Carter Carburetors ~ Advertised CFM Ratings and Corrected CFM Flow Ratings ~

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69 Cuda 440

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Carter Carburetors

Advertised CFM Ratings and Corrected CFM Flow Ratings

Year ....... Engine ....... Model ... Advertised Rating ... Corrected Flow Rating
1962 ....... 361/305 HP .. AFB ............ 500 ........................ 470

1962 ....... 383/343 HP .. AFB ............ 525 ........................ 500

1962 ....... 413/420 HP .. AFB ............ 625 ........................ 600 .. 'Max-Wedge'

1963 ....... 383/330 HP .. AFB ............ 575 ........................ 566

1963 ....... 426/425 HP .. AFB ............ 625 ........................ 600 .. 'Max-Wedge'

1964 ....... 383/330 HP .. AFB ............ 575 ........................ 566

1964 ....... 426/365 HP .. AFB ............ 575 ........................ 566 .. 'Street Wedge'

1964 ....... 426/425 HP .. AFB ............ 750 ........................ 710 .. 'Max-Wedge'

1965 ....... 273/235 HP .. AFB ............ 500 ........................ 485

1965 ....... 383/330 HP .. AFB ............ 575 ........................ 566

1966 ....... 426/425 HP .. AFB ............ 625 ........................ 580 .. 'Street Hemi'

1966 ....... 383/325 HP .. AFB ............ 575 ........................ 566

1967 ....... 383/280 HP .. AFB ............ 575 ........................ 537 .. 'A-Body'

1967 ....... 440/375 HP .. AFB ............ 750 ........................ 728

1968 ....... 340/275 HP .. AVS ............ 625 ........................ 630

1968 ....... 383/335 HP .. AVS ............ 625 ........................ 630

1968 ....... 440/375 HP .. AVS ............ 750 ........................ 740

1971 ....... 340/275 HP .. Thermoquad . 800 ....................... 737

1972 ....... 400/265 HP .. Thermoquad . 850 ....................... 787

1973 ....... 440/280 HP .. Thermoquad . 850 ....................... 787

1974 ....... 360/245 HP .. Thermoquad . 850 ....................... 787
 
Nick-Nack

Be advised, that the '1962' 413/410 HP and 413/420 HP engines were called
'Maximum Performance Packages'.

The Carter AFB #3447 {1 7/16' Primary x 1 11/16" Secondary} flowed at 600 CFM's.

These #3447 AFB's were also utilized for the '1963' 426/415 HP and 426/425 HP
'Maximum Performance Packages'.
 
Well that manifold ( above post..) ,had such a huge plenum.. Did it really matter?...
 
Abodybomber said:
Well that manifold ( above post..) ,had such a huge plenum.. Did it really matter?...
Click to expand...

Uno Momento. But Wait.

'Stage II'

In June 1963, Mopar changed to the Carter #3705S AFB which had
both 1 11/16" Primary and Secondary Throttle Openings.

Also, the Air-Horn was increased 3/4" in Diameter.

The #3705S was advertised at 750 CFM's, but Flow tested out at 710 CFM's.
 
Paul, this is a great subject. Glad you are doing it. I have a question. Most of "us" are aware that Carter used "sumthin" other than "what everybody else used" to measure CFM.

In your "corrected" column, what was the procedure used for measuring? In other words, what were they corrected "to" from "what they were"?

This has always been something I have wondered about, but have never found anyone that knew the specific answer.

Thanks, btw for another really interestin article.
 
Rusty-Rat-Rod

A Very Good Question

Most of Carter Carburetors 'CFM-Ratings' were based upon generalized 'advertised'
guestimates.

Calculations were based upon Throttle-Bores sizes and Venturi openings.

1} Unfortunately, Air-Flow is 'not' Air-Flow.
2} Street Engines operate below maximum capacity.

The ratio of how much air the engine can pump is called, as you know
VE {volumetric efficiency}.

As a general estimate, the following Engines operate at;
Street Engines .......... 75%
Modified Engines ....... 85%
Race Engines ............ 90%

~ Advertised Ratings ~

Most calculations performed at Carter for the AFB used 75% as a guestimate.

The AVS was rated at approximately 85%, as it was designated as a Performance upgrade.

