Buying new A4,330i, G35, CTS, C320
#61
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
oneactor1@aol.com (Steve Grauman) wrote in message news:<20040214221655.21920.00001947@mb-m14.aol.com>...
> >Not all... but some-- the point is that the vehicle engine/drive layout does
> >not necessarily mean that the car has a particular characteristic... the
> >suspension has a great deal to do with it.
>
> FWD cars all understeer, and most AWD cars do too. No level of suspension
> tuning can ever make this not true, and anyone with tuning experience knows it.
No, not true. I know for a fact that FWD cars can be tuned for
oversteer. Raise the pressure in the rear tires, or reduce their
section width. Put a very large anti-roll bar in the rear, and a
smaller one up front. Use a harder rubber compound on the rear tires
than on the front.
It can be done, because I've seen it. On my '83 GTI, I was able to
make it neutral at the limit through tire pressure and a large rear
anti-roll bar.
> The Integra Type R, Volkswagen Corrado and 1990 Lotus Elan SE represent some of
> the best FWD cars ever devised, all of them understeer.
While that has something to do with drivetrain layout, it's also
designed that way from the factory. MBs and BMWs also understeer
directly from the factory, because ham-fisted drivers do the right
thing for understeer when they overcook it - they lift.
My quattro oversteers at the limit because that's the way I've set it
up. I used tire pressure alone to get it to do this.
--
Jonesy
> >Not all... but some-- the point is that the vehicle engine/drive layout does
> >not necessarily mean that the car has a particular characteristic... the
> >suspension has a great deal to do with it.
>
> FWD cars all understeer, and most AWD cars do too. No level of suspension
> tuning can ever make this not true, and anyone with tuning experience knows it.
No, not true. I know for a fact that FWD cars can be tuned for
oversteer. Raise the pressure in the rear tires, or reduce their
section width. Put a very large anti-roll bar in the rear, and a
smaller one up front. Use a harder rubber compound on the rear tires
than on the front.
It can be done, because I've seen it. On my '83 GTI, I was able to
make it neutral at the limit through tire pressure and a large rear
anti-roll bar.
> The Integra Type R, Volkswagen Corrado and 1990 Lotus Elan SE represent some of
> the best FWD cars ever devised, all of them understeer.
While that has something to do with drivetrain layout, it's also
designed that way from the factory. MBs and BMWs also understeer
directly from the factory, because ham-fisted drivers do the right
thing for understeer when they overcook it - they lift.
My quattro oversteers at the limit because that's the way I've set it
up. I used tire pressure alone to get it to do this.
--
Jonesy
#62
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
Greg Reed wrote:
> You wrote "when they spinn [sic], they give car normal acceleration to the
> center of the circle." They don't.
Actually they do, if you check your physics book. What you feel however
is that you get out of the circle, this isn't however the direction
where you're accelerated to.
> job of it than those of a FWD car. Whatever advantage a FWD car might gain
> over RWD due to having more vehicle weight over its drive wheels is *more*
> than lost as a result of this overtaxing of the tires on the front of the
> car when it's driven at the limit of adhesion.
However, your forgetting that pressing the clutch, an FWD driver
suddenly gains back all the lost friction he has when accelerating. The
wheels start spinning free, and in this case we again have exactly the
same amount of side-wise-friction like the RWD cars. So we don't lose
anything here, we get the maximum spinning speed, and we're at the same
situation as RWD cars, since exactly when they lose their grip, you
can't push more power to the wheels either, or you're getting out of the
circle and hit the wall. No advantage to RWD here.
> And when a RWD car is understeering (as they are often designed to do), at
Not our old BMW Compact, I can't get it to do anything else than
oversteer, it's balance of weight is so ed up. Accelerating will
make the end lose it's grip with the 100hp engine. Yuck . But that's
the cars fault, not RWD.
> When a FWD car is understeering, if the driver is applying (or lifting)
> throttle, the front wheels have just traded in some of their available grip
> to be used for acceleration or deceleration, leaving less grip available for
> controlling lateral acceleration. Ergo, less vehicle control.
However, in this case FWD car hasn't lost it's grip on the backwheels at
any point. It's still in control, and it's not losing it's grip. The
situation here is easily fixed by taking off the power from frontwheels.
However, in the case of your RWD car, your backside is now out of the
control, and pressing clutch for example might not be enough. The back
is out of control and will push the car on opposite direction than
frontwheels, not happening with the FWD.
> entering a snowy curve with your FWD at a speed that can be just barely mana
> ged -- the speed at which any *additional* speed would result in a loss of
> lateral grip. Now add power. The car stops turning in toward the center of
> the circle and starts understeering right into that guard rail. And if you
> instead *lift* the throttle too much or too quickly, you'll get the exact
> result from loss of grip due to engine braking.
However, proven in the real world, if I add any more power, in this case
in the snow, my car would start accelerating to the direction where my
front tyres are pointing to. I've might have lost some of the lateral
grip, but I however have possibility to actually get the car going where
I wanted. Don't try that with RWD car, it'll result that the backpart
will get off and hit the wall, and after that, the front hits the wall.
