Zach McAfee

Ok here goes. I was going to tackle this by myself but I guess 26,000 heads are better than one.

I'm working on a fully electronic system operated by pulling plunger solenoids. This would be the easiest to install, but I'm concerned about the strength of the solenoids and the sudden opening of the valves. The only way the solenoids will work is if I can find an inexpensive DC/DC step up transformer.
Question 1: Where to find a 12V primary 24V secondary transformer.
Question 2: Sudden opening a problem?

Another option is in another thread about using door lock mechanisms to open the valves. Apparently these are availabe at Radio Shack, but again the sudden opening of the valves. I'm convinced there will be no strenght problem here and they will already operate off of 12V.

The last and probably hardest to retrofit is a servo (electric motor) to control the valves to open proggresively (3500-4000?). This would be a more complicated circuit but I can get the EEs at school to design that for me.
No question here, just more complicated & more expensive.

I'm not giving up on this one, it is possible and we need it! If I do all the hard work it should be much easier than the electro-pnuematic systems for Joe RX-7 to install on his car.

I'm posting my progress here.
http://www.zaxjax.com/electronicAPVS.htm

Thanks for the help!

Samps

I've thought about a servo driven system. In my opinion, it would be easier to use only one push or pull type servo and couple the two rotating arms together somehow. This would ensure that both sleeves opened at exactly the same time and cut back on the cost and complexity. A signal could be taken from the ECU to operate the servo. The only major road block that stands in my way is the VDI. The VDI has a bigger impact on performance and is alot harder to fabricate parts for due to its location. Right now I have the air pump working only to operate the 6th ports and VDI with a simple hose clamp and some hose barbs. My system seems to work flawlessly and only cost about $5, but it retains the air pump.

Zach McAfee

Well, if you wire them parallel they *should* operate at the same time. I'd like to stick with two servos/solenoids so this will be more of a retrofit kit rather than a one time will-fit. Also, the ACV may get in the way of any levers or whatever it would take to couple the two valves.

I also want to use the Summit RPM switch to simplify the circuit. Apparently it just grounds, or closes the circuit you hook it up to. Nice and easy for $45 more.

cbrinega

If you want accurate and repeatable control over the amount that the auxiliary ports are open as a function of RPM, then you need some kind of circuit that has a method of location feedback. You could build a custom setup, but you might be better off if you look into using a servo motor like those used in radio controlled planes and boats.

I've considered trying to build something like this, but I want my ports to work normally first. They are currently stuck closed, so I cannot test anything out to make sure that it is strong enough to rotate the sleeves.

Send me a PM if you need some help with circuitry designs. I'm an electrical engineer with a Master's degree, and "Controls" was my favorite lab in school.

Here are a couple of servo links. You can also do a web search for "servo motor" to find sellers. You should be able to find some high torque, fast acting ones for around $10 or $15 each.

http://www.ferrettronics.com/index.shtml
http://www.rdrop.com/~marvin/explore/servhack.htm

The solenoid should work too, but I wouldn't count on making it open progressively. It's pretty much an all or nothing device.

---Cornelius

Thaniel

I have thought of doing the solenoid thing. I figure connecting both valves to a cable and then to the solenoid. I planned on using a spring to close the system and the solenoid only to pull to open (kinda like the pnematic system is now). The extra feature I would like to add is to wire it into the pressure sensor so that it doesn't hold the solenoid on when during cruise (don't want to over heat it). Oh, yah. Another reason I have thought of the cable connection is so the solenoid is not mounted so close to the heat.

By the way. I don't expect the sudden opening of the 6 ports to be a problem. The 89+ actuates a solenoid that routs air to the actuators. That soleniod doesn't open slowly so neither will the 6 ports.

Zach McAfee

Good point. At the dyno this weekend I watched the actuators under full load. They do open quickly so I'm not too concerned about it anymore.

KiyoKix

I'm curious on this setup, didn't someone already try an electronic setup. I'm very interested but for a slightly different purpose on the car (which I shall remain tight lipped ...or tight teethed).

SureShot

The 6-port actuators are in a very hot area, so any actuators would have to be very durable and heat shielded.

I am still using the stock air pump, until I find a suitable electric compressor (to work the VDI also).
My ACV is removed so I use a crude "slit in the hose" pressure regulator. It makes a purring sound as the engine revs - kinda unique.

