[fwdtamiya]

A roller barrel throttle has all the intake openings on the throttle body on one shaft. Esentially think of two pieces of PVC. One inside the other, cut holes for 4 ports in each. At closed throttle, the inside roller (imagine its not hollow so that air can only go thorugh the holes not length wise) has the ports facing up and down, as you open the throttle the inside rotates, and as the ports on the inside piece and the outside peice line up thats how the engine sees air. If you look at normal IRTBs there is still a bar in the air path and a butterffly that restrict airflow. With the roller set up when the inside piece and outside peice line up theres no restricition. Yu don't have as fine of control at small throttle openings, which is why you usually only see them on race cars, all Champ Cars have roller throttles. I hope that made sense, I can draw a pic on photoshop after work if people are still confuzed.

I understand it, nitro rc cars sorta use this setup. Definetly doesn't seem streetable on a full size car

 

[the blue potato]

A roller barrel throttle has all the intake openings on the throttle body on one shaft. Esentially think of two pieces of PVC. One inside the other, cut holes for 4 ports in each. At closed throttle, the inside roller (imagine its not hollow so that air can only go thorugh the holes not length wise) has the ports facing up and down, as you open the throttle the inside rotates, and as the ports on the inside piece and the outside peice line up thats how the engine sees air. If you look at normal IRTBs there is still a bar in the air path and a butterffly that restrict airflow. With the roller set up when the inside piece and outside peice line up theres no restricition. Yu don't have as fine of control at small throttle openings, which is why you usually only see them on race cars, all Champ Cars have roller throttles. I hope that made sense, I can draw a pic on photoshop after work if people are still confuzed.

I think you are fairly close - here is more info:
http://www.jenvey.co.uk/~Vtype.htm

 

[Agent935]

I honestly don't think FM will offer an ITB kit. It's just something they do for some custom engines. Over on ^.net Keith said that this isn'this engine but one that is being built for their test-bed car "Elvis". I also think he said that they aren't cosworth itbs but very similar and they are mounted on a webber adapter from Mazda comp.

 

[airbrush1]

it's defenitely a neat concept.... kinda like an on/off switch with limited part throttle control.... NOT something I'd like to drive on the streets..... but would be an interesting idea for an all motor drag car for instance....

 

[Guest]

Re: Flyin' Miata IRTBs?

This from Mark @ FM:

"The parts being used right now are from Titan Motorsports which is an offshoot of Cosworth in the UK. I don't know if they are available in the US officially. The flange is from Boig, which we just happened to have around the shop.

Not sure if we are even going to offer the roller throttle bodies yet, so I'm not sure
about a theoretical price. At this point we have yet to decide if we are going to sell the IRTB kit. We should make a decision soon once we can proven that the system is viable on Elvis. Also, the throttle bodies on Elvis right now are extremely expensive so they may not be realistic to sell. They sound amazing though."

 

[firedog25]

That motor is pure metal sex.