Lift Off Oversteer absent from low powered FF cars?

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SergioRZ

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I rarely drive any FF's... but when I do, usualy in the 200bhp range (or less) like the Civic Type R for example, I always find myself wondering why it doesn't do any lift off oversteer like it does in the real world. And I mean NO lift off at all... I can only upset the rear end of the car by pushing the handbrake. This is very suprising...

Do you feel the same way, or do you have real world like lift off oversteer with FF cars in GT5? Maybe I'm doing something wrong...?
 
In order to force this, I abruptly life the throttle and rip the steering from left to right or vice versa. This normally will upset the rear end enough to act like lift-off over steer.
 
I agree 100%

Back in GT4 the lift off oversteer in some of the license tests was sublime, from what I remember. I'm not sure it's even limited to FWD. There's a few RWD cars I can't get to oversteer without throttle to save my life.

I think the physics model might have done away with it.
 
GT4's lift-off oversteer was mostly absent for many front-wheel drive cars.

GT5 is more realistic in this regard. The only problem is that some have identified a lack of engine-braking when you lift in the game.

From experience, this engine-braking has a lot to do with lift-off oversteer in front-drivers. This is why it is harder to do this on automatics, which don't downshift as you slow down. A rare exception is the CVT Sentra... in "L" mode, it stays at torque peak all the time... so it's very easy to kick the rear end out when lifting off.

Aside from that, it's fairly realistic... the behavior is correctly modelled if you're comparing it to an automatic version of the car. That extra x percent of tail-out you'd get with a manual is absent, though... sadly.

If you want to make your car tail-happier, you can play with the brake balance and ABS a bit.
 
On something like the Civic, stiffen up the rear (stiffer springs, MUCH stiffer rear anti-roll bars) to get it more lively at the rear. I have noticed that it's nowhere near real life on the '91 CR-X. My daily beater is a '91 CRX, and the "Scandinavian Flick" is a sure-fire way to get the tail wagging a bit - even more so if you do the flick, then bend into the turn WHILE lifting off the throttle. I can usually get all four tires drifting by doing this - the rears sliding, the fronts spinning, all great fun.
 
The only time i got lift-off oversteer on my EG civic was when i installed a set of coil-overs and sway bars, i have not tried this in the game yet.
 
psychot|K
I agree 100%

Back in GT4 the lift off oversteer in some of the license tests was sublime, from what I remember. I'm not sure it's even limited to FWD. There's a few RWD cars I can't get to oversteer without throttle to save my life.

I think the physics model might have done away with it.
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And you think that's a modeling error ? It is not.

Scotty
 
I doubt you're doing anything wrong OP, it's just not done right in GT5. I have tried using no ABS and get a bit of trail braking but that's as close as you can get, it is fun, but I doubt anyone could do a laptime anywhere close to a time with ABS on. I think lift off oversteer is almost exclusive to mid engined cars in GT5, unfortunately it has been toned down in everything else. There might be a few exceptions as I have not driven every car.
 
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When Prologue came out lift off owersteer was great,FFs were fun to drive,then they took it of.This game is for masses.-ex player with G27
 
In the real world, lift off oversteer is present in ANY car, regardless of drivetrain layout. the amount that is there depends on the suspension settings. I can speak from experience as I've successfully looped an Evo, S2000, Miata, RX-7, MR2 and GTi from lifting in a corner.

Most factory cars will have a spring and sway bias toward understeer ... soft in the rear and a little harder in the front with a bigger sway. This leads to understeer on and off the throttle. Shift this toward the rear (soften front, stiffen rear) and you will begin to get an oversteer happy car all around. A RWD car will overseer on lift and throttle and an FF car will develop oversteer on lifting.

Some cars are set up with more of an oversteer than others from the factory (Evo, STi, S2000 ... cars meant to go fast), where passenger cars (Civic, Mercedes sedan, etc) are heavily biased for comfort and understeer for safety. You will need to work more on those cars to induce oversteer.
 
