Just saw this video on Youtube. Any idea of what they are using to actuate the trumpets/air horns? Appears to be a spring load arm to drive it back to its extended position. Had thought about using a stepper motor or a pwm linear actuator to control something like this in the past.

http://www.youtube.com/watch?v=evjWV...d1FAAAAAAAAYAA

 

the 787B looks to use miata headlight motors, but there must actually be a stepper in there since the length isn't two position. there is a pulley setup, so it pushes and pulls, kind of like a miata window regulator.

if you did 2 positions, a headlight motor has the two stops built into it.... add a spring to make it pop back....

 

http://www.rotaryeng.net/Mazda_R26B_US.pdf

 

That video is from Xtreme Rotaries in Australia. I think that is a sports sedan he looks after.

Not sure on the actuation, might have read somewhere it was a mazda part, but I would think this is something he is quite capable of producing himself.

 

Here is a video of a FormulaSAE car with a home brew variable intake. It definitely looks like it needs some dampening, but very quick to respond. There are more details in the video description.

http://www.youtube.com/watch?v=EPcpm...ure=plpp_video

 

I was bored at work, this was a good read, thank you.

 

I was thinking about a stepper controlled with the idle stepper control from the megasquirt, at engine start program slightly over max steps to oe posotion so you are sure the trumper is at the mechanical stop, then from there on it should work fine with just a curve with rpm input