Drift Vs Grip Which Is Faster?

[ernos5]

I recently saw some video's on youtube comparing drifting through the first 2/3 of the corner and driving normally at the limit, although the variation of skills between the two drivers sometimes is under question...

Does anyone know for sure which is faster, or whether a slight angle of drift gets you through the corner slightly faster?



thanks

oh btw these are the links

http://au.youtube.com/watch?v=t-FyLFf5emE

http://au.youtube.com/watch?v=TuSlDuZezWk

[nae]

apparently 5 degrees of slip angle on the tyres is the
most efficient grip/drive ratio

i have no source and not even sure where i got the info from

[freedom_honda]

ohh live for speed.
that was before Patch Z. (cuz ive seen that ages ago)
and AI before Patch Z was REALLY slow.
if you do the same aganist a decent driver(real) i dont think drifting will be able to keep up.

[twoshots]

Does this help?
http://www.tut.fi/plastics/tyreschool/m ... html#3_1_9

[Ciro Pabón]

IMHO, drifting always slows me down.

The only circumstance that makes me drift is when I have no idea of the layout of the track.

Drifting won't make you faster in a road, but it makes you more confident, because you can "lateralize" the car and stop it pretty quickly if you misjudge a curve.

However, when you kart (which is very different of racing cars with a differential), drifting is for rookies. It's a defect you have to correct. Nobody drifts a light car, except by mistake or ignorance. On the other hand, a lot of people driving a single seater tends to do the same as in a heavy car (and compared with a single seater, every stock car is heavy).

What's so attractive in drifting? I'd say that drift cars are cars that the fans can imagine owning themselves...

When I've drifted, I've found it pretty similar to rallying off-road, except that you pull the handbrake or sidestep the clutch at much higher speeds (150-160 kph, instead of 80-100 kph as in a rally).

I found that is easier drifting in my old GT when it used to have ply tyres.

I discovered later in my life that the famous Kunimitsu Takahashi used this factor (ply tyres have a larger slip angle, that's evident) when he started to drift in normal racing. I'd say that this means that you are using inferior equipment (high slip angle tyres AND heavy cars).

If you are using a light car, drifting is no good. The car has no inertia to carry you through the curve and the momentum "wasted" in drifting is too much to be compensated by the early exit. By early exit I mean that the car is pointing towards the inside of the curve "since the entrance", because you have a ton of understeer, so you shave some hundredths before accelerating.

You can, specially in the wet, to "brake" the car with the drifting and, after that kind of braking, you end pointing in the right direction, or I've seen some drivers driving like that. It makes easier to overtake them, as they "open" the inside of the curve on the entrance, before they "shake" the rear to start the drift.

Another thing I don't like about drifting is the fact that if you "loose" the drift and allow the rear tyres to "bite", you're heading toward the wall. That's not the way to treat your car.

So, drifting is not for me. Drifting, my friend, won't make me faster, unless I become suddenly some kind of genius driver, something I don't expect at this time of my life. Even Takahashi had a terrible F1 trial at Japan.

[jammer84_03]

its all about corner radius and momentum. its also varies on the driver and how he chooses to run his car and how it is setup.

our two drivers have completely different dring styles and its very eveident when we pull the data up after a run. one has a slight drift through a corner, and the other just takes the corner a little deeper trying to get a good jump on his exit. momentum is absolutely key. one likes to carry more through the corner (drift) and the other likes to get faster acceleration out of the corner.

it really is amazing to see the splits of eiher driver in comparison when our sessions are over. the edge does go to the driver with the drift. he has the car on an absolute knife edge and has excellent car control.

for a good look at a driver that has a very drift style of driving, check out raphael matos. after getting a looks at some of his data, the guy barily uses the brake. he keeps a ton of entry speed to the corner, and uses the gas to keep the rear where he wants it, and uses it as well to help rotate him through the apex of the corner

[gcdugas]

Faster for a lap or faster for the race? I could never see the drift style making the tires last a decent stint.

Then there is fuel mileage considerations.

Then there is the fact that the front tires in the drift style handle almost no lateral load so you have that much less contributing to maintaining speed through the corner.

In grand slalom skiing they talk about carving the corner vs. chatter. I think it is the same question. Go with the carve.