> Now let's try the same hypothetical experiment with a RWD. Enter the corner
> just below the skid threshold and apply power. Rear wheels come out from
> behind you (a little bit). Correct with a bit of opposite lock, and you're
Now this hypothetical experiment however happens at lower speed with
your RWD, or in other words, your back is lost more easily than the FWD
car starts to understeer. And this is the worst part. I know fixing RWD
is easier than FWD's slide, but RWDs slide happens at a lower speed,
since there isn't that much friction at the front wheels (you need
weight to the backwheels), and there's not as much friction on the
backwheels, since you need to accelerate also. What happens at the limit
speed is another question.
When we have this limit speed with RWD at 30 km/h and with FWD at
35km/h, which one is eventually better?
> I really do believe that the *only* advantage of FWD is that it presents its
> driver with a less-intimidating dance when grip is lost than does RWD. But
> when it comes right down to it, *I* can go faster through any given curve
> with RWD than FWD. And if the limit at which I can take that corner is
Can you? I have my doubts on that one. I know you can more easily FIX
it, but when are you going to lose the grip? If earlier, then your fix
won't help.
Btw, your still forgetting that the RWD loses grip easier than FWD, and
pointing to only the fact what happens at the limit. Now please also
remind us, how did you manage to get more grip with RWD than with FWD.
- Yak
> You wrote "when they spinn [sic], they give car normal acceleration to the
> center of the circle." They don't.
Actually they do, if you check your physics book. What you feel however
is that you get out of the circle, this isn't however the direction
where you're accelerated to.
> job of it than those of a FWD car. Whatever advantage a FWD car might gain
> over RWD due to having more vehicle weight over its drive wheels is *more*
> than lost as a result of this overtaxing of the tires on the front of the
> car when it's driven at the limit of adhesion.
However, your forgetting that pressing the clutch, an FWD driver
suddenly gains back all the lost friction he has when accelerating. The
wheels start spinning free, and in this case we again have exactly the
same amount of side-wise-friction like the RWD cars. So we don't lose
anything here, we get the maximum spinning speed, and we're at the same
situation as RWD cars, since exactly when they lose their grip, you
can't push more power to the wheels either, or you're getting out of the
circle and hit the wall. No advantage to RWD here.
> And when a RWD car is understeering (as they are often designed to do), at
Not our old BMW Compact, I can't get it to do anything else than
oversteer, it's balance of weight is so ed up. Accelerating will
make the end lose it's grip with the 100hp engine. Yuck . But that's
the cars fault, not RWD.
> When a FWD car is understeering, if the driver is applying (or lifting)
> throttle, the front wheels have just traded in some of their available grip
> to be used for acceleration or deceleration, leaving less grip available for
> controlling lateral acceleration. Ergo, less vehicle control.
However, in this case FWD car hasn't lost it's grip on the backwheels at
any point. It's still in control, and it's not losing it's grip. The
situation here is easily fixed by taking off the power from frontwheels.
However, in the case of your RWD car, your backside is now out of the
control, and pressing clutch for example might not be enough. The back
is out of control and will push the car on opposite direction than
frontwheels, not happening with the FWD.
> entering a snowy curve with your FWD at a speed that can be just barely mana
> ged -- the speed at which any *additional* speed would result in a loss of
> lateral grip. Now add power. The car stops turning in toward the center of
> the circle and starts understeering right into that guard rail. And if you
> instead *lift* the throttle too much or too quickly, you'll get the exact
> result from loss of grip due to engine braking.
However, proven in the real world, if I add any more power, in this case
in the snow, my car would start accelerating to the direction where my
front tyres are pointing to. I've might have lost some of the lateral
grip, but I however have possibility to actually get the car going where
I wanted. Don't try that with RWD car, it'll result that the backpart
will get off and hit the wall, and after that, the front hits the wall.
> Now let's try the same hypothetical experiment with a RWD. Enter the corner
> just below the skid threshold and apply power. Rear wheels come out from
> behind you (a little bit). Correct with a bit of opposite lock, and you're
Now this hypothetical experiment however happens at lower speed with
your RWD, or in other words, your back is lost more easily than the FWD
car starts to understeer. And this is the worst part. I know fixing RWD
is easier than FWD's slide, but RWDs slide happens at a lower speed,
since there isn't that much friction at the front wheels (you need
weight to the backwheels), and there's not as much friction on the
backwheels, since you need to accelerate also. What happens at the limit
speed is another question.
When we have this limit speed with RWD at 30 km/h and with FWD at
35km/h, which one is eventually better?
> I really do believe that the *only* advantage of FWD is that it presents its
> driver with a less-intimidating dance when grip is lost than does RWD. But
> when it comes right down to it, *I* can go faster through any given curve
> with RWD than FWD. And if the limit at which I can take that corner is
Can you? I have my doubts on that one. I know you can more easily FIX
it, but when are you going to lose the grip? If earlier, then your fix
won't help.
Btw, your still forgetting that the RWD loses grip easier than FWD, and
pointing to only the fact what happens at the limit. Now please also
remind us, how did you manage to get more grip with RWD than with FWD.
- Yak
#63
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
> My quattro oversteers at the limit because that's the way I've set it
> up. I used tire pressure alone to get it to do this.
