richard spencer schrieb:
> dont leave it at that tell us why you think that. dick spencer
>
The traction control creates a negative effect against to go straight, this has
something to do, with this, how the traction control works.
The traction control needs a exactly base parameter - on salt, no chance - that
the system can calculate from the feedback, which he get from the wheels -
means
grip or no grip - the right correction.
This works on a smooth surface and with a constant contact area from the tire
to
the ground.
Also it's necessary that the contact area between surface and tire got a
minimum
of size.
The salt is to rough, the salt stucks on the tire during the run - no constant
contact area. Also, to go fast, the tire needs to be very small.
Tom Burkland said it the right way - running on salt is like running on snow.
A wide tire runs on salt like on ice.
At last, the speed himself.
The traction control helps to eliminate slipping wheels during acceleration,
but
we are not on the quarter mile. we like to go fast.
The traction control can work in two ways.
The easiest way. Over the brakes. That means, the traction control managment
manipulate the grip/no grip, that he brakes this wheel which lost the grip.
This works only by low speed - up to 100 mph. If you do this on high speed, it
can happens, that in the moment when the brake got the "signal" to "stop" the
wheel, this wheel needs not anymore the correction. The result, you will get on
one side full grip, on the other you are losing the complete grip.
Which roadster drive got not this expierence on the salt, when he got a
left/right side different grip and the car tries to spin.....welcome to the
club
of the stiff neck.
The other way, is over the motor managment.
A high complex computerprogram controls the motor managment, which sends a
signal to the ignition system, this reduced, with a correction, the
torque/power.
This sounds very simple, but is in reality a extremely complex control system.
Also this system got his problem by high speed.
Now someone will say - by the formula 1 it works.
Yes and no.
It works, due to a very smooth surface and a extrem downforce. In other words -
what they called no grip, is for us sticking on salt. The range is on a totally
other level.
>From the outside it looks, like the car goes perfect straight or around the
corner. The reality is, that this system supports only the driver, and the car
still tries to go sideways. It's only the skill and reaction/correction of the
driver, which keeps the car straight.
And if the system loose for one second the control, the car will go sideways
out
of balance and will crash.
On the salt, with the small tires, with less downforce and each second,
changing
contact/grip conditions, the traction control system will have no chance to
make
the right correction to the right time.
It's hard enough for the driver, to get this feedback, he needs to keep the car
straight. A traction control which "jumps" around, makes it only more worst.
By the way, it's doesn't matter if the not powered wheels (steering) goes in a
(little bit) different speed as the powered. If the contact is enough to steer
the car with this wheels, it's okay. The not powered wheels can slide on a
straight way instead of rolling.
There are two big enemies for high speed - this is
- not enough grip
- (too much) downforce
It's all the time a compromise between downforce and enough grip.
Normally the perfects status is
- if you call standing with the whole weight on the ground as 0%
- and lift off from the ground as 100%
- you has to be by 99.5%
??????????
Sound strange, oh, sure.
To explain. You can't reduce the resistance of the car body when you drive.
This is a fix number, depense to the type of car you run, a roadster got a
higher drag as a streamliner.
But you can reduce the resistance of the tire to the ground.
So less this resistance is, so faster you can go.
The problem is, if you reduce this resistance, you are also loosing the grip.
So you have to know how much downforce (means resistance from the wheels to the
ground) and how much grip you need.
The best way is, to create the downforce only with the body shape. Any kind of
wings, carnards means - to create a air brake - and this costs speed.
With a special kind of high speed air flows (very small wings) you will get a
resistance (like a air brake) but with the added downforce, you also get more
speed. It needs a lot of aerodynamic expierence to find a solution that you get
at last a plus on speed.
So the question for traction, is not a question for a traction control - it's a
question of the compromise of downforce and resistance.
If you got enough power you can increase the downforce, which will eliminate
the
traction/grip problem.
But too much power means, loosing grip.
Don't forget, the grip of the salt is only a fraction of the grip, which a
pavement can create.
See ya
Thomas "Pork Pie" Graf
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