Question of the Day: Do You Care About Accurate Horsepower Ratings?

question of the day do you care about accurate horsepower ratings

As you may have seen, Car and Driver did what they're supposed to do and stuck five Nissan GT-Rs on dynamometers to find out just what's up with the cars' world-beating performance. Er, I should say to find out what's up with the discrepancy between their various performances. C&D concluded that U.S. non-press cars make about 520 hp at the crank. Our man Berkowitz concluded that Nissan is feeding the buff books (and Edmunds) ringers. Regardless, does it matter? Here's a for instance… You know the Bugatti Veyron and how it makes 1,001 hp from its quad-turbo, 8.0-liter W16 motor? Well, in Europe it makes 1,020 hp. Something to do with the difference between our more accurate SAE net and the funny Euro (probably metric) whatever system. How does Bugatti explain it? The engines actually produce 1,040 hp, so who cares? And that's kinda my point. Remember when Mazda got "nailed" a few years ago for overrating the horsepower in the Miata. They said it made 155 hp, but in reality it only made 142 hp. Did it really effect the car? Or, closer to (my) home 2006 Subaru WRX had 230 hp when I bought it. Then a few months later the SAE rejiggered how they measure horsepower. Now my car makes 224 hp. Which is actually three horses less than my 2001 WRX. Do i care? Actually, I do. That really pissed me off. You?

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  • Davey49 Davey49 on Aug 22, 2008

    I suppose a better question would be Do you care about horsepower ratings? My answer would be no.

  • Qa Qa on Aug 24, 2008

    argentla - thanks so much for taking the time to answer my question. Makes things much clearer. Following your example then, if the V6 were tuned to deliver peak torque of 220 ft-lbs at 4,295 RPM with similar curve characteristics (using multi-ports and variable valve lift) as the Turbo Four, they would perform about the same on the drag strip correct?

  • Qa Qa on Aug 24, 2008

    argentla - If your 160Hp V6 were coupled to a transmission that keeps it spinning at its torque curve 2,400-4,000 rpm, it should outrun the I4 turbo. Yes? Again exactly identical cars with equal weights.

  • Joeaverage Joeaverage on Aug 25, 2008

    I think modern HP ratings are too often taken out of context by advertising departments. They fail to mention how heavy the vehicle is, what RPM the HP is reached at, and what the cruising RPM is b/c the HP or max torque is at the wrong RPM. A good example is my 9 year old CR-V. It has an advertised 146 HP and I feel confident that it has it all but the driver has to run the engine right up the red line to get it. Max Torque is close to the highway engine speeds but the torque feels low compared to alot of other cars I've driven. That said we've been quite satisfied with it for 162K miles now though a sixth gear for it's five speed manual tranny would have been welcome. Use that sixth gear to drop the rpms another 350-450 rpm. Leave the other gears where they are now. I numbers I am interested in are: rpm of max hp rpm of max torque hp per lb vehicle weight (to which I'd add the weight of our family, a full tank of gasoline, and a full load of luggage). # Dynamic88 : The Model A perspective - Recently a friend gave me a ride around town in his Ford Model A - 1931 Vintage. He said the engine made 37 horsepower. Most published figures I’ve seen rate it at 40. I’m not going to quibble. What impressed me is that for the most part, the A is quite capable of keeping up with city traffic. Sure, starting off from a stop is a bit slow - you can’t shift real fast, you need to hesitate a bit or it’ll grind. But as far as HP goes, 40 is all that is needed for city driving. Yeah I like Model-As. I want to own one someday. I owned and drove a 40HP Super Beetle (~2000 lbs) for several years in Italy. It was my daily driver. It was fine for 80% of my needs. It was too slow on the steep mountain roads though. 3rd gear all the way up if I was carrying three or four people. A proper five speed would have prob fixed that - same low gear and same high gear with more gears in between. I drove it from the northern Italian border to Sicily a few times and even out on the autostrada it was fine up to about 70 mph. A higher gear would have been nice but with four speeds there wasn't enough torque to take advantage of it. We experimented with that. My roomate's US Spec Beetle had the 3.88 gearbox that the Karmann-Ghias came with and 40 HP wasn't enough umph paired with that gearbox. The 65 HP engine could do something with it however. The higher gear was nicer on the open highway though. The "perfect" power to weight ratio for me was my '84 Rabbit 'vert. 90HP from 1800cc and still relatively lightweight (~2300 lbs). 120 mph top end and plenty of power for around town. My ideal target HP to weight is around 100HP with a 2300 lb vehicle and five or six manually selected gears. If I could do it with a 1.4L then I'd be satisfied. Instead of making each generation of vehicle heavier, make each generation the same power and with the same weight and let the fuel mileage increase through tech advancement.

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