AWD Seriously flawed...?

[Impreza STi]

In GT3, I find that there are serious issues with the AWD systems.

First of all, most cars feel like they use "torque applied to secondary axle" physics, very much like the latest version of Racer, as opposed to "connected to differential drive" physics, even with VCD implemented. That and the VCD does not have any effect when implemented on such cars, as if it was 0% LSD all the time. In order for VCD to work, you need limited-slippage.

The main drive wheels ALWAYS get power, and are the first ones to slip. They may be the front or the rear wheels. Most cars it is the rear wheels. When you do a redline launch in said cars, even with 50/50 bias, all the power makes its way to the rear wheels. It is just WRONG to see a Subaru Rally Car (or any rally car) roast the rear wheels all the way through 1st, even with 50/50 power bias.

Then, I tried the Escort Rally Car, and noticed the front wheels spun excessively. Every time I tried to do donuts, to would torque steer to holy heck and drive straight. I set the power bias to 90 rear/10 front, but it made no difference, ABSOLUTELY no difference. The rear wheels would not spin much, only on the initial couple milliseconds of launch.

The same thing happens with the Escudo Pikes Peak. This would also explain the extremely long front wheel burnouts in the Escudo and the CTR2. Main drive is to the front, secondary rear, reverse from most of the other AWD cars in GT3. Thoroughly screwed is GT3 AWD physics.

The only cars I have seen in GT3 that have good AWD physics are the GT-R and the Impreza STi, WITHOUT the VCD upgrade. The front and rear wheels actually feel connected in those two cars.

Let's hope GT4 has good AWD physics!

 

[Driftster]

Lol...yeah, like a STOCK EVO...stock EVO's allways smoke all their tires, same goes for the skyline...wait...NO THEY DON'T which is why it's gay

 

[ving]

not saying thats it right or anything but upon launch there is considerably less weight on the front wheel compared to the rear and that prolly wht the fronts spin... thats why high powered FF cars in the game tend to need TCS on and RWD cars of the same power dont.

just a theory

 

[Impreza STi]

Well the front wheels should not be spinning when only 10% of the power is going into them, and yet they still do on the Escudo, CTR2, and Escort Rally Car. Also, the stock Audi S4 in GT3 has the same excessive front wheel spinning problem. VCD doesn't really help, like the others...

 

[ving]

i dont have that problen with the s4!

 

[Driftster]

it is FAKE, a stock Evo has 300HP......Evo's don't do crazy burnouts....Skylines have 300HP..they don't do crazy burnouts...the new STi's have 300HP..they don't do crazy burnouts....it's gei geigei gei gei ge

 

[ving]

hey, at the begining of the game there is a disclaimer that say the car may vary in colour, shape, and performance from RL...

so why are you expecting them to behave like real cars?

 

[Impreza STi]

Well, lets see, in GT2 they act realistic, in Viper Racing the act realistic, in ... hmmm, what other game has good AWD? ... ah yes Live For Speed has good AWD physics, why does GT3 have crappy AWD physics then?

 

[TingBoy]

wait, so ur saying u can't do donuts in AWD cars? I find them to be the easiest to do them in. Anyways, I don't think the AWD system is flawed. When ur talkin about the front wheels smoking, are you talking about starts or while turning? If ur talking about starts, are you doing the slow to flooring it start-offs? You need to slowly accelerate a little bit when you start off then floor it when you're going about 15 mph or so.

 

[RazorGTR]

Originally posted by Driftster
it is FAKE, Skylines have 300HP..they don't do crazy burnouts...it's gei geigei gei gei ge

While I will agree with you guys on the EVO and Subbies issue, the fact is the Skyline has an electronic variable torque split factory standard, instead of a preset of front to rear bias such as the EVO and Subbie use in their center diff. That is to say while crusing or under mild acceleration, it is only in 2wd. The amount of front wheel torque applied is made via the signals from three different sources. The throttle position sensor, laterall and longitudal G-force sensors, and the ABS system which can pick up the difference in front to rear wheel speeds.

Yes even standard you can do dounuts with a GTR, increasing the power only magnifies this. Now as mentioned about smoking up the rears on a hard launch. Well hate to burst your bubbles but that does happen. I've done it time and time again at the drags. This happens until enough front wheel bias torque is applied which takes about 1 full second.
You can also induce oversteer quiet easilly when going through a slower corner and a foot full of throttle.

 

[Tofu4G63]

If you think it is flawed do this quick comparison and tell me if you feel the same way.

