Ever build a flow bench?
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Ever build a flow bench?
I'm interested in hearing from anyone who has put
together their own flow bench for hobby or professional
purposes
What's the parts list look like? How much did you buy,
mod and make. Estimated outlay, space required and
satisfaction with the end result.
As a supplemental - would a BOSCH MAF or an Air Valve
from a BMW in the circuit serve to provide quantifiable
data about changes?
Thanks,
Ken R.
together their own flow bench for hobby or professional
purposes
What's the parts list look like? How much did you buy,
mod and make. Estimated outlay, space required and
satisfaction with the end result.
As a supplemental - would a BOSCH MAF or an Air Valve
from a BMW in the circuit serve to provide quantifiable
data about changes?
Thanks,
Ken R.
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Here are a few DIY instances
"Build Your Own Flow Bench"
"Flow Bench"
"Home-built Flow Benches" pg 68
("How to Build & Modify SBC V-8 Cyl Hds" Vizard, D. ISBN: 0879385472)
"Da Flow Bench"
"EZ Flow System"
.
"Flow Bench"
"Home-built Flow Benches" pg 68
("How to Build & Modify SBC V-8 Cyl Hds" Vizard, D. ISBN: 0879385472)
"Da Flow Bench"
"EZ Flow System"
Last edited by Slalom4me; Jan 31, 2006 at 03:39 PM.
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
There's also a company called Audie Technologies that has a small unit that uses a shop-vac for its vacuum/pressure source. It uses an equation to arrive at the 28" depression numbers since the shop-vac can't flow enough air. It's similar in concept to the old SuperFlow 250 bench.
-Jeb
-Jeb
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
The segment in the book by D. Vizard gives two examples of using a
vacuum cleaner.
The first, simpler example is prefaced with the remark "any self-respecting
vacuum cleaner should be able to generate a fair amount of pressure
and vacuum when stalled... you'll need a manometer at least 6', maybe
as much as 10' high." He says that while it won't be sufficient to guage
the cfm flowing, it will be sensitive and useful for testing "the all-important
prefomance of valve seats and how seat geometry affects flow."
The second slightly more complex example depends on a powerful
shop vac and it is suggested that to get beyond 5", it may be useful
to couple in a second vacuum cleaner.
In contrast, the article about the MSD flow bench states that unit
has perhaps double the flow capacity many folks could make use of.
When I saw that I started looking to see how they keep the cabinet
together under the kinds of pos/neg loads the system can create.
.
vacuum cleaner.
The first, simpler example is prefaced with the remark "any self-respecting
vacuum cleaner should be able to generate a fair amount of pressure
and vacuum when stalled... you'll need a manometer at least 6', maybe
as much as 10' high." He says that while it won't be sufficient to guage
the cfm flowing, it will be sensitive and useful for testing "the all-important
prefomance of valve seats and how seat geometry affects flow."
The second slightly more complex example depends on a powerful
shop vac and it is suggested that to get beyond 5", it may be useful
to couple in a second vacuum cleaner.
In contrast, the article about the MSD flow bench states that unit
has perhaps double the flow capacity many folks could make use of.
When I saw that I started looking to see how they keep the cabinet
together under the kinds of pos/neg loads the system can create.
.
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Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Okay, I read all the links. The mag articles in the first link are fubar. Those are only good for comparing flow for increases or losses, but you can't begin to put CFM values on it. There's more to it than just comparing percentages.
The last link looks legit, and the 2nd one mentions measuring velocity pressure. The 3rd one doesn't have enough detail.
The qualifier here, is I've never seen a flow bench in person, but there's some fundamental things these guys aren't considering.
The last link looks legit, and the 2nd one mentions measuring velocity pressure. The 3rd one doesn't have enough detail.
The qualifier here, is I've never seen a flow bench in person, but there's some fundamental things these guys aren't considering.
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
I've seen one that a guy built that was instrumental for the development of one professional unit.
You can do alot with slant tube manometers.. I know of a grad student in charlotte that build a slant tube manometer that measured pressure differentials of .001psi He had 10 bucks in the rig
I agree.. the worst part would be putting a value on the data as well as getting a standard result. Big deal, you just couldn't comprare data on 2 days and you couldn't give you a firm number.
