GT500 dyno test on TG

The main reason topgear and many other car mags questioned the gt500's 500 hp claim is that it's performance doesn't quite indicate it is making the full 500 hp. Take for example a bmw m5 or merc e63, both have about 500hp and both weigh substanstially more (e63 has an auto:blink:), but they both outaccelerate it by a wide margin. Although, it could be the stangs live rear axel bouncing up and down as it launces. That would explain the sluggish e.t.'s but not low trap speeds in the 1/4 mile:p.

It's still a good bang for the buck even at 450hp for about 40 grand US, if you like going fast in a straight line:D. But, a better deal would be an EVO9 for 30g's, with 10k left for mods8).

btw, It does have uprated brembo brakes, but they do seem on the smallish size for a 2ton car with a massive iron block in front.
 
But then they would have to individually quote different power figures for RWD, AWD, manuals, automatics, LSD and non-LSDs, and every combination thereof, as each will produce a different WHP as they all affect drivetrain losses. That would be a pain. Crank HP is a much easier number to understand for the vast majority of people - WHP has too much fudge factor.

Yep. The WHP depends on much more outside factors than BHP.

But that wasn't the point of the Mustang segment in Top Gear,
they wanted to show how a hugely powerful engine is nothing
without the rest of the car being up to the task.

They didn't bach Americans, because they clearly showed that Roush
already makes a Mustang which is a lot less poweful, but a lot faster
and more manouverable.
 
Although I am not a fan of the pony car at all, I still think it was not too cool to have one of the main points of the review be so blatently inaccurate. The car in question does not matter at all. You could put the Lambo or the Veyron on that dyno and it will show 10~15% less power from the retail quoted HP.

Everybody knows company figures rate their engines on crank horsepower measured when then engine is on a stand in a lab.

Putting it on a dyno only caused drama and I can see how it makes interesting TV but it is very unlike Top Gear to throw a side jab like that. I hope they don't do slip up like this again in the future.

I can see they tried to show the GT500 was a boat but they had the overpowered 730hp Brabus SL600 the other week and it was in the same category.
 
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The moral of the story is "don't go for a big name and big BHP promises".

The segment illustrated that perfectly,
it's a shame some people got it so emotional.

randy.jpg
 
it should be pretty apparent by now that for all the glory of top gear clarkson doesn't know nearly as much about cars as he'd like us to believe. when they tested 3 mustangs (base 4.0 v6, GT500 blown 5.4L V8, and roush 4.6L blown V8) he thought they all had the same 4.6 engine. in fact, he thought the GT500 had the same suspension as the V6 stang.

i've noticed a lot of other instances where they just dont really know what the hell they're talking about. its either ignorance or they just want to make fun of american stuff. thats fine, we've got plenty of limey jokes. celebrities are just out of touch with reality for the most part, i guess this goes for the UK as well.

oh and the GT500 has IRS while the roush that he said was BETTER than the GT500 has the "ancient" live axle design. i find that pretty comical in itself.
 
When they start dynoing all the other cars to see what their "actual" horsepower is, call me.
 
I am still having trouble seeing how some of you are so sure about the purpose of this segment only to show that the Roush was a better stang. The did not have to put the GT500 on a dyno to accomplish this task. This was an overall review of a car which later was compared to another version of this car. But to say that them putting the car on a dyno was to show that the Roush was better makes no sense.

As for TG giving out WHP. I think that would be a great thing. Lets take the Impreza for instance. They don't test every single model that's in the range. If they test a particular car, give us the WHP for that particular car. If they test the STI, give us those numbers. Yeah there's a lot of outside factors involved in how much that number will be off from the number that is quited in the brochure, but hey guess what, these same factors are present when you buy that car and when you drive that car. I'd much rather know what is actually pushing the car rather then what is pushing the drivetrain. I remember back about 4 or 5 years ago a car magazine put an AMG SL on a dyno and they found an incredible 150+ hp loss through the transmission. Sure as hell something I'd like to know if I'm looking at picking up a car with a claim of "monster hp".

