Why are all throttle bodies butterfly valves? - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Insert BS here A place to discuss anything you want

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 09-29-2010, 09:55 PM   #1
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default Why are all throttle bodies butterfly valves?

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.
cardriverx is offline   Reply With Quote
Old 09-29-2010, 09:56 PM   #2
Junior Member
 
Join Date: Jun 2007
Location: Grayslake IL
Posts: 410
Total Cats: 2
Default

Its cheap.
Aricjm15 is offline   Reply With Quote
Old 09-29-2010, 10:03 PM   #3
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

Quote:
Originally Posted by Aricjm15 View Post
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.
cardriverx is offline   Reply With Quote
Old 09-29-2010, 10:13 PM   #4
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

Prototype of my next throttle body:

Name:  DSC_0064.jpg
Views: 77
Size:  60.9 KB
fooger03 is offline   Reply With Quote
Old 09-29-2010, 10:25 PM   #5
Crumple Zone Tester
iTrader: (7)
 
mgeoffriau's Avatar
 
Join Date: Jul 2009
Location: Jackson, MS
Posts: 7,656
Total Cats: 447
Default

WOT at F1.2
mgeoffriau is offline   Reply With Quote
Old 09-29-2010, 10:27 PM   #6
Elite Member
Thread Starter
iTrader: (12)
 
Join Date: Jan 2007
Location: Hermosa Beach, CA
Posts: 2,575
Total Cats: 11
Default

lol, that would be slick it if would seal.


But realy, anyone have any hard information?
cardriverx is offline   Reply With Quote
Old 09-29-2010, 10:28 PM   #7
Junior Member
 
Join Date: Jun 2007
Location: Grayslake IL
Posts: 410
Total Cats: 2
Default



edit.
wtf non working image. Links. http://motorsport.bdg.com.au/roller.html
Aricjm15 is offline   Reply With Quote
Old 09-29-2010, 10:30 PM   #8
Elite Member
iTrader: (1)
 
Join Date: Jun 2005
Location: Charleston, SC
Posts: 2,980
Total Cats: 14
Default

Just guessing (I don't know the physics of it) that a ball valve would have more drag through it. Again, just a guess.
rmcelwee is offline   Reply With Quote
Old 09-29-2010, 10:31 PM   #9
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Quote:
Originally Posted by cardriverx View Post
And it made me think, why does every OEM use butterfly valves?
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.
Joe Perez is offline   Reply With Quote
Old 09-29-2010, 10:31 PM   #10
Elite Member
iTrader: (10)
 
soviet's Avatar
 
Join Date: Jan 2010
Location: VA
Posts: 3,519
Total Cats: 260
Default

cause it's a big valve. big valves are butterfly valves.
soviet is offline   Reply With Quote
Old 09-29-2010, 10:46 PM   #11
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,899
Total Cats: 1,792
Default

Braineack is offline   Reply With Quote
Old 09-29-2010, 10:47 PM   #12
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,899
Total Cats: 1,792
Default

Braineack is offline   Reply With Quote
Old 09-29-2010, 10:54 PM   #13
Crumple Zone Tester
iTrader: (7)
 
mgeoffriau's Avatar
 
Join Date: Jul 2009
Location: Jackson, MS
Posts: 7,656
Total Cats: 447
Default

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).
mgeoffriau is offline   Reply With Quote
Old 09-29-2010, 10:59 PM   #14
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Delicious and Moist.
Posts: 26,327
Total Cats: 1,926
Default

Quote:
Originally Posted by mgeoffriau View Post
WOT at F1.2



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?
Joe Perez is offline   Reply With Quote
Old 09-29-2010, 11:13 PM   #15
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 36,198
Total Cats: 2,584
Default

hyper #2
18psi is offline   Reply With Quote
Old 09-29-2010, 11:15 PM   #16
Elite Member
iTrader: (2)
 
fooger03's Avatar
 
Join Date: Jan 2009
Location: Columbus, OH
Posts: 4,133
Total Cats: 188
Default

Quote:
Originally Posted by mgeoffriau View Post
WOT at F1.2
I LOLd too
fooger03 is offline   Reply With Quote
Old 09-30-2010, 12:59 PM   #17
Junior Member
 
Join Date: Feb 2010
Posts: 277
Total Cats: 4
Default

Quote:
Originally Posted by Braineack View Post
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.
Sam TII is offline   Reply With Quote
Old 09-30-2010, 01:02 PM   #18
Elite Member
iTrader: (1)
 
Join Date: May 2009
Location: Jacksonville, FL
Posts: 4,685
Total Cats: 216
Default

Quote:
Originally Posted by Braineack View Post
Is that some sort of prototype robot vagina?
Full_Tilt_Boogie is offline   Reply With Quote
Old 09-30-2010, 01:08 PM   #19
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,899
Total Cats: 1,792
Default

just a dual roller barrel design.
Braineack is offline   Reply With Quote
Old 09-30-2010, 01:12 PM   #20
Elite Member
iTrader: (1)
 
Join Date: May 2009
Location: Jacksonville, FL
Posts: 4,685
Total Cats: 216
Default

You've disappointed me for the last time...
Full_Tilt_Boogie is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
Expected intake temps on the track? tazswing Race Prep 20 10-03-2015 12:04 PM
Back to Stock Part Out!! Turbo Parts, MS2 Enhanced 01-05, Suspension, and MOAR! StratoBlue1109 Miata parts for sale/trade 16 10-02-2015 10:39 AM
Time to start learning and play with tuning The Gleas MEGAsquirt 3 10-01-2015 10:30 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 08:45 PM.