Barry Grant 6-pack Part two flow test
#1560529
01/07/14 05:47 PM
01/07/14 05:47 PM
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Joined: Oct 2006
Posts: 427
Sweden
Mopar Guy
OP
mopar
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OP
mopar
Joined: Oct 2006
Posts: 427
Sweden
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There are some guy´s out here that say the BG six pack carbs flow whay less than the Holley`s but i whas surpriced today when i got the chans to flow test them at a well known head porting guy that have a flow bentch. Whe started out whit flow testing a brand new out of the box Holley outboard carbs that Holley say 500cfm and it flowed 532,6 cfm And a out of the box BG that whas stated at 355 cfm flowed 510,5 cfm at same underpresiure so i almost dropt my face  There is no way these are as smal as some say only about good for a 383 engine  If you consider al 3 carbs flow above 510 out of the box and compare that to a Holley set whit that smal center carb i would be very supriced if there not at least almost equal whit al 3 carbs on full throttel  The only modification i did on the center BG carbs whas that i milled of the choke tower and that cant make sutch a big difference !?
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Re: Barry Grant 6-pack Part two flow test
[Re: Mopar Guy]
#1560530
01/07/14 06:50 PM
01/07/14 06:50 PM
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Joined: Mar 2009
Posts: 2,467
Sydney,Australia
tex013
top fuel
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top fuel
Joined: Mar 2009
Posts: 2,467
Sydney,Australia
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that's interesting . The BG is a annular isn't it ? I wonder how that will work . The only guy I know to have used them , I think on a Ford , was not thrilled performance wise . May pay to try and flow the carbs on manifold ?
I do like that they are mechanical not vacuum outers
Tex
New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
3690lbs through the mufflers
New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
Power by Tex's Automotive
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Re: Barry Grant 6-pack Part two flow test
[Re: sshemi]
#1560533
01/07/14 07:26 PM
01/07/14 07:26 PM
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Joined: Oct 2006
Posts: 427
Sweden
Mopar Guy
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OP
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Sweden
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Quote:
At what pressure where they flowed?
28 ! Do that matter as whe compared at same
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Re: Barry Grant 6-pack Part two flow test
[Re: Mopar Guy]
#1560534
01/07/14 07:35 PM
01/07/14 07:35 PM
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Joined: Jun 2003
Posts: 3,325
Truckville, the capital of NY
85_Ram_4speed
master
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master
Joined: Jun 2003
Posts: 3,325
Truckville, the capital of NY
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I thought, and it was my understanding, that 2 barrel carbs were rated differently than 4 barrel carbs. And to figure the difference you take the 500 cfm rating and divide by 1.5 which gets you at 333 cfm. While not exact, it is supposed to get you close, to compare apples to apples. So maybe that is why the BG carb is rated at 355, but actually flows similarly to the Holley when side by side. I mean, how can the beloved 4412 Holley 500 CFM 2 bbl carb that is essentially 1/2 of a 750 CFM 4 bbl flow almost 2/3 of the 4 bbl. But if you use the above formula, take that 333 CFM and double it (666 cfm), it sure comes alot closer to matching the 4 bbl value of 750 CFM. EDIT: found this..... The American Society of Engineers (ASE) decided to measure the flow of 2bbl carbs at one level of manifolcd vacuum (mercury/Hg) and rated 4bbl carbs at another level. The conversion factor is 1.414. soooo... 500 cfm / 1.414 = 353 cfm 
Outcast Dodge guy.
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Re: Barry Grant 6-pack Part two flow test
[Re: 85_Ram_4speed]
#1560535
01/07/14 07:41 PM
01/07/14 07:41 PM
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Joined: Oct 2006
Posts: 427
Sweden
Mopar Guy
OP
mopar
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OP
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Joined: Oct 2006
Posts: 427
Sweden
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Quote:
I thought, and it was my understanding, that 2 barrel carbs were rated differently than 4 barrel carbs. And to figure the difference you take the 500 cfm rating and divide by 1.5 which gets you at 333 cfm. While not exact, it is supposed to get you close, to compare apples to apples.
So maybe that is why the BG carb is rated at 355, but actually flows similarly to the Holley when side by side.
How ever you calulate they flow almost alike wouldent you say !? What i whas after in this realety test is that the BG dont flow as bad as some out there say ! BG are most likely flowed wet and Holley dry as i now did when compareing them 
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Re: Barry Grant 6-pack Part two flow test
[Re: ppmracing]
#1560539
01/12/14 11:47 PM
01/12/14 11:47 PM
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Joined: Jan 2003
Posts: 14,506
So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,506
So. Burlington, Vt.
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Quote:
The right pressure to flow them at ( Holley 20,4cfm) as far as i know.
Then the so called 500cfm outbord carbs flow 434cfm on my Superflow digital bench.
2bbl carbs are rated 3"Hg, and 4bbl carbs at 1.5"Hg.
the 20.4"H2O equates to 1.5"Hg.
this is supposed to more accurately represent the pressure drop across the carburetor in operation(in an OEM type application).
as an example, a stock type 383 motor with a stock type 2bbl running at 5000rpm at WOT will have a higher pressure drop across the carb than the same engine with a stock type 4bbl on it.
this disparity in test pressures is why 6pak set ups are "1300cfm", but dont really have 53% more flow capacity than a std 850 4bbl.
the flow ratings were achieved at different pressure readings. 3.0"Hg for the 6pak, 1.5"Hg for the 4bbl.
also, carb flow ratings "should" be wet flow numbers.
for roughly 12.5 A/F ratio, i approximate the wet flow as 92% of the dry flow.
so, to my way of thinking, that 434cfm works out to 399cfm calculated wet flow @ 1.5"Hg.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Yes they are annular boosters in those carbs !