The Thermoquad was rated at the high-level of 90%.
-----------------------------------------------------------------------------------------

~ General Carter Carburetor Formula {High CFM Flow Rate}

Throttle Bore {multiply by} Venturi {multiply by} .743 = Bore CFM
 
RustyRatRod said:
Paul, this is a great subject. Glad you are doing it. I have a question. Most of "us" are aware that Carter used "sumthin" other than "what everybody else used" to measure CFM.

In your "corrected" column, what was the procedure used for measuring? In other words, what were they corrected "to" from "what they were"?

This has always been something I have wondered about, but have never found anyone that knew the specific answer.

Thanks, btw for another really interestin article.
Click to expand...

Rusty I read somewhere that the Carters were flowed "wet" and should be closer to "truth."

Just like cams or any other rating, it would be great if they were standardized so you can accurately compare 'em.
 
67Dart273 said:
Rusty I read somewhere that the Carters were flowed "wet" and should be closer to "truth."

Just like cams or any other rating, it would be great if they were standardized so you can accurately compare 'em.
Click to expand...

That would be too simple,like everyone aftermarket cam wise using the same measuring specs.
 
CFM Air-Flow Test

We took a Carter AFB from a 273/235 HP 'Commando' and flow-tested it
at the University of Binghamton {New York} Engineering Department.

Carter #4294S
Primary ....... 1.437" {1 7/16"} ....... Venturi .. 1.063"
Secondary ... 1.563" {1 11/16"} ...... Venturi .. 1.250"

Now, this AFB was 'advertised' at 500 CFM.

And depending on what articles you read, these AFB's were rated at
anywhere from 470 to 525 CFM's.

After some tweaking, and a little polishing of the throttle bore and venturi areas, we maxed out at 516 CFM's.

Primary ........ 1.437 x 1.063 x .743 x 2 = 227 CFM
Secondary .... 1.563 x 1.250 x .743 x 2 = 289 CFM

Net CFM's = 516
 
69 Cuda 440 said:
CFM Air-Flow Test

We took a Carter AFB from a 273/235 HP 'Commando' and flow-tested it
at the University of Binghamton {New York} Engineering Department.

Now, this AFB was 'advertised' at 500 CFM.

After some tweaking, and a little polishing of the throttle bore and venturi areas, we maxed out at 516 CFM's.

Primary ........ 1.437 x 1.063 x .7854 x 2 = 240 CFM
Secondary .... 1.563 x 1.125 x .7854 x 2 = 276 CFM

Net CFM's = 516
Click to expand...

That's good info,sir. Thanks!
 
69 Cuda 440 said:
CFM Air-Flow Test

We took a Carter AFB from a 273/235 HP 'Commando' and flow-tested it
at the University of Binghamton {New York} Engineering Department.

Carter #4294S
Primary ....... 1.437" {1 7/16"} ....... Venturi .. 1.063"
Secondary ... 1.563" {1 11/16"} ...... Venturi .. 1.250"

Now, this AFB was 'advertised' at 500 CFM.

And depending on what articles you read, these AFB's were rated at
anywhere from 470 to 525 CFM's.

After some tweaking, and a little polishing of the throttle bore and venturi areas, we maxed out at 516 CFM's.

Primary ........ 1.437 x 1.063 x .743 x 2 = 227 CFM
Secondary .... 1.563 x 1.250 x .743 x 2 = 289 CFM

Net CFM's = 516
Click to expand...

I posted the Carter AFB #4294S specifications above.
 
Mopar Hustle Stuff Catalog

Carburetor ............. Engine ....................... CFM Rating

AFB #3853 .............. 273/235 HP ....................... 460

AFB #3249 .............. 361/305 HP ....................... 450

AFB #3447 ...............426/425 HP {Max-Wedge} .. 570

AFB #3258 .............. 383/343 HP {Front Carb} .... 465
AFB #3259 .............. 383/343 HP {Rear Carb} ..... 475

AFB #4326 .............. 440/375 HP {1967} ............ 750

AFB #4742 ............... 426 Street Hemi {1970} ..... 570

AVS #4933 .............. 340/275 HP ....................... 630

AVS #4367 .............. 383/335 HP ....................... 630

AVS #4737 .............. 440/375 HP ....................... 750

Thermoquad #4872 ... 340/275 {1971} ................ 800

Thermoquad #6324 ... 440/280 HP {1973} ........... 850
 
Chooch

The 1962 383/343 HP 'Dual-Quad' Carburetors, with approved upgrade AFB Carbs.

