Taking a curve in neutral ?

[flipper35]

Originally Posted by cockerpunk

this is incorrect.

proper, fast, braking will including braking while entering the corner.

Jackie Stewart always went into a corner neutral, not gear but no gas no brakes. He seemed to do OK at it.

[cockerpunk]

Originally Posted by flipper35

Jackie Stewart always went into a corner neutral, not gear but no gas no brakes. He seemed to do OK at it.

its almost like we've learned something about driving in the last *checks notes* 60 years.

proper braking means you will be using the brake on corner entry. its faster. period.

[ted]

Originally Posted by cockerpunk

this is also incorrect.

if you are on the power before the apex, you've run too late of an apex line, and over slowed.

proper throttle application is at the apex. this will also help you learn how much of a late apex you should be taking. on the power before the apex = too late. on the power after the apex = too early.

ahh perhaps we are saying the same thing.
The apex of the corner determines where I apex my car.
When I apex the car I'm on gas, to get back on top of the tire.
I like a lot of roll speed mid corner.
Track out thru a little power oversteer on less than perfect asphalt, helps rotation.

PCA teaches pitch and catch, requires gas/brake weight transfer car control.

Neutral is like neuter.

[ted]

I have an admission to make, I like to left foot brake.
Sometimes when I'm on top of the tire I load up the brake and gas at the same time.
And no it's not in a 935 or a turbo car.

[ted]

Shifting a Dog ring box or towing downhill neutral not recommended.

[livi]

Low revs. Less noice. More comfortably sailing.

[Tervuren]

Depends on what yer driving.
Rules are different with a solid axel and no diff.
Rules are also different with high downforce.

There are solid axel vehichles out there where the weight is going to concentrate on the outside wheels leaving the inside wheels almost, or actually floating.
With a lack of differential not being on throttle will cause understeer that has to be overcome by even more steering angle.
This is because the outside rear under engine braking will be dragging against the desired direction of rotation.
It creates a massive friction fight, kills momentum and cornering force both.
In such a vehichle, feathering on throttle after corner weight transfer is akin to pushing the rear corner of a peice of paper across your desk.
Less steering angle is required, better conservation of momentum, and higher cornering force.

Originally Posted by cockerpunk

this is also incorrect.

if you are on the power before the apex, you've run too late of an apex line, and over slowed.

proper throttle application is at the apex. this will also help you learn how much of a late apex you should be taking. on the power before the apex = too late. on the power after the apex = too early.

[ted]

Originally Posted by T77911S

there is a track i go to that has a long sweeping curve out of a sharper one.
so i am excelling very hard but i also have to shift in the middle of the curve.
i was uneasy about it at first but all was fine,

i also have a circle track friend that is very good. i was telling him about getting sides in the 930 several times. he said, if you get into trouble just push the clutch in.

that takes all the weight distribution out caused by being on the gas or off the gas and the car goes "neutral"

trailing throttle oversteer much?
you never push in the clutch it will roll.
over and over.

[javadog]

Originally Posted by Tervuren

Depends on what yer driving.
Rules are different with a solid axel and no diff.
Rules are also different with high downforce.

There are solid axel vehichles out there where the weight is going to concentrate on the outside wheels leaving the inside wheels almost, or actually floating.
With a lack of differential not being on throttle will cause understeer that has to be overcome by even more steering angle.
This is because the outside rear under engine braking will be dragging against the desired direction of rotation.
It creates a massive friction fight, kills momentum and cornering force both.
In such a vehichle, feathering on throttle after corner weight transfer is akin to pushing the rear corner of a peice of paper across your desk.
Less steering angle is required, better conservation of momentum, and higher cornering force.

I hate to say it but a lot of this is wrong, too.

I probably still have some vehicle dynamics books left over from all the books I sold. Maybe I should look through them and offer them up for sale here…

[svandamme]

Originally Posted by GH85Carrera

. On the streets, with traffic of other idiots on the road, coming to a red light soon, in gear or not should make zero difference at 30 to 50% cornering ability.

Till some yokel does something and you need to get out of that corner fast.
Staying in gear adds control. fact.
it determines your ability to change your energy state fast


its like standing at the red lights.. in neutral
No bueno , cannot get away fast if a truck comes barreling on to you

being at an intersection waiting... with your wheels already turned to cross.. no bueno somebody rear ends you and you shoot into upcoming traffic.

Neutral has no purpose or merit other then at the MdDonalds Drive, or in a fully developed Tjam

[svandamme]

Originally Posted by masraum

Really? SNIP
You contradict yourself a couple of times in your post.

