New Veyron Test

[tforth]

no way will Bugatti ever claim it goes through the bends like the 2003-4-5 super cars because it simply cannot.

is answered by:

"

easy to drive and crushingly capable on the sort of twisting roads that would test a hot hatch (i.e. 'b-roads' if this is not already obvious) is little short of miraculous. At the outset of this test, none of us could have imagined that the Veyron would leave the Enzo trailing in its wake on such a road.

but it isn't nimble like the lighter weight counterparts. It just isn't possible.

Who said that it was nimble? I have just provided info (repeatedly, I might add) that it's faster than its nearest competition on twisty roads - 'period'

And what is with all the weight vs. handling crap. Weight, or mass, has no direct relationship with the centripetal acceleration (i.e. 'g') experienced by a vehicle during a cornering manoeuver. Center of gravity, track, roll stiffness, roll center position, coefficient of friction of the contact patch on the given surface, transient contact patch stability, etc. would play into this metric. I suppose that next your going to claim that weight is what limits its top speed as well...

[graywolf624]

And what is with all the weight vs. handling crap. Weight, or mass, has no direct relationship with the centripetal acceleration (i.e. 'g') experienced by a vehicle during a cornering manoeuver. Center of gravity, track, roll stiffness, roll center position, coefficient of friction of the contact patch on the given surface, transient contact patch stability, etc. would play into this metric. I suppose that next your going to claim that weight is what limits its top speed as well...

Thats where your wrong. Weight, or rather mass has a significant effect on handling. cg roll stiffness roll couple influence the contact patch.. But.. F=ma.. Thus the force required to accellerate a car laterally (realizing that the new force vector is a combination of lateral and vertical forces) is higher for a higher mass car. Thus requiring more friction force on the tires, and hence more grip. Now the items you mentioned influence more grip based on the amount of tire that stays connected to the road during turns (invarious situations), but there is a point where it just won't be enough. Cars arent just light for acceleration purposes. Actually, I've just oversimplified.. Why? Because mass also influences the friction force. The coefficient of friction is a function of the force pushing down, gravity. Thus at least theoretically (we wont get into things like tire deformation), heavier mass increases the friction at the tires. Hence a heavier car would theoretically have a higher tire grip, but it requires a stronger force to hold it to the turn.

If your arguement worked we could go auto xing with a semi if we lowered the ride height and installed better suspension.

edit: clarity, man my kingdom for a white board.

[tforth]

Quote: And what is with all the weight vs. handling crap. Weight, or mass, has no direct relationship with the centripetal acceleration (i.e. 'g') experienced by a vehicle during a cornering manoeuver. Center of gravity, track, roll stiffness, roll center position, coefficient of friction of the contact patch on the given surface, transient contact patch stability, etc. would play into this metric. I suppose that next your going to claim that weight is what limits its top speed as well... Thats where your wrong. Weight, or rather mass has a significant effect on handling. cg roll stiffness roll couple influence the contact patch.. But.. F=ma.. Thus the force required to accellerate a car laterally (realizing that the new force vector is a combination of lateral and vertical forces) is higher for a higher mass car. Thus requiring more friction force on the tires, and hence more grip. Now the items you mentioned influence more grip based on the amount of tire that stays connected to the road during turns (invarious situations), but there is a point where it just won't be enough. Cars arent just light for acceleration purposes. Actually, I've just oversimplified.. Why? Because mass also influences the friction force. The coefficient of friction is a function of the force pushing down, gravity. Thus at least theoretically (we wont get into things like tire deformation), heavier mass increases the friction at the tires. Hence a heavier car would theoretically have a higher tire grip, but it requires a stronger force to hold it to the turn. If your arguement worked we could go auto xing with a semi if we lowered the ride height and installed better suspension.

You're right in the sense that mass is directly related to the accel. rate. The point I was trying to get across is that mass in isolation does determine the accel rate. There are many other factors that play into this.

Specifically, I was irritated by the general statement that because the Veyron weighs 'x', it cannot do 'y'. That's like saying: because a car has a 4 cylinder engine, it cannot travel faster than 'y' mph. These are oversimplification statements. The Veyron appears to be somewhat of an exception in this regard, as several reviewers have stated that it feels approx 300-400 kg (660-880 lbs) lighter than it is. However, I am not aware of anyone credible saying that it feels as light as an Elise...

