Potentiometer for running Cyclone solenoid?

[eclipsh]

I'm looking into a way to electronically control the operation of my Cyclone intake so I can tune when it switches over using a dial.

I was thinking I could take the 5v (?) signal going to the tachometer and use it as a reference for a potentiometer. If I understand the gizmos correctly, I could set it to allow current through once a certain voltage is reached and use that to flip the solenoid (or a relay which would flip the solenoid).

I might be dead wrong on the tool I need to do this so I thought I'd ask arround here. What tool do I need that will cause a switch to flip when a chosen voltage is reached? Of course, it has to work in a car to be of use.

Thanks for any ideas you can send my way.

Before any odd comments show up: I have all the necessary parts to run the intake, I am just looking into a tunable method of triggering it.

I'm not getting rid of it either, I prefer mid-range torque over high end.

[SolidBoostTSi]

Originally Posted by eclipsh

I'm looking into a way to electronically control the operation of my Cyclone intake so I can tune when it switches over using a dial.

I was thinking I could take the 5v (?) signal going to the tachometer and use it as a reference for a potentiometer. If I understand the gizmos correctly, I could set it to allow current through once a certain voltage is reached and use that to flip the solenoid (or a relay which would flip the solenoid).

I might be dead wrong on the tool I need to do this so I thought I'd ask arround here. What tool do I need that will cause a switch to flip when a chosen voltage is reached? Of course, it has to work in a car to be of use.

Thanks for any ideas you can send my way.

Before any odd comments show up: I have all the necessary parts to run the intake, I am just looking into a tunable method of triggering it.

I'm not getting rid of it either, I prefer mid-range torque over high end.

The only thing I can think of is to use a stepper motor and potentiometer. I run a Cyclone too but I have the DSMChips trigger off the FPR solenoid.

[eclipsh]

If I understand you right, you're thinking I want to adjust how much the butterfly valves are opening with a motor. Interesting idea, but I was thinking of something else.

I want the valves to open fully using the stock JDM parts. I just want to control when they open with a variable electronic control. I would use the RPM signal to determine when they opened via the vacuum canister using some sort of voltage sensitive switch to trigger the solenoid. Get where I'm going with this?

It'd be fun to change what rpm the intake kicked at. Turn it from 4100 rpms to say, 3800 or 4500 based on the turbo/exhaust/displacement etc. With the chip we both have that is a static setting. With something like I'm talking about it would be more dynamic and another way to tune our cars (much like VVTi etc for cam tuning).

[GVR4592]

http://store.summitracing.com/partde...5&autoview=sku

[eclipsh]

Gold star for you today! (Oh wait... you already have five... never mind.)

That is exactly the sort of thing I am looking for. $42 isn't too bad either, though I was hoping to find something for $10 at an electronics store


Edit: found this little gem for building one: http://www.electronic-circuits-diagr...opic.php?p=285

It looks like building a voltage comparator as shown on page 3 of the PDF file below should do the trick along with a potentiometer. Might be fun to learn how to build one and do a tech write up on it.

http://www.national.com/an/AN/AN-4.pdf#page=1

If anyone else wants to try this thing this link might help too:
http://www.corral.net/tech/powerplant/arm/

[eclipsh]

A friendly guy on the electronics forum linked above drew this circuit diagram for building an RPM Switch.

Now I just have to figure out what all tha parts are


(Seriously, anyone know what a Vss and Vdd are, and what is going on at the switch portion? The rest is simple, just got lost there. Don't want to bug the guy who drew it, he already helped a ton.)

[VelocitàPaola]

Vdd = positive voltage source.
Vss = negative power source (ground).

Z1 is a zener diode... a rectifier or regular switching diode won't work.

The switch is a simple 12VDC SPST relay with a diode to protect against inductive kickback.

What else do you need to know?

[eclipsh]

Originally Posted by VelocitàPaola

Vdd = positive voltage source.
Vss = negative power source (ground).

Z1 is a zener diode... a rectifier or regular switching diode won't work.

The switch is a simple 12VDC SPST relay with a diode to protect against inductive kickback.

What else do you need to know?

OK, I think I'm even more confused...

So am I actually feeding current in at Vdd and grounding Vss?

I want to learn how to build this but I think I may be jumping a little too far into the pool without swimming lessons.

My understanding is that the IP going to the negative terminal of the OP-AMP is the signal from the tachometer. I'd be feeding in power to the +12 in the upper right and attaching a ground wire to the bottom right +0v.

So on the 12v SPST relay do I attach to the open sides on the right and run wires to the solenoid? It's been about 9 years since my electronics class. I'm just happy to recognize resistors and diodes.

EDIT: So are Vss and Vdd just markers without any attachments? Also, if the relay is just a basic 12v, can I use a spare 12v 30A I have lying around from the car?

I'm also thinking of putting a 5v fuse in the line exiting the circuit just heading to the solenoid as a precaution. Is that really necessary given this setup?

[VelocitàPaola]

Why would you use a fuse rated at 5V if the circuit is running off +12V supply?

Is this easier to understand?

[eclipsh]

Yes, that diagram is much easier to understand

I'm tired.. I was thinking the solenoid triggered on 5v too, not 12v. I'll double check all the values before building this.

So am I correct in my statements above besides the fuse?


VelocitaPaola (Paul) has generously offered to burn some circuit boards or BUILD these if we can get a few people together and make the price reasonable. Please PM him or myself if you'd be interested.

FYI, this little device will do a lot more than just run an intake. It'll trigger anything you want at a set RPM. P1 up in that little diagram is a rotating dial which you can use to select an RPM which will trigger the solenoid and then whatever 12v output you choose. More fun than you can shake a stick at! (yes I'm trying to save myself some cash, buy now!)

I'll be wiring the LED in the circuit such that I can stick it up on my A-pillar as an indication light while the unit itself is tucked inside the center console or under the dash.

I'll also be ordering the components for this sometime shortly. If some of you want to get in on this but can't build it, let us know. Remember, Paul says he can also put the whole thing together for you.

[VelocitàPaola]

Actually, I just thought of one last thing...

This tach signal trigger circuit will only work if your tach signal is based on a linearly rising 0 V to +5V signal. I don't know how the 4G63s control system is configured to produce the tach signal, but for the 420A, it's based on pulse width.

[eclipsh]

I'll go double check tomorrow but it is my understanding that it is a 0 to 5v signal. Boy will I feel dumb if it isn't...

[VelocitàPaola]

Oh, and you don't necessarily need a fuse. That zener diode grounds the whole circuit out if there's a voltage spike... it's a type of voltage spike protection.

[eclipsh]

My voltage numbers coming from the 90 coilpack are:

~1.9v @ 1200 rpm
~3.0v @ 2000 rpm
~4.8v @ 3000 rpm
~6.8v @ 5000 rpm

Assuming my measurements were a bit off (hard to hold set RPM) it looks like the signal sends between .0015v and .0016v per 1 rpm.

I will also check the rpm voltage signal at the ECU shortly and see if that is in fact a 0+5v system