Take of of said cars in question leave them at stock power stock everything except give it an oil change and buy the VCD.

Do a few laps at trial moutain with the VCD first set at 50% then do a few laps at 10% and tell us if you feel any kind of difference and see what your lap times are. This will not work if you are riding the walls or cutting corners anywhere. Stay on the track at all times and avoid drifting. Let us know if you still think the AWD systems are flawed. If you still do just becuz of the burnout thing.... well then you should be more worried about the amount of smoke that comes from the tires when your doin this burnouts cuz I think that the burnouts are lame in this game.

 

[FuJi K]

a OEM center diff on a STi is split at 35:65 front/rear. If they're applying the viscous coupling physics to it, the tires that slip more than wanted will let loose and all the power will go to those tires. Viscous coupling is only good to a point.

I can do dough nuts easy by pulling the e-brake and letting it get a little sideways before applying the power.

1. turn and accelerate to about 30mph in 1st gear (mind you I have JDM STi 6spd gear ratios in my racing tranny on my STi Ver 6)
2. press e-brake/parking brake and let the car get sideways a little.
3. while still pressing the e-brake, get back on the gas via tip of your thumb(sp?) and let the RPMs climb up then lift off of the e-brake. This is the best way to simulate a clutch drop to get the rear tires loose.
4. while still turning, either give it WOT or adjust throttle variably.

I can't really get a dough nut started because of the grip settings I have for my STi Ver 6 unless I pull the e-brake. Mind you I've been tuning my STi ever since GT2. I have the best setup for me so far.

FuJi

 

[TingBoy]

Originally posted by Tofu4G63
If you think it is flawed do this quick comparison and tell me if you feel the same way.

Take of of said cars in question leave them at stock power stock everything except give it an oil change and buy the VCD.

Do a few laps at trial moutain with the VCD first set at 50% then do a few laps at 10% and tell us if you feel any kind of difference and see what your lap times are. This will not work if you are riding the walls or cutting corners anywhere. Stay on the track at all times and avoid drifting. Let us know if you still think the AWD systems are flawed. If you still do just becuz of the burnout thing.... well then you should be more worried about the amount of smoke that comes from the tires when your doin this burnouts cuz I think that the burnouts are lame in this game.

I'll do that as soon as it turns Friday and I get back from school. My parents don't let me play games on weekdays =(.

 

[Impreza STi]

Well I did more than burn out with the AWD cars, I did take the Escort, CTR2, and Escudo on multiple laps, and they torque steer like holy heck when I put on the gas out of the corners. This is with 10 front / 90 rear power bias mind you.

Now I never said there was anything wrong with the Scooby or the GT-R. The Subaru is wierd, because with a full tune, I did donuts and all four wheels smoked in first, second, third, fourth, but when I hit fifth, the front wheels came out of the spin cycle and left the rears spinning on their own. Shift down and the fronts come back into the spin cycle.

Now as for on the track, the rally cars feel like ALL power is going to the rear wheels upon slippage. It makes for good RWD-ing, but not good for traction. An active clutch differential IRL would not allocate 100% power to one axle when slipping unless you don't have the chip plugged in or you set the L.S.D. to 0%.

 

[Impreza STi]

Now a viscous clutch diff is very much like an automatic transmission. The problem it has is lag, the short time between when the impeller spins up and when the fluid forces the other impeller to move. Mechanical diffs are the ones that allocate 100% power upon full slippage.

 

[Impreza STi]

I watched many videos of Impreza STi's doing redline launches. They rev to red, spool up, and e-e-t a short four-wheel chirp and they are off. If the AWD car has Limited-slip on all three like the Scooby, with 300 HP you should not be able to do crazy rear-wheel burnouts on launch with a near 50/50 power bias.

 

[FuJi K]

If you haven't noticed, the Imprezas AWD System is much different from the Legacy. The rears of the Impreza will spin freely is they're spinning faster than the fronts. Remember that the rears are losing traction more than the fronts because of the rears swinging around (more slip angle).

I did notice that AWD push with the stock diffs. So far with all my tuning, getting the Full Customization LSD helped cure this a little and helped a lot if you set it right.

Because we can't transmit as much steering input as we could in real life, setting the front acceleration diff high pulled the car out quicker out of turns but then pushed right after.

I adjusted the initial settings and that resulted in a more stable and less twitchy effect as in over-under-lift off throttle-oversteer.