I sympathise with what you said about tyre pressure. Another good thing to
do if you want oversteer is - because front tyres get the brunt of wear - to
move them to the back, while keeping those in the front pretty new.
However, I have to say in the case of my Quattro it is still mostly
understeer that I get on sharp bends, unless braking heavily or lifting the
gas pedal abruptly half way. I've found the best way to tackle sharp
cornering is by lifting off the accelerator just before the sharpest point
and then flooring the pedal there or a tiny wee little before that to allow
for turbo lag. If on the other hand, I try to kick on the gas too early it
is mostly understeer I get for the beginning of the corner, then if a bit
lucky and depending a lot on the quality of tarmac, some oversteer. Now, I'd
like to hear how you tackle your corners.
It must also be said that if you set your car up for blunt oversteer - which
will usually happen mostly when braking, then you might be interfering with
the stock design of your EBD brake system - my car does not have ESP, and in
the event of an emergency stop half way through a sharp bend that might be
very dangerous because there wouldn't be a way to prevent your car from
spinning then.
JP
#64
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
>He's got some strange sources--- we all know the Prelude SH 0-60 was more
>like 6.7 seconds than 7.7 seconds...
Prove it, I can. 7.1 is about the best time I've ever seen for an SH and that's
generous. And I'd like to see links from actual road tests, not just some guy
making claims about what his car can do.
>The only vehicle tested that ever exceeded 1.0 g in the skidpad test was the
>Ferrari F40 and F50 and McLaren F1. I'm not sure where you're getting your
>numbers, but they are way off.
More lies, several other cars have recorded over 1.0g including the 911 GT3 and
the new Ferrari Enzo. Here's a link to the C&D article where the GT3 pulls
1.03g, the 2nd highest ever recorded by a street car:
http://caranddriver.com/article.asp?...&page_number=1
>like 6.7 seconds than 7.7 seconds...
Prove it, I can. 7.1 is about the best time I've ever seen for an SH and that's
generous. And I'd like to see links from actual road tests, not just some guy
making claims about what his car can do.
>The only vehicle tested that ever exceeded 1.0 g in the skidpad test was the
>Ferrari F40 and F50 and McLaren F1. I'm not sure where you're getting your
>numbers, but they are way off.
More lies, several other cars have recorded over 1.0g including the 911 GT3 and
the new Ferrari Enzo. Here's a link to the C&D article where the GT3 pulls
1.03g, the 2nd highest ever recorded by a street car:
http://caranddriver.com/article.asp?...&page_number=1
#65
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
>Porsches are famous for their brakes, engines and handling at high speeds on
>good open roads. Now, the moment you take them to a mountain pass, it's a
>completely different story.
This is a foolish, ignorant statement that you have absolutely no ability to
back up with fact. I've provided links showing that FWD cars maintain better
traction in poor weather and that a GT3 is capable of 1.03g on the skidpad. And
I'm sick of being the only one here who's required to back up what I say.
> Apart from the fact that Peugeot holds the best
>rallye suspension scheme in the world
This has little to do with anything, and I'd argue that it's a false statement
to boot. When Peugeot's Rallye record looks anywhere near as good as
Mitsubishi's or Subaru's, we can talk about it. And what about the fact that
Audi dominated rally and road racing in the 1980s and early 90s? What about the
fact that Audi held overall victories at LeMans for 3 years straight and took
2nd overall the fourth year? Or that they've won the ALMS for four years? Or
that Randy Probst won the Speedvision Touring series for the third time last
year in an RS6? What about the fact that Porsche won the Paris-Dakar rallye on
their first try? Or that they have 16 overall victories at LeMans, more than
any other company? How about the fact that the Carrera gets it's name from the
Carrera PanAmerica race which Porsche won several times? Or that their total
number of victories as a company puts anyone else's to shame? This puts Porsche
and Audi in a league way above any French manufacturer. Ever notice how few
positive things the automotive press has had to say about the Renault Clio V6?
>Apart from that if a
>bend is sharp enough an FWD will always tract better than an RWD for obvious
>plain physics reasons
More false information. FWD maintains an advantage only in bad weather. The
1991 Lotus Elan SE Turbo had fantastic handling, but a 944 Turbo from 2 years
earlier would destroy it on any track.
>Now, on the subject of FWD and RWD, the windier and more slippery the road,
>the more superior FWD is over RWD, given similar engines, suspension
>schemes, brakes and weight.
You're ignoring the fact that mid and rear-engined cars like the Boxster and
911 share most of if not all of the traction benefits of FWD cars. Either start
backing up your (obviously false) claims with facts or conceed defeat.
>good open roads. Now, the moment you take them to a mountain pass, it's a
>completely different story.
This is a foolish, ignorant statement that you have absolutely no ability to
back up with fact. I've provided links showing that FWD cars maintain better
traction in poor weather and that a GT3 is capable of 1.03g on the skidpad. And
I'm sick of being the only one here who's required to back up what I say.