I just got a digicam & hope to post some pics next week.

Zach McAfee

The solenoids I bought are industrial beasts. Take a look at them on the page. I would still use heat sheilding just in case. The only thing that would concern me is servos and heat, since they have plastic casings and gears.

SureShot

If your actuators need more than 12 v., you're looking at a DC-DC converter at maybe 2 amps?

Zach McAfee

I don't think it would be any more than 2 amps. According to the stats on these solenoids they draw very low amperage. I'll post the stats on them while I'm at work tomorrow.

ebay7

Well, come to think of it, my air compressor setup has been running flawlessly. Parts and labor wasn't bad either, $19.99 at pepboys and then 10minutes to hook it up using factory aux/vdi solenoids for triggers.

Don't mind seeing servos running on my other rex.

Here's my setup:

silverrotor

iTrader: (1)

I guess that makes the 2 of us, ebay7.

patman

iTrader: (3)

hey ebay7 where did u get the air compressor or what is it off of?

i saw a guy on the other forum using 17 lbs door solenoids... i was thinkin about that method but worried about overheating them when they have to stay open for a long time...anybody know about that?

-Pat

ebay7

you can find them at pepboys, kragens, autozone, grand auto.


You referring to door actuator solenoid burning out or the air compressing burning out?
The trick is the air compressor does NOT have to stay on for the duration of the race/whatnot.
All you gotta do is re-arrange the plumbing and solenoids to trap/release air depending on rpm/load. For example, a 15sec 1/4 mile would only require the compressor to operate for < 1 second. Otherwise the thing would scream like a **** for 14 seconds.

KiyoKix

Hmmm...how's that RPM switch thingie wired up that people use for the VDI???

ebay7

You really don't need the RPM switch if your car is an S5, unless of course you didn't like the factory rpm settings.

Thaniel

Looks pretty good. I would much prefer electric actuators over the Pnematic. Keep updating the progress. My intake is comming off for a cleaning this winter. Would be a good time to mod it.

Zach McAfee

I'm working with cbrinega on a servo actuator system. Servos are much stronger and dependable than the solenoids in my opinion (now that I've read up on the articles cbrinega sent me). The solenoid system would return via a spring, while the servo returns electronically.
The complications now lie in the circuitry. We may use a "555" timer to create the pulses which communicate with the servo.

wozzoom

Suggestion: couldn't you connect to the actuators using something like a bicycle brake cable? This way the servo could be moved from directly on top of the exhaust.

Other than that, I'm very interested to see how you solve this. Keep up the good work.

slvr7

iTrader: (1)

Here's a link to a circuit plan that can adapted to function as an rpm switch.


http://cp_www.tripod.com/rotary/pg13.htm

I built one a little while ago, and it seems to work fine. The modification I made to the plan is this:
The entire rev limiter circuitry coming off pin 8 is deleted. Instead, use a small relay with the coil switched to ground through pin 8. The chip can switch 50ma current, I *think* this means a relay coil measuring 250 ohms or more will be safe on this. Now you can use the relay to operate a VDI, or 6th port solenoid. Simple to hook up - 12V +, ground, tach signal (from trail coil) and your switched line.
I built mine into a 3" x 5" hobby box. The parts were under $10. I added led's for power and 'switched on' state. There seems to be plenty of rpm adjustability through the 50k pot. I'll be using it for VDI on my S4 this spring.

Any EE's [cbrinega?] who could comment or improve the design would be welcome. One thing I do find, the relay can 'chatter' a bit on & off around the set point.

Curtis
'86 gxl autox'r

Josepi

Anyone ever thought of using the pressure sensor as a relay control for a solenoid?

If a certain voltage is met, then the power gets passed on to the solenoid?

slvr7

iTrader: (1)

Oh yeah, on another tangent, anyone notice that the Renesis is still using those air diaphram acutators for the sixth ports?
The electro-servo route seems much more refined.

Good luck, Zach. Keep us posted!


Curtis
'86 gxl autox'r

gold87na

msd make a little device that is just a rpm activated switch

Zach McAfee

I've managed to take on a billion projects including my 18 credits at school so I haven't done anything but a little research since the last post. The only good news I have is that I'm taking a controls class called "process & system dynamics," so I might get something out of that. The final project is to design a control system, maybe a system to open up two valves, who knows?!