As to slip angle, that is a function of wheelbase, tract width, and the corner radius. In an ideal world you would have 4WS and there would be equal steering angle input to both front and rear axles as the rear tires track in exactly the same path as the front tires and there would be less steering input to the outside wheels because they are farther from the radius point. That way the axles of all four tires are pointed the radius point of the corner and you have the least amount of scrub (fighting among the tires against each other) and the tires are able to maximize their lateral grip capacity. The car CG rotates 90 degrees to the theoretical line pointing to the radius point also. This is the theoretical ideal.

Without 4WS the rear tires will track on a radius that is narrower than that of the front tires. I have read that the supposed ideal slip angle will be that which causes the rear tires to track in the path of the front tires which also achieves the ideal rotation of the car as well.

[Ogami musashi]

The slip angle is a question of tyre compound first, next is the way the whole directional system uses it.


IMHO drifting (i mean really drifting that is having the whole car being translated by inertia) is interesting on low grip surfaces simply because griping here can't be done a sufficient speed.

As you climb the grip ladder drifting becomes slower and slower.

I think there's also some little misconceptions. A turn is not only a centripetal action, it involves a torque to point your car. Not only this seems logical to have your car pointed to the exit, but the whole lateral force generation requires a torque on the first step (at the turn in).

Sometimes you can have a little torque induced slide on the rear wheels that can help you through the narrow turns but that's only a benefit when you can't obtain from your car enough torque from the start.

There's also another largely known drift sequence on cars that a driven on the limit (that is almost every car either slow enough or not precise enough to allow that) when the limit of the tyres is frequently overshooted to be corrected.

That allows to get to a decent speed and use the width of the track to carry the speed.

F1 cars are just the opposite and sliding occurs only by mistake and only in some turns that offer very little grip.

So i think it is safe to say that on grip surface, the drift with large slip angle is way slower (especially in karting as said by Ciro) but that sometimes some specialized and little ways can work.

[alexbarwell]

Some setups (like honda a couple of years ago)have trouble getting heat into tyres to work properly, so a bit of drift can help in the first few laps, but keep it up and you run out of useable tyre way too soon. Any energy expended forcing the tyre to drift is not really being used in the useful (mostly forward) direction and the more that can be redirected positively through steering the better. Exceptions would be complexes like 'the bus stop' or other sharp chicanes where steering around it makes for a wide and very slow line. Having said that, I've done a bit of auto-testing involving 360 degree spins and must admit a bootfull of power and a good dose of lock and handbrake gets you round much faster, and it makes your tyre man happier too...

[Jersey Tom]

Depends on the car, the track, and the driver.

Something like a F1 car loses a lot of downforce with chassis sideslip / yaw / "drift." There isn't much other gain, so "drifting" the corner costs a ton of time.

A sprint car, or stock car, works well at high sideslip in some scenarios. A stock car with the massive side profile, when you overyaw it into a corner drops downforce but increases drag and side force. You can brake and turn in later, maybe even net more cornering force. Nascar teams will effectively rotate their rear axle a couple degrees to the right, so the chassis sits at higher side slip through the corner.

That works well at something like Martinsville or Phoenix, but on a superspeedway it would be very slow.

Being loose after the apex, on corner exit, is never fast.

[marcush.]

theres a optimum level of slip for a given tyre under a certain vertical load.
A old bias ply tyre does like a lot more slip angle (drift) than a radial type tyre.
Generally slip angle will need energy ,so a low power car will possibly not exploit alot of slipangle ,because the gains made laterally will be sapped by parasitic losses longitudinally.
So as long as your vehicle is NOT power limited when cornering,you will be faster exploiting optimum slip angles,these depend on individual tyre make etc....

[Ciro Pabón]

Well put, marcush. However, with the current levels of downforce and the grip of modern tyres, I believe the effect is minimal. As usual, we would LOVE to have some hard numbers, even if tentative.

As you say, with old tyres and, better yet, on unpaved roads, the effect is quite notorious, like WRC proves. I mentioned what I felt in my old cars.

Just in case, for your entertainement, here you have a classic description, that you made me remember (thanks, it was interred deep down my PC! I haven't read it in years and still makes me shiver... ) and that I think is mandatory reading for would-be-drivers.:

Enzo Ferrari on Tazio Nuvolari, long before drifting was re-invented in the "Far East"

"At the first bend, I had the clear sensation that Tazio had taken it badly and that we would end up in the ditch; I felt myself stiffen as I waited for the crunch. Instead, we found ourselves on the next straight with the car in a perfect position.