> Apart from the fact that Peugeot holds the best
>rallye suspension scheme in the world
This has little to do with anything, and I'd argue that it's a false statement
to boot. When Peugeot's Rallye record looks anywhere near as good as
Mitsubishi's or Subaru's, we can talk about it. And what about the fact that
Audi dominated rally and road racing in the 1980s and early 90s? What about the
fact that Audi held overall victories at LeMans for 3 years straight and took
2nd overall the fourth year? Or that they've won the ALMS for four years? Or
that Randy Probst won the Speedvision Touring series for the third time last
year in an RS6? What about the fact that Porsche won the Paris-Dakar rallye on
their first try? Or that they have 16 overall victories at LeMans, more than
any other company? How about the fact that the Carrera gets it's name from the
Carrera PanAmerica race which Porsche won several times? Or that their total
number of victories as a company puts anyone else's to shame? This puts Porsche
and Audi in a league way above any French manufacturer. Ever notice how few
positive things the automotive press has had to say about the Renault Clio V6?
>Apart from that if a
>bend is sharp enough an FWD will always tract better than an RWD for obvious
>plain physics reasons
More false information. FWD maintains an advantage only in bad weather. The
1991 Lotus Elan SE Turbo had fantastic handling, but a 944 Turbo from 2 years
earlier would destroy it on any track.
>Now, on the subject of FWD and RWD, the windier and more slippery the road,
>the more superior FWD is over RWD, given similar engines, suspension
>schemes, brakes and weight.
You're ignoring the fact that mid and rear-engined cars like the Boxster and
911 share most of if not all of the traction benefits of FWD cars. Either start
backing up your (obviously false) claims with facts or conceed defeat.
#66
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
Except in snow or ice or rain-- you failed to mention that numerous tests
have proven that the safe limit for handling (at the limit of adhesion and
traction) is at significantly HIGHER speeds in inclimate conditions with FWD
vs. RWD... Your arguments are well taken for dry, clean, oil-free pavement;
however, when poor conditions are present, you need the additional weight of
the drivetrain over the drive wheels to ensure traction at higher speeds.
"Greg Reed" <inet_user@hotmail.com> wrote in message
news:4030c2ec@post.newsfeed.com...
> *** post for FREE via your newsreader at post.newsfeed.com ***
>
> Michael Burman wrote:
>
> <snip my stuff>
>
> > Let's take a simple example, and later I will give you a little
> > practical test you can do (and whichs results you should know without
> > doing it).
> >
> > Car's front tyres point where you want to go. Whether there is grip,
> > or there isn't, they always point to that direction, and when they
> > spinn, they give car normal acceleration to the center of the circle.
> > It doesn't matter whether they have full grip on the road, or not,
> > it'll go to that direction, as the tyres keep spinning and
> > accelerating the car. The backtyres on the other hand have full grip
> > all the time in FWD cars, since they're not accelerating, and are
> > just passively following the car, giving it better side-wise-grip.
> >
> > On the other hand, with RWD car, we have front tyres, which do have
> > full-grip. So, we can point to any direction we want, but where do we
> > get the sidegrip? Goash, we don't have it when you accelerate the car,
> > since backwheels lose their grip -> car loses it's side-wise-grip. Now
> > we would need to get back this grip to actually GO somewhere, sliding
> > won't make our car go where we wanted, and it won't make the car go
> > faster.
> >
> > How did you plan to get more grip to backwheels with RWD, when there's
> > less weight & spinning takes away all the grip? You planned to drive
> > forward with front tyres only? Won't work.
> >
> > And why are backwheels so important? And you don't believe they are?
> > Take your handbrake and pull. What happens to the car? Does it spin?
> > Oh yes. If you lock the front tyres however, what happens? Car goes
> > straight forward, it won't spin.
> >
> > Easier, change old-used-tires to your backwheels and brand new ones to
> > front. Push brakes, your car will again go sidewise. Is this the
> > behaviour you wanted? Now you can't go forward, nor can you accelerate
> > the car, since the tyres can spin to whatever direction, and they
> > don't give you acceleration to the direction you wanted. If backtyres
> > pull to the right and you want to straight forward, you have a nice
> > problem.
> >
> > This added to the fact that RWD cars have much less weight on the
> > spinning wheels, which makes them spinn empty on ice, makes them awful
> > winter cars, you just get stuck everywhere. If you push more gas, your
> > car starts to shake and tries to go sidefirst. I'm sure the guy next
> > to you likes it, when you kick his car with your backside.
> >
> > Don't fight the physics, try it. Even an FWD car can oversteer if
> > needed, just put shitty tyres to the back. And please explain, how do
> > you fight against the laws of physics, if you say RWD car is better at
> > winter, when there's little friction. My RWD car just gets stuck every
> > winter to few hills, I can't do anything.
>
>
> This would all make perfectly good sense. Except that one of your
premises
> isn't quite right:
>
> You wrote "when they spinn [sic], they give car normal acceleration to the
> center of the circle." They don't.
>
> The reason that the tail end of a car does the things you describe when
> yanking the emergency brake is also the reason why FWD cars are less adept
> at driving and steering at the same time: When a wheel's speed isn't the
> same as the surface over which it's traveling -- when it stops rolling --
it
> loses the ability to control lateral acceleration (that is, to prevent a
> sideways slide). In your example, applying the parking brake causes the
> rear wheels to be going more slowly than the road, thereby causing the
rear
> of the car to lose lateral stability. But the exact same rules apply to
the
> front wheels of a FWD car. When you press the accelerator (or lift off
for
> engine braking) on a sufficiently slippery surface, the front wheels'
speed
> will no longer match that of the road, thereby losing the ability to
control
> lateral acceleration. The result? The front end of the car keeps going
in
> the direction of its momentum, unaffected by the position of the steering
> wheel. Also called "understeer."