Part # ....... Primary x Secondary ...... Venturi Size ....... Advertised CFM

#2798 ......... 1 7/16" x 1 9/16" ....... 1.063" x 1.125" ........ 445
#2799 ......... 1 7/16" x 1 9/16" ....... 1.063" x 1.125" ........ 450

#3258 ......... 1 7/16" x 1 9/16" ....... 1.063" x 1.250 " ....... 465
#3259 ......... 1 7/16" x 1 9/16" ....... 1.063" x 1.250" ........ 475

#9502 ......... 1 7/16" x 1 11/16" ..... 1.186" x 1.563" ........ 570
#9503 ......... 1 7/16" x 1 11/16" ..... 1.186" x 1.563" ........ 570
 
Maximum Performance Carburetors

1962 '413' Maximum Performance
#3447 .......... 1 7/16" x 1 11/16" ..... 1.186" x 1.563" ........ 570 CFM

1963 '426' Maximum Performance {Stage 1}
#3447 ......... 1 7/16" x 1 11/16" ..... 1.186" x 1.563" ......... 570 CFM

The #3447 AFB Carburetors came thru with the smaller {4 5/8"} Air-Horn.

When dialed-in and Flow Tested. They 'Flow' between 597 and 602 CFM's.
_______________________________________________________________
 
Maximum Performance Carburetors

'Stage II' upgrades for {June 1963}

#3705 ......... 1 11/16" x 1 11/16" ........ 1.437" x 1.563" ........ 700 CFM

Though advertised at 750 CFM's. When flow-tested, they came in between 695 and 705 CFM's.

The #3705 AFB Carburetor came thru with an improved Fuel-Line arrangement, and
a larger Air-Horn {+ 3/4"} over the earlier #3447 AFB Carburetor on the Maximum
Performance Packages.
 
69 Cuda 440 said:
We took a Carter AFB from a 273/235 HP 'Commando' and flow-tested it
at the University of Binghamton {New York} Engineering Department.
Click to expand...
Do you recall the pressure drop and set up?
Pressure drop is, of course, a critical variable, but entry and exit will influence the cfm as well. I'd think with a carb bolted to the bench, exit is less important but an air cleaner base or stack on the top could make a measurable difference.
67Dart273 said:
Just like cams or any other rating, it would be great if they were standardized so you can accurately compare 'em.
Click to expand...
The OEM's write the specifications to meet their own needs and the suppliers have to meet those specs. Granted there usually is negotiation and equivalents can and do get worked out. Setting standards is often done within an industry and there probably was little incentive at the time for either the auto makers or the carb manufacturers. I suspect that when flow ratings were published for the public it was because that carb was being sold aftermarket, or the car's marketing called for it.

"Some automobile manufacturers rate Holley carbs at other pressure drops, giving different flow ratings than Holley's specification. Example: Chrysler rates the 2210 two-barrel at 2.0-in.Hg pressure drop at WOT and uses a reduced cfm rating.
"Holley standardized flow rates at 1.5-in.Hg pressure drop for three- and four-barrel carburetors; 3.0 in.Hg for one- and two-barrel carburetors."
Click to expand...
from Mike Urich & Bill Fisher Holley Carburetors & Manifolds (HP Books) revised edition 1978 p.81
Note: This book carries the bias and authority of Urich being VP of engineering at Holley and the book is Holley p/n 36-73
 
Good Call 'Mattax'

Here a '2' Holley Carbs that we Flow-Tested

Carb # .... CFM Rating ..... Type ......................... Flow Tested
#3310-1 .... 780 CFM .... 'Vacuum Secondaries'........ 788

#4780 ........ 800 CFM .... 'Double-Pumper' .............. 780
 
Good for comparison. Seems like your University set-up was similar to Holley's.

Interesting to note that both Holley carbs you tested are listed with the same venturi and throttle bore diameters, and both had downleg boosters:
P venturi 1-3/8
S venturi 1-7/16
P throttle 1-11/16
S throttle 1-11/16
 
Mattax said:
Good for comparison. Seems like your University set-up was similar to Holley's.