[graywolf624]

The point I was trying to get across is that mass in isolation does determine the accel rate. There are many other factors that play into this.

Except that isn't what you said.. You said it wasnt directly related, which it is. Of course theres many factors, but anyone who doesnt think it is significant is quite honestly a fool.

Specifically, I was irritated by the general statement that because the Veyron weighs 'x', it cannot do 'y'. That's like saying: because a car has a 4 cylinder engine, it cannot travel faster than 'y' mph.

No, its like saying that the best 4 cylinder will never produce as much power as the best 12 cylinder. Which is true. We aren't comparing a pinto to the veryon here, we're talking about the freaking enzo..

[tforth]

You said it wasnt directly related, which it is. Of course theres many factors, but anyone who doesnt think it is significant is quite honestly a fool.

As I have already stated, you're right. What I meant, was that looking at weight/mass in isolation as being the determinant for cornering prowess is as 'fool'ish as the statements that have been made about the Veyron not being able to do certain things (which it apparently has) because of its weight. So, to get back to my original analogy; it is the same as stating that a 4 cylinder can't do certain things in isolation of other considerations.

More specifically, the simplistic (lateral) FBD for a car experiencing a constant radius turn, in equilibrium is a = V^2/R = Ff/m, where Ff is the effective force of friction. This, can be rewritten as Ff = m*V^2/R. When you consider this as a rigid body, as opposed to a particle, you would also sum the moments, which is basically caused by the distance separating the C of g from the contact patches.

All that being said, if a designer does a good job maintaining the contact patch over all 4 wheels during this condition (and this where the benefit of AWD comes in) and the drive to offset the scrub loss (due to the slip angle at, or close to the limit of adhesion) is distributed to fill the friction circle on the contact patches that are maxing out purely with lateral accel., your Ff can actually exceed comparable cars.

As you have already stated, there is an obvious linear relationship with normal force and vehicle weight/mass, as well. So it just comes down to whether the designer can overcome the moment load effect, which will tend to overburden the 'outside' contact patches, with clever suspension design along with AWD.

We aren't comparing a pinto to the veryon here, we're talking about the freaking enzo..

evo No. 096, Pg. 101 - continued, Jethro Bovingdon states: "It blows the Enzo, Carrera GT and Zonda into the weeds. That sounds ridiculous but it's no exaggeration."

[nthfinity]

evo No. 096, Pg. 101 - continued, Jethro Bovingdon states: "It blows the Enzo, Carrera GT and Zonda into the weeds. That sounds ridiculous but it's no exaggeration."

I can't help but say its the driver. thats why its so important to run around a track.

[graywolf624]

No offense, but your still missing the point.
Firstly, I'm unsure if you understand Awd has nothing to do with contact patch. Contact patch is an aspect of roll center, couple, camber, dynamic camber, and other functions. All awd does is distribute forces of acceleration among multiple wheels. A tire friction force has a limit, as defined by the normal force times the coefficient of friction. This force, as you've represented it, Ff, must be less then the forces applied to the tires from acceleration, braking, and turning. AWD just deals with distributing the acceleration, not the braking or turning which is just as important to handling. The only influence awd has on handling is how soon you can get the power down. In fact it hinders carrying weight into the turns since the systems are heavier then fwd and rwd systems.


Now, to the part you definitly don't understand. A cars handling isn't a factor of a stead state constant radius turn, it is more a function of its transition too and from the steady state. How much you can carry in and out, how soon you can get on the power. These are the important parts of the system.

