GT and the understeer tradition

[GT Motion]

Kind of disappointed no one's done a g27 --> DFGT comparo yet to back up my findings.

Oh well...

I don't have either of those wheels however I do play on a G25 and have used both that and the controller and I cannot feel any significant issues with understeer/oversteer, it feels how I would expect it to.

 

[Scaff]

And what comes to the part of ABS, I was testing the situation when ABS had not activated, but it was turned on in the menu. The car handled differently with ABS on and off in the menu, but in neither case did the ABS system actually activate, no lockup, just threshold braking. YET there still was a difference in handling.

Do you understand what Im getting at?

I do, but if you are braking in a car with ABS fitted, the ABS may well be activated long before lock-up occurs (which is 100% slip).

Have a read of this.....

ABS Control In Super-Slow-Mo
In order to best explain how the ABS "depends" on the base braking system, let's have a look at a typical ABS event at the micro level - from the processing algorithm's perspective.

Say you are driving down the highway at 75 MPH (the posted speed limit, of course) when all of a sudden the truck in front of you spills its load of natural spring water across all three lanes of traffic. Now, this alone would not be so bad, except the water is still sealed in 55-gallon drums - one of which would certainly make a mess of your car's front fascia. Time to take evasive action.

Being the trained high-speed individual that you are, you immediately lift off the gas, push in the clutch (you are driving a manual transmission, right?), and simultaneously nail the brake pedal...but in the heat of the moment you hit it a little too hard.

Meanwhile, the ABS is hanging back watching the world go by, seeing a constant stream of 75 MPH signals from its four wheel speed sensors. Let's call this "observation mode." Upon your application of the brake, however, the ABS snaps to attention, its antenna up, ready for action. You have just hit the brake pedal after all, and who know what's coming next.

After 50 milliseconds (it's actually much faster than that - 7 to 10 milliseconds is typical - but it makes the math easier) the ABS takes another snapshot of the wheel speed information in an attempt to figure out what's going on. This time the wheel speed sensors are all reporting a speed of 74 MPH. Doing a quick calculation, the ABS determines that in order to have slowed 1 MPH in a 50ms period the wheels must be decelerating at a rate of 0.91g's. Because you are driving a sports car, the engineer who calibrated the system 'taught' the ABS that your car is capable of decelerating at this rate, so the ABS continues to hang back and watch the event from the spectator's booth. No problem so far.

The next 50ms, however, are a little more interesting. This time around, the wheels are reporting 72.5 MPH. Now, it may not seem like a big jump, but to slow 1.5 MPH in a 50ms window equates to a deceleration of 1.36g's. Not alarming, but the ABS 'knows' that based on this deceleration level, the wheels are probably beginning to slip a little more than they should - after all, your car is probably not decelerating at quite 1.36g's..and any error between the two indicates slip.

ABS is now in "ready mode." It's probably too soon to jump in, as the wheels might spin back up on their own in the next 50ms loop, but things are definitely looking bad!

As the first barrels of spring water bounce left and right, missing your car by inches, you stay on the brake pedal but push even harder. This time around, the left front wheel speed sensor is registering 68 MPH - a 4.5 MPH drop in the last 50ms, or a deceleration level of 4.1g's. Doing the math faster than you can (after all, you are busy dodging barrels of spring water), the ABS quickly comes to the conclusion that, unlike the left front wheel at this moment, the car cannot possibly be decelerating at 4.1g's. Best case is that the car was decelerating at 1.0g (or thereabouts) over the last 50ms, so the 'real' vehicle speed is still somewhere around 71.5 MPH, even though the left front wheel speed is reading 68 MPH - a 3.5 MPH error.

So, based on a wheel deceleration of 4.1g's, a slip level of 5% (3.5 MPH 71.5 MPH), and a couple other factors not listed here, the ABS jumps in and enters "isolation mode." (Note that the wheels are nowhere even near "wheel lock" - the 100% slip point.) The first thing the ABS does is shut off the hydraulic line from the master cylinder to the left front caliper, isolating the driver from applying more pressure - after all, it was the driver that got us into this mess in the first place.

Next, the ABS starts work in "decrease mode," releasing the excess pressure from the left front caliper in order to allow the left front wheel to reaccelerate back up to the vehicle's actual speed - 71.5 MPH in this case. Since the ABS knows how quickly the wheel is decelerating (4.1g), how fast the car is actually going (71.5 MPH), and the pressure-torque characteristics of the left front caliper/pad/rotor assembly (we'll come back to this one in just a second), it can precisely calculate how long to open its release valve to vent that extra pressure, leaving just enough pressure in the caliper to maintain 1.0g of deceleration (or thereabouts).

Let's say that calculated time turned out to be 10 milliseconds (this again makes the math easier later on). Bang! Valve opens, pressure is released, and 10ms later it closes, leaving just the right amount of pressure in the caliper so that the wheel spins back up to exactly 71.5 MPH, but continues to decelerate at 1.0g. Everything is going as planned.

Time to close the loop and enter "increase mode." Once the ABS sees that the left front wheel has returned to near the 'real' vehicle speed, it slowly reapplies pressure from the master cylinder to make sure that maximum sustainable brake force is being utilized. To this end, the ABS calculates precisely how long to pulse open the isolation valve, slowly building pressure at the left front caliper until once again the left front wheel begins to slip. It performs this calculation based on - you guessed it - how quickly the wheel is re-accelerating, how fast the car is actually going, and the pressure-torque characteristics of the caliper/pad/rotor assembly.

