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NYCRAT Apr 17th, 04, 7:02 PM I did the math and came up w/880 @100%VE,836 @95% and 792 @ 90%VE ((468*6500)/3456)*vol eff= CFM I don't know how to determine volumetric efficency ,does anyone? do you think 50 cfm either way would make that much of a difference? Thanks, Andy three85stroker Apr 17th, 04, 7:25 PM The average V.E. for most street engines, be it in a geo metro or a F-50 Ferrari, is usually in the neighborhood of 80-85%. You don't start getting close to and over 100% V.E. w/o extremely precise tuning (like a race team) or forced induction. I'll email you a page from a book I have for figuring V.E. if you give me your email address. But in the mean time, according to the same book to figure carb size run this formula: ((rpm x displacement)/3456)xV.E. where the rpm is the max rpm you plan to run, displacement is in cubic inches, and V.E. is in decimal form (80%would be .80). In most cases, you'd probably be better off to choose a carb that is the first available size down from you calculation, so if you came up with 730cfm, go with a 700cfm, it's much better as far as torque and throttle response goes. graemlins/thumbsup.gif NYCRAT Apr 17th, 04, 7:46 PM Stroker(name?) Thanks for the input. If the offer for the info still stands you can e-mail me @ vaderfixer@yahoo.com So I'm thinking 800 cfm holley DP Andy thrasher Apr 17th, 04, 9:15 PM Really need to know the whole combination to provide the correct answer. Even with all the info there will be many answers ranging from 3310VS THE BEST CARB EVER MADE :rolleyes: 750DP 750HP-DP 830DP Annular 830HP-DP 830HP Annular-DP 950HP-DP-Actual cfm of around 820-830. 850DP 1000HP-Actually around 870cfm If it is primarily a street driven car the 750DP would be good but undersized. Personally I wouldn't want to under carb a 468ci engine behind a 4spd and 4.10's. If you are a bit more concerned with performance and low ET's the 950HP would get my vote. And no they don't flow 950cfm.They flow 820-830cfm. | ||