Cylinder Head Flow Testing Discussion?

BigYellowIron

BigYellowIron

Diesel Tech
Joined
Aug 22, 2007
Messages
1,400
Can we discuss the method used to flow test our cylinder heads.
How are shops doing this testing?

I will be honest, I dont know much about this, hence starting this thread.

The research I have done shows most of the flow benches using a vaccuum. I know this has been discussed before about sucking the air thru the head and forcing it thru.

I just want to see what we can learn about flow testing a head.

Proceed....
 
I am NO expert, but i hve researched this in the past....and not found any flowbench that testes under boosted conditions.

Everything I found only works on vacuum like you said. Therefore any flowbenching on our heads are speculative, accurate under a vacuum, but speculative under boost. Again I'm no expert!!!

I know when my head was being tested the gains in porting were hard to determine and the results difficult to reproduce. I have a mildly ported and polished CR head. Basically bowl work, gasket matched exhaust and some polishing.
 
there are a lot of pressure flow benches , Ciro Batton was the first to have one . 3 6 71 super chargers with a small block chevy turnning them
 
certainly, they have to be out there, but not readily available
 
Flow bench

Extrude Hone has one. They can match the flow in each cylinder just like on a tip. Been there,..done that.
 
OK, so how does the pressure ones work? at what psi are they pressurized at when measuiring the flow?
 
It will be intersting to see where this thread goes.

I think the key question here would be how would you measure percentage increases pressurized, to know your making a better flow

I would be thinking using the known orifice method might be of some assistance but I think there may be much more involved because as we know, pressure tends to go down when the passage in question is releived but I dont know how easy it would be to be able to tell you where gains are made or lost in the port.

I think the sensors and programming would be very expensive - ergo thats why there arent many in the country

That being said - if you can make a port flow exceptionally well using the vacuum method, it would stand to reason those gains would be mirrored under pressure.

I know we did some testing about 15 yrs ago with some very rudimentary manomter probes and a 5hp vacuum attached to a 12" pipe stub on the exhaust port, so port flow was as is seen by the motor, instead of reverse flow thru a cylinder. There were some differences between the two tests, but nothing we could quantify and say" this is it"

For those of you who are interested in cheap home flow benches - these are two of many available

http://performancetrends.com/ez_flow_system.htm

Flow Bench | Air Flow Measurement | Air Flow Analysis

For those of you who are interested in latest technology this is a good article as well


Cylinder Head Flow Testing - The Future of Flow Testing - Circle Track Magazine
 
with the new pc based technologies - the pressure can be anything they want, and the software converts the numbers to the 28" standard used i nthe industry

Real world testing/comparisons has put most of these units in the 98% percentile accuracy for flows as say compared to a superflow

the difference being you cant do everything with these cheap units that a superflow can do - meaning for the most part they just measure gross airflow which for the home builder is usually more than enough
 
Info on Extrude Hone Flow Testing

j-rod said:
Pressure or vacuum?
Click to expand...

I talked to Rick Miller at Extrude Hone today. He said they have a 1020 Super Flo Flow tester they use on cylinder heads. It is a pressure tester. He said the Cummins head is relatively close (cylinder to cylinder) and he can normally inclrease total over all flow by around 15% and match the cylinders to one another in the 2%to 3% range.

Rick's tn is 724-861-8694.

I can tell you from mine the finished product is like teflon with oil on it. The head has been off a couple times and it remains as when 1st done. You will need NEW valve seats installed which is NOT that expensive.
 
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