In our hypothetical little world, the ABS calculated that four pulses of 5ms each were necessary to build the wheel pressure back up to the point that the wheel began to slip again, returning to "isolation mode."

The cycle is repeated on all four wheels simultaneously until either the driver gets out of the brake pedal, or until the car has come to a stop. Hopefully, this did not include punting a spring water barrel or two along the way as the ABS kept all four wheels slips in the 5%-10% range, allowing you to turn and swerve to your heart's content as the drums bounced out of your path. Happy car, happy driver.

Source - http://www.stoptech.com/tech_info/wp_abs_bigbrakekits.shtml

I've highlighted the important part in bold, but you would do well to read the entire thing.

Now working on the assumption that PD have modeled the ABS system in a similar manner to real-world system, then the ABS will kick in when x% slip is detected. Which would put it right in the area of threshold braking, which is between the point of zero slip and the drop-off to lock-up (which varies from tyre to tyre and car to car).

As you can see from the above slip curves, the largest amount of grip exists when the tyres are slipping to a certain degree. The source of that graph also contains a solid description of how ABS works.

The curve relating to straight line braking is the Longitudinal Mu Slip Curve.

The far left of the curve is zero slip. So at zero slip, the tire has no traction. A tire needs to be in slip to generate traction.

The peak of the curve is the tire's maximum grip level, which occurs at a given amount of slip. A very good racecar driver is capable of modulating the brakes to keep the tire operating at or very near the peak of this curve. This is called threshold braking.

Once you exceed the peak of the mu slip curve, traction becomes unstable and the wheel rapidly slows down relative to roadspeed and locks up. This happens very quickly. It is not possible to modulate the brakes to have the tire stay in a given location past the peak of the curve. The tendency will always be towards lockup.

As you can see, as the tire approaches lock-up (towards the right of the graph) the tire's traction decreases. So a locked wheel/tire is much less efficient than a tire operating at the peak of its mu slip curve.

ABS operates in the range of slightly before the peak to slightly past the peak of the mu slip curve. When the ABS computer senses excessive slip (by comparing a given wheel speed to the wheel speed of the other tires), the ABS system releases brakeline pressure to the wheel with excessive slip to get it rolling near road speed again. The tire is now operating to the left of the peak. It then reapplies brake pressure until it senses excessive slip again and repeats the cycle. Many times per second. So ABS keeps the tire operating around the peak of the mu slip curve, but does not maintain at the very peak of the slip curve.

The more sophisticated the ABS system, the closer it is able to operate at the peak of the mu slip curve.

Source - http://www.standardshift.com/faq/index.php?n=Standardshift.ExtendedFAQ


So in closing, yes I do understand what you are saying, I just think its based on a false premise. If a car is fitted with ABS and that ABS is active and you are braking on the limit (threshold), then the ABS is active or at the very least is going to be coming on and off.


Regards

Scaff

 

[Tweetman_277]

Its the Tyres overheating... If you brake in pure straight lines, or just not to 100% all the time, no freak understeer

 

[SuperCobraJet]

Lol wtf is 15 pm?

Anyway This always annoys me about Driving games. They never set the damn suspension, TCS, ECS, ASC, etc settings the SAME as the real life cars have when in stock form. I dont understand how they can claim any realism aspects without this, it is such a MASSIVE flaw.

Assuming they could even do that, I don't see the relevance of it on eliminating understeer. The vast majority of stock form real-life cars understeer. Some to more of an extent than others.

I don't quite understand this whole understeer discussion, which has been brought up on GTP more than once.

In reality the neutral to slightly loose setup of a car is at the mercy of so many variables it is practically impossible to achieve and if achieved, very difficult to maintain. At least in a push to the limits of the car, which is a given in most racing.

For example, NASCAR cup cars are designed, engineered and hand-built to a track, specifically to achieve that very purpose. Multi millions are expended in an ongoing basis for R&D and the components to produce it. Yet come the race, it is still a huge challenge to achieve and maintain the consistency of a "neutral setup". It could be said that likewise the majority of tracks they run on, only have two corners, so it doesn't sound like it would be that complex, but it is. Therefore if practically unlimited resources on a two corner track can't hardly achieve it, then it is not that simple or easily done, especially in a production car.

As to the game, with a full compliment of suspension and wieght balance adjustments (the latter mysteriously missing in GT5?) and the other tuning options (ABS etc) it should be possible to get close too, if not achieve a neutral balance in most cars.

 

[keitshi]

I do, but if you are braking in a car with ABS fitted, the ABS may well be activated long before lock-up occurs (which is 100% slip).

Have a read of this.....


Source - http://www.stoptech.com/tech_info/wp_abs_bigbrakekits.shtml

I've highlighted the important part in bold, but you would do well to read the entire thing.

Now working on the assumption that PD have modeled the ABS system in a similar manner to real-world system, then the ABS will kick in when x% slip is detected. Which would put it right in the area of threshold braking, which is between the point of zero slip and the drop-off to lock-up (which varies from tyre to tyre and car to car).

