Regular or premium unleaded? Follow the manufacturer's recommendation.

Dear Car Talk | May 01, 1996
Dear Tom and Ray:
Our service
man tells us that we would get better mileage as well as a
cleaner engine
if we use unleaded premium gas instead of the recommended --
and cheaper --
plain unleaded. We do not have money to waste. What do you
say? -- George
TOM: Well, if you had money to waste, I'd say sure, use
premium unleaded!
RAY: A waste of your money is ALL you'll get from premium
fuel in your car,
George. Some cars require premium gasoline because they have
high
compression ratios and require the higher octane fuel to
prevent pinging.
But yours isn't one of those cars.
TOM: You won't get measurably better mileage, you won't get
a cleaner
engine (because almost all regular unleaded has the same
detergents found
in premium gasolines), and your car will create more
pollution.
RAY: Sounds like a deal, huh?
TOM: So stick with the manufacturer's recommendation for
octane. No more,
no less. And save your hard-earned money for luxuries you'll
be able to
really enjoy-- like crushed Corinthian seat covers.
Our service
man tells us that we would get better mileage as well as a
cleaner engine
if we use unleaded premium gas instead of the recommended --
and cheaper --
plain unleaded. We do not have money to waste. What do you
say? -- George
TOM: Well, if you had money to waste, I'd say sure, use
premium unleaded!
RAY: A waste of your money is ALL you'll get from premium
fuel in your car,
George. Some cars require premium gasoline because they have
high
compression ratios and require the higher octane fuel to
prevent pinging.
But yours isn't one of those cars.
TOM: You won't get measurably better mileage, you won't get
a cleaner
engine (because almost all regular unleaded has the same
detergents found
in premium gasolines), and your car will create more
pollution.
RAY: Sounds like a deal, huh?
TOM: So stick with the manufacturer's recommendation for
octane. No more,
no less. And save your hard-earned money for luxuries you'll
be able to
really enjoy-- like crushed Corinthian seat covers.
Got a question about your car?