Andrew/David/Peter (in alphabetical order!)
Many thanks for your replies, from across the world by the looks of it. I'm intrinsically attracted to efi vs a carb from my experiences with other cars: currently I've got a '90 Chevy truck with a 5.7L/350 small chevy and a 5-speed manual, and a '95 Corvette 5.7L LT-1 auto which I'm supposed to be selling to make way for the Bristol. The truck is 2-barrel tbi, does about 19-22mpg imperial and revs at 2200 at 80mph. It weighs 100kg more than the Bristol & has worse aerodynamics. The Corvette is port injection, does 22-30mpg and has the same rpm at 80mph as the truck. Prior to the truck I had a '54 Ford Popular (Anglia to David I'd guess) with a stroked (to 6.3L/383) small Chevy, 3 speed auto and a Holley vac secondary carb, which did 11-15mpg, can't remember the gearing alas. Admittedly the Pop hot rod was a hoon-around sort of car but the truck and the 'Vette both use almost half the fuel of both the Pop and the Bristol. The Bristol revs at c.2900 rpm at 60, so with a 5500rpm red line that gives a theoretical top speed of c.120mph. I attribute the huge fuel consumption differences to 2 things: the gearing and efi. Surely even tbi will atomise the fuel much more finely, and control the mixture much more? Plus the Holley's self-learning via it's wide-band oxygen sensor (once initial paremeters are entered) suggests it will continually refine and control it's fuelling? So I'm thinking that even a modern carb will be less efficient than efi?
But I'm not an engineer - far from it, I'm just someone who's fscinated by how cars work and loves making them run better. So keep sending in the advice! I have lots to learn.....
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