With the full customize LSD, it's only front and rear diff adjustibility. The center, VCD, is like Subaru's DCCD (Driver Controlled Center Differential), but just allowing more RWD bais adjustment.

try these diff settings and give me your feedback.
Initial F/R: 25 / 25
Accel F/R: 25 / 45
Decel F/R: 1 / 25

yes it's odd but you need more rear slip angle. The front is set like a 1-way where as the rear a 1.5-way.

FuJi
I need to find my memory card...

 

[Tofu4G63]

Ok totally off topic but can anyone guess who originally came out with the viscous coupling and used it in their AWD vehicle?

 

[ving]

i shall quote myself her because it is the only post that makes sense of it all...

Originally posted by ving
hey, at the begining of the game there is a disclaimer that say the car may vary in colour, shape, and performance from RL...

so why are you expecting them to behave like real cars?

 

[Sleek Stratos]

I was recently doing some donuts like Zanardi would have so I don't believe there's a major problem, of course Zanardi could do donuts with an MR "CART" car so that's way more credit to him.
And ving is right, look at the disclaimer people.

 

[TheTubaMan2]

Ok back to the guys question which is still relevant because the idea of the game is to make it realistic that and the strategically placed dream car is what makes gt3 cool. Now my theory is that not all the cars use the same type of 4wd or awd. The idea is the engine placement and tires effect the smoking of the tires, for instance the escudos engine is in the rear and is huge. The balance make the escudo burn. The skyline has a small engine in the front so they burn. So the basic theory is that the game has more weight and handling complexities than we originally thought.

 

[Impreza STi]

Has anyone tried the Escort Rally Car to confirm it's unusual pushing behavior?

 

[Impreza STi]

I still find it difficult to believe that the Escudo PPV would lose so much traction to the front wheels with a 10% front 90% rear power bias. For that to happen, the VCD must set the clutch for the rear at about 100% LSD and the front clutch at around ... 10%, guaranteeing power to the rear, but allowing a little power to the front. Note that in such a setup the rears MUST spin for the fronts to spin as well, since the near 100% rear clutch friction won't allow the other end to slip first.

 

[FuJi K]

so....to my understanding, there are different AWD systems. Each will function differently depending on the differentials.

Some AWD systems are more advanced like the WRC cars in real life where steering input, yaw angle, g sensors all work together so the Computer can control the hydralic diffs.

Some are FWD based, RWD based, or All-Wheel/4WD based.

When you launch hard spinning all the wheels, they all will spin. Then depending on which type of center diff, it'll transfer power to either front or rear tires. FWD based AWD will send power back to the front if they're slipping and if lots of torque is still being transmitted to the diff, if viscous coupling, it'll let loose and all the torque will go to the front wheels. If clutch type, it'll slip and will keep slipping until the tire grips. Yes, clutch type do hold but they still have a little slip as well. Now if it's a gear type, it'll not slip and power will transmit to both front and rear tires.

The tire with less weight will always slip first upon launching or coming out of a turn. The VCD makes the center diff on the AWD cars RWD based AWD system's like Subaru's DCCD but just more RWD torque split ratio.

Try this...
Put on Super Soft tires, put on tire damage, go to free run or 2 player battle or where ever Tire Damage can take effect, and do several launches with various AWD vehicles. If the fronts turn green first before the rears then it's a FWD based (you should put more torque to the rear w/ VCD adjustment) or vise versa. If the car is underpowered, do several launches to heat the tires up so you'll know if the fronts or rear are getting more torque then the other end..

FuJi

 

[deimos]

Impreza STi, have you ever tried driving a RWD car on a rally track (eg silvia ks) after driving a rally car. You will notice the rally cars DON'T handle as if they are RWD. Even on the road they act differently enough from the RWD cars with the same amount of BHP.

 

[jervinator]

Originally posted by TheTubaMan2
Ok back to the guys question which is still relevant because the idea of the game is to make it realistic that and the strategically placed dream car is what makes gt3 cool. Now my theory is that not all the cars use the same type of 4wd or awd. The idea is the engine placement and tires effect the smoking of the tires, for instance the escudos engine is in the rear and is huge. The balance make the escudo burn. The skyline has a small engine in the front so they burn. So the basic theory is that the game has more weight and handling complexities than we originally thought.

Well, there are a few minor flaws there. The type of AWD system does makes a difference; Nissan's ATESSA ain't nothing like the Subi's system. And the balance of the car also makes a difference.
However the Skyline's engine isn't exactly small, and it's trans is rather big. And the Escudo's engine actually is smaller and prob'ly lighter (race-spec 2.5 liter V-6 vs street-spec 3 liter I-6).
And then there is how high up the center of gravity is. That has an effect on weight transfer, as does the suspension stiffness....