>
> The front wheels "point where you want to go" in RWD cars as well as FWD
> ones. In FWD cars, they are additionally responsible for affecting
forward
> motion. Whenever lateral forces are being applied to the front tires (as
> when turning), any application of the throttle increases the likelihood of
> these tires breaking free and therefore losing their lateral grip. In a
RWD
> car, however, the front tires never have to do anything except "point
where
> you want to go," leaving all accelerative functions to the other axle at
the
> back end of the car. Therefore, when applying throttle in a curve, the
> front tires won't lose their lateral grip until the *speed* of the car (as
> accelerated by the rear tires) finally exceeds their lateral grip
> capability. The action of applying or lifting throttle won't, in and of
> itself, contribute to the front tires losing lateral grip as is the case
> with FWD. So while the back of a RWD car might step out under
acceleration,
> at least the front tires will still be assuring that the car is going in
the
> direction the driver wants it to go -- or at least will be doing a better
> job of it than those of a FWD car. Whatever advantage a FWD car might
gain
> over RWD due to having more vehicle weight over its drive wheels is *more*
> than lost as a result of this overtaxing of the tires on the front of the
> car when it's driven at the limit of adhesion.
>
> And when a RWD car is understeering (as they are often designed to do), at
> least the front wheels are devoting all of their available grip to
> controlling lateral acceleration -- that is, to trying not to understeer.
> When a FWD car is understeering, if the driver is applying (or lifting)
> throttle, the front wheels have just traded in some of their available
grip
> to be used for acceleration or deceleration, leaving less grip available
for
> controlling lateral acceleration. Ergo, less vehicle control.
>
> Now that the theory is out of the way, let's do another experiment -- one
> far more like real-world driving than yanking on the parking brake. Try
> entering a snowy curve with your FWD at a speed that can be just barely
mana
> ged -- the speed at which any *additional* speed would result in a loss of
> lateral grip. Now add power. The car stops turning in toward the center
of
> the circle and starts understeering right into that guard rail. And if
you
> instead *lift* the throttle too much or too quickly, you'll get the exact
> result from loss of grip due to engine braking.
>
> Now try entering that same curve with just a bit too much speed -- so that
a
> slide is inevitable. Now it doesn't matter *what* you do, you're going to
> hit
> the guard rail.
>
> Now let's try the same hypothetical experiment with a RWD. Enter the
corner
> just below the skid threshold and apply power. Rear wheels come out from
> behind you (a little bit). Correct with a bit of opposite lock, and
you're
> still heading in nominally the direction you want to head. The front
wheels
> never stopped rolling. You've missed the guard rail.
>
> Next we enter that same curve with just a bit too much speed. The car
> begins to slide -- butt end out. A bit of opposite lock on the wheel, and
> you're still heading in nominally the direction you want to head -- albeit
> with a bit more butt sticking out than in the first example. And since
all
> of the front tires' grip is being devoted to keeping the car going in the
> direction they're pointed (they're not trying to accelerate or decelerate
> the car), you have a better chance of still missing the guard rail.
>
> I really do believe that the *only* advantage of FWD is that it presents
its
> driver with a less-intimidating dance when grip is lost than does RWD.
But
> when it comes right down to it, *I* can go faster through any given curve
> with RWD than FWD. And if the limit at which I can take that corner is
> faster in the RWD car, then it stands to reason that for any given speed,
> the RWD car is farther from the limit, and therefore, farther from being
out
> of control. (And a car that is sliding *isn't* necessarily out of
control.)
>
> - Greg Reed
>
> --
> 1976 Cadillac Fleetwood 75 9-Pass sedan
> (FS: http://www.dataspire.com/caddy)
> 1989 Audi 200 Turbo Quattro 5-Speed sedan
> 2000 Oldsmobile Intrigue
> 2001 Chevy Astro AWD (wife's)
>
>
>
>
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have proven that the safe limit for handling (at the limit of adhesion and
traction) is at significantly HIGHER speeds in inclimate conditions with FWD
vs. RWD... Your arguments are well taken for dry, clean, oil-free pavement;
however, when poor conditions are present, you need the additional weight of
the drivetrain over the drive wheels to ensure traction at higher speeds.
"Greg Reed" <inet_user@hotmail.com> wrote in message
news:4030c2ec@post.newsfeed.com...
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>
> Michael Burman wrote:
>
> <snip my stuff>
>
> > Let's take a simple example, and later I will give you a little
> > practical test you can do (and whichs results you should know without
> > doing it).
> >
> > Car's front tyres point where you want to go. Whether there is grip,
> > or there isn't, they always point to that direction, and when they
> > spinn, they give car normal acceleration to the center of the circle.