Now, by designing a system with a better dynamic camber and less roll you ensure a larger contact patch to the ground which ensures a larger coefficient of friction, and thus a larger Friction Froce (Ff). However, the required Ff to hold the system through a turn is actually a function of the mass of the vehicle, the important part. When you turn the wheels in the front of the car, the friction force changes. Simplistically this angle can be broken down into 2 components, 1 at the 90 to the direction of travel of the car, and 1 at the opposite of the direction of travel. If these combined are greater then the Ff the cars tires will lose traction (This occurs both at the rear of the car and the front). The force that is at 90 to the current direction of travel is that which makes the car change direction. It actually makes the car accelerate in the lateral. As I described earlier to you, this force is a function of Mass x acceleration. The bigger the mass the larger that friction force that is required to allow the same amount of acceleration into the turn. Now.. assuming we have a car that weighs almost 1000 lbs more. Do you honestly think for a second given that the lighter car has a competent designed suspension that you can gain enough friction force to overcome that 1000lbs. Do you understand the order of magnitude of increased friction force necessary? You aren't going to see that sort of gain over another best in world super car. It may be quicker in certain situations due to the higher top speed and potential to get the power down earlier (which your article mentions), but the enzo will quite obviously be able to enter the corner at a higher speed and hold this higher speed through the turn (something even the articles you posted admit).

Its great that your a fan and all. But the simple reality is, mid length tracks the enzo will eat the veryon for breakfast. Tracks with long straights.. Veryon. Very short tracks are debateable, as depending on how tight you may have to come to a complete stop, which benefits the higher horsepower. Which brings us to Nfinitys point: handling on one back road tells about as much about a car as a drivers opinion. Nothing. Was it tight, Sweepers, number of straights? In fact there is even a larger concern... If your suspension is designed for the track it will be less then competent on the road. Tracks are generally smoother then roads, race car suspensions are not designed to cope with potholes and other undulations and cannot be as fast on those sort of roads. For a good example, on a track the camaro I use to have would have left a wrx for dead. On a road the situation would be reversed.. Why? The minute I hit a pothole in the camaro I lost traction as my suspension was designed for smoother race tracks.

enzo:
3,262 lbs
weight distribution: 43.9-56.1
F 245/35ZR-19
R 345/35ZR-19

Veryon
4,300 lbs.
rear tires
335/R21.3
front tires
P265/ZR19.7BSW run flat performance

[graywolf624]

In an awd car an capable driver can keep the car slightly oversteered and still apply power proppeling the car thru and out of the corner at higher speeds....

Thanks but I just explained that with the portion of getting the power on early. It is only one portion of handling though. And I never denied it can be better then expected... But some things just arent possible. There is a limit.

[graywolf624]

the part of awd making the car capable of going thru corners with more power than rwd cars are very important, and alot of people on here and elsewhere just say its an heavy pig and leave it with that, and they dont know shit about what awd does with a cars handling for them its just a matter og weight and tires....

I never said anything overal, I just said it cant handle as well as the enzo.. That is all I said. And the extra weight offsets much of that awd advantage. Less acceleration the more mass, since you put more on the lateral.

Getting the power on early is important but as miatas routinely demonstrate, it certainly doesn't overwhelm the concept of a light car.

[nthfinity]

so this is why those AWD Audi (DTM?) cars were regularly winners? nope, they couldn't hold thier new found position on the track after taking 4-5 positions on the standing start.

[nthfinity]

Originally Posted by brembo Originally Posted by nthfinity so this is why those AWD Audi (DTM?) cars were regularly winners? nope, they couldn't hold thier new found position on the track after taking 4-5 positions on the standing start. dont even know what you mean by that....but happy new years anyway...

Happy 2007 to you too!

[tforth]

Your quote:

Firstly, I'm unsure if you understand Awd has nothing to do with contact patch.

My quote:

All that being said, if a designer does a good job maintaining the contact patch over all 4 wheels during this condition (and this where the benefit of AWD comes in) and the drive to offset the scrub loss (due to the slip angle at, or close to the limit of adhesion) is distributed to fill the friction circle on the contact patches that are maxing out purely with lateral accel., your Ff can actually exceed comparable cars.

As stated above, one of the benefits of AWD (when designed/developed properly) is that it can selectively apply torque to any and all wheels which have not exceeded their maximum grip level. As you should know, the effective friction force on any contact patch is the vector addition of BOTH the lateral and longitudinal force components (the defining axes of the friction 'circle'). Your response may be: well if the front outside tire has exceeded it's max grip level (i.e. understeer), does it really matter whether you can apply more at the rear? Well, in certain cases yes, because by increasing the torque at the outside rear wheel in this condition, you could increase weight transfer to the rear, and thereby decrease the (in general) over-loading condition at the front outside, while at the same time increasing the normal (and therefore Ff) force at the comparatively under-loaded rear wheel. This, is just one specific example of how AWD can benefit in the turns.

