Electric throttle bodies and exhaust cutouts

[IsaacHayes]

Hmm, yeah since there is going to be power the whole time to keep it open cause of the spring that might burn up the motor... Unless you just do it for the time you are WOT down the 1/4.

I imagine they use PWM to some how keep it open at a certain position.

[TurboProject]

Hmm, yeah since there is going to be power the whole time to keep it open cause of the spring that might burn up the motor... Unless you just do it for the time you are WOT down the 1/4.

I imagine they use PWM to some how keep it open at a certain position.

I'm not totally certain how they work but I'm pretty sure PWM is a big part of how servos work.

If you're in to RC stuff(planes/cars/boats) just think about the servos for the radio systems. They are just a regular motor with gear reduction...and three wires that are controlled with electronics to give positioning control.

[Joseph Upson]

Hmm, yeah since there is going to be power the whole time to keep it open cause of the spring that might burn up the motor... Unless you just do it for the time you are WOT down the 1/4.

I imagine they use PWM to some how keep it open at a certain position.

Actually no, you just need to reduce the current to a low enough level to avoid overheating the motor. Under normal driving conditions it always has voltage to meet the throttle commands. I'm sure it uses a variable resistance circuit as pwm would probably cause to much fluctuation in throttle position. It probably works the same way slot cars do, the further you press the trigger the faster the cars go.

I disassembled the cover and there is what appears to be a variable resistance strip inside along with contact slide terminals like what you would see in a fuel sending unit.

Basically you would treat the motor like a relay, supplying enough voltage to activate it without burning it up. If it has the number of winds that a relay coil does then a direct connect to the battery wouldn't hurt it but because of how these motors tend to be wound with thick wire the current would be to high so resistors would need to be added until the right level to hold it open is reached.

[Chris88CL]

I got bored and tested a 3500 TB with 12v straight from a battery tonight. It opens like a friggin shotgun, haha. It's awesome.

Reverse the polarity and it closes 100% WITHOUT grinding that little tab. Very interesting to note. No grinding is necessary, you just need a switch that will reverse the polarity and you are set.

Another small issue would be hooking the TB up to exhaust tubing. One end would be easy enough with a flange but the other end would be a little more difficult. You would need some way to attach a smooth pipe meant for a silicone coupler to exhaust tubing. Sure you could weld a pipe and fitting on if you have the ability to weld aluminum, but not all of us do.

Other than that I see no issue with using a 3500 TB as an electronic cutout. Im going to give it a go when I finish welding up my exhaust. The question is where to put the cutout? Im tempted to do it right at the end of the turbo downpipe before the resonator or cat.

[Joseph Upson]

I'm sure it has its limits, I believe before the cat would be to hot a location. I plan on locating it at the rear just ahead of the muffler.

You should cut away a good portion of the housing that encloses the motor to allow better ventillation for cooling, it just may hold up that close to the exhaust outlet.

[pocket-rocket]

One end would be easy enough with a flange but the other end would be a little more difficult. You would need some way to attach a smooth pipe meant for a silicone coupler to exhaust tubing.

I don't think cutouts have anything hooked to the other side when they are installed, just open right to the atmosphere so you wouldn't have to worry about silicone couplers or anything.

[IsaacHayes]

If you have a good straight through muffler having a cut out right before it won't do much... Dynomax Ultraflo is like straight through pipe on the inside..

I would rather it close mechanically. As a fail safe and that way less stress/heat on the motor keeping it held close all the time.

Too bad it doesn't seal 100% air tight, I could use that as a valve for firing my pneumatic air cannon. Man that'd be sweet!! Big diameter open in a flash! wow!

[Joseph Upson]

If you have a good straight through muffler having a cut out right before it won't do much... Dynomax Ultraflo is like straight through pipe on the inside..

I would rather it close mechanically. As a fail safe and that way less stress/heat on the motor keeping it held close all the time.

Too bad it doesn't seal 100% air tight, I could use that as a valve for firing my pneumatic air cannon. Man that'd be sweet!! Big diameter open in a flash! wow!

Air cannon, as a kid I made tennis ball cannons out of campbell soup cans which have just the right diameter. Tape a few together poke a small diameter hole the size of a pencil lead in the side of the bottom can near the bottom, squeeze a little lighter fluid inside about midway so it can roll down the sides push tennis ball in a few inches and stick a match near the hole. I had the cannon sitting on the ground pointing straight up for this.

Not encouraging you to duplicate that since it's so easy to go to jail over a mis interpreted experiment.

[IsaacHayes]

Yeah, besides pneumatic is way more powerful!

[Weston19]

Why not just hook up some sort of motor with a linkage to the cast iron cutouts? You could mount the motor away from the heat and headlight motors are very strong and run of 12v......

[IsaacHayes]

Good idea. Use the old fashion cable cutout with a motor. You could even use the TB if it rotated enough for that.

[Z26-T]

Personally I would do it as close to the engine as possible... Doing it right before the muffler I don't see much of an advantage because if you get a high flo muffler it makes the use of the cut out basically worthless, especially with having to cut holes in your exhaust, running wires and a switch (even though none of that is really all that hard).

I say cut a hole, stick it in and try it. If you burn it up, you learned that it burns up. If not, rock on.

I don't see that much of an advantage using a cut-out, besides the sound. If you have a non-restrictive exhaust set up ( i dunno, 2.5" mandrel with high flow cat/muffler ) what will you really gain from using a cut out? 3 HP?

[Joseph Upson]

Personally I would do it as close to the engine as possible... Doing it right before the muffler I don't see much of an advantage because if you get a high flo muffler it makes the use of the cut out basically worthless, especially with having to cut holes in your exhaust, running wires and a switch (even though none of that is really all that hard).

I say cut a hole, stick it in and try it. If you burn it up, you learned that it burns up. If not, rock on.

I don't see that much of an advantage using a cut-out, besides the sound. If you have a non-restrictive exhaust set up ( i dunno, 2.5" mandrel with high flow cat/muffler ) what will you really gain from using a cut out? 3 HP?

The purpose of the cutout in my application is to allow maximum flow from the turbos and be able to switch back to flow through mufflers with superior silencing ability to avoid disturbing neighbors and damaging hearing particularly in the low frequency range from the drone of a continuous high flow exhaust a few short feet away from you in a car as small as a Fiero. You also end up turning the volume up on the radio further complicating the matter.

Some people like the performance sound from an exhaust system so it may not serve a power gain purpose at all. I like the sound of my turbos and the attention they tend to draw when they're not muffled.

[gectek]

the QTP cutouts are great, and they arent that much, they use a gear reduction motor and open in about 5 secs and close just as fast, put it on a 3 way switch and have at it, the come in sizes up to 5" IIRC, i have one on my GA and it works like a charm, no need in frying a perfectly good TB(plastic aprts remember) the motor is about $147 the cutout is like $45 more if you need it

[Joseph Upson]

the QTP cutouts are great, and they arent that much, they use a gear reduction motor and open in about 5 secs and close just as fast, put it on a 3 way switch and have at it, the come in sizes up to 5" IIRC, i have one on my GA and it works like a charm, no need in frying a perfectly good TB(plastic aprts remember) the motor is about $147 the cutout is like $45 more if you need it

I'm going to use cast iron cutouts for simplicity. I have no real use for my electric throttlebodies and thought exhaust cutouts would be a good experiment. The non metal parts have to withstand the heat generated being in direct contact with the engine. I don't know exactly what type of material it is but it doesn't appear to be as simple as plastic from what I observed in a chipped area, it may be a ceramic type material which has high heat resistance.