carb size formula for street and race apps
what do yall think of this formula for sizing a carb to a particular motor
for street: cubic inches x max rpm x .85 divided by 3456
for race cubic inches x max rpm x 1.15 divided by 3456
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| Bernica |
11-18-2014 12:00 PM |
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| cycleguy55 |
11-18-2014 12:25 PM |
Quote:
Originally Posted by lon
(Post 1326651)
what do yall think of this formula for sizing a carb to a particular motor
for street: cubic inches x max rpm x .85 divided by 3456
for race cubic inches x max rpm x 1.15 divided by 3456
|
Would 'performance street' be somewhere in the middle? Something like: cubic inches x max rpm x 1.0 divided by 3456 |
| Dimis |
11-18-2014 03:25 PM |
Quote:
Originally Posted by lon
(Post 1326651)
what do yall think of this formula for sizing a carb to a particular motor
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1 x (Pick up phone) + (Dial) 502.759.1431 = best carb for any application ;)
Enjoy |
| lippy |
11-18-2014 04:04 PM |
That formula seems to work pretty well for my application. It gives a size of 850 and that's essentially what I have. But I agree you should speak with a carb guy and get him to optimize for you.
I hear very good things about ProSystems and AED. But several people swear by Braswell if you can afford the extra dough. Dave Braswell is apparently one of the top carb guys on the planet, so you may want to speak with him. Also, their carbs are not modified Holleys. They are 100% Braswell made and have some neat features and beautiful construction.
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| DanEC |
11-18-2014 04:47 PM |
Seems a bit short for the street - works out about 633 CFM for my 459 hydraulic lifter motor. Half way in between for street-performance works out about 745 CFM and that is probably believable.
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this formula is from the Edelbrock website
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| Bernica |
11-18-2014 08:00 PM |
Quote:
Originally Posted by lippy
(Post 1326679)
That formula seems to work pretty well for my application. It gives a size of 850 and that's essentially what I have. But I agree you should speak with a carb guy and get him to optimize for you.
I hear very good things about ProSystems and AED. But several people swear by Braswell if you can afford the extra dough. Dave Braswell is apparently one of the top carb guys on the planet, so you may want to speak with him. Also, their carbs are not modified Holleys. They are 100% Braswell made and have some neat features and beautiful construction.
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I went with Pro Systems. I did their initial spec questionnaire which asks all about your build. Then I ended up talking with Patrick about my specific uses of the car. Ended up with an 858cfm with manual secondaries and all the good stuff (race floats, etc). Patrick will tell you that once you have one of his carbs, you are part of the family. In my case, he just said not to ever touch it without calling him first. The Dude abides!:cool: |
| mrmustang |
11-19-2014 06:09 AM |
Quote:
Originally Posted by lon
(Post 1326651)
what do yall think of this formula for sizing a carb to a particular motor
for street: cubic inches x max rpm x .85 divided by 3456
for race cubic inches x max rpm x 1.15 divided by 3456
|
There is no magic formula that covers all engine configurations, the formulas out there are just a starting point and nothing beats an engine, in the car, on a chassis (forget about an engine dyno tune) dyno.....So with that said, what are your engine specs?
Bill S. |
| blykins |
11-19-2014 07:06 AM |
Exactly. Lots of things play into what size carb you need...engine efficiency being one of them.
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