Hammond drives the GT500

[280Z Turbo]

http://www.youtube.com/watch?v=MneTKjKHG0Q

This link will probably stop working, but there's nothing I can do about that.

I was dissapointed with his review. The GT500 is rated at 500 bhp, not 500 whp. And his old Mustang was rated at 350 gross bhp, which is different from today's SAE net bhp (and whp).

Also, I got the feeling he was just bashing solid rear axles because they're "old" just like he did with leaf springs on the Corvette. There are a lot of solid axle racecars and drag racers prefer them, so I don't think it was strictly a cost decision.

A pretty sucky review, but who cares? That's not what Top Gear is for.

[sandertheshark]

Well, it did get around the track in the exact same time as a 400bhp Vauxhall Monaro VXR, and was two seconds slower than a 415bhp Roush Mustang with an indy rear, so they've got a point there about how the extra muscle is wasted by cheap suspension.  It might be fine with a live axle, but I think the GT500 should at least have an LSD and some much better springs and shocks than what it's got.

But you're right about the rwhp thing.  That was retarded and hamster should know better.

[giant_mtb]

Looked to me like he had an absolute blast driving it.

[CMan]

I watch TG because they cut cars in half and make limos, and because they launch Reliant Robins into space. Not for their accurate specs.

But anyway, I'd kill for Hammond's GT390.

[JYODER240]

I car that makes 470hp at the wheels makes a lot more than 500 at the crank.

[TheIntrepid]

I'd kill for his 390. Timeless cars, those 60s Mustangs.

[S204STi]

Meh, I like the GT500 although I would never own one.  I much prefer Hammy's 390.

[CMan]

We seem to be reaching a general consensus that classic 'Stangs p3wn.

I always figured that if I had $30k or $50k to blow on a toy, I wouldn't be buying a new Mustang or a new Corvette. I'd be buying a '70 Chevelle, or a '68 Mustang.

[SVT666]

I car that makes 470hp at the wheels makes a lot more than 500 at the crank.

I've never seen a GT500 come close to pulling 470 rwhp.  The most I have seen is 445 rwhp, which would put it at around 505 hp at the crank.

[SVT666]

Well, I just watched the video and I gotta say, I mightily dissapointed in Hammonds knowledge (or lack thereof) of the difference between wheel horsepower and crank horsepower.  You know, I would love a GT390 as well, however I don't feel like fucking around with carburators, spotty reliability, uncomfortable seats, terrible ride and handling, crappy A/C, crappy heater, etc., etc.  Give me the GT500 please.  You can make it just as loud and obnoxious and be more comfortable and a helluva lot faster.

[CMan]

I car that makes 470hp at the wheels makes a lot more than 500 at the crank.

447 HP, actually.

[JYODER240]

I've never seen a GT500 come close to pulling 470 rwhp.? The most I have seen is 445 rwhp, which would put it at around 505 hp at the crank.

Did you see the dyno the used? I wouldn't really expect it to be accurate.

[SVT32V]

It might be fine with a live axle, but I think the GT500 should at least have an LSD and some much better springs and shocks than what it's got.

Every Mustang with a V8 since 1982 has come with a limited slip differential, of course the GT500 is no exception.

[SVT666]

Did you see the dyno the used? I wouldn't really expect it to be accurate.

I don't think you heard them right either, because Hammond said 447 whp.

[JYODER240]

Still, 447whp equates to about an unrealistic 11% drivetrain loss assuming it makes 500 at the crank. Don't most FR layouts have closer to a 17-20% drivetrain loss?

[SVT666]

Still, 447whp equates to about an unrealistic 11% drivetrain loss assuming it makes 500 at the crank. Don't most FR layouts have closer to a 17-20% drivetrain loss?

No.  Mustangs have 12% drivetrain loss.  Evidenced by most GT500's have between 440 and 445 rwhp and regular Mustang GT's dyno at 265 rwhp.  12% drivetrain loss pegs the GT at 300 crank hp and the GT500 at 500 crank hp.  Drivetrain loss is from the moving parts and how much force is required to turn or move those parts.  That's why an aluminum lightweight driveshaft and flywheel will lower the drivetrain loss and the wheel horsepower will go up without the engine crank horsepower increasing.

[JYODER240]

I really doubt it only has a 12% loss, thats really low even for a FF or MR layout. I suspect that the Mustang makes more power than what Ford claims.

[SVT666]

I really doubt it only has a 12% loss, thats really low even for a FF or MR layout. I suspect that the Mustang makes more power than what Ford claims.

12% is pretty typical and mid engined cars are around 10%.

[MX793]

Still, 447whp equates to about an unrealistic 11% drivetrain loss assuming it makes 500 at the crank. Don't most FR layouts have closer to a 17-20% drivetrain loss?

