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The truth about GROSS hp vs NET hp

The truth about GROSS hp vs NET hp

The examples in this article hasn’t aged well as 99.99% of automotive specs sheets nowadays only show net horsepower ratings, but it still makes for interesting reading, especially as there are still a couple of hold-outs advertising gross horsepower in this day and age. We led the way back then in exposing this practice.

I just got the press release for the new 2008 Chevy Avalanche, to be launched mid-October, claiming their 5.3-litre V8 to have 355 hp. I also read a review in Wheels magazine where the writer assumes the Tahoe has 355 hp, and that the Murano has 265 hp. And then there is another review on AutoMiddleEast where they use Ford ME’s explanation that net hp means power at the driven wheels. Also, a lot of people assume that since Nissan ME claims the Infiniti G35 has 330 hp locally, the American-market models have more catalytic converters or something to reduce their power to 306 hp. They are all WRONG!

I didn’t spend four years in journalism college, so I am not a “professional” writer. I did spend more years than that studying engineering in college. But that’s not why I know the difference between GROSS power and NET power. I know it because I simply looked it up on the internet. Back in the last century.

GROSS POWER
Before 1972, most American automakers rated their engines in gross hp, under Society of Automotive Engineers (SAE) standards. Gross hp was measured using a test engine running on a stand without pumps, extra fans or anything else installed. It is the maximum theoretical value of power, and nowhere near what a car gets on the road. Gross hp figures were so often manipulated by car manufacturers and marketers that the SAE decided to adopt a new standard of power that took accessories into account.

NET POWER
The SAE chose to use net hp ratings, which measures engine power at the flywheel, but still not counting drivetrain losses. It does take into account all accessories, intake and exhaust systems. By 1972, most carmakers quoted power exclusively in net hp. Net ratings are more accurate than higher gross ratings. Many people incorrectly report net hp as being measured at the drive wheels. They confuse net hp with wheel hp, which is even lower. Wheel hp is what you get when power at the drive wheels is measured using a dyno. The worldwide standard remains net hp however (whether under American SAE, European ECE, German DIN or Japanese JIS rules). The same story applies to all torque ratings too.

The Middle East seems to be the only market in the world which reports power in gross figures and gets away with it due to the ignorance of the traditional media. Kudos to Germans for sticking to the net power standard here.

Change is happening with the others though. While the Avalanche press release is an oversight, General Motors, Nissan, Toyota and others do mention “gross hp” in most advertising materials nowadays, though the public doesn’t know the difference. So people continue to assume that the 158 net hp Toyota Camry is a lot less powerful than the 187 gross hp Honda Accord. Chevy and Toyota even jump between net and gross for different models, as do many of the “comprehensive” car buyer guides in most local magazines. What a mess.

We exclusively list NET hp for all cars on this website (except maybe for Chery, but give them a break).

What do you think?

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Comments

  1. Dude, let me be the first one to THANK YOU soooooooooo much for this.
    can you put this up on the front page please please. in CAPS and BOLD.

    everyone i meet tells me the wrong bhp numbers for their cars and they say since its gcc spec, less emission standards etc bullcrap. i try not to laugh real hard right in their face since they have fallen for the sales talk. :mrgreen:

  2. I have heard that the petrol in UAE is also having high sulphur in it so cars with direct injection has to be reworked to use it without damaging the engine so this results in further bhp loss

    Is that true and can you give more details on that?

    I have also seen that Infinity guys lie about the bhp by using the gross figure for publicity

  3. Mashfique Hussain Chowdhury Author

    It is true that Lexus simply removed the direct injection feature from their IS, GS and LS models, but they do give the correct net hp ratings for the GCC. Direct injection has problems with high-sulphur petrol, which apparently we in the GCC have. America reduced sulphur in their fuel back in the late 90s.

    Oddly enough, VW GTI and BMW 335i turbo engines also have direct injection, but I have no idea how they manage in this region. Power ratings are advertised the same. Time will tell if the engines hold up.

  4. Mashfique Hussain Chowdhury Author

    I just found this article:

    http://www.middle-east-online.com/english/?id=11417

    It says Saudi has high-sulphur petrol while UAE has lower sulphur. But the GCC is considered one market, so the same cars get imported to most countries in this region.

    I guess the BMW and VW turbo motors can survive in the UAE at least.

  5. what about the new porsche cayenne (it has direct fuel injection) 😐

  6. Dear Author,

    Your explanation is absolutely correct however, internet information is not always accurate. Your description of Gross hp is correct, however net hp is with all accessories fitted, and hence the net varies from region to region based on the specs of the vehicle which will be different in accordance with local regional specs such as GSO, SASO, GOM, US, JAPAN, North America, Latin America etc and the list goes on. Also if you are well aware that nowadays many manufacturers are putting net hp. And yes Honda Accord has more hp than Camry, Camry gross hp is only 170, and Accord net hp is 172.

  7. Mashfique Hussain Chowdhury Author

    The 2007 Accord 2.4 is rated at 166 net hp in USA and 168 net hp in Singapore. Differences between regional standards are not more than 10 hp, even lesser in most cases. The Accord IS more powerful than the Camry 2.4, but only by 8 to 10 hp, and not by 30 hp as most people here believe due to misleading marketing. Consequently, the Middle East has no specific standard, but at least standardising to net hp ratings would be a start.

  8. In my humble opinion the usage of horsepower NET or GROSS is an inferior measure of power. The world has moved on to using SI (International system of Units) for measuring anything and everything (except of course the US and UK) So why cant we standardise our measurement of power like the rest of the world and use the Kilowatt (KW)?

  9. I also think there should be a consumer guide on this web site for the warranty the different dealers are giving

    Many people for example mistake the bmw 5 years.100 000kms service contract with 5 years warranty which is actually only 2 years
    There are other bullshiters on the market as well

  10. Just put that biatch on a dyno and call it a day.. Thanks alot for the info..

  11. Ford is the only US car manufacturer that reports in NET POWER for GCC. That is due to the fact that lots of ford models are producted in Germany ie Focus, Mondeo

    Great info and article above. Thanks.

  12. I wish Dyno test were not expensive in UAE. Rest of the world taking your cars to the rollers cost a resonable price.

  13. Good info for the masses around..Every time automiddleeast gives engine ratings they always state the gross figure!! even in that wheels magazine same story..

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