Premium gas? Not in my Ford! Or my Lexus, or my Mercedes...

Ford Motor Co., which currently sells one trim level of one model that requires premium fuel, is now bragging in a press releases that not one of the cars and trucks in its 2009 lineup (except that one trim level car) will require premium fuel.

That's right, a car maker that essentially does not make and has not made something is pleased to announce and that it will continue not making that thing, all in the name of saving its drivers cash. From the release:

With per-gallon prices hovering around $4, customers are sensitive to every penny spent at the pump, and Ford Motor Company is leveraging technologies to help consumers avoid an even further hit to their wallets. Ford, Lincoln and Mercury vehicles, including luxury models like the all-new 2009 Lincoln MKS, run -- and run well -- on regular unleaded gas, a true competitive advantage given today's skyrocketing fuel costs.

Whether this is news or just some half-baked piece of public relations spin is beyond this forum's scope. But it does raise the endlessly debated topic of whether most cars, including high-end, $80,000 European luxury machines, actually need the high-test fuel that their user manuals so strenuously recommend.

The number of cars requiring or recommending premium has exploded in recent years. According to Kelley Blue Book, fully 279 current-year model trim levels fall in those categories, or 14% of all trim models for all models of cars available. That's up by two-thirds from 2002, when 167 cars and trucks, or 7% of the total industry fleet, called for the pricey petrol. That's a startling increase, especially since the underlying technology involved -- the internal combustion engine -- hasn't changed that much in the last six years.

The issue here is knocking, which is what happens when some of the gasoline in a cylinder ignites at the wrong time. That's more likely to happen in engines that run hotter or have higher engine compression. And due to some complicated issues involving organic chemistry, the higher the octane rating, the less likely that is to happen.

As Ford points out in its release, the only car it makes that can't run on regular unleaded is its Shelby GT500, which has an engine with a supercharger that can increase temperature and compression. The reason that Ford's fleet can run on the cheap (OK, not quite as ungodly expensive) stuff is essentially because its engines don't run that hot, don't have turbochargers or superchargers or don't have particularly high compression.

Is that the case for other car makers? Few can agree on this. Mercedes makes 38 vehicles for which premium gasoline is recommended. That turns out to be every model Mercedes sells, according to a spokesperson. And Eric Noble, president of auto consultancy the Car Lab, says that "there are no false premium fuel stickers on gas caps," arguing that with gas at $4 plus, car makers would prefer to advertise their cars as Ford has: cheaper to run.

Defenders of the 92 octane juice claim it boosts performance. Indeed, Ford claims that it adds five horses and four foot pounds of torque to its new Lincoln MKS sedan.

Yet according to an article in Scientific American, most cars don't need anything more than the 87 octanes delivered by regular gas, and a few years ago, a spokesman for Porsche admitted that the fancy German cars, all of which come with recommendations to use premium fuel, "will run on regular fuel without damaging the engine." Some critics even suggest that car makers use a premium recommendation (rather than a premium requirement) as a kind of status add-on, making the car seem fancier.

The debate may rage, but consumers are voting with their wallets. With the spread between regular and premium widening to as much as 40 cents lately, sales of premium have been tumbling, down to about 8% of the market according to data from the U.S. Energy Information Administration, from 16% in 1997. And with 35.6 million gallons of premium fuel sold a day, 2007 was the worst year for premium since 1983.

-- Ken Bensinger

Photo: Karen Bleier / AFP/Getty Images

Comments

[Alex]

I have Toyota Sienna 2004 (6 cyl., 3.3.L) and I’ve made clear experiment: 15K on 87, 15K on 91, 15K on whatever is cheaper (87, 89 or 91: 91 first, 89 if it costs less then 91 over 10 cents per galon, or 87 if it costs 20 cents less compare to 91 or 89 if it costs 10 cents or less over 89 at the gas station of fueling). Also, I tried to find the best deal in the area of drive. During the experiment I kept records of the cheaper gas and adjusted results at the end of every 15K. The result was obvious to me: it doesn’t matter what gas are you using – the spending per 15K would be pretty much the same. So, if 91 is not required, there is no big difference (less than 2% of total spending).

[Bob Greenwell]

will ethinol harm my 2003 Ford Crown Vic?