Oh, and I distinctly remember audi entering American race series, about 20 years ago, in I believe Trans-Am and some other series, where they cleaned up so convincingly with their 'outlandish' and 'ponderous' AWD sedans. This also happened in the Australian touring car series in the late 90s with the A4. I'm sure their are other examples people can come up with.

Now, to the part you definitly don't understand. A cars handling isn't a factor of a stead state constant radius turn, it is more a function of its transition too and from the steady state. How much you can carry in and out, how soon you can get on the power. These are the important parts of the system.

Hmmm, what exactly is that I have stated which would validate this claim? I have specifically provided the example of the steady-state max. lateral accel. rate condition, as it is the easiest to define from a physics/mathematics standpoint (i.e. objectively again). I am not aware of having downplayed the importance of turn-in, or the transient conditions.

Do you honestly think for a second given that the lighter car has a competent designed suspension that you can gain enough friction force to overcome that 1000lbs. Do you understand the order of magnitude of increased friction force necessary? You aren't going to see that sort of gain over another best in world super car.

As you yourself have mentioned, since the Ff is mu*Fn, the Ff increases with mass... As long as tires are sized appropriately and can therefore handle the heat energy into them, all should be well.

but the enzo will quite obviously be able to enter the corner at a higher speed and hold this higher speed through the turn (something even the articles you posted admit).

Where exactly?

Its great that your a fan and all. But the simple reality is, mid length tracks the enzo will eat the veryon for breakfast.

...and your proof is where exactly? BTW, the only credible track test I am aware of in the public media pitting (with the same driver) the Enzo against the CGT and SLR, and Murcie for good measure, was the ams review from many moons ago, where they recorded top speeds at Nardo (which, surprise, surprise the Enzo won, kind of like a Veyron would now...). More importantly, in the area where any real supercar should show its peers who's boss, at an actual road course, guess who won? No, not the esteemed light on its heels Enzo; rather the 'old school' CGT, by approximately 1s. Yes, it was a 'tightish' course, but the CGT also smoke all of its peers in 200 km/h - 0 as well. So, in my not so humble opinion, I wouldn't choose the Enzo as your 'best-in-class' benchmark. FYI, I posted this ams video here a while back. It was obviously based on their mag article, which included the braking data. I have that copy (somewhere as well).

Which brings us to Nfinitys point: handling on one back road tells about as much about a car as a drivers opinion. Nothing. Was it tight, Sweepers, number of straights? In fact there is even a larger concern... If your suspension is designed for the track it will be less then competent on the road. Tracks are generally smoother then roads, race car suspensions are not designed to cope with potholes and other undulations and cannot be as fast on those sort of roads.

So, I guess evo et al should pack their bags, since you guys are the unofficial experts, and your statements should never be questioned? Regarding the comparative track data, as I have stated before, check out revlovers.com, as they actual ran a couple Veyrons against pretty much everything that is fast, including the 'beloved' Enzo. BTW, it wasn't even mentioned as a comparable to the Veyron, when they ran it at Hockenheim.

As I have stated repeatably, I have info, which I have provided from numerous public sources regarding my position. Where exactly is yours?

[RC45]

Originally Posted by tforth Oh, and I distinctly remember audi entering American race series, about 20 years ago, in I believe Trans-Am and some other series, where they cleaned up so convincingly with their 'outlandish' and 'ponderous' AWD sedans. This also happened in the Australian touring car series in the late 90s with the A4. I'm sure their are other examples people can come up with.

The difference is that the racing AWD Audis werer prepped, lightened and actually demonstarted their results in races and on TV.

The Veyron has ONLY been the subject of very subjective, poorly documented and rather dubious "tests".

[graywolf624]

Your response may be: well if the front outside tire has exceeded it's max grip level (i.e. understeer), does it really matter whether you can apply more at the rear? Well, in certain cases yes, because by increasing the torque at the outside rear wheel in this condition, you could increase weight transfer to the rear, and thereby decrease the (in general) over-loading condition at the front outside, while at the same time increasing the normal (and therefore Ff) force at the comparatively under-loaded rear wheel. This, is just one specific example of how AWD can benefit in the turns.