As you can see from the above slip curves, the largest amount of grip exists when the tyres are slipping to a certain degree. The source of that graph also contains a solid description of how ABS works.


Source - http://www.standardshift.com/faq/index.php?n=Standardshift.ExtendedFAQ


So in closing, yes I do understand what you are saying, I just think its based on a false premise. If a car is fitted with ABS and that ABS is active and you are braking on the limit (threshold), then the ABS is active or at the very least is going to be coming on and off.


Regards

Scaff

Thanks about the ABS info. I did not know exacly the criteria for ABS operation, interestin to read. I knew that it monitored tire rotation but didnt consider how much. I stand corrected.

I do know tire slip angles and traction. But the thing remains that I drove a car with ABS on and off in gt5, unable to rotate the car with brakes when ABS was on and could with ABS off. How do you explain that? Try what I did, am I seeing things?

edit: Heres a thought, Im driving at highway speeds on a road in a real car say a regular ff hatch. I turn sharply while applying moderate brake (like a panic evasion). The car only has ABS. I will spin and cause an accident most likely. Do that in gt5 and nothing happens, I just understeer. Turn off ABS, then it does what I expect.

 

[CSLACR]

Thanks about the ABS info. I did not know exacly the criteria for ABS operation, interestin to read. I knew that it monitored tire rotation but didnt consider how much. I stand corrected.

I do know tire slip angles and traction. But the thing remains that I drove a car with ABS on and off in gt5, unable to rotate the car with brakes when ABS was on and could with ABS off. How do you explain that? Try what I did, am I seeing things?

I tried it and had the same effect. But that was with 5/5 brake bias. If the rear brakes lock first, the car will start to rotate, at which point locking all four wheels will result in only one thing: Continuing to rotate. I really think you have two problems here, first, to high corner speed entry / to hard braking for turn in, and/or improper brake bias.

 

[Scaff]

edit: Heres a thought, Im driving at highway speeds on a road in a real car say a regular ff hatch. I turn sharply while applying moderate brake (like a panic evasion). The car only has ABS. I will spin and cause an accident most likely. Do that in gt5 and nothing happens, I just understeer. Turn off ABS, then it does what I expect.

Why would you spin?

In very simplistic terms understeer is when you front tyres have less grip than your rear tyres.

Your applying braking force (and the majority of it as that) and steering force to the front tyres, your rear tyres have no direct steering force applied to them and a small amount of the braking force.

Assuming your brake bias is fine you far more likely to understeer in this situation, as your front tyres have now reached the limit of grip prior to the rears. What ABS would do in this situation (and exactly what it is designed and was invented for) is do its damnedest to allow you to steer out of the situation in question.

In the situation you have described here a front-wheel drive car is not going to spin at all, with or without ABS.

To initiate a spin in either of these situations you would need either another rapid change of direction, to lift of the brakes sharply or a combination of both.

I would recommend downloading the first of my tuning guides (link in my signature), which contains a detailed breakdown of the exact causes of under and oversteer.

Now one thing to keep in mind with GT5 is that from my early testing it would seem to share at least one trait with GT5. That is the brake bias is of limited effect until you switch the ABS right off, then it starts to play a major role in what is happening. With a default setting of 5:5 it has a far to high rear bias and would start to cause a car to step out at the back under braking.

Be under no illusion however, no road car would ever be set-up in this way, quite the opposite. Manufacturers heavily bias the brakes to the front, often more than is required, for the simple reason that understeer is a much more desirable trait in a road car that oversteer, particularly when braking from high speed.

Regards

Scaff

 

[Mad Matt]

A few hours playing with a Mk3 MR2 seems to suggest that the under-steer/over-steer is not far off the real thing. In general the feel of balance seems OK. It's a bit hard to tell because the in game car appears not to have an LSD whereas the European version with six speeds all did.

The only thing that caught a bit was braking and changing down caused more instability than I expected.

Of course I'm a lot braver in the game and more inclined to keep my foot in so catching over-steer moments is a little easier than in real life.

I'm also interested in the whole braking thing. Some cars have emergency brake assist (or similar) which will increase braking force for you if they think you're doing an emergency stop. I don't think that's modelled in the game.

To be honest braking in the game can be tricky as I can't feel the force like I can in a real car so it's easy to treat it as an on/off switch. I suppose it is to GT5s credit that it makes me pay for that more than in the previous version.

Finally I hope to test the Fiat Barchetta as I wasn't very happy with that in GT4 where it seemed to me to be an under-steery low traction nightmare which it wasn't in real life. I also noticed a huge difference by putting sports suspension on in real life, which wasn't matched correctly in GT4 (in my opinion). So, I'm looking forward to see the difference that makes in GT5 on the dynamics of cornering, lift off over-steer and braking.

 

[thedeester1]

I saw it in previous versions but dont think this version is too bad to be honest. They seem to have got the lift off oversteer pretty close. At one time in Prologue there wasnt any then there was an update and it was overdone then the last time it seemed pretty natural.