As for the GT500 being down on the power. If you do a simple search for stock GT500 dyno runs, you will see most numbers match what TG got and which is inline with the car being 500hp at the crank.
 
take the tranny out and run it on a dyno? how is this different to running the car, in gear, disengaged from the engine, and turning the drive train with the wheels?

ok theres more parts and linkages involved, plus you got the tyres to compete with, but in a round abouts way they both are seeing how hard it is to turn the drive train. i believe you must be able to get a round abouts idea of transmission loss from a rolling road. accurate ? no. round abouts ? yes


No, you can't get an accurate or even vaguely accurate number from a rolling road *unless* you have that specific engine tested first. A local car club had their cars all tested on a dyno last weekend, and six identical Hondas put out six *very* different results.
 
i know its not that easy to do on the spot, but with a computer and the correct software it shouldnt be too bad. and letting the car coast with clutch pressed in (not in nuetral, it needs to be in gear still) seems like a decent round about way to figure out the loses.

im sure the machine can detect spin down rate, resistance, torques or whatever as the car is basically slowing down disengaged from the engine. the rolling road should be able to detect the amount of power needed to turn the drive train and gear box, and with some clever maths work out a decent estimate.(obviously only in one gear mind)

now obviously, you take it with some salt, because it is just an estimate and the software that works it out is only as good as the programmer and the useful equations wont be cock on either. yes if you want the true reading you have to get an engine dyno.

And if you do as you proposed - congratulations, you just blew up about half of the European-made automatic transmissions ever made! So, no, that's a BAD idea.

I've seen some of these dynos that try to "estimate" crank horsepower from rear wheel horsepower. They're hilariously inaccurate.

This is an 1100 horsepower (at the rear wheels) twin-turbo Viper.

IMG_1042.sized.jpg


According to the owner, he took it to a dyno shop that had that estimating software installed. It estimated that he had 2000 crank horsepower. Um, no.
 
oh and the GT500 has IRS while the roush that he said was BETTER than the GT500 has the "ancient" live axle design. i find that pretty comical in itself.

Sorry, no. Ford killed the IRS in the GT500. It's a stick axle. Which is why my buddy is building up a 03 Cobra (with IRS) instead. Ford doesn't even offer it as an option, and a lot of people are really disappointed - and Ford's claim of "it will add $5000 to the car" is BS, since people have already swapped the older IRS into the GT500.
 
The main reason topgear and many other car mags questioned the gt500's 500 hp claim is that it's performance doesn't quite indicate it is making the full 500 hp. Take for example a bmw m5 or merc e63, both have about 500hp and both weigh substanstially more (e63 has an auto:blink:), but they both outaccelerate it by a wide margin. Although, it could be the stangs live rear axel bouncing up and down as it launces. That would explain the sluggish e.t.'s but not low trap speeds in the 1/4 mile:p.

FYI, BMW and Mercedes have been *underrating* their crank horsepower for a while now - and it's widely known in the industry.
 
take the tranny out and run it on a dyno? how is this different to running the car, in gear, disengaged from the engine, and turning the drive train with the wheels?

ok theres more parts and linkages involved, plus you got the tyres to compete with, but in a round abouts way they both are seeing how hard it is to turn the drive train. i believe you must be able to get a round abouts idea of transmission loss from a rolling road. accurate ? no. round abouts ? yes

Not even round-abouts. Running the transmission on a test stand will tell you how much power the transmission consumes when it's powering the car, especially in terms of an automatic. When you put an automatic in neutral, you shut everything down - all the pumps, all the valves, everything goes into a standby mode. You cannot tell how much power it consumes from that standpoint.
 
oh and the GT500 has IRS while the roush that he said was BETTER than the GT500 has the "ancient" live axle design. i find that pretty comical in itself.

