HP 101: Top Gear provides false info on GT500 horsepower rating
Someone help us understand what's going on here. In the latest episode of Top Gear, Richard Hammon revisits the Ford Shelby GT500 that the British motoring show tested late last year. For comparison's sake, Hammond brings along his own classic Shelby GT390. We're used to Top Gear bashing our U.S. ware at every opportunity, and the GT500 again takes a licking for having a suspension that can't handle the car's power. But when Hammond wheels out a portable chassis dyno to accurately measure the GT500's horsepower, he seems surprised to learn that the car produces 447 horsepower. Of course, that's 447 wheel horsepower, meaning the horsepower is being measured at the wheel where parasitic drivetrain losses are in effect and reduce the manufacturer's flywheel horsepower rating a good 10 to 20%. In fact, if you factor in a 10% drivetrain loss on Ford's flywheel horsepower rating of 500, you get 450 wheel horsepower, which is pretty darn close to the 447 achieved by Hammond's "rolling road". For some inexplicable reason, however, Hammond and his comparitavely giant co-host, Jeremy Clarkson, ding the GT500 for producing 53 less horsepower than advertised. Huh?
You can view the segment after the jump for the time being (until it gets yanked off YouTube) and make your own judgment, but from our perspective the segment appears highly misleading to viewers who don't know the difference between horsepower ratings at the wheel and the flywheel. What's up, Hamster?
[Source: Dubspeed Driven]
Reader Comments (Page 1 of 5)
TDIMeister 3:33PM (3/05/2007)
Does anyone really take Top Gear for anything more seriously than automotive *entertainment*?
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Stanton 3:35PM (3/05/2007)
Top Gear is fun and entertainment, that's it. Eye-catching production values, and no substance. Technical expertise on the show hovers somewhere between 'embarrassing' and 'non-existent'.
This is the show, after all, in which Clarkson repeatedly talks about cars having 'x' quantity of 'torques'.
Entertainment, not journalism. Fun to watch, unquestionably, but I feel sorry for anyone who takes very much of what they say seriously.
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ruggels 3:39PM (3/05/2007)
Crazy... who'd expect a car to dyno at the wheels what it's rated at in print. Wait... Wait.. my GTI and Jetta both dyno at or above 200hp... crazy europeans.
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Jason 3:44PM (3/05/2007)
Uh oh, the Brits are dogging on American cars... time to get up in arms. Raise those 40's of PBR, shotguns, and confederate flags high boys!
Gimmie a break - simple fact is that no car company in the US ever rates their cars in horsepower at the wheels. If they did rednecks with 20% drive train loss because of their insanely heavy drive train components wouldn't be so quick to dog on everything that didn't have an American V8 in it.
You'd see rednecks cry when their LS1 made less than 290whp in their heavy ass 5000 lb cars with shitty suspension.
And even more cries from ricers whose bolt on intakes and far can exhausts didn't make the claimed 40hp that eBay promised.
Engine dynos and manufacturers promises (including Shelby) are for retards. WHP is where it's at.
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C. A. Martin 5:52PM (3/05/2007)
Wow.
Not one "dumbasses should know better", but "no one should take them seriously".
God forbid blaming Clarkson and co. for anything....
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Paul Cebo 3:46PM (3/05/2007)
The show may lack technical expertise, but it is a fact the the suspension that underpins the Mustang is ancient technology, and quite sad really.
It's interesting to note that immediately after testing the GT500 Mustang on the track, they test a Roush Mustang which actually makes quite a bit less horsepower (415HP so about 370HP at the wheels), but has an upgraded suspension and brakes. It's actually 2 seconds faster around the loop.
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Jason 3:48PM (3/05/2007)
And along the lines of what #7 says, Clarkson has nothing but praise for the Roush Mustang.
You can make a car as powerful as you want, but if all it does is smoke tires and understeer because of crap suspension, none of that hp really matters for anything other than burnout competitions and people whose mouths run better than their cars.
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murciealgo142 3:54PM (3/05/2007)
When i saw this episode i coulnt belive they were dissing it for 447 hp at the wheels. Top gear does alot of fasle/ biased testing when it comes to american cars, but this time it went to far- either they are completly stupid, or they did it on purpose...how sad.