However, the basic premise, ... the game has more weight and handling complexities than we originally thought. , is probably more true than you know.

 

[Impreza STi]

I read up on viscous clutches, and they actually are very similar to auto transmissions. According to the books, they have the problem of exponentiality. Since fluid resistance increases exponentially, a little slip between the impellers goes unnoticed, but the more slippage, the more force is placed upon the slow-spinning impeller, and that force increases exponentially with the fluid speed. This means if you are doing a 6th geer burnout donut, 6th topping near 200, so much force would be acted upon the front wheels (assuming main power is to rear) they should break loose too and spin a lot, or launch the car forward drastically when you stop donutting. Yet I end up doing these 6 geer donuts in every car "RWD-based" and only the rears are toasting the pavement.

Now if only skid marks were implemented...

 

[Epinionator89]

In GT3, I find that there are serious issues with the AWD systems.

First of all, most cars feel like they use "torque applied to secondary axle" physics, very much like the latest version of Racer, as opposed to "connected to differential drive" physics, even with VCD implemented. That and the VCD does not have any effect when implemented on such cars, as if it was 0% LSD all the time. In order for VCD to work, you need limited-slippage.

The main drive wheels ALWAYS get power, and are the first ones to slip. They may be the front or the rear wheels. Most cars it is the rear wheels. When you do a redline launch in said cars, even with 50/50 bias, all the power makes its way to the rear wheels. It is just WRONG to see a Subaru Rally Car (or any rally car) roast the rear wheels all the way through 1st, even with 50/50 power bias.

Then, I tried the Escort Rally Car, and noticed the front wheels spun excessively. Every time I tried to do donuts, to would torque steer to holy heck and drive straight. I set the power bias to 90 rear/10 front, but it made no difference, ABSOLUTELY no difference. The rear wheels would not spin much, only on the initial couple milliseconds of launch.

The same thing happens with the Escudo Pikes Peak. This would also explain the extremely long front wheel burnouts in the Escudo and the CTR2. Main drive is to the front, secondary rear, reverse from most of the other AWD cars in GT3. Thoroughly screwed is GT3 AWD physics.

The only cars I have seen in GT3 that have good AWD physics are the GT-R and the Impreza STi, WITHOUT the VCD upgrade. The front and rear wheels actually feel connected in those two cars.

Let's hope GT4 has good AWD physics!

To experiment, I have been recently driving backwards on Laguna Seca to test the AWD physics on the dirt patch on the left hand side of the corkscrew corner.

*All vehicles in the game have some sort of rear-drive bias, directing most torque to the rear wheels. Even with torque adjusted 50%/50%, it still happens.

*I noticed that more torque is applied to the front wheels the harder you push the accelerator.

*Also, the Audi TT happens to be front wheel drive until you buy the Variable Center Differential (VCD) that allows adjustment of torque between the front and rear wheels. I found this out because the rear wheels never seemed to drive the car no matter what.

*The Audi A4 seems to be the best vehicle that executes full 50%/50% 4WD because both sets of wheels spin evenly, unlike the other cars where the rears spin first.

*One more thing: In real life the different vehicles have different types of four wheel drive/all wheel drive systems. For example, Subaru allows 90% of torque to drive the front wheels and 10% for the rear, although it is not true in GT3. All the cars in GT3 have the same game-version of AWD.

Overall, I hope Gran Turismo 4 makes each car unique and that the four wheel/all wheel drive systems are true-to-life.

(Oh, and the description for VCD says that the settings can range between 0% front/100% rear and 100% front/0% rear even though we all know this is not true once you buy it).

 

[kensei]

Most 4wd cars in GT3 with default setting have understeer for me, most it can be tuned out with suspension tweaks, some better than others. I would rate one or two 4wd cars in my top 6 cars in GT3.

I noticed in GT4P, not that the physics engine is final or anything, that the 4wd cars mosty have massive oversteer, at least for me. Odd but then again the pyhsics engine is not final in Prolouge.

All in all it can be worked around or gotten used to.

Not FF cars in GT3....hahaha, at least they are MUCH MUCH MUCH better in GT4P.

 

[Victor Vance]

Ok totally off topic but can anyone guess who originally came out with the viscous coupling and used it in their AWD vehicle?

It Might be Lamborghini. I remember the commentator dude in TNFS saying something about the Diablo's 'revolutionary' viscous coulpling system. But I dunno what it is or what it does.