You can do alot with slant tube manometers.. I know of a grad student in charlotte that build a slant tube manometer that measured pressure differentials of .001psi He had 10 bucks in the rig
I agree.. the worst part would be putting a value on the data as well as getting a standard result. Big deal, you just couldn't comprare data on 2 days and you couldn't give you a firm number.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Spell out this method they're using with the u-tube...
They're pulling 28" across a hole in a piece of wood.
Then they bump up the sucking power as needed to pull 28" across the heads. What are they comparing then? 28=28
Or are they just doing step one, then putting the heads on there with the same vacuum power, and pulling less pressure across the heads? They're comparing apples to oranges just to get their %
Man, now I should build one. LFE is the surefire way to go. There's also orifice plates that can be used and calibrated to a good lfe.
They're pulling 28" across a hole in a piece of wood.
Then they bump up the sucking power as needed to pull 28" across the heads. What are they comparing then? 28=28
Or are they just doing step one, then putting the heads on there with the same vacuum power, and pulling less pressure across the heads? They're comparing apples to oranges just to get their %
Man, now I should build one. LFE is the surefire way to go. There's also orifice plates that can be used and calibrated to a good lfe.
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
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From: Edmonton AB
117478 Lamb Vacuum Motor PREMIER Part#201P $253.70/ea
110-120 volt -- 13.5 Amps
Waterlift 120", CFM 115.8, AirWatts 549
This is known as a tangential discharge style (look for the 'Turbo'
-style outlet tube.) These ones have higher Waterlift ratings and lower CFM
ratings than the annular discharge style (series of slots around the
circumference above the mounting section.)
The unit described above appears to offer the highest combined
Waterlift and CFM ratings. Three of these in the cabinet would
probably do the job - for many SBC's anyway. At 13.5 amps each,
you would want to make proper provisions for juice, I think.
Here is a link - New Central Vacuum Motors by Lamb Ametek
.
110-120 volt -- 13.5 Amps
Waterlift 120", CFM 115.8, AirWatts 549
This is known as a tangential discharge style (look for the 'Turbo'
-style outlet tube.) These ones have higher Waterlift ratings and lower CFM
ratings than the annular discharge style (series of slots around the
circumference above the mounting section.)
The unit described above appears to offer the highest combined
Waterlift and CFM ratings. Three of these in the cabinet would
probably do the job - for many SBC's anyway. At 13.5 amps each,
you would want to make proper provisions for juice, I think.
Here is a link - New Central Vacuum Motors by Lamb Ametek
.
Last edited by Slalom4me; Feb 1, 2006 at 03:25 AM.
Team Owner
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Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Naw, those ratings probably mean 120" at zero flow, and 116 cfm at zero head loss. 28" inches is a ton of pressure. These shop vacs I looked up are rated at about 200 cfm max, with nothing hooked up to them. 28" is a ton of air pressure though... could pull that 200 down to 30 cfm even.
I bet you'll need at least 5 hp worth of motors to get that much flow.
Although if you're only measuring single ports, then it shoudn't take much cfm right?
I bet you'll need at least 5 hp worth of motors to get that much flow.
Although if you're only measuring single ports, then it shoudn't take much cfm right?
Last edited by CentralCoaster; Feb 1, 2006 at 12:15 AM.
Drifting
Joined: May 2003
Posts: 1,730
Likes: 1
From: Charlotte NC
St. Jude Donor '05
Originally Posted by CentralCoaster
Spell out this method they're using with the u-tube...
not a u-tube but a slant monometer. Works the same just the slants are more accurate depending on the angle.
like this..
Team Owner
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by Alvin
not a u-tube but a slant monometer. Works the same just the slants are more accurate depending on the angle.
like this..
like this..
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
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From: Edmonton AB
Originally Posted by CentralCoaster
I bet you'll need at least 5 hp worth of motors to get that much flow.
Although if you're only measuring single ports, then it shoudn't take much cfm right?
Although if you're only measuring single ports, then it shoudn't take much cfm right?
I may be responsible in part for this because I initially wrote
"... for hobby or professional purposes..."
I retract the 'professional' part.I can say from personal experience that those vacuum motors can
generate significant negative pressure and cfm. If you've only used
the junky ones that seem to be sold by the hardware stores today, I
can see why you'd be sceptical. The unit above is typically selected
for high grade central vac systems in multi-story buildings.
I don't dispute that the latest SuperBlo XG w/ 12,000² CFM would be
a great addition in the home shop, but it ain't gonna happen (at my
place, anyway.)
