converting to 28h2o
converting to 28h2o
(OP)
Hope someone can help. I know there is a formula to convert a flowbench reading from 10" H2O to 28" H2O. The flowbench I have access to is 10". Thanks.
David
David
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
|
RE: converting to 28h2o
New_Flow = Old_Flow * ( New_Pressure / Old_Pressure ) ^ .5
334.664 CFM = 200_CFM * ( 28 / 10 ) ^ .5
334.664 CFM = 200_CFM * 1.673320053
===================================================
example for Holley 500 cfm 2-barrell carb
at 2-barrell rating at 3.0 inches Hg. -VS- 1.5 inches Hg
4-barrell rating
353.55 CFM = 500_CFM * ( 3.0_Hg / 1.5_Hg ) ^.5
As you can see ..a Holley 2-barrell 500 CFM carb is really a very small carb ( 354 cfm ) ..when compared to a Holley 4-barrell 500 CFM carb
Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
http://www.mindspring.com/~meauxracing/
RE: converting to 28h2o
10 to 28 = 1.673320053 conversion factor
1 / 1.673320053 = .597614305
28 to 10 = .597614305 conversion factor
Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
http://www.mindspring.com/~meauxracing/
RE: converting to 28h2o
Cheers
Greg Locock
RE: converting to 28h2o
353.55 CFM = 500_CFM * ( 3.0_Hg / 1.5_Hg ) ^.5
===============================================
Should be
353.55 CFM = 500_CFM * ( 1.5_Hg / 3.0_Hg ) ^.5
=================================================
Greg, there is another small correction factor used by SuperFlow with the normal conversion factor
this might be a small Reynolds type correction ???
Most people just use the Test Pressure Conversion equation i just posted as its pretty close (Linear)
if you use the additional SF correction factor , its
even closer
if the Test Pressure is too low , the air speed will be low
and if theres a bad curve or any problem area in port or valve area , it won't show up at low airspeeds because air is flowing slow enough to follow bad curve , but at higher speeds (Test Pressures) , the same port will flow different numbers or in a live engine make less HP than the flow bench predicts.
Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
http://www.mindspring.com/~meauxracing/
RE: converting to 28h2o
additional info ;
SuperFlow doesn't use a Laminar Flow Element
they use Orfices.
When flowtesting on SF bench
especially above 20 inches of water
the flow is always in turbulent range (> Reynolds laminar value )
Larry Meaux (meauxracing@mindspring.com)
Meaux Racing Heads
MaxRace Software
ET_Analyst for DragRacers
http://www.mindspring.com/~meauxracing/