Efficient Carburetors?

[stangmon97]

Hi guys, I'm new and this will be my first thread but I'm on a mission.

Im 18 and I started the restoration on my second car and soon to be daily driver- a 1949 Buick Super fireball 8- 45,632k miles

it has a 248 c.i straight 8 with 110 hp that runs amazing

but the problem is...as you could imagine...I'm getting terrible gas mileage, 5 mpg around town MAYBE and 10 MAYBE on the highway. The engine has been totaly cleaned out, re-tooled and re-sealed

So my question to everyone here is what they know about efficient carburetors,

I've looked into:
Predators
Ellison's
Kendig's
Woodworth's
Fish's
and of course the Pogue but excluding the pogue, which is the best? benefits and downfalls? tips? any kind of advice?

thanks- Anthony

[Pinhead]

If you're only getting 5 to 10 mpg I would be looking into the engine before the carb. What's the compression ratio? Of course mixture preparation before it gets into the cylinder is important, but it's what goes on inside the cylinder that nets the real good MPG...

[stangmon97]

[quote=Pinhead;5675]If you're only getting 5 to 10 mpg I would be looking into the engine before the carb. QUOTE]

i cant say its exactly 10 on the highway, once the car gets about 55-80 mph it gets somewhere between 15 and 20mpg, but from the speeds of 0-50 it sucks up gas, that and the engine has already been overhauled once =\

[Brian P]

All my carb fiddling experience is with motorcycle side-draft constant-velocity carbs; you can do things with those that can't be done with traditional automotive fixed-venturi carbs.

That engine layout with a single carb, no matter what kind it is, is going to have one troublesome issue: cylinder-to-cylinder variation. The cylinders closest to the carb will be getting something different from the cylinders at each end.

Is that engine a side-valve (flat-head)? If so, they're inherently less efficient than overhead valve engines.

Don't forget ignition timing, either.

Don't hesitate to put modern instrumentation on your old-school engine. A vacuum gauge and an air/fuel ratio gauge might shed some light on what's going on.

[stangmon97]

Originally Posted by Brian P

Is that engine a side-valve (flat-head)? If so, they're inherently less efficient than overhead valve engines.

it is an overhead valve engine

[Pinhead]

That straight-eight wold look mighty fine with two banks of four motorcycle carbs on the side of the engine. Would probably run a lot better and get better mileage to boot!

[stangmon97]

Originally Posted by Pinhead

That straight-eight wold look mighty fine with two banks of four motorcycle carbs on the side of the engine. Would probably run a lot better and get better mileage to boot!

well what are you suggesting

[Pinhead]

Something like this.



Or this.

[stangmon97]

that would be sick, but how would I be doing as far as mpg with that kind of setup

[Pinhead]

I would be crazy to try to put a MPG figure on the combination. However, as BrianP said,

All my carb fiddling experience is with motorcycle side-draft constant-velocity carbs; you can do things with those that can't be done with traditional automotive fixed-venturi carbs.

Also, as he mentioned, you may want to install a more modern ignition system with vacuum advance. That alone could net 20% gain (as stated by Steve Davis HERE).