In previous versions I spent hours on the LSD (not the drug) just to get a natural feeling car. Some cars just have understeer. Not just the FF ones either. I had a classic Impreza a few years ago for road and some track days. It was, for a 4wd shocking for understeer. Talking to other scooby drivers at track days there were all sorts of mods. Anti roll bar bushes. Differing drop links for the front and rear. Top anti roll bars across the engine bay and the boot. The list was endless you could have thrown a whole lottery win into making that car neutral or oversteer.

I was once told that the car was designed to understeer since Subaru based its marketing on rally success. Apparently rally drivers dont like oversteering cars since the surfaces they drive on are often loose and the back of the car will come out naturally anyway. Im not sure how true that is but when you look at the top rally cars over the past few years a whole lot are front wheel drive and they are supposed to be the worst model for understeer.

 

[keitshi]

I tried it and had the same effect. But that was with 5/5 brake bias. If the rear brakes lock first, the car will start to rotate, at which point locking all four wheels will result in only one thing: Continuing to rotate. I really think you have two problems here, first, to high corner speed entry / to hard braking for turn in, and/or improper brake bias.

I had brake bias at 2/0 and the car was the citroen c4 hatch. I specifically did not brake hard to avoid what you are saying.

 

[Scaff]

In previous versions I spent hours on the LSD (not the drug) just to get a natural feeling car. Some cars just have understeer. Not just the FF ones either. I had a classic Impreza a few years ago for road and some track days. It was, for a 4wd shocking for understeer. Talking to other scooby drivers at track days there were all sorts of mods. Anti roll bar bushes. Differing drop links for the front and rear. Top anti roll bars across the engine bay and the boot. The list was endless you could have thrown a whole lottery win into making that car neutral or oversteer.

Most road cars are biased towards understeer full stop. Manufactures want a car that's natural state is to understeer, simply because its the safest and easiest for the man in the street to deal with.

4WD are also prone to understeer almost to the same degree as FWD cars, particularly with the diff set-ups most run for the road. Even the most famous of the WRC 4WDs, the Audi Quatrro was an understeering nightmare on tarmac (watch any footage of the tarmac rallys from its debut year to see exactly what I mean).

I was once told that the car was designed to understeer since Subaru based its marketing on rally success. Apparently rally drivers dont like oversteering cars since the surfaces they drive on are often loose and the back of the car will come out naturally anyway. Im not sure how true that is but when you look at the top rally cars over the past few years a whole lot are front wheel drive and they are supposed to be the worst model for understeer.

How a rally driver likes a car set-up depends as much on the driver as anything else, but the days of mad tail-out exploits pretty much died with the birth of 4WD machines. Neat and tidy is the way to go in the WRC these days.

In regard to the current top WRC cars being FWD, not true I have to say. They may be based on FWD road cars, but the lot of them are 4WD machines.


Regards

Scaff

 

[keitshi]

Why would you spin?

In very simplistic terms understeer is when you front tyres have less grip than your rear tyres.

Your applying braking force (and the majority of it as that) and steering force to the front tyres, your rear tyres have no direct steering force applied to them and a small amount of the braking force.

Assuming your brake bias is fine you far more likely to understeer in this situation, as your front tyres have now reached the limit of grip prior to the rears. What ABS would do in this situation (and exactly what it is designed and was invented for) is do its damnedest to allow you to steer out of the situation in question.

I know, yet with ABS on it understeers but with ABS off it oversteers in gt5. Is that not the opposite?
edit: That is good reasoning but dont forget weight transfer. Mind you I have experienced that situation in reality, though not at such high speed, maby I was dreaming?

It was a yaris on tarmac, the newer model in gt5 speed at 70km/h brake and turn tail comes loose. I did catch it no harm done, but I cant do that in gt5 with the same car. The yaris is very nervous on the limit in reality, but in gt it is so calm and neutral.

In the situation you have described here a front-wheel drive car is not going to spin at all, with or without ABS.

To initiate a spin in either of these situations you would need either another rapid change of direction, to lift of the brakes sharply or a combination of both.

Oh, I mean not a complete spin, but that the tail comes loose and you go allmost sideways. Obviously if you lift at the edge you will fling back.

Be under no illusion however, no road car would ever be set-up in this way, quite the opposite. Manufacturers heavily bias the brakes to the front, often more than is required, for the simple reason that understeer is a much more desirable trait in a road car that oversteer, particularly when braking from high speed.

Regards

Scaff

Yes thats why I had brake balance at 2/0. Regular cars are set for understeer yes, but tires and setups can only do so much to a point. If you go past the performance limit of tires and car, you will lose controll. When doing high speed braking weight transfer is really high, so there is really not much holding the rear tires, even if the car is setup for understeer, you will lose the tail.

 

[thedeester1]

Most road cars are biased towards understeer full stop. Manufactures want a car that's natural state is to understeer, simply because its the safest and easiest for the man in the street to deal with.

4WD are also prone to understeer almost to the same degree as FWD cars, particularly with the diff set-ups most run for the road. Even the most famous of the WRC 4WDs, the Audi Quatrro was an understeering nightmare on tarmac (watch any footage of the tarmac rallys from its debut year to see exactly what I mean).



How a rally driver likes a car set-up depends as much on the driver as anything else, but the days of mad tail-out exploits pretty much died with the birth of 4WD machines. Neat and tidy is the way to go in the WRC these days.

In regard to the current top WRC cars being FWD, not true I have to say. They may be based on FWD road cars, but the lot of them are 4WD machines.


