So I am desiging the throttle body for Pitts FSAE car, and I was thinking of making a rotary valve throttle body (like a ball valve just with a cylinder) because it would be eaiser to make on the mill if I cannot get a throttle plate waterjetted.

And it made me think, why does every OEM use butterfly valves? So I searched... and nothing. There are a lot of different types of valves, and I cannot find one OEM that doesent use a butterfly. Maybe butterfly valves have better flow at mid throttle? Or at idle? IDK, anyone have any input? I mean it sure seems a rotary/ball valve would have much nicer flow at WOT.

 

Its cheap.

 

It does not seem like it would be a huge difference price wise. But even then, on high dollar performance cars, the TB is still a butterfly.

 

Prototype of my next throttle body:

 

WOT at F1.2

 

lol, that would be slick it if would seal.


But realy, anyone have any hard information?

 

edit.
wtf non working image. Links. http://motorsport.bdg.com.au/roller.html

 

Just guessing (I don't know the physics of it) that a ball valve would have more drag through it. Again, just a guess.

 

It's cheap and easy to build them so that they seal well.

Racers in the past have experimented with slide throttles, which give you that obstruction-free opening. It's very difficult to make them seal up well.

Ball valves are common in pneumatic and hydraulic applications, however the tight fit and teflon seals mean that they require a lot of force to operate. Go to the hardware store and find a 2.5" ball valve. Open and close it. Compare this to a throttle plate which, with the spring removed, require virtually no force at all to open and close.

 

cause it's a big valve. big valves are butterfly valves.

 

 

 

Any interesting ideas for improving flow through a butterfly valve? Dimpled surface on the disc perhaps? I have no idea if that makes any sense or not (other than in a completely amateur Mythbusters kind of way).

 

Ok, serious-hat time.

Is there an actual problem with butterfly valves that merits doing something more exotic? Would increasing the diameter of the orifice by 2% provide equivalent flow capability to removing the shaft? Would you be able to actually quantify the difference?

 

hyper #2

 

I LOLd too

 

Barrel throttles FTW. If you want a design like that, look into Champ/Indy/IRL cars.

OEM likes the butterfly design because they're smooth and easy for the average person. Barrels and other designs tend to have really harsh on-off sort of characteristics.

 

Is that some sort of prototype robot vagina?

 

just a dual roller barrel design.

 

You've disappointed me for the last time...