> > It doesn't matter whether they have full grip on the road, or not,
> > it'll go to that direction, as the tyres keep spinning and
> > accelerating the car. The backtyres on the other hand have full grip
> > all the time in FWD cars, since they're not accelerating, and are
> > just passively following the car, giving it better side-wise-grip.
> >
> > On the other hand, with RWD car, we have front tyres, which do have
> > full-grip. So, we can point to any direction we want, but where do we
> > get the sidegrip? Goash, we don't have it when you accelerate the car,
> > since backwheels lose their grip -> car loses it's side-wise-grip. Now
> > we would need to get back this grip to actually GO somewhere, sliding
> > won't make our car go where we wanted, and it won't make the car go
> > faster.
> >
> > How did you plan to get more grip to backwheels with RWD, when there's
> > less weight & spinning takes away all the grip? You planned to drive
> > forward with front tyres only? Won't work.
> >
> > And why are backwheels so important? And you don't believe they are?
> > Take your handbrake and pull. What happens to the car? Does it spin?
> > Oh yes. If you lock the front tyres however, what happens? Car goes
> > straight forward, it won't spin.
> >
> > Easier, change old-used-tires to your backwheels and brand new ones to
> > front. Push brakes, your car will again go sidewise. Is this the
> > behaviour you wanted? Now you can't go forward, nor can you accelerate
> > the car, since the tyres can spin to whatever direction, and they
> > don't give you acceleration to the direction you wanted. If backtyres
> > pull to the right and you want to straight forward, you have a nice
> > problem.
> >
> > This added to the fact that RWD cars have much less weight on the
> > spinning wheels, which makes them spinn empty on ice, makes them awful
> > winter cars, you just get stuck everywhere. If you push more gas, your
> > car starts to shake and tries to go sidefirst. I'm sure the guy next
> > to you likes it, when you kick his car with your backside.
> >
> > Don't fight the physics, try it. Even an FWD car can oversteer if
> > needed, just put shitty tyres to the back. And please explain, how do
> > you fight against the laws of physics, if you say RWD car is better at
> > winter, when there's little friction. My RWD car just gets stuck every
> > winter to few hills, I can't do anything.
>
>
> This would all make perfectly good sense. Except that one of your
premises
> isn't quite right:
>
> You wrote "when they spinn [sic], they give car normal acceleration to the
> center of the circle." They don't.
>
> The reason that the tail end of a car does the things you describe when
> yanking the emergency brake is also the reason why FWD cars are less adept
> at driving and steering at the same time: When a wheel's speed isn't the
> same as the surface over which it's traveling -- when it stops rolling --
it
> loses the ability to control lateral acceleration (that is, to prevent a
> sideways slide). In your example, applying the parking brake causes the
> rear wheels to be going more slowly than the road, thereby causing the
rear
> of the car to lose lateral stability. But the exact same rules apply to
the
> front wheels of a FWD car. When you press the accelerator (or lift off
for
> engine braking) on a sufficiently slippery surface, the front wheels'
speed
> will no longer match that of the road, thereby losing the ability to
control
> lateral acceleration. The result? The front end of the car keeps going
in
> the direction of its momentum, unaffected by the position of the steering
> wheel. Also called "understeer."
>
> The front wheels "point where you want to go" in RWD cars as well as FWD
> ones. In FWD cars, they are additionally responsible for affecting
forward
> motion. Whenever lateral forces are being applied to the front tires (as
> when turning), any application of the throttle increases the likelihood of
> these tires breaking free and therefore losing their lateral grip. In a
RWD
> car, however, the front tires never have to do anything except "point
where
> you want to go," leaving all accelerative functions to the other axle at
the
> back end of the car. Therefore, when applying throttle in a curve, the
> front tires won't lose their lateral grip until the *speed* of the car (as
> accelerated by the rear tires) finally exceeds their lateral grip
> capability. The action of applying or lifting throttle won't, in and of
> itself, contribute to the front tires losing lateral grip as is the case
> with FWD. So while the back of a RWD car might step out under
acceleration,
> at least the front tires will still be assuring that the car is going in
the
> direction the driver wants it to go -- or at least will be doing a better
> job of it than those of a FWD car. Whatever advantage a FWD car might
gain
> over RWD due to having more vehicle weight over its drive wheels is *more*
> than lost as a result of this overtaxing of the tires on the front of the
> car when it's driven at the limit of adhesion.
>
> And when a RWD car is understeering (as they are often designed to do), at
> least the front wheels are devoting all of their available grip to
> controlling lateral acceleration -- that is, to trying not to understeer.
> When a FWD car is understeering, if the driver is applying (or lifting)
> throttle, the front wheels have just traded in some of their available
grip
> to be used for acceleration or deceleration, leaving less grip available
for
> controlling lateral acceleration. Ergo, less vehicle control.
>
> Now that the theory is out of the way, let's do another experiment -- one
> far more like real-world driving than yanking on the parking brake. Try
> entering a snowy curve with your FWD at a speed that can be just barely
mana
> ged -- the speed at which any *additional* speed would result in a loss of
> lateral grip. Now add power. The car stops turning in toward the center
of
> the circle and starts understeering right into that guard rail. And if
you
> instead *lift* the throttle too much or too quickly, you'll get the exact
> result from loss of grip due to engine braking.