I looked at him, his rugged face was calm, just as it always was, and certainly not the face of someone who had just escaped a hair-raising spin. I had the same sensation at the second bend. By the fourth or fifth bend I began to understand; in the meantime, I had noticed that through the entire bend Tazio did not lift his foot from the accelerator, and that, in fact, it was flat on the floor.

As bend followed bend, I discovered his secret. Nuvolari entered the bend somewhat earlier than my driver's instinct would have told me to. But he went into the bend in an unusual way: with one movement he aimed the nose of the car at the inside edge, just where the curve itself started.

His foot was flat down, and he had obviously changed down to the right gear before going through this fearsome rigmarole. In this way he put the car into a four-wheel drift, making the most of the thrust of the centrifugal force and keeping it on the road with the traction of the driving wheels.

Throughout the bend the car shaved the inside edge, and when the bend turned into the straight the car was in the normal position for accelerating down it, with no need for any corrections."

Nuvolari è bruno di colore, Nuvolari ha la maschera tagliente, Nuvolari ha la bocca sempre chiusa, di morire non gli importa niente…
Lucio Dalla song on Nuvolari


Lucio Dalla is crazy, IMHO...

Just to remember the master at Donington, 1938 (notice the clear drifting):
[youtube]http://www.youtube.com/watch?v=YmCJvDUWXaY[/youtube]

Finally, some words about his style (sorry, totally OOT, I was carried away! ):

Nobody else like him join an incredible sensitivity of the car with an inhuman courage
-- Enzo Ferrari --

He was a man that outraged the reality and he did things that were absurds... for youngs of that period, and me among them, Nuvolari represented the courage, an unlimited courage. He was the myth, the unreachable.
-- Michelangelo Antonioni --

Nuvolari is the greatest driver of the past, the present and the future
--Ferdinand Porsche --

Until in the world it will be spoken about automotive sport, will remember Nuvolari
-- Lord Howe --

Nuvolari, as well as being my greatest opponent, is the best driver in all times. He is not a master but an artist of driving. A master could teach. The art can't be taught.
-- Achille Varzi --

Art can't be taught.... sigh.

[marcush.]

Don´t get me wrong,I ´m not telling you to let the car slide and get sideways,this is just show and belongs to Drift challenge which is, well, entertaining .
I speak of maybe 2 to 5° of slip angle wich is barely visible to the casual observer .The real art is not and never get over the top maximum of lateral and longitudinal grip as soon as it counts in term of lap time.You need to go over these limits to get the tyres up to temp ,but if you don´t have the proper way to do it ,you might have abused the tyres before your qualy lap has even started.
íf you don´t push ,the tyres will not generate any heat to speak of nor will they stick.So with the no slip angle approach you will be dead slow because the tyre is slow(cold).Yoü might induce a little slip angle with toein or out ,generating the necessary heat ,but then you can´t exploit the potential because the tyres will overheat dramatically in a very short time...
Of course you can generate some heat braking and accelerating but as you can see in F1 theres good chances to create a confusion...and slolom driving does only one thing :getting rid of the marbles you pick up on the front tyres.
So ..back to square one...and YES,Nuvolari,Röhrl,Senna to name a few were real masters in exploiting this clean approach never overdoing this.

[Ciro Pabón]

Well, yes, that was I was talking about when I referred to a minimal effect. In the video I posted (the Donington one) you can see a larger effect, but then on the vertical curve shown (where the load on the tires diminishes) and that's with old ply tyres and no downforce at all. Thanks for your explanation.

BTW, does anybody knows of a program or software able to find the ideal trajectory for a particular curve? (the minimal time curve, that is)

Beckman announced its intention to derive it in his famous series on Physics of Racing, but he never produced anything practical, AFAIK.

[Jersey Tom]

Regardless of the tire, loose past the apex will not the fastest way around the track... unless you're talking about absurdly high overyaw and heaps of AWD power in which case your drive force becomes part of your cornering force.

It's not too terribly difficult to write software in Matlab to find "ideal trajectories" but you need a lot of very detailed tire, aero, vehicle, and track data. Detailed to the point such things are typical very expensive and/or confidential.

Lap sim software is out there, but to get anything useful out of it you need a LOT of good data. Engine maps, aero maps, combined slip F&M data, track data, K&C data..