This may be old news, but car mfr's are re-assessing their hp ratings in connection with a new SAE standard that is intended to more accurately portray "real life" horsepower.

I haven't seen any results for Nissan, but some of them are having to lower their previous ratings. I know, for example, the people over on the Acura forums are anguishing over the new numbers. The TL, to use a Maxima comparison, has been advertised at 270hp since its 2004 intro, but it will now be listed at only 258hp under the corrected standard.

I suspect our Maximas are going to hold pretty close to the advertised 265hp, but if anyone has info on the revised ratings, I'd like to see it.

 

Me too, sick of manfactures throwing crank numbers out, when we all know the wheel numbers are what really count...

 

No comment other than

There's a fair amount of evidence here than the 265hp/255tq in this engine may really be more like 275-280hp/260-270tq, so I don't think an SAE cerftified rating is going to drop the numbers at all. I suspect if Nissan does a 25th AE version this year they may bump the numbers up a tad to more accurately reflect reality, despite not making any changes. Sorta like how the "260hp/260tq" G35 sedan was uprated after a few years when it was really making more than 260/260 to begin with.

 

Both are important, but I wouldn't want to get rid of crank ratings. Knowing power at the wheels is just a little something us enthusiasts can be aware of and take advantage of that non-enthusiasts will not.

 

Agree, my point was manufactures will use the highest of the two for marketing purposes vice actual performance...

 

Well, actually, it appears mfr's were in some cases using things like special oil sumps (to reduce hp losses from crank "thrashing"), low-drag power steering pumps, and so on, to establish their advertised hp. The new SAE standard will require that the engines be dynoed using "real world" setups, just like on the actual cars rather than using special "test engines".

It would certainly appear Acura was using a ringer engine for their tests. That would help explain why the TL - with very similar engine output, weight, etc., feels less powerful than the Max.

The interesting part is that certain engines, such as the 'Vette Z06, actually gained hp. That one went from 500 to 505.

 

I must admit that I was a little skeptical of this report. So I sent a friend of mine -- who has access to SAE technical papers -- both quotes from Mike_TX who seems to know the most about this topic. Here is his reply:

"The story is pretty accurate on a whole. Each of the OEM's purchase competitive products for benchmarking and thus know what the true HP is. In general the Japanese companies inflate the numbers by rigging the tests as noted in the article, which until now was a 'legal' form of cheating (usually about 10% high)."

Good work Mike_TX! This is the place to get up to the minute information.

 

I don't know if Nissan has already started with this new rating system or perhaps they're tired of us holding their feet to the fire, but they do seem to have lowered their rating system for new models. Not just for the '04+ Maxima, but the 35th Anniversary 350Z is in no way ony making 13 more hp than the previous car. Most of the '287hp' cars are putting down 230-240whp on a Dynojet and I saw a dyno chart yesterday of a '300hp' car that put down 270whp with only test pipes. I was told the car put down 260whp in 100% stock form. The only real issure I have with the chart I saw was that it did not come from a Dynojet but supposedy they have their software calibrated to reflect Dynojet numbers. If the 300hp 350Z really does put down 260whp then we would have to call that underrated and certainly on a different rating scale.



As for the TL, I am not sure I buy the 258hp number. Those cars are much heavier than a Maxima and I have seen bone stock ones trap 98mph with luggage in the trunk. I am usually inclined to believe Hondas power ratings.


If some cars actually gained power with the new rating I bet the insurance companies are going to stick it to them, especially Dodge with the SRT4.

 

I'm not sure that the SAE certified rating methodology restricts a manufacturer from advertising an engine that makes say '250 certified hp' as only 210 or 230. I think it just says that you can't advertise more than 250.


But

 

I saw one with minor mods (300chp version) lay down 250whp/230 ft-lb, ive also seen the 05G35s put down the exact same #s.

 

I'll just say that I'm very skeptical of that blanket statement. There's the running joke that Japanese engines are rated in ponys and German engines are rated in horses, but I think that whole joke really had more to do with lack of torque due to smaller displacement Japanese engines. 10% sounds a little excessive. If that was true, a 270hp TL would drop down to only 243hp. 10% is a lot.

