I am not feeling the ports open at 3,800 RPM's?

Does cleaning them out with carb cleaner help if their stuck?

I have a custom exhaust, but it retains a cat and dosn't have a free flow muffler, so it should have enough backpressure to be opening with my setup?

rx7raca

well this was going to be my orignal plan.

i was going to buy an electric air pump from pep boys, then buy an V-afc, and program it to the air pump to open the ports, very easy an can be set up easily.

now what i wanna know if anyone has ever thought of doing this an is it possible, my friend says it is. so i just might try it.

what does everyone else do with there s4s?

rx7raca

ya they should open, only problem i see is that if they are stuck your gonna have to either, try to loosen them up from the outside of the LIM or take off the LIM an clean them.

but that is off topic, we need to figure out how to get them to work with an electric aip pump on the s4.

Zach McAfee

Search for 'silverrotor' and his electronic setup.

wozzoom

Not going to work with the V-afc. The V-afc is specifically designed for Honda electricals. There is no way to set the flapper type and sensor type for the RX-7 in the V-AFC.

The simplest plan is what Zach mentioned with the RPM switch and the stock airpump. Cost is $50 bucks from summit. Then use the RPM switch to control the EGR solenoid on the vacuum spider. Plum the EGR solenoid into the 6-ports and your done.

Currently I'm running a summit RPM switch attached to an electric air pump from Autozone. (Used for air horns...cost $20) Works great when you don't have the airpump anymore.

87RXGhey7

going off topic, how do you unstick your ports? I finally got mine hooked up, but they dont open, I figure they stuck. whats the easiest way?

ilike2eatricers

Check the archive for cleaning 5th and 6th ports.

Black13B

iTrader: (1)

wozzom is right.

SAFC lets you choose the sensor styles (plunger, etc), as where VAFC is pre-programmed.

1987RX7guy

iTrader: (3)

There is no easy way to clean and make sure they operate great. You have to remove the intake top and bottom(Be carefull of the MOP lines!) then remove the sleves and start spraying everything with carb cleaner untill all the crap and gunk is gone. Then re-install.

rx7raca

well i dont have my air pump either so i will have to buy an electric pump as well.

one question i do have is...how long have you had your elect. ap an how long do you think they will last, we all know an have heard of them getting really hot shorting their liftspan. so thats one of my main conserns.

1987RX7guy

iTrader: (3)

rx7raca- Why not just buy a pre-silencer? It will probably cost close to an electric setup and you don't have any extra load on the alternator.

Black13B

iTrader: (1)

Extra electrical load is a poor excuse to stray away from mods. Beef up your electrical system, and upgrade your alternator, if you are concerned about electrical load.

rx7raca

well i know im not, i could care less, an if i have any problems ive got a fd alternator.

an no im not taking out my straight pipes

im not sure about that rev thing from sumit, it doesnt look like a smart way to open my ports. i read somewhere about pple having trouble with it because it wouldnt respound till about 5k. i think you have to mess around with it to get it to open at the right time or something.

is there any other way to send the single to the air pump? see i thought the V-afc you could program it to send the singnal to the pump at a certian rpm.

Black13B

iTrader: (1)

No, that "rev thing" is an RPM Switch. It closes a switch when you hit a certain RPM. There is little tabs inside the switchbox so you set the RPM you want. If anyone had them not work until 5k RPM, then they set up the switch wrong.

The VAFC does send an electronic signal to activate the VTEC, but unfortunately you can't customize any other variables which are needed to make it recognise our engine.

vectorminds

i think msd also makes rpm actuated switches... im not sure if they just work with msd ignition boxes or what... but they seemed like they were universal... i dont know how much they cost though

you could always do the thing with the double valve setup off of the airpump line to open the ports... there is that writeup on rotaryressurection.com about that

rx7raca

what if you run a vaccum line to one of the nipples on the intake manifold. for example i believe the oil injectures go off the DC, im not sure how much psi goes to those injectures but it must be at least 2 psi no?

i think i might try that but im not sure if it will work. what do you guys think? how much psi is created from the vaccum system.

wait, i jus thought of something an i feel pretty stupid if im wrong. doesnt the vaccum system only work when its at idle? grrrr

Black13B

iTrader: (1)

You've got the pressure backwards.

The diaphrams TAKE air (blow into them) to push open the port. Vacuum would created the exact opposite of what you are trying to accomplish.

wozzoom

Reliability of the small electric air pumps is fine as long as you don't have them on 100% of the time. (IE: Trying to pass emmisions with it) For opening and closing of the 6-ports, they are perfect because they are only on when the engine is above 4000 RPM.

The Summit RPM switch works great except for one thing. They are made for piston engines. So instead of being adjustable from 2000-7000 RPM, they go from 4000-14000 RPM on RX-7's. This isn't a problem because you want the 6-ports to open at 4000 RPM anyway.

Black13B

iTrader: (1)

Unfortunately if you set up the pump like most others, the pump will fight itself to compress the air. You really only need it to pump the psi for a second to snap them open, and then the pressure in the line (it should be airtight) will hold them open. When you let off there should be an electronic valve that opens up the line and dumps the air, which in turn would close the ports.

Some just let the compressor keep compressing the air. I am not certain, but I dont think the diaphrams have a dump valve for excess air (because it operates on such a low pressure system).

You can risk diaphram failure or premature electric pump failure.

You see how I mean switching from electric to air to mechanical gets complicated.

wozzoom

Nope. Nope. Nope. I guess I'll take the time to clarify how I did this.

I used:
1) One summit RPM switch
2) One 12V air pump (used for air horns)
3) Some 1/8 inch vac hose
4) One 1/8" vac TEE.
4) One 12V radio shack relay

-Hook the RPM switch to the primary coil. Set it for 4000 RPM
-Wire the RPM switch to the 12V relay. (Otherwise the air pump will burn out the RPM switch)
-Hook the air pump to the relay
NOW THE IMPORTANT PART:
-Run the vacuum hose from the air pump to the 1/8" TEE. Run 1/8" vac hose from ONLY ONE side of the TEE to the 6-ports. Leave the other side of the TEE OPEN! (Yes. Open to the atmosphere.)

The thing you have to remember is that the air-pump puts out about 7-8 PSI. The 6-ports need less than 3 PSI depending on how clean the sleeves are. Once the 6-ports open, the excess pressure goes out the open side of the vacuum TEE. When the pump turns of, the pressure from the line bleeds back out through the TEE and the 6-ports close.

So this solves all the problems. No rupturing of the actuator diaphragms, no need to wire in a 3-way dump valve, no worrying about electric air pump failure. NOT Complicated at all.

rx7raca

hmm this is geting tricky. this going to be harder than i thought. i knew the pump was going to be a pain because of the lifespan...but then again the pump is fairly cheap an if you breaks no big deal.

i read the whole thread from silverrotor about his ordeal on the pump an such. some of the things they talk about though are rather confusing, i dont know how to do everything with the electrical system so its pretty hard to understand.

i guess the best thing to do is buy all the supplies an try it for myself an see how things work out. an then tune it to how ever i think its best.

may i ask how you guys are running your ports?

rx7raca

thank you very much, you have made my day. i was waiting for some1 to really tell the real way of doing this. not that the other members didnt help me an i thank you, but this jus sums it up an helps alot.

thank you i will be buying my supplies very soon.

one more question i do have to ask tho. which in your mind is the best air pump to buy. or should i say which one did you buy.
thanks again