robullrich":2cbto7gw said:
Hi all,
I'm gearing up for a new build and I need some info on air flow. I'm looking to do a an Offenhauser triple 1v on my 200ci. I'm trying to figure out the optimal CMF for the engine and how can I achieve that with the Carbs. In other words, does 3 1v carbs rated at 150cmf = 450cmf? Is it that simple? Thanks!
Yes x2 (or three!).
The wrong combination of parts can have you loose a lot of horsepower on what you expect. I'm not sure its peak air flow, but having the right access to the combustion chamber...that makes power. A large 1970 to 1972 log head with 170 cubic inch combustion chamber is considered best, and the Offy intakes for those have 1 7/16" outer holes rather than 1 to 1.09" of the small log Offy. Air fuel mix needs room to propagate a nice roosters tail for peak air flow. See
datac's
/viewtopic.php?t=70151
For general carb flow figures (some from the Ford Falcon Six book by the Schjeldahl Bros.
http://vb.foureyedpride.com/showthread. ... or-options
Holleys 1904,1908,1909 before the Autolite 1100/1101 replacement Holley 1940, and well before the 1978 to 1983 200 3.3 Holley 1946
All CFM's at 3"Hg flow drop.
1952 = 1904 215/223/262 and
1960 = 1904 144 engine. 130/150/170cfm for the 1904,
1960 late 1908 144 and 170, 135/150cfm for the 1908,
Early Holley 1909 series was rated at 170 CFM and 125/150cfm for the small 1909.
1962 1909 was 170
Autolite 1100 Sizes and Applications
1100 and 1101 Autolite 1-bbl 1.00-, 1.10-, and 1.20-inches. Mustangs had either 1.10- or 1.20-inch depending on model year and configuration. Basic bore size was 17/16-inches.
1.00 Venturi(120 CFM): 144 ThriftPower Six, 1.4375 Throttle, 84 to 90 hp
1.10 Venturi(150 CFM): 170 ThriftPower Six, 1.4375 Throttle,105 or 101 hp, then derated 68-69 200's
1.20 Venturi(185 CFM): 200, 250 Six, 1.4375 Throttle
The 1101 TB measures 1 11/16". Venturi measure 1.29" It is rated at 210 cfm. 1.6875" throttle 1969 only 250
The Carter YF first saw use on California emissions 170 and 200ci sixes in 1967. In '68-'69, only 170 and 240ci sixes got the Carter YF, which means you will never see one on a Mustang .
Ford suffered from anti trust legislation, and had to sell off Autolite as it held a range of patents owned by Presolite and Bendix Technico. The Autolite 1100/1101 was no longer able to be made by Ford, so they outsourced it to Holley and for a time, it was sold as a Motorcraft untill Ford had to settle on the Bendix Tecnico patents.
The 1940 Holley carb was a two size carb with 26 part numbers, 15 of which were large 1.29" venturi which could be taken out to 1.352", and potentially flow 212 cfm according to one sourece at Ford Six performance. The small bore 1940 was probably 1.10" bore, and flowed about the same 150 cfm as the old 1.10 venturi 1100 Autolite.
The YF Carter was an old Jeep carb, and in 1967 it got updated to the YFA for Fords, AMC's, Chevrolet 230'S.
In Fords, they had to use Carter carbs during the anti trust lawsuit, and Autolite was in a state of bankruptcy by 1969.
YFAs came in 150, 187, 193,195 and 200-cfm sizes.
YFAs came in 150 cfm 170 CID 1970 Maverick
YFAs came in 187cfm in 1970 200 cid Mavericks
YFAs came in 193, or 200 cfm, 195 cfm in 1975 -1979 L-code 250'S
1970-1973 250 Carter RBS L-code Only one size-215 cfm-was produced
1978-1983 in 202 cfm 200 CID T,B, X code 3.3
For a Offenhauser or Edelbrock tripower, the best flow rates at 3" (and 1.5" Hg respectively in brackets).
Three Carter RBS's probably won't fit, but would make 645 cfm (or 456 cfm).
Three 1940 Holleys with 1.352" venturis, probably 636 cfm (or 450 cfm).
Three 1101 Autolites with 1.29" venturis, probably 630 cfm, (or 446 cfm).
Three 150, 187, 193, 195, or 200 cfm YFA's 450, 561, 579, 585, 600 cfm (or 318, 397, 410, 414, 424 cfm)
For the myridas of other tri power carb combinations, Three 120, 130, 135, 170, 185 are 360, 390, 405, 510, 555 cfm (or 255, 276, 286, 361, 393 cfm).
I think the best Ak Miller suggestion was to use the 1101 center carb at 210 cfm, and any two 1100 outer carbs (120, 150, 185).
Thats 450, 510, 580 cfm (or 318, 361, 410 cfm)
The ICT and ICH combinations of ex Land Rover, Bedford/Vauxhall or replacment VW Beetle/Variant Weber carbs flow about 156 cfm at 1.5" Hg, or 468 cfm, which despite the 1.14" venturi, flows more than any of the above carbs. Pretty good for a lowly 4 cylinder 1600 to 2300 cc 1-bbl that had trouble making more than 80 hp in stock form. On a 200 with 264 Clay Smith Cam, it makes 181 hp at the flywheel. The 250 with two 1100's and one 1101 Autolite can make over 220 flywheel hp based on 97 mph 1/4 miles in an automatic 2600 pound Mustang
As litte as 255 cfm, or as much as 468 cfm if measured as a 4-bbl carb is.
An early Rambler 232 i6, or 345 IHI Truck 2-bbl Holley flows about 265 cfm, and Holley's 350 and 500 cfm carbs flow that at 3"Hg. They made net figures of about 100 to up to 180 horsepower depending on instillation. In fact, the big 400 was downgraded to a 1.21" venturi 2150 Motorcraft 356 cfm 2-bbl carb the years it made 178 to 158 net hp. Putting a smaller 350 cfm carb often made more power in those.
4-bbl carbs like the Nikki 1979-1984 Mazda RX-7 (313-326, with 364 CFM possible blue printed, stock)
https://c1.staticflickr.com/9/8121/8761 ... c375_z.jpg
Some of the Rolls Royce and Bently 6.75 liters (1976-1986 Camaruge, Silver Wraith, 1983-1986 early Mulsane Turbo), or 1974-1980 Benz 280C W116/123 and 280S W116, the 1977-1982 BMW 320/6 / 520/6 and 1978-1982 Opel 2500/2800/3000 used the GM like Solex 4A1 4-bbls, they flow the same amount as tri-power carbs and get approx 115 to 200 net flywheel hp, even less than the 180 to 220 hp our 3.3 and 4.1 sixes can and do get. The Solexes were smaller, and Q jet like copies like the 4360 Holley 430 cfm 4-bbl carb became. But when boosted with a big twelve bolt boiler lid and Garret Air Research turbo, it went from a humble 197 hp to about 296 hp net in a Bentley. So again, not a lot of flow at all.
http://blog-imgs-14-origin.fc2.com/d/i/ ... /4A1-3.jpg
Not very big at all, but the combination really works well in practice. As restricted carb engine racing provees, air flow isn't everything.
See
kevinl058 and
FalconSedanDelivery
/viewtopic.php?t=64712
and
JD for triple carb instillations that
really work.
yes thats really about the gist of it! Though it can also matter in the type of linkage you use like a progressive or straight. So then with the progressive it's the one center 150cfm carb working and starting around half throdle the other two carb's start to open. With the straight linkage it's the 450cfm of all there carb's all the time. Good luck 