Regards

Scaff

Not wanting to get into an argument but the rear wheel drive was pretty much killed by the Mini Cooper. My Dad had videos (and they were remakes) of it destroying all comers (1960's?). If you get the chance try to watch them as a Britisher you will swell with joy as I did, I think. It was tiny FF and its power to weight ratio took it farther than the big engines with rwd.
I know also that some cars are based on road cars but have differing drive trains. However in most of the groups now they have to be the same for homologation purposes (have to build so many road cars before they can rally it. It has to keep the same body and drive train. Almost everything else is upgraded). The rules changed in the late 80's I think with group B i think it was (Maybe wrong on the group). Manufacturers were modifying road chassis with different drive trains and super engines and unrecognisable body work. This soon became a place to test concept cars which were not really safe and some people did die as a result. The RS2000 is probably the best remembered along with the Metro 6R4.

I had a metro once. Ok it had 4wd the 6R4 but you wont wanna crash one at more than 130mph. Someone wrote mine off in a Queue shunt. Their bonnet knocked down the back seat. I looked back saw a Ford badge, then thought OMG the petrol tank and got out of the drivers window sharpish!

I never got to drive a quatro yet....Not an old one anyway. Ive driven some of the newer ones at track days with a "bend it you mend it" agreement. Ive also driven an Evo VI and none understeer like the scoob!. I miss those track days I have a Golf TDI GT now...Its not bad its 130bhp and does 50 to the gallon but its not the same as a 270bhp scoob!

EDIT: There are the 4wd versions in rally that do fit thats why manufactures build limited editions in 4wd...The last time I looked it was only 500 road cars but I dont follow it so closely now.


Ok The C4 had 4wd but the Xsara probably the most successfull car in WRC was FF (You got me on one)!

 

[VXR]

I've driven extensively since passing my test on Dartmoor's off-camber roads, Scaff. Whilst I might not have any professional training, having driven many different types of vehicles in my six years with a license, I'm not wet behind the ears with regards to car control, corner entry, instinct or ability to get on the pace.

What makes you think I lack experience? That I don't like GT thus far but like Forza? That just proves these sims aren't and wont ever be black and white with regards to realism if you're using one as a benchmark and dismissing the opinions of others and their driving experience because they prefer the feel of the other. I enjoy reading what you write, because posts with knowledge are always welcome, but I don't think you can state any authority with your driving experience on a computer game any more than I can (and I'm sure I have done, no need to hunt the quotes!).

I'm sure we could all equate a feeling we get in either of the games that feel more like our own driving experiences and with the way I drive, it feels closer to the FM experience than GT's.

 

[Scaff]

Not wanting to get into an argument but the rear wheel drive was pretty much killed by the Mini Cooper. My Dad had videos (and they were remakes) of it destroying all comers (1960's?). If you get the chance try to watch them as a Britisher you will swell with joy as I did, I think. It was tiny FF and its power to weight ratio took it farther than the big engines with rwd.

Sorry but not even close to correct.

Yes the Mini was a giant killer, but it was far from the case of the death of RWD in rallying.

The Escort Mk1 and Mk2 were both rear wheel drive, competed after the Mini and was the most successful rally car ever (not WRC car that we will come to later).

Then we can look at the likes of the early group B cars, such as the Renault 5 Turbo (RWD), Lancia 037 (RWD) and Opel Manta 400 (RWD). All RWD, all long after the Mini debuted.

I went to my first rally (RAC rally of GB) with my dad aged 5 and have been a fan ever since (now 40).

I know also that some cars are based on road cars but have differing drive trains. However in most of the groups now they have to be the same for homologation purposes (have to build so many road cars before they can rally it. It has to keep the same body and drive train. Almost everything else is upgraded). The rules changed in the late 80's I think with group B i think it was (Maybe wrong on the group). Manufacturers were modifying road chassis with different drive trains and super engines and unrecognisable body work. This soon became a place to test concept cars which were not really safe and some people did die as a result. The RS2000 is probably the best remembered along with the Metro 6R4.

EDIT: There are the 4wd versions in rally that do fit thats why manufactures build limited editions in 4wd...The last time I looked it was only 500 road cars but I dont follow it so closely now.

Manufactuers do not now have to build a 4WD version of the car for homolgation purposes:

• Modified front and rear suspension layout and attachment points
• Add-on turbocharger even if the production car does not have one
• Modified transmission and additional transmission tunnels in order to fit a 4x4 transmission even if the production car is 2 wheel drive. Consequently differentials and gear box are free.
• Modified engine intake and exhaust systems
• Modified engine position (the engine can be relocated by a maximum of 20mm as compared to its original position and can be tilted by 20° around the crankshaft axis)
• Modified wheelbase (±20mm) and track widths (1550mm max)
• The maximum car width allowed is 1770 mm
• Minimum length of 4000mm

Source - http://www.rallycars.com/Cars/Cars_Background4.html

They have not for a good number of years. Ford do not make a 4WD version of the Focus and Citroen do not make a 4WD version of the C4.

Ok The C4 had 4wd but the Xsara probably the most successfull car in WRC was FF (You got me on one)!

