Author Topic: Large or small main air bleed?  (Read 1761 times)

Offline 68rs/ss

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Large or small main air bleed?
« on: March 11, 2024, 06:41:59 PM »
Just curious and looking to be educated some. I am wondering if there are any benefits to running either a small or large main air bleed carb on a performance build? I've done a few carbs that were all newer and were all LMAB. I realize the big bleed carbs use bigger jets and bigger primary rods while the smaller bleeds use smaller jets and rods. Is one better than the other for performance or tuning? I see in Cliff's book that there is a section showing how to change and add restrictions to the bigger bleeds, thus, using the smaller jet and rod combination after.
At the end of the day, would either work equally well or is there a benefit somewhere to using one or the other? Guessing the A/F would be similar if both were tuned to a same application, just a different way getting there?
Hope this is a dumb question.
Phil

Offline Cliff Ruggles

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Re: Large or small main air bleed?
« Reply #1 on: March 22, 2024, 01:43:33 AM »
I prefer the smaller MAB's if I'm building a carb for one of my engines.  It just takes too much jet for the large  MAB models to do the same thing.....

Offline Erick

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Re: Large or small main air bleed?
« Reply #2 on: April 26, 2024, 05:40:20 AM »
Was there an "official reason" for this change?

Offline Cliff Ruggles

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Re: Large or small main air bleed?
« Reply #3 on: April 30, 2024, 01:15:03 AM »
Ever tightening emission standards for the most part.  For quite a few years they decided to go that direction, then went to the excellent single MAB design instead and stuck with that instead....