ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Sunday, July 21, 1996 TAG: 9607220016
SECTION: BUSINESS PAGE: 1 EDITION: METRO
COLUMN: Gasoline
SOURCE: GREG EDWARDS
"Fill 'er up with high-test or regular?"
Some of us older folks remember the days when we pulled into a service station and a snappily uniformed attendant - or possibly a guy in a dirty T-shirt with a greasy rag in his back pocket - would walk up to the driver's side window and ask that question.
Decisions, decisions. Should we save a little money for the movies and put regular or low-grade, 35-cents-a-gallon gasoline in the tank, or should we give our car a treat and feed it some "high-test," the premium grade of gasoline, for a few pennies more? Was putting a tiger in our tank worth an extra buck?
Nowadays, with self-service gasoline stations dominating the marketplace, we pull up to the pumps and ask ourselves - not an attendant - the question: "Premium, mid-grade or regular?" A decision still has to be made.
And according to the American Automobile Association, many people are making the wrong choice and wasting money by putting a more expensive gasoline into their vehicles than they need. Buying a higher octane gasoline than our cars require won't give them more power, better fuel economy or cleaner engines, AAA says.
A motorist who uses premium, when regular will do, will turn $374 more a year into engine exhaust than she needs to, based on an average difference of 17 cents per gallon in price and an annual fuel consumption of 550 gallons, AAA says. The motorist might as well pile the money up in the driveway and set it on fire.
AAA quotes government and industry figures that show purchases of premium gasoline amount to almost 20 percent of U.S. gasoline purchases, although less than 10 percent of the cars on the road require premium gasoline for top performance.
But not everyone agrees people are buying too much premium. Not surprisingly, the oil industry doesn't.
Tom Hogarty, an economist with the American Petroleum Institute, a trade association representing the U.S. petroleum industry, said the AAA figures are wrong. They don't take into account the large number of light trucks and vans on the highway that benefit from higher octane fuel, he said.
Some cars may also be designed to use an octane rating just a little higher than what's available at the pump, meaning their owners should buy the next highest rating, Hogarty said.
Regular gasoline accounts for 68 percent of U.S. sales; midgrade 12 percent; and premium, 20 percent, Hogarty said. People are currently buying about the right amount of premium but too much regular and not enough midgrade, he said.
But Bill Berman of AAA said Hogarty is the one who's wrong and is using a different definition of what's premium than the automakers do when they specify a fuel for a vehicle.
Aside from whether the AAA's or the petroleum industry's is the correct position on the use of premium, burning the wrong kind of fuel in a vehicle has consequences other than the wasting of money.
A fuel's octane rating is an indication of how fast it will burn. Gasoline generally comes in 87 octane for regular, 89 for midgrade and 93 for premium. Higher octane gasolines, which are formed by adding ethanol or some other additive to the fuel, actually burn slower than regular-grade gasoline.
Some high-performance cars with high-compression engines require high octane gasolines to prevent engine knock, which is an engine noise and vibration cause by the premature ignition of gasoline in the combustion chamber. Engine knock can lead to loss of power and engine damage.
Modern cars that require premium gasoline have sensors that retard the ignition spark to prevent engine knock, if a lower-grade fuel is used. But premium gasoline should always be used in cars that require it, AAA says, because retarding the spark causes poor performance and lowered fuel economy.
But, again, AAA's real concern is that people who don't need premium fuel are buying it because they expect to get more power, better mileage or some other benefit. Vehicles that run well and don't knock or ping on regular gasoline will not gain from a fill up with premium fuel, the association said.
H.P. Marshall, a retired professor of mechanical engineering at Virginia Tech, suggests that people using premium gasoline drop down to the next lowest grade and see how the car runs.
Some new cars designed to use regular gasoline might even run less well on a premium fuel, according to Bob Warren, service manager for Magic City Ford in Roanoke. Using a higher grade gasoline in a car designed to run on regular can confuse the on-board computer with its sensors and valves that manage the operation of its modern automotive engine, he said.
Besides too low a grade of gasoline, knocking and pinging can be caused by mechanical problems such as poor timing, carbon build-up and faulty pollution-control equipment, Warren said. But the cheapest way to approach the problem is to first switch to a higher grade or different brand of fuel, he said.
Switching brands can help, AAA said, because the octane of gasoline may vary slightly from brand to brand from what's listed on the pump and may be just enough higher in a particular brand to prevent knocking without costing extra money.
Warren advises people to read the owner's manual that came with their cars to make sure they're using the right kind of gasoline. Unlike owner's manuals of years ago that went over a lot of basic stuff that people already knew, manuals with today's modern, computerized cars contain much essential information about the operation of the car, Warren said.
"You have to read that book," he said.
LENGTH: Long : 110 linesby CNB