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CoffeeJones 3:52PM (3/05/2007)
I like the older series/seasons where they'd talk about a car in the studio.
I remember one ep where Jeremy struggled with opening a fold-flat seat in a minivan, and eventually broke it.
It's very down-to-earth.
Now he's just screaming. "ITS EPIC! IT! IS! PHENOMENAL! But unfortunately, it lacks the prerequisite Italian insanity, so it's rubbish. Also it drives like a Golf with mustard up its bottom."
Top Gear is entertaining, but IIRC we haven't had a single car this season thats not under $60k.
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gecko 3:58PM (3/05/2007)
BHP is much more of an accurate rating of the car's HP, because no matter how much power the engine provides its the power that hits the ground that matters.
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Annonymous 4:08PM (3/05/2007)
How do we know if the dyno software hasn't already accounted for the drive train losses?
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Jason 4:03PM (3/05/2007)
#9 - BHP isn't the same as WHP.
BHP is the measure of HP at the crank without any accessories (aircon, power steering pump, etc.)
http://en.wikipedia.org/wiki/Brake_horsepower#Brake_horsepower_.28bhp.29
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RITmusic2k 4:03PM (3/05/2007)
gecko,
BHP stands for 'brake horsepower', which, despite the odd name, is just another name to describe crank horsepower. I think you meant 'WHP'
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Stanton 4:05PM (3/05/2007)
No, sophisticated European car manufacturers do not give wheel horsepower values for their cars.
And good work going off on tangents about the GT500's suspension, which of course has nothing at all to do with whether or not the experts at Top Gear know the difference between rated engine horsepower and wheel horsepower.
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Jason 4:33PM (3/05/2007)
murciealgo142... I don't see how them strapping the car to a dyno and reporting the actual numbers is false reporting.
Them making up a number out of the sky would be false reporting. Actually dynoing the car on the show seems pretty real-world to me.
Unless you can think of a different way to measure real world horsepower.
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Shipey 4:23PM (3/05/2007)
"You'd see rednecks cry when their LS1 made less than 290whp in their heavy ass 5000 lb cars with shitty suspension."
Umm... My 2002 Z28 SS made 332WHP right off the showroom floor. That's considerably more than the 325HP flywheel rating.
Next you'll tell me Grand Nationals were overrated at 245hp.
One more thing, there's nothing... NOTHING old about the mustang's suspension. It is absolutely the best solid-axle rear ever designed. OH, you don't like solid axles? Well too bad! Mustang racers demanded them. They're an absolute necessity for serious drag racing. Ford understood that, and made sure the car had the best possible suspension characteristics the solid axle could provide. Based on sales, this was obviously a huge mistake.
Put down the NAWZ bottle and try being a little more open minded.
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isilex 5:02PM (3/05/2007)
This issue was mentioned on FinalGear.com - "it has been pointed out that the last time they did this, with the cheap supercars (Clarkson's Masarati-with-a-cheap-SS-badge, etc), they actually mentioned that and said the machine allowed for that in converting wheel hp into bhp." ... "i see the GT500 complainers have decided to ignore my explanation that a rolling road CAN workout power at the flywheel quite easily just by letting the car coast on the machine out with the clutch disengaged. still 450Bhp is alot for that car. 450-500 who cares its still gonna rip your face off." ... I am just quoting for people who are interested: http://forums.finalgear.com/showthread.php?t=17408
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Punkey 4:17PM (3/05/2007)
Because the Society of Automotive Engineers certified that the engine produces 500 HP at the flywheel. That means that an independent observer went to Ford's plant, and spent a whole day testing the engine to make sure that it produces the specific numbers that Ford said it would.
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Rocket Punch 4:21PM (3/05/2007)
I think we all know they know the difference between HP vs WHP, an I think most of us know this show is more about entertainment than technical this and that.
If you watch the whole segment, they are really making a point of how a car is more than just BHP.
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Sean Hopman 4:25PM (3/05/2007)
I really like reading up on autoblog, but hey, have you ever thought about changing the name to ilovefordblog.com
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