I guess we'll learn more as more and more companies switch to the new rating system, but it may be tough to get the whole story. From what I hear it's voluntary not mandatory, and if there are any "guilty" parties out there they may make improvements to their engines in the meantime so that when they go to certified ratings they don't look as bad, or maybe even "gain" some power. From a PR perspective, there are plenty of ways around this.

 

10% is def excessive....however every nissan I have come across has made the advertised power. Maybe I am lucky?

 

I don't understand what the point was then if they make it voluntary. But, if a company doesn't volunteer the true numbers, then that should raise a flag in itself.

 

Someone please post a link to the article

 

Tell that to the 5.5g guys with "255hp"

 

Are you on cook rock?

 

Mine dynoed 197 with a loss rate of 23% thats 255.84 hp. The 02 manual I saw dyno made 208whp (253.65), The rest were 4th gens dynoing in tthe 150s-160s. Guess Im just lucky.

SR20: yes, i smoke rocks on an hourly basis

 

I just got this confirmation from a friend. There is a bar graph on the paper's site about Toyota that did not copy here. See Post # 21 below for that graph.

http://www.detnews.com/2005/autosins...A01-283759.htm

Asians oversell horsepower
Toyota, Honda inflated claims of engine muscle; new tests force automakers to come clean with buyers.

By Jeff Plungis / Detroit News Washington Bureau
Wednesday, August 17, 2005

Horsepower rating corrections:
Vehicle ___ 2005 __ 2006
Acura MDX _ 265 __ 253
Acura RL ___ 300 __ 290
Acura RSX _ 160 __ 155
Chevrolet Corvette LS7
___________500 __ 505
Cadillac XLR _ 440 __ 469
Ford Explorer*210 __ 210
Honda Civic _ 200 __ 197
Lexus LS430 _ 290 __ 278
Pontiac G6 __ 200 __ 201
Toyota Corolla 130 _ 126
Scion xB ___ 108 __ 103
*New powertrain

WASHINGTON -- After years of touting ever higher horsepower numbers to win new customers, Toyota Motor Corp., Honda Motor Co. and possibly other automakers are now backtracking on some of those claims.

Strict new tests developed by the industry's top engineering group are prompting the carmakers to roll back horsepower estimates on several key vehicles, including the Toyota Camry, America's best-selling car, and Honda's luxurious Acura RL. For the 2006 model year, Toyota says its Camry equipped with a 3-liter V-6 engine generates 190 horsepower. In 2005, Toyota said the same car with the same engine had 210 horsepower.

The revised ratings comply with new Society of Automotive Engineers standards designed to eliminate subjective interpretation in establishing horsepower claims.

While Toyota and Honda are retesting their entire vehicle lineups, other automakers generally are retesting only cars and trucks with updated powertrains. Over time, most automakers are expected to comply with the new guidelines, and horsepower ratings for other vehicles could be revised.

Detroit's automakers say they have been conservative in calculating horsepower and don't expect to have to reduce horsepower ratings on many vehicles. In fact, after retesting, the Big Three have revised horsepower ratings upward on several vehicles.

The changes are likely to raise questions among customers. "Horsepower is a big draw," said Jim Sanfilippo, an automotive marketing expert at AMCI Inc. "This is at best difficult to explain," he added. "Toyota and the other companies better have a good answer when customers ask questions about what happened."

The Camry has been a best-seller for years and a linchpin in Toyota's strategy to increase sales in North America.

Honda is reducing horsepower ratings across its Acura brand. The flagship RL sedan will lose 10 horsepower, to 290 from 300. The popular MDX SUV will fall from a rating of 265 to 253. Less powerful models such as the Honda Civic will see smaller reductions.

"From what we've seen so far, this is going to affect the Japanese and the Europeans a lot more than the domestic manufacturers," said Mark Brueggemann, senior market analyst for Kelley Blue Book. Brueggemann said engines have not changed, so car shoppers won't notice any drop-off in performance during test drives. But consumers look at horsepower when they're deciding which models to test drive and buy.

For example, the 190-horsepower Camry will compete against a new Hyundai Sonata that advertises 235 horses under the hood. "This could have a possible effect of eliminating a car from consideration," he said.