The Xsara is a long way from being the most successful WRC car, that would be the Lancia Delta (4WD), with the most successful team being Ford (as of this year) with only RWD and 4WD cars.

I've driven extensively since passing my test on Dartmoor's off-camber roads, Scaff. Whilst I might not have any professional training, having driven many different types of vehicles in my six years with a license, I'm not wet behind the ears with regards to car control, corner entry, instinct or ability to get on the pace.

I've been driving in excess of twenty years and have countless hours of track time and proving ground time and would still consider that I am still learning.

I have taught drivers, both the practical skills and the theory behind vehicle dynamics, yet given all that I would still not make the definitive statement you do.

I base my comments on your own, that you had not felt understeer in your own car often and that you could touch the brakes in GT5 and know it terminal understeer. To be honest it sounds to me that you do still have a lot to learn about exactly what a car does on the very limit.

If you can book a session at a skid pan, honestly it will teach you a lot. I still do one every few years and its a great refresher.

What makes you think I lack experience? That I don't like GT thus far but like Forza? That just proves these sims aren't and wont ever be black and white with regards to realism if you're using one as a benchmark and dismissing the opinions of others and their driving experience because they prefer the feel of the other. I enjoy reading what you write, because posts with knowledge are always welcome, but I don't think you can state any authority with your driving experience on a computer game any more than I can (and I'm sure I have done, no need to hunt the quotes!).

I've not mentioned Forza at all and you quite clearly do not know my views on it at all if you are trying to drag things in that direction.

I'm sure we could all equate a feeling we get in either of the games that feel more like our own driving experiences and with the way I drive, it feels closer to the FM experience than GT's.

Once again you are assuming a position that I don't actually hold.

If you actually knew my opinion you would know that I believe neither of these titles gets it 'right' and that each have their own strengths and weakness's. However it does seem to show your own feelings on the matter in a clearer light.



Scaff

 

[CSLACR]

It was a yaris on tarmac, the newer model in gt5 speed at 70km/h brake and turn tail comes loose. I did catch it no harm done, but I cant do that in gt5 with the same car. The yaris is very nervous on the limit in reality, but in gt it is so calm and neutral.

I've experienced what you speak of in other FF cars, and understand what mean. In some ways, you are right, certainly, that it's next to impossible to make FF cars in GT5 oversteer no matter your input. My only blockade has been that I haven't driven nearly a single FF car in GT5. (in real life)
But instead of 2/0, try a more lifelike brake bias. Keep in mind, FF means usually 65/35 weight distribution.
Given that, I'd aim for 7/3 as a starting point, and also, remember that GT5's ABS is a one-for-all standard, which means it's probably much better than the system in your Yaris.

Yes thats why I had brake balance at 2/0. Regular cars are set for understeer yes, but tires and setups can only do so much to a point. If you go past the performance limit of tires and car, you will lose controll. When doing high speed braking weight transfer is really high, so there is really not much holding the rear tires, even if the car is setup for understeer, you will lose the tail.

No sir, it is only when you go past the limits of the driver that you lose control.

 

[thedeester1]

We could argue this all day but the Delta car was changed to the integrale so didnt win 3 championships on the bounce.. Ok so the c4 has now surpassed that making Citroen king of an era! 7 on the bounce! The Evo lancer took 4 on the bounce. The Delta though it won more was a much changed car between models. Its like saying the Xsara and the C4 are the same car? I dont see where you get the ford reference from....Most driver wins is Lancia and most manufacturer titles is still lancia with 10? I can only find 2 drivers and 3 manufacturers wins for ford? since WRC began in 1973.

EDIT: Maybe Ford is the most competed?...I dont think it took a break like some manufacturers did?

 

[keitshi]

I've experienced what you speak of in other FF cars, and understand what mean. In some ways, you are right, certainly, that it's next to impossible to make FF cars in GT5 oversteer no matter your input. My only blockade has been that I haven't driven nearly a single FF car in GT5. (in real life)
But instead of 2/0, try a more lifelike brake bias. Keep in mind, FF means usually 65/35 weight distribution.
Given that, I'd aim for 7/3 as a starting point, and also, remember that GT5's ABS is a one-for-all standard, which means it's probably much better than the system in your Yaris.

I tried other settings too like 5/3, 2/0 being the lowest. Im allso leaning torwards the thought that ABS in gt5 is not the same as ABS in most regular cars.

No sir, it is only when you go past the limits of the driver that you lose control.

Ah, yes that is the truth.

 

[NOS Waster]

Kind of disappointed no one's done a g27 --> DFGT comparo yet to back up my findings.

Oh well...

I have tested G27 vs. DFGT and i get better times on the G27.

Equipment makes no difference in lap times when purely comparing the equipment (unless it is controller versus wheel).

Being used to one wheel more than the other and being able to utilize one more than the other is the only reason you might get better lap times on one.

It's just like the average racer in iRacing. You can run roughly middle of the pack with Logitech equipment, but spending $2000+ or more will not gain skill. Practice and training gains skill.

Just use the wheel you feel more comfortable (or are faster) with and your lap times will continue to get better.

 

[Mike712]

1 question for all the "these cars suck they are unrealistic they understeer like mofos" people.