TouringBubble
In the real world, lift off oversteer is present in ANY car, regardless of drivetrain layout. the amount that is there depends on the suspension settings. I can speak from experience as I've successfully looped an Evo, S2000, Miata, RX-7, MR2 and GTi from lifting in a corner.

Most factory cars will have a spring and sway bias toward understeer ... soft in the rear and a little harder in the front with a bigger sway. This leads to understeer on and off the throttle. Shift this toward the rear (soften front, stiffen rear) and you will begin to get an oversteer happy car all around. A RWD car will overseer on lift and throttle and an FF car will develop oversteer on lifting.

Some cars are set up with more of an oversteer than others from the factory (Evo, STi, S2000 ... cars meant to go fast), where passenger cars (Civic, Mercedes sedan, etc) are heavily biased for comfort and understeer for safety. You will need to work more on those cars to induce oversteer.
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While it's true to say that any car can experience lift off oversteer by some tuning work, it cannot be denied that this effect is more pronounced in rear engined cars. After all, the main cause of this phenomenon is the sudden shift of weight from the back to the front of the car, which undoubtedly is more significant an effect in a rear engined vehicle.
 
Wolf-M
... it cannot be denied that this effect is more pronounced in rear engined cars. After all, the main cause of this phenomenon is the sudden shift of weight from the back to the front of the car, which undoubtedly is more significant an effect in a rear engined vehicle.
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I 100% agree that MR cars are more prone to lift off and snap oversteer. The oversteer is caused by shifting the weight forward and off the rear wheels, changing to coefficient of friction and causing loss of traction.

However, oversteer more pronounced in rear mounted MR cars due to the location of the weight in the car and how that affects polar moment of inertia and the difference in CoF in comparison to a front engined car. It's even worse in a RR car like an older Porsche or VW. The shift in weight (consider a % shift when lifting) is similar between layouts in most cases.
 
I think part of it is some car's default setting seem way too stiff, wereas in a real car you get enough weight shift to initialize oversteer just by lifting mid corner, in GT5 the car's setup might mean it wouldn't do the same thing.
 
TouringBubble
I 100% agree that MR cars are more prone to lift off and snap oversteer. The oversteer is caused by shifting the weight forward and off the rear wheels, changing to coefficient of friction and causing loss of traction.

However, oversteer more pronounced in rear mounted MR cars due to the location of the weight in the car and how that affects polar moment of inertia and the difference in CoF in comparison to a front engined car. It's even worse in a RR car like an older Porsche or VW. The shift in weight (consider a % shift when lifting) is similar between layouts in most cases.
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Hmm, I've got a '78 Ferrari 308 GTB, which is a MR. Never seen any weight shifting in the car! The weight, aside from sloshing of fluids (e.g., gas in the tank), isn't moving. What it is is a change in dynamic forces. Consider going in a straight line at constant speed (acceleration is zero). Contact force at the wheels is constant, and the balance is based on the weight distribution of the car. Now consider the same car suddenly lifting off the throttle. The car, due to the location of the CG above the contact plane with the road, wants to pitch forward. This increases the contact force on the front wheels and reduces it on the rears.

Now resistance to side slip/yaw is from friction at the wheel/road interface. Simple model for friction is that the friction force is linearly proportional to contact force, or F_fric=mu*F_contact, mu=constant. I'm sure most games use such a model, though in reality it's much more complex (i.e., mu is not constant but a function of contact force itself). Under zero acceleration yaw resistance is provided at all wheels. With that change in acceleration and reduction in contact force, friction force at the front increases, but at the rear it decreases. So it takes less side force to induce a yaw motion.

It's as simple as that. Simple dynamics.
 
Weight transfer is a dynamic effect, but it really is a transfer of weight. Let's say you have a 1000 kg car with a 60 / 40 weight distribution - at rest you have a force of 600 N at the front, 400 N at the back holding the car up. Under steady braking that might change to 750 N / 250 N. The car is not accelerating into or away from the ground, so the weight of the car is being balanced exactly by the reaction force from the ground. The front tyres are supporting a greater proportion of the weight of the car, hence the use of the terms "weight transfer" or "weight shift".
 