>
> Now try entering that same curve with just a bit too much speed -- so that
a
> slide is inevitable. Now it doesn't matter *what* you do, you're going to
> hit
> the guard rail.
>
> Now let's try the same hypothetical experiment with a RWD. Enter the
corner
> just below the skid threshold and apply power. Rear wheels come out from
> behind you (a little bit). Correct with a bit of opposite lock, and
you're
> still heading in nominally the direction you want to head. The front
wheels
> never stopped rolling. You've missed the guard rail.
>
> Next we enter that same curve with just a bit too much speed. The car
> begins to slide -- butt end out. A bit of opposite lock on the wheel, and
> you're still heading in nominally the direction you want to head -- albeit
> with a bit more butt sticking out than in the first example. And since
all
> of the front tires' grip is being devoted to keeping the car going in the
> direction they're pointed (they're not trying to accelerate or decelerate
> the car), you have a better chance of still missing the guard rail.
>
> I really do believe that the *only* advantage of FWD is that it presents
its
> driver with a less-intimidating dance when grip is lost than does RWD.
But
> when it comes right down to it, *I* can go faster through any given curve
> with RWD than FWD. And if the limit at which I can take that corner is
> faster in the RWD car, then it stands to reason that for any given speed,
> the RWD car is farther from the limit, and therefore, farther from being
out
> of control. (And a car that is sliding *isn't* necessarily out of
control.)
>
> - Greg Reed
>
> --
> 1976 Cadillac Fleetwood 75 9-Pass sedan
> (FS: http://www.dataspire.com/caddy)
> 1989 Audi 200 Turbo Quattro 5-Speed sedan
> 2000 Oldsmobile Intrigue
> 2001 Chevy Astro AWD (wife's)
>
>
>
>
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#67
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
You need to read the test results in the August 1998 Car and Driver: Prelude
SH 0-60 with 5-speed manual transmission of 6.7 seconds... 600-ft. skidpad
of 0.96g. Go get the magazine!!
"Steve Grauman" <oneactor1@aol.com> wrote in message
news:20040216194238.22874.00002253@mb-m04.aol.com...
> >He's got some strange sources--- we all know the Prelude SH 0-60 was more
> >like 6.7 seconds than 7.7 seconds...
>
> Prove it, I can. 7.1 is about the best time I've ever seen for an SH and
that's
> generous. And I'd like to see links from actual road tests, not just some
guy
> making claims about what his car can do.
>
> >The only vehicle tested that ever exceeded 1.0 g in the skidpad test was
the
> >Ferrari F40 and F50 and McLaren F1. I'm not sure where you're getting
your
> >numbers, but they are way off.
>
> More lies, several other cars have recorded over 1.0g including the 911
GT3 and
> the new Ferrari Enzo. Here's a link to the C&D article where the GT3 pulls
> 1.03g, the 2nd highest ever recorded by a street car:
>
http://caranddriver.com/article.asp?...&page_number=1
SH 0-60 with 5-speed manual transmission of 6.7 seconds... 600-ft. skidpad
of 0.96g. Go get the magazine!!
"Steve Grauman" <oneactor1@aol.com> wrote in message
news:20040216194238.22874.00002253@mb-m04.aol.com...
> >He's got some strange sources--- we all know the Prelude SH 0-60 was more
> >like 6.7 seconds than 7.7 seconds...
>
> Prove it, I can. 7.1 is about the best time I've ever seen for an SH and
that's
> generous. And I'd like to see links from actual road tests, not just some
guy
> making claims about what his car can do.
>
> >The only vehicle tested that ever exceeded 1.0 g in the skidpad test was
the
> >Ferrari F40 and F50 and McLaren F1. I'm not sure where you're getting
your
> >numbers, but they are way off.
>
> More lies, several other cars have recorded over 1.0g including the 911
GT3 and
> the new Ferrari Enzo. Here's a link to the C&D article where the GT3 pulls
> 1.03g, the 2nd highest ever recorded by a street car:
>
http://caranddriver.com/article.asp?...&page_number=1
#68
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
>You need to read the test results in the August 1998 Car and Driver:
Post a link to it. I shouldn't have to go purchase back issues of magazines
just to see if you're lying. 0.96 Is incrediblly high for a Honda. That still
wouldn't make it faster around a track than a Porsche, but it is high. You also
claimed that the 911 GT3 couldn't break the 1.0g barrier, and I showed you
otherwise!
Post a link to it. I shouldn't have to go purchase back issues of magazines
just to see if you're lying. 0.96 Is incrediblly high for a Honda. That still
wouldn't make it faster around a track than a Porsche, but it is high. You also
claimed that the 911 GT3 couldn't break the 1.0g barrier, and I showed you
otherwise!
#69
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
You must not be looking at the PRELUDE SH== with Honda's ATTS (active
torque-transfer system) that was revolutionary in that it transferred up to
80% of the torque to the outside front wheel in hard cornering and had no
measureable understeer when tested. Car and Driver doesn't have this
article available online-- but I'll try to scan the hard copy I'm looking
at; I would question the 1.03 figure-- but I've seen numbers close to that
by other "supercars". You yourself originally said 7.7 secs for the prelude
(probably the automatic) versus your later figure of 7.1... could it be that
you don't read as many magazines as I do?