I appreciate the critical study of the systems in the links and the
suggestions about budget ways to overcome the shortfalls. But keep it
within scope - something that Joe-schmoe could build up and get some
meaningful results on a reasonable budget.
K.I.S.
.
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
Originally Posted by CentralCoaster
I bet you'll need at least 5 hp worth of motors to get that much flow.
of the motors above work out to.
Here's a formula I came across for determining HP when various motor
parameters are known. This is more your speciality, tell me what you
think.
HP=(V*I*Eff)/746
HP: Horsepower
V: Voltage
I: Current (Amps)
Eff: Efficiency
Assume 82% efficiency (because the site did)
HP = (120*13.5*0.82)/746
- or -
HP = 1.78
Therefore, three motors gives us 5.34 HP
Yes/No
.
Last edited by Slalom4me; Feb 1, 2006 at 01:52 AM.
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Something like that. I'm not trying to be a CFI-EFI, just don't want anyone to get misled. See now you complicated things. 
Unfortunately the mfg doesn't always have any fan curves/tables. So a starting point would be to take that lift value and the free flow cfm, assume it's linear response and guesstimate your flow at 28". (You'll most likely have more than that in reality.)
On that note, that fan right there will probably move about 90 cfm at 28". Better than I expected.
I don't recall what the good shop vacs were rated at... 150-200 free flow, and 90" water column I think. So a shop vac could be used for some stuff, and you could hook up 2 or 3 shop vacs even. You could also blow or suck which ever is easier for what you're testing. And you could still clean the shop with it.
When they flow heads at x amount of lift, is that by setting all 8 valves up, or do they just test one port and multiply by 8? Obviously for the intake theyd have to flow the whole thing.
Testing stuff like tbs would be tough because it takes a helluva a lot of air to get 28" drop across them.
Unfortunately the mfg doesn't always have any fan curves/tables. So a starting point would be to take that lift value and the free flow cfm, assume it's linear response and guesstimate your flow at 28". (You'll most likely have more than that in reality.)
On that note, that fan right there will probably move about 90 cfm at 28". Better than I expected.
I don't recall what the good shop vacs were rated at... 150-200 free flow, and 90" water column I think. So a shop vac could be used for some stuff, and you could hook up 2 or 3 shop vacs even. You could also blow or suck which ever is easier for what you're testing. And you could still clean the shop with it.
When they flow heads at x amount of lift, is that by setting all 8 valves up, or do they just test one port and multiply by 8? Obviously for the intake theyd have to flow the whole thing.
Testing stuff like tbs would be tough because it takes a helluva a lot of air to get 28" drop across them.
Last edited by CentralCoaster; Feb 1, 2006 at 03:20 AM.
Le Mans Master
Joined: Jul 2001
Posts: 8,183
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From: Santa Maria, CA
Originally Posted by CentralCoaster
I've never seen a flow bench
Last edited by pablocruise; Feb 1, 2006 at 03:48 AM.
Thread Starter
Le Mans Master
Joined: Jan 2002
Posts: 9,036
Likes: 13
From: Edmonton AB
About the issues of data valuation, standardized results and repeatability.
The Vizard segment mentions flow bench software by Quadrant
Scientific being useful for the math associated with calibration as
well as other tasks. Quadrant seems to have slipped below the surface
and while I found a site that has their old cam software, I did not find
their flow software.
jburnett mentioned Audie Technology. They have software and
hardware for flow testing. One item of note is 'Flow Quik' - it is said
to dispense with the need for depression adjustment, manometers and
so on. Instead, there is an direct LED read-out of CFM. I suspect
they achieve this with some variation on my opening thought of placing
a MAF device in the circuit.
Audie also offers a fan control capable of handling motors of up to 30
Amp in capacity.
.
The Vizard segment mentions flow bench software by Quadrant
Scientific being useful for the math associated with calibration as
well as other tasks. Quadrant seems to have slipped below the surface
and while I found a site that has their old cam software, I did not find
their flow software.
jburnett mentioned Audie Technology. They have software and
hardware for flow testing. One item of note is 'Flow Quik' - it is said
to dispense with the need for depression adjustment, manometers and
so on. Instead, there is an direct LED read-out of CFM. I suspect
they achieve this with some variation on my opening thought of placing
a MAF device in the circuit.
Audie also offers a fan control capable of handling motors of up to 30
Amp in capacity.
.