EYES ON THE ROAD
By JOSEPH B. WHITE

Counting Horses

New Standards for Gauging Horsepower
Are a Sensitive Subject in Car Business
August 22, 2005
Honey, they shrunk the horsepower!

Consumers who pay attention to horsepower numbers -- and there are a lot of them -- may have noticed that some 2006 cars have less advertised horsepower than they did for 2005. The Toyota Camry, for instance, the No. 1 selling car in America, will be advertised for 2006 with a 190 horsepower, down from 210 in 2005. The Acura TL, rated at 270 horsepower in 2005, is rated at 258 horsepower in 2006.

None of these cars is likely to feel less powerful than before. Nothing's really changed about the engines. What's changed is the way auto makers test cars to determine advertised horsepower.

Measuring horsepower in an automobile isn't like measuring the length of a football field. In the latter case, 100 yards is a 100 yards. But when it comes to horsepower, there's been latitude for a certain amount of what General Motors technical fellow David Lancaster calls "creative interpretation." Under the Society of Automotive Engineers' former engine-power-testing protocols, established in 1990 and reaffirmed in 1995, Mr. Lancaster says auto makers didn't necessarily have to account for such things as the power loss caused by a power-steering pump, or the effect of electronic controls.

There were other loopholes. A car maker could test a car using higher-octane premium gasoline -- which would boost an engine's performance -- even if consumers were told that premium wasn't required. (In fact, for most cars, premium gas isn't really a requirement.)

Under the new SAE rule, car makers are supposed to conduct their horsepower tests under conditions that are closer to the real world. If the car is supposed to run on regular, then regular gas must be used during the test. And components on the test engine must be production components.

"We put language in the standard that says explicitly that the intent of the standard is to give an accurate representation of power in the vehicle," says Mr. Lancaster, who headed an SAE committee that redrafted the procedures.

GM says it intends to take an extra, optional step and "certify" all its horsepower ratings. Among other things, the procedure to certify horsepower figures involves conducting tests in the presence of a witness. European auto makers are already subject to a similar procedure. But while the No. 1 auto maker intends to test new engines under the new standard, but won't go back and retest existing power plants.

At Ford, Karilyn Lytle, manager of V-engine and performance evaluation, says the new rules will have a "very minor" impact. Ford has a policy of testing three production engines three times each to get its horsepower numbers. If the result of those tests is that an engine scores 197 horsepower, "we no longer round" to get to an even 200.

Ford doesn't plan to go the extra mile and "certify" its horsepower ratings, Ms. Lytle said. The process costs money and takes time, and "we haven't felt the need." Like GM, Ford is re-rating engines as new models or new engines come into production.

That's the policy Nissan is following as well. Nissan has propelled its recent recovery in the U.S. market by offering models with more horsepower than its main rivals in several important market segments. But since Jan. 1, when testing to the new standard was required, Nissan has only come up with one new engineapplication to test under the new rules, says company spokesman Dean Case. That model, the Infiniti FX 45 luxury crossover sport utility, is rated at 320 horsepower for 2006, using the new SAE rules. The 2005 model was rated at 315 horsepower -- but Mr. Case says the 2006 would have had an even number if it had been evaluated under the old regime.

By contrast, Honda re-tested all its engines to the new standards, says spokesman Mike Spencer. For Acura, Honda's luxury division, power numbers decreased by 5 to 12 horses, depending on the model, he says.

"We re-tested everything right away," Mr. Spencer says. "We want to make sure consumers have the most up to date and accurate information."

Doug Murtha, corporate product-planning manager for Toyota's U.S. sales arm says the company tried to re-test as many 2006 models as it could. "The majority of the '06 model engines will have been re-tested by introduction," he says.

For Toyota, the new rules mean some changes in practice. The V-6 Camry had been tested using premium fuel. But Toyota doesn't label the car as "premium fuel required." So now the Camry will be tested using regular gas.

What difference does all this make? The performance of a Camry won't change because it has a lower-rated horsepower.

But in the more-is-better world of automotive-power ratings, it's not necessarily a good thing to have a mid-size car that was rated at 210 horsepower drop back below the 200 horsepower number -- which is now the magic number in that segment.

The move to inject some more rigor into the business of horsepower claims touches some sensitive nerves in the car business. In Detroit, the new horsepower rules have been spun as a needed antidote to envelope pushing by certain Asian auto makers -- a Detroit News story last week on the subject was headlined "Asians Oversell Horsepower." In Motor City West, otherwise known as Los Angeles, there's a simmering suspicion that rivals in the Motor City are spinning the new standards to maximum advantage.

The good news for consumers is that the new standards appear to close some loopholes, and should make for advertised horsepower ratings on future vehicles that come closer to reality. Of course, a horsepower figure derived from lab testing isn't going to correlate exactly to the performance delivered to real wheelson a real road, industry engineers say. So enthusiasts who like to test their rides on a chassis dynamometer will still have something to do.

The real challenge for the next several years will be figuring out which cars have been tested under the new SAE standard (which you could call the Truth in Horsepower protocol), and which have been tested under the old Room for Interpretation standard. Some car makers (Nissan for example) are spelling out which cars are tested under the new SAE J1349 protocol in press materials.

Ford's Ms. Lytle suggests a simple way to avoid anxiety about all this: "Drive it and see if you like the performance.

Select premium unleaded gasoline with an octane rating of 91 (Research Octane Number 96) or higher required for optimum engine performance. If 91 octane cannot be obtained, you may use unleaded gasoline with an octane rating as low as 87 (Research Octane Number 91). Use of unleaded gasoline with an octane rating lower than 91 may result in engine knocking and signifi- cantly reduced performance. Persistent knocking can lead to engine damage and should be corrected by refueling with higher octane unleaded gasoline.