How many times have you:

a) driven a family sedan on family car tyres fast on the neighbourhood streets? I mean really fast? 100km/h/60mph around the 90 degree corners fast?

b) driven the same family sedan on family car tyres fast at a race track?

c) driven a moderately fast sports sedan/sports car on STREET sedan tyres fast on the neighbourhood streets? I mean really fast? 100km/h/60mph around the 90 degree corners fast?

d) driven a moderately fast sports sedan/sports car on STREET sedan tyres fast on a race track?

e) driven a high performance street sports car on street performance tyres fast on the neighbourhood streets? I mean really fast? 100km/h/60mph around the 90 degree corners fast?

f) driven a high performance street sports car on street performance tyres fast on a race track?

and finally

g) driven a high performance street sports car on barely street legal super sticky track orientated tyres fast on the neighbourhood streets? I mean really fast? 100km/h/60mph around the 90 degree corners fast?

h) driven a high performance street sports car on barely street legal super sticky track orientated tyres fast on a race track?

??

In only 1 scenario above does the vehicle NOT understeer. Care to guess which one it is? Scenario h). In all other cases the car when pushed hard will undertseer to some degree.

Folks, the only way a NON-race car will NOT understeer is if you drive the damn thing slowly or you have sticky tyres on it on a RACE track.

No grip means no grip - doesnt matter how you arrive at the situtation it is still no grip. You people are ALL entering corners in game at speeds MUCH faster tahn you would in the real life situation and blaming accurate game engine behaviour on "bad physics" - no the "physics" is good, you are just providing the "input speed" to the algorithm being used that gives you a result you dont like - you may not like the result, "understeer", but it is accurate.

Slow down and the understeering goes away... Now isnt that interesting

I've driven a high performance sedan on standard tires at high speeds on both track and road, and I know for a fact that it understeers considerably past 50mph.

I've also driven a Porsche 911 turbo on a track at very high speed on semi slick tyres and that understeered too. I've also driven a Ferrari 599 on a track, didn't notice any understeer, but I wasn't anywhere near the limit of the car.

If you have driven a car in real life at speeds above what is considered normal for public roads, you will know that they understeer, it's just people play games like NFS and Grid and they expect cars to really handle like that a high speeds which is totally not the case.

What you've got to remember is that a car weighing 1000kg or more traveling at high speed has a hell of a lot of linear momentum that keeps it traveling in the same direction, that is why you get understeer in real life and that is why you get it in a realistic driving sim like GT5.

To reiterate on what RC45 said, if you're experiencing allot of understeer you're probably going way too fast!

 

[Scaff]

We could argue this all day but the Delta car was changed to the integrale so didnt win 3 championships on the bounce.. Ok so the c4 has now surpassed that making Citroen king of an era! 7 on the bounce! The Evo lancer took 4 on the bounce. The Delta though it won more was a much changed car between models. Its like saying the Xsara and the C4 are the same car? I dont see where you get the ford reference from....Most driver wins is Lancia and most manufacturer titles is still lancia with 10? I can only find 2 drivers and 3 manufacturers wins for ford? since WRC began in 1973.

EDIT: Maybe Ford is the most competed?...I dont think it took a break like some manufacturers did?

Take a look....

http://www.classicandperformancecar...8/ford_rally_team_outyumps_lancia_record.html

....with 75 WRC wins they are generally acknowledged to be the most successful WRC team in the events history.

Lancia for the record had 74 WRC wins, not bad for a team that last entered in 1992.

Just to note, please don't argue that overall WRC wins is the correct measure, as its the one the WRC themselves use. As this piece from 2009 shows...

http://www.wrc.com/news/features-archive/the-most-successful-wrc-manufacturer-lancia/?fid=1739

...and to argue that the Delta doesn't count because it evolved over the years is a pretty strange one to make given that every single rally car does exactly that year on year. The regulations change and the cars are developed to meet those changes.

However given that Citroen are currently on 68 wins its quite likely that could well change again soon.

This however has got off-topic quite enough now.

Scaff

 

[wook]

Almost every car I drive suffers from oversteer. If I'm serious about the car I'm using I always have to change the set up to MAKE it understeer.

 

[dothackRAVE]

So all this yapping about GT5 being unrealistic... How many of you here who complain about the realism actually have extensive track and racing experience to be credible about it?

And I don't have a problem with understeer really. You just need to think about how the weight shifts when you're going around a corner. That "magic line" the OP talks about is the apex, where you start straightening the wheel out. You end up with oversteer once you do that...

I've also found that the AP2 S2000 in GT5 is pretty much exactly the same as my real life 2007 S2000. Tail happy and agile.

 

[Denilson]

The Speed you have Got when entering a corner decides if it will underster or not. The biggest problem is that you can not "feel" the speed, which make you enter the corner with to much speed, therefore the understear.. The 430 Scuderia is a MR car with little weight on the front axel. The traction is less on the front wheels compared to a FR car. Try to soften the rear suspention, use camber around -2, and bit of toe on the front. The camber and toe should be less agressive on a car with little weight on the front wheels. I drive the same car as you, and it's a dream to drive. I use -1,7 camber and -0,8 toe.. On a FR I use around -2,5-3.5 camber depending on the weight and arond -1,2 toe..