Your wrong. I even remember an interview where the head of development mentioned that IRS would not be "cost justifiable" or something. Just googling I found this:

Chassis modifications include stronger springs and thicker anti-roll bars, wider tires, new alloy wheels (though remains 18-inch) and Brembo front brakes with 4-pot calipers and 355mm ventilated discs. On the downside, the heavyweight engine and transmission worsens front-rear balance from 54:46 to 57:43, while the solid live axle rear suspension of the regular Mustang is retained (note: the previous SVT Cobra employed independent suspensions).

Not sure about the Rousch tho..
 
First, i would like to say i have a mustang. A 2002 GT with an aftermarket supercharger. A Kenne Bell 1.7Ltr unit.

I have had my car dynoed a number of times. One thing that must be made very clear is that rear wheel dynoes are not all the same, and do not come to the same number. It is recomended that when you dyno a car to see what an aftermarket part has done, you use the same dyno.

That being said, most mustangs experts will tell you to calculate a drive-train loss of 15%. Most Stock GT's dyno at between 220-230rwhp. Brake HP is advertised at 260.

To take a car with an advertised 500BHP, and dyno iat 447rwhp, and not tell people the difference is misleading! As far as the car itself. As a mustang fan, I think it is terrible. A complete horror. The main problem is the fact it weighs to much. Close to 4000lbs. Compare that to my 2002 mustang at 3300lbs (3500 with driver). Add to that all that weight over the nose, and you get a car that smokes its tires at the start, and can not change direction for its life.

Another note. The GT500 is NOT an aftermarket car. It is a production ford car. SVT makes the GT500, similar to BMW M and AMG.

The Roush is an aftermarket car, and as such does not have to worry about some of the things that the GT500 would. It also has the advantage of having the smaller and lighter 4.6 under the hood, which makes it much more balanced. The Roush is the better car. It had better be, it cost $15,000 more then a Shelby GT500.

That being said, If you like drag racing (i do not) the GT500 is hard to beat. For very little money, Slicks and a pulley change on the blower, you have a very fast car. much faster in a straight line then anything for the money. I just wish it could stop and turn as good as it can go straight.

http://www.youtube.com/watch?v=D8ari3hZJXs
 
The new Mustang is a car that I never liked in the first place, or even the Shelby GT-Almost-500. But, I can agree that the review was pointlessly short and seemed there just to bash on the Americans a bit more before the series ended. Now the whole thing has been blown out of proportion, and everybody is upset at Top Gear over it, it seems especially my fellow Americans. I just take it with a grain of salt and move on to other things.

When I watched the review at first, I assumed that they were showing the horsepower just to compare to the Roush Mustang with its' modified suspension and fewer ponies, but I guess I was wrong, eh?
 
Didn't read the whole thread but I noticed that they didn't have a fan in front of the car for ventilation. That could have affected the car's HP output.
Also it might have had that air filter issue that were affecting the early GT500s that the magazines tested.
 
No there isn't!! It doesn't produce the 500BHP at the wheels, that was proved.

Y0ou missed the point, the dyno only shows horsepower at the wheels, instead of at the crank, which is what every manufacturer in the world quotes. Actually if you take normal dyno results and add the drag, it produces MORE than 500hp. TG failed to mention this.
 
When they start dynoing all the other cars to see what their "actual" horsepower is, call me.

They would have to pull the engines out of every car they test, a little inconvenient don't you think?
 
They would have to pull the engines out of every car they test, a little inconvenient don't you think?

Perhaps the point is (and this was not made clear on the show at all so may not be the point) ...European car manufacturers apparently tend to underestimate their BHP, to give a more accurate indication to the "general public" of what the real power of a car is. I have heard, for example, BMW does that on their diesel models (but don't quote me... I don't remember the source! :cry:)

This was maybe what Richard was getting at, but a line actually saying that, and giving manufacterer/model examples would have at least removed any accusations of bias.

edited to add: :blush: Um, yes, note to self... read all the posts before jumping back in... :blush:
FYI, BMW and Mercedes have been *underrating* their crank horsepower for a while now - and it's widely known in the industry.
 
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