15%-17% from what I've seen.  Older cars might have been a little bit more.

[JYODER240]

I've heard that the lowest you'll ever see in either a MR,RR, or FF setup and you'll get about a 12-15% loss. I don't buy that a Mustang only has a 12% loss.

[SVT666]

15%-17% from what I've seen.? Older cars might have been a little bit more.

That would mean a Mustang GT is producing 320 hp and that GT500 is producing 535 - 540 hp....which they are not.

[JYODER240]

That would mean a Mustang GT is producing 320 hp and that GT500 is producing 535 - 540 hp....which they are not.

Judging from the acceleration times from the Mustang GT 315-320 would make a lot more sense.

[SVT666]

The biggest factor is what type of Dyno they are using.  Any performance shop that is any good will tell you to use a Dynojet for bragging rights and Mustang Dyno for accuracy and there is typically a 10% difference in horsepower ratings between the two dynos.  The dynomometer is a bigger factor then anything to determine accurate wheel horsepower.  I have seen Dynojet readouts on a stock 2005 Mustang GT that pegged it at 285 whp which would mean the crank hp is (using your 15% drivetrain loss) 335 hp. and a Mustang Dyno reads 265 whp on a stock Mustang GT.  Still using your 15% drivetrain loss the car makes 312 hp at the crank.

[SVT666]

Judging from the acceleration times from the Mustang GT 315-320 would make a lot more sense.

Don't forget gearing has a big impact on acceleration and the Mustang has 3.55 gears in the stock rearend.? If you stick 2.73 (stock in the 1996 Mustang GT)? in the back end acceleration will slow down with the same engine power.? Drop 4.10 or 4.30 gears in and acceration gets a lot faster without increasing power.

[JYODER240]

I've heard that since Ford was burned for the overrated 99 Cobra's they've been underating their engines a bit. I've heard the Ford GT and the Mustangs make more power than whats listed. For example I think my engine is rated at 297hp under the new standards. My Z weighs less than the Mustang GT but a Mustang will beat me in a race, whether its from a dig or a highway roll. Most dyno results put the Z at about 240-245whp. I just don't see how the Mustang GT can only make 3 more hp yet be so much quicker.

[SVT32V]

No.  Mustangs have 12% drivetrain loss.  Evidenced by most GT500's have between 440 and 445 rwhp and regular Mustang GT's dyno at 265 rwhp.  12% drivetrain loss pegs the GT at 300 crank hp and the GT500 at 500 crank hp.  Drivetrain loss is from the moving parts and how much force is required to turn or move those parts.  That's why an aluminum lightweight driveshaft and flywheel will lower the drivetrain loss and the wheel horsepower will go up without the engine crank horsepower increasing.

It is generally accepted in the mustang world that the 300 Hp mustang GT is definitely underated, based on its rwhp it is clearly in the 320 crank hp range.  Most previous mustangs have had ~15% loss through the same drivetrain (same tranny and 8.8 inch rear).  The '05 and up should have slightly more loss since the driveshaft is two-piece, this joint wil eat up a bit more hp.  This engine was not dynoed under the new SAE conditions so it can be underrated.

The GT will dyno right around where the 320 hp 2001 cobra also did at 270 ish at the wheels.

[Raza]

It is generally accepted in the mustang world that the 300 Hp mustang GT is definitely underated, based on its rwhp it is clearly in the 320 crank hp range.  Most previous mustangs have had ~15% loss through the same drivetrain (same tranny and 8.8 inch rear).  The '05 and up should have slightly more loss since the driveshaft is two-piece, this joint wil eat up a bit more hp.  This engine was not dynoed under the new SAE conditions so it can be underrated.

The GT will dyno right around where the 320 hp 2001 cobra also did at 270 ish at the wheels.

Welcome to the forums!   Good early post.

[SVT666]

I've heard that since Ford was burned for the overrated 99 Cobra's they've been underating their engines a bit. I've heard the Ford GT and the Mustangs make more power than whats listed. For example I think my engine is rated at 297hp under the new standards. My Z weighs less than the Mustang GT but a Mustang will beat me in a race, whether its from a dig or a highway roll. Most dyno results put the Z at about 240-245whp. I just don't see how the Mustang GT can only make 3 more hp yet be so much quicker.

What's the rear end gear ratio on your car?

[Raza]

What's the rear end gear ratio on your car?

The Mustang has more torque.  Is it too simplistic to assume that that's a factor?

[SVT666]

The Mustang has more torque.? Is it too simplistic to assume that that's a factor?

It is definitely a factor, but so is gearing.  I'm just saying that the Mustang does not make 330 hp and the GT500 does not make 540 hp.