The changes are already having an impact among die-hards who prowl Internet chat rooms like AutoWeek's Combustion Chamber, Edmunds Town Hall and GM Insidenews. In a recent posting on AutoWeek's site under the heading, "Acura hurt by new SAE hp standard -- numbers were inflated," one chatter said: "Bottom line is if you sell me a car with the promise of say 300 hp, I want my 300 hp!"

Toyota had to advertise based on the new SAE testing procedures because of a California state law, said company spokesman Bill Kwong. The company then decided to use one set of ratings for all of its U.S. ads. "We hope it won't be confusing," Kwong said. "If you drive a 2006 or 2005, it drives the same. It's the same car. Customers are not getting anything less or anything more."

Honda spokesman Mike Spencer predicted it would take a few years for customers to understand the changes, but eventually all manufacturers will be using the new SAE tests. "We've been using SAE procedures all along, it's just that SAE changed their procedures," he said.

The news is better for General Motors Corp. and Ford Motor Co. Some models such as the Chevrolet Corvette and the Ford Fusion sedan are faring better under the new testing procedures, which could give them a much-needed edge in the marketplace. The Cadillac XLR roadster with a Northstar engine saw its horsepower rating go from 440 to 469.

"We have confidence that our customers will get the power they pay for," said GM spokesman Thomas Read. "It's going to give the consumer a better rating for their engine."

As the new testing procedure is phased in, it may be tricky for consumers. For example, the Ford Five Hundred sedan is rated at 203 horsepower for 2006, the same as the 2005 model. But the 2006 rating does not reflect the new SAE testing procedure, because Ford is not going to the expense of retesting its existing engines, said company spokesman Nick Twork. The company will use the new SAE test only when it overhauls a powertrain, as it did for next year's Explorer, Twork said. But Twork said Ford does not expect significant drop-offs in horsepower as the new test is phased in. When Ford unveiled its midsize Fusion sedan in January, it projected 210 horsepower. When it was tested under SAE's official protocol, the engine received a 221 horsepower rating, Twork said. "We typically like to underpromise and overdeliver," Twork said. "We feel we've been pretty conservative, and we don't anticipate any major changes."

DaimlerChrysler is using the new SAE procedures on any model with changes in its powertrain, said spokesman Cole Quinnell. He said the company expects new ratings to be within 3 percent of the old ratings, with some going up and some going down. DaimlerChrysler is making a special effort to test high-performance models, like the Dodge Viper V-10. The Viper now tests at 510 horsepower, up from 500 in 2005. "We've wholeheartedly embraced the new procedures," Quinnell said. "We hope it shows our credibility."

When an engine doesn't measure up to its advertised performance, it can hurt. Mazda Motor Corp. reintroduced the rotary engine with its RX-8 sports coupe a few years ago. It had a high horsepower rating. But when drivers got inside, they discovered weak low-end torque, meaning that the rocket-like acceleration they'd expected was missing.

Ford pulled its high-performance Mustang Cobra from the market a few years ago when enthusiasts complained the engine did not live up to its billing. Ford tweaked the engine before selling it again.

SAE says it tightened its horsepower rules when engineers noticed some elements in the old test were prone to interpretation. "We tried to tighten language that was open to interpretation," said Dave Lancaster, a technical fellow at General Motors Corp. who chaired the SAE committee that wrote the new requirements.

Under the old testing procedures, there were small factors that required a judgment call: how much oil was in the crankcase, how the engine controls were calibrated and whether a vehicle was tested with premium fuel. In some cases, the little adjustments added up to a big change in horsepower ratings. The new SAE procedures allow less wiggle room.

John Di Pietro, road test editor at Edmunds.com, said the drop in horsepower ratings for '06 models they have tested are not especially dramatic. For vehicles such as a midsize family sedan, the reputation of the manufacturer will likely be more important, Di Pietro said. "It will be up to the salesman to ensure they understand the engine hasn't actually lost any power," he said.

You can reach Jeff Plungis at (202) 906-8204 or jplungis@detnews.com.

 

i wonder whats going to happen once they retest some of the nissans that are out.

 

Scary Stuff.... See if you can find stats for the VQ35DE

 

 

I expect that every NEW Nissan vehcile since 2004 will be pretty close.