RUFin
When Prologue came out lift off owersteer was great,FFs were fun to drive,then they took it of.This game is for masses.-ex player with G27
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Totally agree with you on that! I miss lift off oversteer too, it's absence is yet another one of the ways the physics model has been watered down for the mass market. Also, modluating the throttle to recover the rear like you would in a in a RWD car real life car doesn't work in GT5 (you just carry on power sliding), best way to recover the rear in this game is to come off the throttle altogether, which wouldn't work in real life as that would just just induce lift off oversteer. The physics model feels watered down & plain wrong in some areas to me & yes I have driven a few race cars in real life, both RWD & FWD.


:grumpy:
 
BobElHat
Weight transfer is a dynamic effect, but it really is a transfer of weight. Let's say you have a 1000 kg car with a 60 / 40 weight distribution - at rest you have a force of 600 N at the front, 400 N at the back holding the car up. Under steady braking that might change to 750 N / 250 N. The car is not accelerating into or away from the ground, so the weight of the car is being balanced exactly by the reaction force from the ground. The front tyres are supporting a greater proportion of the weight of the car, hence the use of the terms "weight transfer" or "weight shift".
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Um, not really. Even if you have a rigid suspension there would be no "transfer of weight". It's strictly an F=ma thing. The inertial properties aren't changing at all. What is changing is the "a" thing, and that causes changes in contact forces with the ground. But as most of the population don't understand/care about kinematic/flex body simulations, the rather misleading term "weight transfer" has unfortunately been accepted.
 
I was doing an online shuffle race last night, and I ended up racing with an FTO, and I have to say that the liftoff was present 👍
 
First I also thought lift off oversteer is too light. However, you should keep in mind that low powered cars with sport, not to mention racing tires, just dont carry enough speed to break the superior traction of those beasty tires.
It's much more evident on comfort , sport hard tires.
 
tigermilk
Hmm, I've got a '78 Ferrari 308 GTB, which is a MR. Never seen any weight shifting in the car! The weight, aside from sloshing of fluids (e.g., gas in the tank), isn't moving. What it is is a change in dynamic forces. Consider going in a straight line at constant speed (acceleration is zero). Contact force at the wheels is constant, and the balance is based on the weight distribution of the car. Now consider the same car suddenly lifting off the throttle. The car, due to the location of the CG above the contact plane with the road, wants to pitch forward. This increases the contact force on the front wheels and reduces it on the rears.

Now resistance to side slip/yaw is from friction at the wheel/road interface. Simple model for friction is that the friction force is linearly proportional to contact force, or F_fric=mu*F_contact, mu=constant. I'm sure most games use such a model, though in reality it's much more complex (i.e., mu is not constant but a function of contact force itself). Under zero acceleration yaw resistance is provided at all wheels. With that change in acceleration and reduction in contact force, friction force at the front increases, but at the rear it decreases. So it takes less side force to induce a yaw motion.

It's as simple as that. Simple dynamics.
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You are correct, and you're discussing the CoF in the same way I was. when discussing an MR specifically, I was talking about the positioning of the weight over the wheels.

When the car begins to oversteer, the pivot point is, essentially, over the front wheels. In a front engined car, most of the weight (the engine) is over the front wheels. When the engine is moved to the rear, this relationship changes, and therefore the way it slides and corrects also changes.

If you've ever raced different drivetrain layouts, you learn that you correct for oversteer in each in different ways. In a FF car, you countersteer and floor it so that the drive wheels essentially pull you out of the skid. In a FR car, you modulate the throttle to balance the weight so that the rear tires regain some traction, but the torque doesn't keep them slipping. An MR car is different, even though still RWD. If you lift too much, the rear gets too much traction you get snap oversteer as the suspension and tires try to deal with the weight positioned so far back. Therefore, you apply more throttle than in a FR and with more delicate steering inputs to keep it in line.

And "weight" discussed here has nothing to do with weight distribution in terms of suspension. A car can have a perfect 50:50 distribution at the tires and still have a large portion of the physical weight distributed unequally. That's the magic of distributing weight between 4 points with varied spring rates.
 
