First of all, it is quite normal for your car to have disproportionately
lower gas mileage that a heavier vehicle. The reason is simple. When you
have a big engine on a relatively light vehicle (your "little" Newport
compared to that RV), your engine is running statistically at lighter
loads. Internal combustion engines (especially throttled spark ignited
engines) are more inefficient at light loads. That's why most high powered
cars are gas guzzlers even when not driven fast. As mentioned in other
responses, the modern engine has better fuel management, but that will only
make a huge difference if your fuel mixture is WAY off. If you are say
only 5% richer off the soichiometric air/fuel ratio, you only loose about
5% fuel economy compared to an EFI engine on the same vehicle. Now, in
theory, the advantage of multiple carburetion is that at part throttle, you
can run off two relatively small venturies, so (again, in theory) your
throttle response and fuel delivery at low speeds/loads should be descent,
while you still get a low restriction fuel delivery system at full
throttle. But I have heard that its very tough to keep these carburetors
well adjusted, I don't know. The other very important parameter in fuel
economy is what rear end gears you have. Most Imperials are geared high
(all 60's Imps had 2.94) which keeps the revs down and saves fuel (as well
as give you an excellent top speed potential). My guess is your Newport
has 3.31 or 3.55. If my guess is right, that could be another source of
your high gas bill. Installing taller gears will cost you (in addition to
the cost of the gears!) in terms of acceleration at low speeds, but you
will get better fuel economy, lower engine noise, and better top speed. As
for the tires, one of the major advantages of radial tires was improved
fuel economy. But don't expect to get 14 mpg by just changing tires!
D^2
At 09:26 PM 1/18/2002 -0500, you wrote:
>Just curious ---- A friend of mine owns a 35 ft motorhome with a V 10 triton
>engine and weights at least 18000 LBS makes 8 miles per gallon. Me with my
>55- 331 cid Newport 2- 4 barrel carburetor weighing around 5000 LBS making 8
>mpg also ---if I am on a turnpike. I am sure some of you with the 413 and 440
>engines with a single 4 barrel carb. are experiencing the same thirsty
>powerplants. Will new steelbelt tires improve gas mileage, still have the
>old H 78x 15 4 ply Remington Cushion Air tires. Any thoughts on this . I
>would appreciate very much.. Sincerely Dieter in Pa 55 Newport
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