Thread: 2BBR vrs 4BBR?

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Yes, I'm a newbie.... Besides 2 and 4 what is the main differences between a 2BBR and 4BBR? Will a 4BBR use more gas then a 2BBR?

The four barrel uses the front two barrels (primaries) until the accelerator is pushed past a certain point and then the back barrels (secondaries) open up and supply more fuel. Some secondaries are opened mechanically by carb linkage and some are opened by vacuum generated by the engine.

More gas?...YES.

actually a 4 barrel can be more fuel efficiant than a 2 barrel, that is as long as you keep your foot out of the secondarys.

Originally posted by stepside454
as long as you keep your foot out of the secondarys.

Yea....... that'll happen

Peddle is designed to go all the way to the floor, It's a rule ..... I think.

Originally posted by stepside454
actually a 4 barrel can be more fuel efficiant than a 2 barrel, that is as long as you keep your foot out of the secondarys.

I remember hearing that 30 years ago.
Is it really true?
I guess it could be - if the 4BBL primaries are smaller?
Its that 'keep your foot out of it' thing.

Thats hard to do!

I suppose the mechanical rigs were better than vacuum in saving gas or vice versa?

Bert

More selection of jets and tuning info make a 4bbl. easier to tune, whether for power or mileage. Highway use, I consistently get more MPG out of a 4bbl.