Supercheyenne
What does this say about your driving skills? :nervous:
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It means I drive at the limit. A common saying in autocross is, "If you haven't looped it or hit some cones, you're not driving hard enough."

I think being voted Driver of the Year for 2010 in my region says plenty about my driving skills. =)
 
TouringBubble
It means I drive at the limit. A common saying in autocross is, "If you haven't looped it or hit some cones, you're not driving hard enough."

I think being voted Driver of the Year for 2010 in my region says plenty about my driving skills. =)
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Also this: "If everything seems under control, you're just not going fast enough." - Mario Andretti.

I don't know how anyone can say GT4 had lift-off oversteer, did you ever play it? The cars were as dead as Tommy Wiseau's acting when coming off the throttle. I've driven one or two cars in GT5 that have had a little lift-off, but it's not like I've experienced in real life. French superminis, for example, are renowned for their lift-off oversteer scariness but I haven't seen any yet (though I've only driven the 207 GTi...).

I'm not sure this is a physics engine thing, though, it seems to me more to do with default settings of various cars, particularly the default tyre choice. It seems too generic to me. That said, engine braking is more or less absent from what I can tell, and that's a shame.
 
The engine braking issues seem to have a bearing, as does the tire choice. It's been mentioned a few times already, but you can't expect a 200hp car on Sport Softs to have drastic lift off oversteer. Put it on Sport Hards or Comfort Softs and see how it acts with some stiff suspension in the rear. The weight (distribution) definitely moves around, and if they are using any decent physics model, the lift off oversteer should be present.

And I don't remember the handling characteristics of GT4 honestly ... it' been a while since I've driven that one. Might have to load it up though.
 
This now makes me want to find a Clio 172 in the UCD and try to make it tripod on bends :D

lift off oversteer can be quite scary on public roads, especially on roundabouts with big curbs!
 
The term you are looking for is 'The Polar moment of Inertia' Weight shift exsists on all cars.

Lets not get too detailed but just think of it as the percentage of wieght spread between all four wheels. Then think of the forces you as a driver/passenger feel IRL.

As a car accelerates/brakes and steers this percentage of wieght will shift around the four corners of a car.

It is this weight shift that we as drivers control and manage to maintain, to achieve a lap time.

Think about a standard FF car and think about the shape of an F1 car, the wieght is centralised in the F1 car to create as balanced a c of g as possible.

Now think about the shape of a road car by comparison. Due to the 'haphazard' design constraints of a road car the polar moment of inertia will always be bigger. This is due to the increased distance the center of gravity is from the optimum point in the car.

As the weight 'shifts' the tires will be loaded/unloaded and that will dictate how much grip each wheel will have. This in turn will determine how the car can be driven ( inertia managed) and will turn into the under/oversteer we strive to control in every corner.
 
waboo
The term you are looking for is 'The Polar moment of Inertia' Weight shift exsists on all cars.
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TouringBubble
However, oversteer more pronounced in rear mounted MR cars due to the location of the weight in the car and how that affects polar moment of inertia and the difference in CoF in comparison to a front engined car.
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Yeah, I stated that earlier, but it fell on deaf ears. =) Thanks for the clearer explanation.

There is a lot to vehicle dynamics. It's kind of like suspension, where many people know just enough to get in trouble. I've done this myself. It's weird ... as you learn more and more, the original ideas you had will become false, then true then false again depending on how you look at it. "Yes, stiffer sways add grip ... but too stiff lowers grip ... but depending on the car and spring rates, they still add grip even though it causes the rear to loose grip." Lol.

Either way, I enjoy a good discussion.
 
GT5 Prologue had great lift off oversteer, power oversteer & engine braking. I drove in that sim right up till the day before GT5 was released & I've gotta say that I was seriously not impressed with the new physics in GT5. I'm getting used to them but they still don't feel realistic enough for a self titled "Driving Simulator", very disappointing.


👎


PS: Good point about the lack of engine braking contributing to the lack of lift off oversteer.
 

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