Four wheel drive distribution

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KiwiBoy

KiwiBoy

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From what I have seen on many different car brochures, they say that their four wheel drive system (eg. Audi, Subaru, Mitsubishi...) has the ability to distribute power between the wheels to the one wheel with the best traction. So I am wondering if GT4 has included this in the game or is it just a fixed ratio between the front and rear wheels?
 
It's fixed in GT4 when racing, while being adjustable when setting the car up if you have the appropriate device with a name I forgot. :crazy:

Regards
the Interceptor
 
you mean the AYC, Adjustable Yaw Controller.
power is diverted to the outside wheels when corners (makes sense, outside wheels have a larger radius)
with the AYC you can control how much of that power is put to the outside wheels.

i have a stock EVOVIII MR that i'm testing this with,
with the AYC set fairly high, the initial oversteer at turn-in is incredible, just a matter of sliding the car across the corner after that.
 
Did you search?
Just wondering. In time we will see if this stays here... However, in the mean time... :D

Actually, I don't think he is reffering to the AYC.

It is the VCD that you are wondering about...
Variable Center Differential.

This is an aftermarket part that allows you to change the distribution of power from front to rear on 4wd cars.

However, that isn't even really what the question is about.
This is more about advanced 4wd systems and their ability to detect wheel spin.

In Gran Turismo there is only one car I know of with this sort of system being used (although many cars in the game should have it in place).

The Skyline GT-R R34.

Evidence of this can be found by driving the car without a VCD equipped and then following that test by running with a VCD system equipped.

After a bit of time you will notice that the Skyline runs best without VCD because it stays in Rear Wheel Drive format until the front wheels are needed (which is rare).

Hope that's what you were wondering about. 👍

btw, AYC is similar but it is not unique to 4WD since cars like the honda prelude come with AYC standard.
 
4WD = Part-time four-wheel-drive (there's a lever or button that switches between RWD/FWD and 4WD)

AWD = All-time four-wheel-drive (always on, cannot be "turned off")

VCD = A center differential that allows you to adjust the default torque split between the front and rear axles.

AYC = A differential that allows a computer-controlled splitting of torque between the left and right wheels.

Open Differential = A differential which merely allows the left wheel to spin faster than the right wheel, and vice versa. Prefers to route torque to the wheel with the least amount of resistance, leading to getting stuck in the mud/snow/ice/etc. and somewhat awkward drifting, caused by only one wheel spinning.

Locked Differential = A differential which keeps the left and right wheels spinning at the same speed. Good for off-roading; keeps both wheels turning. Terrible on pavement; eats at tires and drivetrain components when making a turn.

Limited-Slip (a.k.a. Positraction) Differential = A differential that allows the left and right wheels to spin independently of each other, yet limits the amount of "slip" that can occur between both wheels. If one wheel starts spinning much faster than the other one, the differential will react by transferring more torque to the non-spinning wheel.

Many AWD cars have open differentials, just like many FWD and RWD ones do.
Sportier models tend to have LSDs, just like sportier FWD and RWD models do.
Locked differentials only really see use on 4WD SUVs and trucks, and are used off-road.
AYC is Mitsubishi's name for that particular techonology, just like V-TEC is just Honda's name for Variable Valve timing. I'm not sure how many companies use AYC, but Honda has it and calls it "SHAWD" (super-handling-all-wheel-drive), and I believe AYC is a part of Nissan's ATESSA AWD system, which is what Skyline GT-R's have.
I don't really know much about the usage of VCD's on real cars, but it's certainly plausible.
 
Kent
btw, AYC is similar but it is not unique to 4WD since cars like the honda prelude come with AYC standard.
Click to expand...
I know a lot of honda guys and I'm familiar with most of the honda stuff. The only Prelude to the best of my knowledge that has anything familiar to AYC, is the SH. (Not a standard model)

A friend of a friend used to own one. Beings he thought it was the fastest car on the street, it stuck out in my memory when I seen this thread. :lol:
 
the advantage of the ATESSA-ETS system in the R34 is that when the front wheels are pointing straight, the distribution will be 50/50. giving you that 4wd launch. but as the front wheels start turning, the computer will start to distribute the power to the rear wheels.
launch like a 4WD, corner like a FR, and exit like a 4WD.
well, this is how its supposed to be in real life, dunno how accurately GT4 depcits it.
 