I'm not an instructor, I tried to explain why it worked for me but to be fair maybe maybe the explanation sucks, but I do know neutral doesn't work in practice. And that At least my driving isn't wrong I just can't explain what I do and have ben doing right for 20 years, based in trial and error. Been on race tracks and the Porsche instructor saw me drive and said I was doing allright. Which matters more to me then my abilty to explain it

Trailbraking and oversteer etc , sure those work but technically those are workarounds for special circumstances.
Like odd surfaces or special combinations in corners.

In a single turn
a consistance turn angle
even surface
Straight line in
Straight line out
There would be only 1 way to get through it in an ideal way fastest way for a specific car
and it would not involve trail braking with oversteer.
or it would have to be a hairpin bend.. a hand brake turn so to speak

Which well you'de probably want the clutch in for that so your engine does'nt stall along with the wheels stopping

[cockerpunk]

Originally Posted by svandamme

I'm not an instructor, I tried to explain why it worked for me but to be fair maybe maybe the explanation sucks, but I do know neutral doesn't work in practice. And that At least my driving isn't wrong I just can't explain what I do and have ben doing right for 20 years, based in trial and error. Been on race tracks and the Porsche instructor saw me drive and said I was doing allright. Which matters more to me then my abilty to explain it

Trailbraking and oversteer etc , sure those work but technically those are workarounds for special circumstances.
Like odd surfaces or special combinations in corners.

In a single turn
a consistance turn angle
even surface
Straight line in
Straight line out
There would be only 1 way to get through it in an ideal way fastest way for a specific car
and it would not involve trail braking with oversteer.
or it would have to be a hairpin bend.. a hand brake turn so to speak

Which well you'de probably want the clutch in for that so your engine does'nt stall along with the wheels stopping

this doesnt make sense at all.

trail braking, or as we call it, braking properly, does not mean you are oversteering. and braking properly will always be faster than releasing the brake before turn in.

[svandamme]

if you trail brake while steering in , it will destabilize your back end, which if you do it long enough will induce oversteer
it changes the balance of your car depending
understeer in , trail brake, transfer weight to get oversteer.

https://youtu.be/tvcuGoVhpxw?t=499

[masraum]

Originally Posted by vash

in my youth I did something dumb. well, one of my dumb things.

I was going down a twisty road.
In my moment of brillance I decided to coast down. I pushed in the clutch, and put the car in neutral. WEEEEEEEEEEE!! FUUUUUUNNNNNN! it took very little time to build up some speed. I almost lost it going around a corner immediately. okay, let's stop this stupidity. I put it back into the appropriate gear and motored down the road. Glistening from a fresh sheen of sweat.

I would never corner in neutral ever again. in a 911SC that would have been potentially catastrophic. no bueno. maybe a slow-ass corner, like into a parking space.

Right, overcooking the corner is bad. If the car was in gear and you were on the gas, but going too fast, it still would have been bad or at least would have required letting off and/or braking.

[masraum]

Originally Posted by svandamme

Till some yokel does something and you need to get out of that corner fast.
Staying in gear adds control. fact.
it determines your ability to change your energy state fast


its like standing at the red lights.. in neutral
No bueno , cannot get away fast if a truck comes barreling on to you

being at an intersection waiting... with your wheels already turned to cross.. no bueno somebody rear ends you and you shoot into upcoming traffic.

Neutral has no purpose or merit other then at the MdDonalds Drive, or in a fully developed Tjam

But this question is NOT about best practice for safety or traffic. This question is about the PHYSICs of how the car will handle coasting in neutral. So, imagine you were on a beautifully smooth track with no curbs and great traps to ensure that you don't go off and hit something and no other cars. If you could get up to 90 and roll through a fast sweeper in neutral is the car going to gradually lose speed but be just fine or pirouette or explode or ....

[masraum]

Originally Posted by svandamme

I'm not an instructor, I tried to explain why it worked for me but to be fair maybe maybe the explanation sucks, but I do know neutral doesn't work in practice. And that At least my driving isn't wrong I just can't explain what I do and have ben doing right for 20 years, based in trial and error. Been on race tracks and the Porsche instructor saw me drive and said I was doing allright. Which matters more to me then my abilty to explain it

Yep, I get it and I think that you're probably a fine driver. I think you understand how it works on a track or the road in practice.

I think the main problem is that you're answering a slightly different question (fastest way through/around a corner or best way on a track to go through a corner or something like that) instead of "is this old statement true? Will coasting work from a physics point of view, or is there something about the physics of coasting in neutral that would make the car handle weird."

Trailbraking and oversteer etc , sure those work but technically those are workarounds for special circumstances.
Like odd surfaces or special combinations in corners.

In a single turn
a consistance turn angle
even surface
Straight line in
Straight line out
There would be only 1 way to get through it in an ideal way fastest way for a specific car
and it would not involve trail braking with oversteer.
or it would have to be a hairpin bend.. a hand brake turn so to speak

Which well you'de probably want the clutch in for that so your engine does'nt stall along with the wheels stopping

In many ways, you're probably better suited to say this than I have. I've driven aggressively, but never been on a track. So most of you will stop reading.