 

Rounding 197 to 200 hp is not as bad as 190 to 210. Not only did they round to the nearest 100 hp, but exceeded it by 10.

 

I sure it was not rounding. They used the loopholes in the old test method to tweak extra HP from a test engine that would not show up in a production engine. Misleading advertising.

It appears (but is not certain) that Nissan did not engage in this kind to tweaking -- particularly in their most recent engine test results.

 

5.5gens have been calculated to make 245hp/265lb ft. of tq. based on dyno runs from different members, me included. We're getting lower HP than advertised, but the TQ is much higher.

Nissan does play with numbers.

 

You are looking at different HP numbers. The adversited number is at the flywheel of the engine mounted on an engine stand. The dyno runs you discuss are base on HP at the drive wheels based on an engine mounted in a vehicle transmitted throught a transmission and drive shafts. There is always loss between the flywheel and the drive wheel, so the number should be less. What this tells me is that Nissan understated the advertised torque at the flywheel.

 

SilverMax_04 is right...and please don't talk about how the dyno automatically adjusts it's nuumbers to take into account the loss of power through the drive train. I have seen some dyno sheets here that show 265 HP or more claiming that the reason for the number is that, while the dyno only recorded 215 at the wheel, the dyno KNOWS that there is a xx% loss in the drivetrain and accounted for it, resulting in the 265 HP figure. Unless the dyno has a crystal ball, there is no way it can really know how much is lost through the drivetrain. I say let every vehicle be tested by HP at the wheel under strict conditions. That way we will all know what kind of power each vehicle puts to the pavement.

 

Mine made 255.8/277.92 (197/214 whp/wtq)

 

What kind of strict conditions? I would assume you mean that they ALL need to be tested at the same facility, on the same kind of dyno, at the same temperature, the same humidity, etc.

 

also, that is assuming there is a 12% loss thru the drivetrain. The real figure for 6MT is 18% and the 4AT is 23%. The 5AT, I have yet to see a dyno for.

 

There is enough variability between each OEM's bench dyno for recording flywheel HP. When you then add the additional variables that occur when measureing drive wheel HP, the numbers would mean even less than they currently do.

 

We can ask for tighter controls and still be realistic. I am talking about those variables for which we can easily account like the ones quoted in the article (oil level, grade of fuel used, pulley size, etc.) that match what the car would use under the same conditions the manufacturer provides/suggests to the consumer.

You have a point but you have a better understanding of dynos than I do, I don't know the particulars. What additional variables occur when measuring drive wheel horsepower that do not occur when measuring flywheel horsepower? If you are talking about the variables of power lost through each vehicles drivetrain, that is exactly the kind of variable I want to have influence over those whp numbers. Is there no way (air temp and pressure, altitude, etc notwithstanding) to be able to say "Hey, that Toyota, from the factory, regularly produces xxx HP and that Nissan xxx HP at the wheels." and have it mean something?

 

So are you guys saying all these dyno #'s mean nothing, whether neasuring from the crank, or @ the wheels?

 

That's my point exactly NmexMAX. I think all that matters is what we can typically expect from a given vehicle's drivetrain. That is engine, transmisiion, everything that comes stock on the car to put power to the pavement. I'd like to think that there is a reliable way to get at least an average number that means something, that takes into account what the car is made of without trying to account for the varying environment in which the car will be used.

 

That's what the SAE correction factor is for

 

That is not my point. Car manufacturers have selling success using advertised HP numbers. SAE has revised the accepted basis for making those bench measurements to determine advertised HP. The HP at the wheel will always be less than this number (unless the manufacturer really understates the bench HP). There are also more variables when measuring wheel HP -- which gear is being used, is the trannie auto or manual, how much air in the tires, etc? No manufacturer will want to use a number that is harder to replicate and is lower than the numbers quoted by other manufacturers.

Keep measuring your wheel HP, but the manufacturers will continue to only use the higher HP number -- witness the "cheating" by Toyota and Honda to get the highest number they could justify by bending the previous rules.

 

Are you serious? No one in these forums with an '04 or '05 SE/5AT has baseline dyno'd their ride....

 

I havent seen one....but if you've got one go for it.