ConceptS14
the advantage of the ATESSA-ETS system in the R34 is that when the front wheels are pointing straight, the distribution will be 50/50. giving you that 4wd launch. but as the front wheels start turning, the computer will start to distribute the power to the rear wheels.
launch like a 4WD, corner like a FR, and exit like a 4WD.
well, this is how its supposed to be in real life, dunno how accurately GT4 depcits it.
Click to expand...

You're close, but you seem to have a misconception about the way the system works. When the front and back wheels are traveling at the same speed the torque split is approximately 10% front, 90% rear, basically making it a rear-wheel-drive car. But when a loss of traction at the rear wheels is detected(IE: rear wheels traveling faster than front wheels), the system begins to distribute more torque to the front wheels, making it an all-wheel-drive vehicle when needed. Basically what I'm trying to say is, the car is rear-wheel-drive, whether it's traveling in a straight line or cornering, until the rear tires break loose, then it becomes all-wheel-drive. Hope that helps. :cheers:
 
ConceptS14
i sort of disagree with you and i sort of dont.

http://rbmotoring.com/gallery/album151/aac?full=1

what i was getting at was the
"Straight-Line Running, Rapid Start-off" (Launch like 4WD);
"Cornering, Steady State"(Corner like FR);
"Cornering, Acceleration"(Exit like 4WD)
Click to expand...

Actually, the table agrees with fangorn...

ConceptS14
the advantage of the ATESSA-ETS system in the R34 is that when the front wheels are pointing straight, the distribution will be 50/50. giving you that 4wd launch. but as the front wheels start turning, the computer will start to distribute the power to the rear wheels.
launch like a 4WD, corner like a FR, and exit like a 4WD.
well, this is how its supposed to be in real life, dunno how accurately GT4 depcits it.
Click to expand...

What you said is basically correct at the end... but what really happens is that the GTR is 0:100 at all times wherein balance and traction are uncompromised. In the presence of high torque and loss-of-traction at launch, the system engages nearly instantaneously, allowing momentary wheelspin at the rear before locking the differential. A lot of GTR draggers have talked about this.

AWD is on only until traction at the rear is stabilized, and the car returns to an FR bias. As soon as the G's level off (as shown in the table), the traction returns to the rear-bias.

In cornering, the AWD starts to kick in on exit. You're correct there.

In essence:
*Drive like an FR
*Loss of traction in acceleration - 4WD kicks in.
*Corner like an FR
*Loss of traction in cornering, onset of oversteer - 4WD kicks in, restores traction, induces understeer to counter oversteer in cornering

Basically in GT4, the GTR understeers, but not as much as any of the other AWD cars. Turn in isn't exactly as sharp as some FRs, but comparable to other heavy FR coupes. At turn in, it does oversteer a little, but at high rpms, it starts to understeer. As we can't see what the car is doing after the launch in GT4, there's no way for me to confirm if the AWD system turns off after the launch. :(
 
i guess what i was forgetting is the fact that the car is generally an FR in steady state. not wrong, just missing a peice of the puzzle.
thanks niky, your post cleared it up.
 
Do all the R34s have the same system or is it production models only? If the R-Tune handles similarly to the M-Spec Nür I'll buy it immediately! :D
 
ConceptS14
i guess what i was forgetting is the fact that the car is generally an FR in steady state. not wrong, just missing a peice of the puzzle.
thanks niky, your post cleared it up.
Click to expand...

👍 no prob.
 
Greycap
Do all the R34s have the same system or is it production models only? If the R-Tune handles similarly to the M-Spec Nür I'll buy it immediately! :D
Click to expand...

Production? The R-Tune is a NISMO creation, and NISMO is to Nissan as M is to BMW, TRD is to Toyota, AMG is to Mercedes, SRT is to Dodge, etc. etc.