I've also read a bunch of books on driving, Bondurant, Frere, Watts, etc..., and I've taken a bunch of physics, so I think between those books, my understanding of the physics discussions, and my aggressive driving (where I actually test theories and what I've read).

Oversteer (sliding rear tires) is probably rarely the best way (it's slow) to come out of a corner. Trail braking to the point that you've got a large slip angle, but you aren't sliding (sliding, leaving black marks, making tire smoke), is probably usually the fastest way into a corner. Then I would assume the fastest way out, most often, is to feed in the throttle to reduce the rear slip angle but increase the front slip angle.

Even if the corner is at the end of a long straight before a short straight (fast in, late apex, slow out) or at the end of a short straight before a long fast straight (slow in, early apex, fast out), I suspect you'd still want to use trail braking with high rear slip angle and then feed the throttle to get higher front slip angle, but the lines and amounts of trail braking and throttle feeding would be different and swap at different points.

[svandamme]

Originally Posted by masraum

Will coasting work from a physics point of view, or is there something about the physics of coasting in neutral that would make the car handle weird."

But it's not coasting perse.

If its coasting; no brakes either..
you gave up ALL controle over the balance.

you have to steer, you cannot avoid that
and steering will make the car weight move around to the outside
you cannot control it in any way except for not steering.

In reality; neutral you will still the brake pedal.

So for RWD, that braking pedal will be on you front wheels with a +- 70 % front bias. and those tires are already working for the steering part.

So not coasting leaves you with only one way to play with the balance
1 its one way only.. you cannot unbrake
2 it affects the grip level of your wheels who are steering
3 your rear wheels aren't doing anything for you other then rolling

it is all about controlling the weight
and coasting or neutral with brake pedal usage is pisspoor control of that weight

It's like cycling with your feet off the pedals
sure you can go down a hill like that
but you won't like it for long

[masraum]

Originally Posted by svandamme

But it's not coasting perse.

If its coasting; no brakes either..
you gave up ALL controle over the balance.

you have to steer, you cannot avoid that
and steering will make the car weight move around to the outside
you cannot control it in any way except for not steering.

In reality; neutral you will still the brake pedal.

So for RWD, that braking pedal will be on you front wheels with a +- 70 % front bias. and those tires are already working for the steering part.

So not coasting leaves you with only one way to play with the balance
1 its one way only.. you cannot unbrake
2 it affects the grip level of your wheels who are steering
3 your rear wheels aren't doing anything for you other then rolling

it is all about controlling the weight
and coasting or neutral with brake pedal usage is pisspoor control of that weight

It's like cycling with your feet off the pedals
sure you can go down a hill like that
but you won't like it for long

Right, but the question isn't "is this a good way to do it" the question is "will it work"

So, lets say with Stijn driving his Cayman, at the track, he can take a particular corner (flat track, no uphill or downhill) at 60mph. If I was going 70 down the straight, put the car in neutral, and then hit the brakes to get the car down to 60 or 58 or 55, would I be able to steer through the corner (I believe as soon as you turn the steering wheel, the car will begin to decelerate). I believe that in neutral, the car will be able to be steered around the corner at pretty close to the same speed. Hell, you may be able to go into the corner at 62, 63 or 65, and let the turn scrub off the few mph so you're still at ~60 mid-corner.

[svandamme]

it all depends on the the corner, and speed you enter
if the speed is below what your car weight , balance and tires can handle, then yes you can coast
if not, you will exit the corner the wrong way

no control , no way to do something bout the excess speed

Most people will be unable to precisely estimate what the ultimate limit for coasting is.
So unless you UNDER estimate with big margin, eg granny it ; you are screwed

You can incrementally test the speeds , creep up and up and up
you will find out when you go out the corner that the previous speed was the limit

EDIT, oh yeah predict it will be understeer, you'll see the tree coming.

[Tervuren]

Take a riding mower with a locked rear drive axle onto pavement.
Put it in neutral and hold the steering over to lock and try to push it in a U-turn from a stop.


Then push it to a few MPH while straight, and then try to make that same U-turn while pushing.
The weight transfer off the inside will free up the rear bind.

Now most of us are not stuntmen, and I don't recommend trying this, but under power get enough weight transfer the inside rear just comes a paper's thickness off the ground on turn in and feather in some throttle.

You'll be able to reduce the slip at both front and rear as the bind from the inside rear is no longer a factor, and the slight torque steer from the outside rear is in your favor instead of against if under engine braking.

Originally Posted by javadog

I hate to say it but a lot of this is wrong, too.

I probably still have some vehicle dynamics books left over from all the books I sold. Maybe I should look through them and offer them up for sale here…