Interesting to note that both Holley carbs you tested are listed with the same venturi and throttle bore diameters, and both had downleg boosters:
P venturi 1-3/8
S venturi 1-7/16
P throttle 1-11/16
S throttle 1-11/16
Click to expand...

Holley Carburetors

The CFM rate almost always come out to their advertised Flow numbers.
 
Carter Carburetors

~ Just A Few Carburetor Listings ~

Model ...... Primary .... Secondary ..... Venturi Sizes .... Advertised CFM
_________________________________________________________

WCFB ....... 1 5/16" .... 1 5/16" ....... 0.937" x 1.125" ...... 385

AFB .......... 1 7/16" .... 1 7/16" ....... 1.186" x 1.186" ...... 450

AFB .......... 1 7/16" .... 1 7/16" ....... 1.063" x 1.250" ...... 450

AFB .......... 1 7/16" .... 1 9/16" ....... 1.063" x 1.125" ...... 470

AFB .......... 1 7/16" .... 1 9/16" ....... 1.063" x 1.250" ...... 500

AFB .......... 1 7/16" .... 1 9/16" ....... 1.186" x 1.313" ...... 575

AFB .......... 1 7/16" .... 1 9/16" ....... 1.063" x 1.563" ...... 575

AFB .......... 1 7/16" .... 1 11/16" ..... 1.063" x 1.563" ...... 600

AFB .......... 1 7/16" .... 1 11/16" ..... 1.186" x 1.563" ...... 600

AFB .......... 1 7/16" .... 1 11/16" ..... 1.186" x 1.313" ...... 600

AFB .......... 1 9/16" .... 1 11/16" ..... 1.186" x 1.563" ...... 650

AFB .......... 1 9/16" ... 1 11/16" ...... 1.250" x 1.563" ...... 680

AFB .......... 1 5/8" ..... 1 11/16" ...... 1.343" x 1.563" ..... 700

AFB .......... 1 11/16" .. 1 11/16" ...... 1.437" x 1.563" ..... 750

AVS .......... 1 7/16" ... 1 11/16" ...... 1.186" x AV ........... 630

AVS .......... 1 11/16" .. 1 11/16" ..... 1.437" x AV ........... 750
 
69 Cuda 440 said:
Carter Carburetors

~ Just A Few Carburetor Listings ~

Model ...... Primary .... Secondary ..... Venturi Sizes
______________________________________________

WCFB ....... 1 5/16" .... 1 5/16" ....... 0.937" x 1.125"

AFB .......... 1 7/16" .... 1 7/16" ....... 1.186" x 1.186"

AFB .......... 1 7/16" .... 1 9/16" ....... 1.063" x 1.125"

AFB .......... 1 7/16" .... 1 9/16" ....... 1.063" x 1.250"

AFB .......... 1 7/16" .... 1 9/16" ....... 1.186" x 1.313"

AFB .......... 1 7/16" .... 1 9/16" ....... 1.186" x 1.563"

AFB .......... 1 7/16" .... 1 11/16" ..... 1.063" x 1.563"

AFB .......... 1 7/16" .... 1 11/16" ..... 1.186" x 1.563"

AFB .......... 1 7/16" .... 1 11/16" ..... 1.186" x 1.313"

AFB .......... 1 9/16" .... 1 11/16" ..... 1.186" x 1.563"

AFB .......... 1 9/16" ... 1 11/16" ...... 1.250" x 1.563"

AFB .......... 1 5/8" ..... 1 11/16" ...... 1.343" x 1.563"

AFB .......... 1 11/16" .. 1 11/16" ...... 1.437" x 1.563"

AVS .......... 1 7/16" ... 1 11/16" ...... 1.186" x AV

AVS .......... 1 11/16" .. 1 11/16" ..... 1.437" x AV
Click to expand...

Frank-n-Beans

Do you need the 'Advertised' CFM Ratings, and/or 'Net' CFM Ratings.
 
Mr. Binks

Carter Carburetor would list their Carbs with an 'advertised' CFM Rating.

The Car Manufacturers would list the Carburetors at their own rating.
 
69 Cuda 440 said:
Frank-n-Beans

Do you need the 'Advertised' CFM Ratings, and/or 'Net' CFM Ratings.
Click to expand...

Actual wet flow ratings would be what I would want them reported at. Advertised ratings are nice to know since it is more of a sales tactic for the public.
 
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