 

[keitshi]

I think gt5 does handle realistically. In fact its the most satisfying virtual drive Ive had. I drive iracing too but thats pure racing. I mostly just like to drive regular cars not race cars. As long as all aids are off, the cars handle like expected and they do oversteer. I dont know for sure but if some of you have trouble with understeer, just turn all aids including ABS off and play with brake balance. It makes a big difference and driving becomes more enjoyable.

 

[HeadsoupBob]

...

 

[keitshi]

I think with GT5 they've used a lot of generalised physics data for a lot of the cars, hence some of them feeling really good and others feeling way off, I don't believe they spent the time to model the physics of all cars individually (yes even with 6 years dev time) hence the inconsistencies.

Totally agree. 👍

 

[niky]

Scaff, thanks for your input here, i'm learning just from your posts I wish more people like you with extensive real life experience discussed these things instead of the "I've driven a performance car around the streets at high speed so know what I'm talking about" or "I took my skyline around a race track a couple of times" people...

We've all learned quite a bit from Scaff over the years. I'm glad GT5 has brought him back out to play. 👍

I think with GT5 they've used a lot of generalised physics data for a lot of the cars, hence some of them feeling really good and others feeling way off, I don't believe they spent the time to model the physics of all cars individually (yes even with 6 years dev time) hence the inconsistencies.

With some cars, they have access to manufacturer data in detail, which provides for a more detailed physics model. With others, they may be basing the models on test data which includes lateral grip, suspension stroke, acceleration and braking measured at a test track... in which case, the condition of the vehicle used may play a huge part in how it compares to your own, personal, experience of the same vehicle.

There's a big variance in how vehicles perform based on testing conditions, tire condition and test-unit condition. All of which might affect how each car in GT5 (or any other driving "sim", for that matter) drives.

I know, yet with ABS on it understeers but with ABS off it oversteers in gt5. Is that not the opposite?

From my experience, whether a car oversteers or not under hard braking in a corner, with or without ABS, will depend greatly on how poorly the ABS is programmed and how badly the manufacturer botched up the brake bias.

I've driven the Yaris pretty hard... and while it's possible to initiate oversteer, it's always short-lived, and generally gives way to four-wheel drift... then understeer.

You might also want to note whether your car is bog-standard and is the same variant as that in GT5. There's a marked difference in suspension tuning between variants meant for different markets, and from my experience, Yarii on the Toyota "sports" suspension tend not to be nearly as twitchy as those on the "comfort" suspension and tend to have a more planted feel... leading to more understeer versus the standard car at the limit... though the initial roll-on understeer as the front suspension compresses all the way to the ground (grinding off pieces of bodywork in the process) in a turn is obviously lessened.

 

[keitshi]

From my experience, whether a car oversteers or not under hard braking in a corner, with or without ABS, will depend greatly on how poorly the ABS is programmed and how badly the manufacturer botched up the brake bias.

Ok, but the effect of removing ABS on gt5 seems to be more oversteer on all cars.

I've driven the Yaris pretty hard... and while it's possible to initiate oversteer, it's always short-lived, and generally gives way to four-wheel drift... then understeer.

Yes, that it does. It is indeed possible. Duration and what comes after is not the concern.

You might also want to note whether your car is bog-standard and is the same variant as that in GT5. There's a marked difference in suspension tuning between variants meant for different markets, and from my experience, Yarii on the Toyota "sports" suspension tend not to be nearly as twitchy as those on the "comfort" suspension and tend to have a more planted feel... leading to more understeer versus the standard car at the limit... though the initial roll-on understeer as the front suspension compresses all the way to the ground (grinding off pieces of bodywork in the process) in a turn is obviously lessened.

It is bog-standard and an allround crap car to begin with.

I would not be bothered with babling about small details in does that do what it does like it should exactly and so on. It just stands out to me that ABS has such a big dampening effect on braking on all cars most notably ff-cars in gt5. I mean come on.. I should be able to flick my hot hatch aroud regardless of ABS.

edit: The yaris in gt5 is the sportier version so it handles better like you mentioned, but its still a yaris. A yaris has its limits, right? The thought that it is not possible to upset it under braking is well... a strech. Because I cant get it to get upset when braking, thus I not happy. ABS bad.

 

[FyreandIce]

So you GT4 troopers, remember the chronic entry and mid corner understeer that plagued that game? I do, and it's in GT5 too.

Now, I've noticed this more and more as I'm finding cars I drive regularly and an average corner goes like this..

Brake
Ease off brake and turn in
Understeer
Straighten wheel and turn in again
Understeer
Get on the throttle just before the apex
Understeer again so you back off and wait for the tyres to bite

Once you pass the apex, you pick up the throttle and suddenly, like you've crossed an invisible line, there's gobfulls of oversteer.


Is anyone else noticing this? It's really starting to annoy me and it was the same in GT4 but more obvious. And here's the magic words - it's unrealistic.

Thread is directed at wheel users. I myself use a g27.


ps, I'm mildy drunk so I'm sorry if my sentence structure is off.

I noticed the same thing.

Not only do cars unnaturally under steer but when understeer occurs, it doesn't act like understeer. The car doesn't start to plow forward, it just keeps turning as tight as it was before. And then, for no reason, when the road goes strait again the car starts oversteering. To be honest, I cannot fathom how anyone can call this games physics "good"