The R-Tune is a faster Skyline GT-R brought to you by the people who brought you the Skyline GT-R in the first place. Needless to say, it'll have ATESSA. :)

Oh, and not all R34's have the same system...many Skylines are purely RWD in the real world. However, in GT4 the only FR R34's are the JGTC ones. If ya wanna check out an FR Skyline, the R32 GTS-t Type M or GTS25 Type S, as well as any R31 or earlier, is the way to go.
 
I know what NISMO is ;) I just thought they might not use the same system as the regular versions.

I bought it today and it really is a (much) faster GT-R, and a handful on N2 tires... Well, I meant GT-Rs when I said R34s as there aren't RWD versions in GT4.

After driving three laps on the 'Ring with the car (still on N2s) I can only wonder why some companies still make different 4WD systems from this. It's very near, if not, perfect.

I have been bit of an anti-Skylinist this far as I didn't like them in GT2 or GT3. Although they were fast they never really suited my driving style. Now I have to change my attitude, they are great cars. 👍

Another question: does the Mine's Skyline have ATESSA too?
 
Greycap
I know what NISMO is ;) I just thought they might not use the same system as the regular versions.

I bought it today and it really is a (much) faster GT-R, and a handful on N2 tires... Well, I meant GT-Rs when I said R34s as there aren't RWD versions in GT4.

After driving three laps on the 'Ring with the car (still on N2s) I can only wonder why some companies still make different 4WD systems from this. It's very near, if not, perfect.

I have been bit of an anti-Skylinist this far as I didn't like them in GT2 or GT3. Although they were fast they never really suited my driving style. Now I have to change my attitude, they are great cars. 👍

Another question: does the Mine's Skyline have ATESSA too?
Click to expand...

Just making sure on the NISMO and FR Skyline points...you'd be surprised how many people aren't familiar with either of those... :)

I would assume that the Mine's Skyline has ATTESA as well, but does it really matter, considering the car can outrun fighter jets...? :lol:
 
Well, the NISMO is the tuning company of Nissan and other than GT-R Skylines (GTS-t and so on) are FR. Correct? ;)

The reason to asking if the Mine's runs on the same system is that in GT4 it understeers, as other R34 Skylines oversteer. :confused:

But it really has outstanding acceleration
burnout.gif
 
I think you guys are forgetting that the R-Tune is FR and FR only. It is 100% RWD with no option for a VCD.
 
Wow, most companies AWD systems are proprietary, and the game has done a good job differentiating each in their respective vehicles. The Quattro system even varies between the TT, S4, RS4, and the RS6's. The TT's characteristicks are very different than the S3, though they are the same platform. The TT's quattro is more of a touring application of Quattro, while the S3's system is a sportier variant. Same between the S4 and the RS4. The RS6's differ in only weight distribution, one being a wagon, and obviously heavier in the back. Nissan's AWD system is a whole different ball of wax. It unlike Subaru's and Mitsi's full time AWD, Nissan's will put power forward when the driving nannies sense the car oversteering. Subi's and Mitsi's systems are much more Full time than either Audi's (VW) or Nissans, the control, (if any) of power distribution is very limited forward and aft.


Edited: for my dislexia acting up today.
 
Ebiggs
I think you guys are forgetting that the R-Tune is FR and FR only. It is 100% RWD with no option for a VCD.
Click to expand...



Greycap
Well, the NISMO is the tuning company of Nissan and other than GT-R Skylines (GTS-t and so on) are FR. Correct? ;)

The reason to asking if the Mine's runs on the same system is that in GT4 it understeers, as other R34 Skylines oversteer. :confused:

But it really has outstanding acceleration
burnout.gif
Click to expand...


Correct. :)

As for the Mine's Skyline...maybe they set it up to understeer more at the limit because otherwise it would be too dangerous...?? I have no idea. :confused:
 
That's funny, I didn't feel much understeer in the Mine's as compared to a regular GTR when punting it around the Autumn Ring.

But then again, as it was sideways most of the time, and I had a grin from ear to ear, I doubt I would have cared. :lol:
 
At the time, stock. SS's. No TCS, ASM, tire-spin city around those tight corners. Lots of fun. :D
 

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