I just explained that to you 3 x.. The problem is with a heavier car the pressure on all 4 wheels is higher. Your assuming that the extra weight will only be encountered on the wheels that are overloaded first.

Oh, and I distinctly remember audi entering American race series, about 20 years ago, in I believe Trans-Am and some other series, where they cleaned up so convincingly with their 'outlandish' and 'ponderous' AWD sedans. This also happened in the Australian touring car series in the late 90s with the A4. I'm sure their are other examples people can come up with.

Cars that weigh mid 2000 lbs.. car that weighs over 4000... Any question? No one said AWD wasn't nice, we said it isnt going to make up for 1000 lbs of extra weight.

Hmmm, what exactly is that I have stated which would validate this claim? I have specifically provided the example of the steady-state max. lateral accel. rate condition, as it is the easiest to define from a physics/mathematics standpoint (i.e. objectively again). I am not aware of having downplayed the importance of turn-in, or the transient conditions

What you don't seem to get is, it is the easiest to show because it doesnt really exist.. It isn't reality. In the real world their is no steady state.

As you yourself have mentioned, since the Ff is mu*Fn, the Ff increases with mass... As long as tires are sized appropriately and can therefore handle the heat energy into them, all should be well.

Yet again, show mathmatically its possible for it to be high enough to make up for the weight. It isn't. The heat energy has absolutley nothing to do with it.. All you need to do is switch the compound on the tire to one that operates at the appropriate temp. The reality is, there is a bell curve on the ideal weight of cars. 4000 lbs is over that.

Where exactly?

The article only tells you about a million times it handles better then expected.. It doesnt say it handles great. Ask yourself why the choice in wording and why it doesnt say it handles better then the enzo?

...and your proof is where exactly? BTW, the only credible track test I am aware of in the public media pitting (with the same driver) the Enzo against the CGT and SLR, and Murcie for good measure, was the ams review from many moons ago, where they recorded top speeds at Nardo (which, surprise, surprise the Enzo won, kind of like a Veyron would now...). More importantly, in the area where any real supercar should show its peers who's boss, at an actual road course, guess who won? No, not the esteemed light on its heels Enzo; rather the 'old school' CGT, by approximately 1s. Yes, it was a 'tightish' course, but the CGT also smoke all of its peers in 200 km/h - 0 as well. So, in my not so humble opinion, I wouldn't choose the Enzo as your 'best-in-class' benchmark. FYI, I posted this ams video here a while back. It was obviously based on their mag article, which included the braking data. I have that copy (somewhere as well).

Do show me where I ever compared or commented on the enzo versus the cgt? I never once touched that arguement.. This is the Veryon versus the enzo.. or hell.. the veryon vs the cgt.. Both will win exactly what Im telling you about. Theres a reason the Veryon has been tracked very little.
It wouldnt suprise me if it never is, they aren't going to want its weak spots displayed officially, and mainstream mags tend to favor tests that favor the given car.

So, I guess evo et al should pack their bags, since you guys are the unofficial experts, and your statements should never be questioned? Regarding the comparative track data, as I have stated before, check out revlovers.com, as they actual ran a couple Veyrons against pretty much everything that is fast, including the 'beloved' Enzo. BTW, it wasn't even mentioned as a comparable to the Veyron, when they ran it at Hockenheim.

First off, evo are not all that impressive. None of the mainstream rags have that much in terms of pro drivers. If I were using a reliable source id be more likely to use smaller racing oriented mags. That being said it doesn't have anything to do with unofficial experts.. It has to do with simple physics. (And for the record I don't know who these revolver.com people are.. )

As for Hockenheim.. Define what you consider it, a tight, mid, or a open track.. Im curious... I'll give you a hint, I wouldnt change its classification much over the last 30 years even with the redesign.

Do yourself a favor.. Sit down and think about it.. Theres a reason very few racing cars (excluding of course off road cars like wrc) are awd. If you could simply build a 4000 lb awd car with a great suspension and handle better then a 3000 lb or lighter rwd car.. Don't you think everyone would be doing it?