Do it yourself electric cutouts?

[MN6WS6]

Are there any instructions online or has anybody ever been successful at building their own electric cutout? These prices seem insane to me, when all it takes is a couple of pieces of steel, a two way electric motor, and time. I'm thinking about trying it, just wondering if anybody has any tips.

[N20LT4Bird]

Sounds cools. let me know how it turns out.

[Black97]

I was wracking my brain about the same thing. Have you narrowed it down to some basics as to how it should work.

Some things to consider. Lots of heat, lots of water / humidity, dust and dirt require a good sealed electric motor.

I've seen some pictures of the cut outs on the market but never paid close attention on how they work and how they are built.

If I was still working in the factory I would have access to all the materials and machines needed to make something like it. But I don't, maybe I can talk my dad into making one for me.

It would be nice to have some stops on the motor so when the cutout is open that it stops automatically.

Looking at this pic, it should be fairly simple. Like I said once you find the right motor, have some mechanical skills and access to some machine shop equipment you should be able to make one. Based on your message you seem to have time. Figuring out the clearances of the valve part may require some trying. If it is too tight it maybe lock up. When it is hot and if you have too much, then it may bypass when you would like to completely shut.

Maybe you can explain to these guys here what you would like to do and they can tell you if they have a motor that suits your needs.

http://www.micro-drives.com/e/index.html

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[TraceZ]

Get a throttle body off a junk car and slice it up. Install a motor.

Presto.

[MN6WS6]

To me, doing it the way somebody else has already done it really doesn't solve anything. The key is to do it a way nobody has done before.

The number one complaint that I hear all the time is "my cutout leaks, so I had to add sealant". Umm, the whole point is so that it seals up by itself, and the fact of the matter is the design is faulty. I mean, sure, it works for an intake side of the motor, because you never do want the throttle blades to completely seal off. Reverse engineering that to use as a cutout was an easy way to make them.

What I propose is a cutout that uses a door on it (instead of a "blade" per se), and the door would swing out of the way. This way, you don't have that slice of metal or the rotating bar restricting airflow, and when it is closed you can actually seal the thing off with a mass produced gasket. You could use a linear push pull motor, and mount it inline with the exhaust so it would be more stealth. Since the motor would be in effect remote mounted (it's not actually attached to the exhaust except through the door) then heat wouldn't be a factor on it's operation. On top of all that, you could probably build it yourself, or even if I built them, you'd be looking at half the cost or less of the current models. I can see it in my mind, but explaining it may not come out like I'm thinking it will look.

My master plan would be to have a remote mounted motor, like under the rear passenger's seat or something. Then the cutout would look just like a normal one, until you flip the switch and it "ghostly" opens by itself.

[Black97]

How are you planning to connect the door with the motor. You still need a machanical connection which in terms transfers some of the heat to the motor unless you make a foot long extension so it will cool down before it gets there.

What kind of door are you thinking about? Sliding or hinged?

What are you trying to solve? Price issue or quality?

On the other hand, why re-invent the wheel?

[Kevin - Blown 95 TA]

There are lot's of issues.

One reason the butterfly valve is a good design is that it can open and close with equal power - it's not fighting the exhaust pressure because half of the butterfly is opening against the flow and the other half is opening with the flow so it is easy on the motor. The better ones on the market have a lot of stainless components, which is expensive & hard to machine but durable. The motor is a regular dc gear motor which has it's polarity reversed to get it to go in the opposite direction - so there is no mystery there, but it does need to be sealed.

If these things sell for $150 or so, you got to ask yourself how long you have to spend at work to get that money vs. how long you would have to mess with designing and building a one-off unit and how much the materials would cost. You have to determine if you can come close to building it with the reliability, quality & cost of a commercial unit.

One idea I had once was to operate one off of manifold vacuum and a small cylinder so that it would open at wide open throttle and be closed the rest of the time. The one drawback to the electrical system is that it is slow - normally that is OK, but you couldn't use it in the way that I was thinking of. My way would require a single-acting cylinder and a spring to open or close depending on the logic used. It would be best to have it held closed by the spring normally, but the problem is that there is more vacuum at the idle and cruise than at WOT. Anyway, I never followed up on it, but bought an electrical one from some guy on the internet when they first came out and have been very pleased with it. FWIW I think the guy had some trouble getting his money back out of all his efforts...

[MN6WS6]

Black 97, it would be a hinged door. Also I'd like to do the remote mount, like underneath the rear passenger's seat, and use a gear drive motor with some speed so that it can open and close faster. My number one reason is price, number two is I don't like the current design, and number three I'd rather build my own and try to make it better.

If I use a small gear drive motor with even just an inch of travel it will do what it needs to do. A hinged door can use a lever action to force the door closed, use a regular cutout cover as your door, and the gear drive will hold the door closed. Since you are using the regular cutout door, you could put a bolt in it to pass inspection at tracks that don't allow cutouts (if it has bolts in it, it obviously can't be remotely opened). Finally, instead of having this huge stainless motor and big mount on your exhaust, you'd have a cutout door with a rod on it, less obvious.

[Joe 1320]

The only way you are going to have a leak free seal is by using a rotor valve. The valve could be electonically or pneumatically controlled. This would be heavier and more expensive, but the result would be perfection.

[Black97]

There's a couple of different design that I could think of that possible could work. But each has it's advantages and disadvantages.

You probably end up constructing several designs until you find one that works to your satisfaction.

Like I said before. The environment is pretty hard on the outside of the car. There are many things to consider.

Heat, Cold (many heating - cooling cycles)
Water, Ice, Snow
Sand, dust, stones, shredded tire pieces, road kills, speed bumps
Corrosion

Keep us posted on your ideas / progress.

[Flash 97 WS/6]

Have you looked at the design of the one JCWhitney sells? The only thing wrong with it I can see it it's 2 1/4"... but for $40 it might be a good place to start. Maybe One on each side of the Y pipe? Possibly use a motor, solenoid or vacuum controller? I really like the automatic WOT opening idea!



Cutout at JCWhitney

[Black97]

That one looks pretty cool. Wonder how well it seals though.

When I was reading about that dash-control cable I thought about the Mad Max movie. He had that little red handle on the shifter to engauge the blower.

Here you could open and close the cut out.