Also, don't try to imply that Honda can't achieve such a figure... they have
next to VW/Audi probably the 2nd best FWD suspension of any car maker with
the double-wishbone front suspension... and you should recall the late 80s
model preludes with 4 wheel-steering that were either 0.93 or 0.94 on the
skidpad.... I'd suggest a little more research on your part!
"Steve Grauman" <oneactor1@aol.com> wrote in message
news:20040216212020.21810.00002102@mb-m14.aol.com...
> >You need to read the test results in the August 1998 Car and Driver:
>
> Post a link to it. I shouldn't have to go purchase back issues of
magazines
> just to see if you're lying. 0.96 Is incrediblly high for a Honda. That
still
> wouldn't make it faster around a track than a Porsche, but it is high. You
also
> claimed that the 911 GT3 couldn't break the 1.0g barrier, and I showed you
> otherwise!
torque-transfer system) that was revolutionary in that it transferred up to
80% of the torque to the outside front wheel in hard cornering and had no
measureable understeer when tested. Car and Driver doesn't have this
article available online-- but I'll try to scan the hard copy I'm looking
at; I would question the 1.03 figure-- but I've seen numbers close to that
by other "supercars". You yourself originally said 7.7 secs for the prelude
(probably the automatic) versus your later figure of 7.1... could it be that
you don't read as many magazines as I do?
Also, don't try to imply that Honda can't achieve such a figure... they have
next to VW/Audi probably the 2nd best FWD suspension of any car maker with
the double-wishbone front suspension... and you should recall the late 80s
model preludes with 4 wheel-steering that were either 0.93 or 0.94 on the
skidpad.... I'd suggest a little more research on your part!
"Steve Grauman" <oneactor1@aol.com> wrote in message
news:20040216212020.21810.00002102@mb-m14.aol.com...
> >You need to read the test results in the August 1998 Car and Driver:
>
> Post a link to it. I shouldn't have to go purchase back issues of
magazines
> just to see if you're lying. 0.96 Is incrediblly high for a Honda. That
still
> wouldn't make it faster around a track than a Porsche, but it is high. You
also
> claimed that the 911 GT3 couldn't break the 1.0g barrier, and I showed you
> otherwise!
#70
Guest
Posts: n/a
Re: Buying new A4,330i, G35, CTS, C320
>I would question the 1.03 figure
So I shouldn't question the .96 for a Prelude, but you can question the numbers
I linked to for everyone to see?
>You yourself originally said 7.7 secs for the prelude
>(probably the automatic) versus your later figure of 7.1
I've seen road tests of the Prelude from everywhere between 7.3 to 7.7 and I'd
be willing to believe 7.1 is possible. My GTi does 0-60 in 6.5, but it has more
torque, a flatter powerband, and curb weight that I believe is lower.
>could it be that
>you don't read as many magazines as I do?
I read nearly every issue every month of 5 or 6 different mags. But I looked at
the last of the Preludes very closely in 2001 while I was shopping for a car,
and I did a *lot* of research on them. I've never seen numbers that high.
Beyond that, I've never seen anyone claim that a Prelude SH would be able to
succesfuilly take on a Porsche, because it simply can't be done. I would paint
myself yellow and run through the streets naked if a 2001 Prelude SH could take
a 2001 Carrera with equally matched drivers.
>Also, don't try to imply that Honda can't achieve such a figure... they have
>next to VW/Audi probably the 2nd best FWD suspension of any car maker with
>the double-wishbone front suspension.
Honda doesn't use the double wishbone setup anymore. They dropped it for cost
and cabin-space issues. I'll agree that Audi makes the best handling FWD cars
on the market right now, as long as we're talking about mainstream autos
avaliable in North America.
So I shouldn't question the .96 for a Prelude, but you can question the numbers
I linked to for everyone to see?
>You yourself originally said 7.7 secs for the prelude
>(probably the automatic) versus your later figure of 7.1
I've seen road tests of the Prelude from everywhere between 7.3 to 7.7 and I'd
be willing to believe 7.1 is possible. My GTi does 0-60 in 6.5, but it has more
torque, a flatter powerband, and curb weight that I believe is lower.
>could it be that
>you don't read as many magazines as I do?
I read nearly every issue every month of 5 or 6 different mags. But I looked at
the last of the Preludes very closely in 2001 while I was shopping for a car,
and I did a *lot* of research on them. I've never seen numbers that high.
Beyond that, I've never seen anyone claim that a Prelude SH would be able to
succesfuilly take on a Porsche, because it simply can't be done. I would paint
myself yellow and run through the streets naked if a 2001 Prelude SH could take
a 2001 Carrera with equally matched drivers.
>Also, don't try to imply that Honda can't achieve such a figure... they have
>next to VW/Audi probably the 2nd best FWD suspension of any car maker with
>the double-wishbone front suspension.
Honda doesn't use the double wishbone setup anymore. They dropped it for cost
and cabin-space issues. I'll agree that Audi makes the best handling FWD cars
on the market right now, as long as we're talking about mainstream autos
avaliable in North America.