All Wheel Drive & CVT Transmission

  • Thread starter Thread starter Epinionator89
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Epinionator89

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All Wheel Drive

Ever since GT3 I've noticed that all the cars in the game have rear-drive bias if they're four or all wheel drive. (Not to be off topic, but the Audi TT in GT3 had front-wheel-drive until you bought the VDC controller--glitch).

In GT4 they happen to say before you buy the VDC controller that you can adjust torque from 0% front/100% rear up to 100% front/0% rear. Sadly, as you may know by now, the controller only adjusts from 10% front/90% rear to 50%/50% after you buy it.

But back to the rear-drive bias--All the cars with four wheel drive usually spin their rear tires first, even if in real life they should be putting most of their torque up front (Honda Element for example). Even after buying the VDC controller and putting torque 50/50 the rears still lose traction first. What do you think about this small error in the GT series? If it's because of space on the disc and not having time to make separate AWD systems, then I'm OK with it.

CVT Transmission

The definition of a CVT transmission is this: it's a transmission with an infinite amount of gears between two preset gear ratios. A ratio is selected depending on speed and gas pedal position to give the engine a balance between best efficiency and best performance.

I've driven the Prius in GT4 and found that it's tuned to raise RPMs when speeding up. Was this something Toyota did on the real-life Priuses?

And I've bought the Honda Insight that supposedly is supposed to have a CVT transmission, but has a five-speed in GT4 instead.

I also bought the Nissan Cube because it says right near the name "CVT". Since I know that Japanese Cubes have a CVT optional, I bought it to see if it had one. Well, it doesn't in GT4. Why say it has a CVT if it doesn't have one?
 
I have noticed that on most AWDs you cannot adjust to 100/0 or 0/100. Disappointing really. I never noticed the RWD bias, I'll have to look for that.

As for the CVT, I wonder if the Cube in real life has set ratio steps, perhaps in sport mode or something. I know some real CVTs have such a mode and behave more like sequential or regular automatics. The Honda Fit (Jazz) has a CVT in the game that behaves like a real CVT, the revs react to % of throttle applied. I got a fully modded Fit without a trans upgrade up to about 200mph on Le Sarthe and then the engine sped up a few hundred rpm to redline, like a real CVT would when it runs out of ratio. Pretty cool attention to detail on the part of PD, I was expecting it to just keep slowly accellerating until I ran out of straight tarmac.

I think the Insight is available with a five speed, so PD probably chose that as the model to represent in the game.
 
Epinionator89
All Wheel Drive
But back to the rear-drive bias--All the cars with four wheel drive usually spin their rear tires first, even if in real life they should be putting most of their torque up front (Honda Element for example). Even after buying the VDC controller and putting torque 50/50 the rears still lose traction first. What do you think about this small error in the GT series? If it's because of space on the disc and not having time to make separate AWD systems, then I'm OK with it.
Click to expand...

Im thinking that when a car is under heavy acceleration the load shifts to the back wheels making them lose traction and if the torque split is 50:50 they would spin first.

Thats my idea on the subject... any others?
 
~Sp33~
Im thinking that when a car is under heavy acceleration the load shifts to the back wheels making them lose traction and if the torque split is 50:50 they would spin first.

Thats my idea on the subject... any others?
Click to expand...
if the load shifts to the back the rear wheels should NOT loose traction since all the load increases grip. the front wheels should spin first since the front gets light.




Epinionator89,

which AWD cars have you tested? the skylines for example have that ETS system so that usally all the power goes to the rear and only when they spin a part of the torque will go to the fronts so giving the car AWD traction with RWD feel.

i have only noticed on my AWD ruf ctr2 with 900hp that the fronts will start to spin first and the car suffers from horrible understeer (and you can't by the VDC for it...damn!)

you also have to think about the weight bias of the car. cars with the engine in the front usually have more weight in the front, thus probably allowing the rear wheels to start spinning before the weight has even shifted (and when they once spin...)


besides, it has nothing to do with the space on the DVD. those physics are only text. the code for the AWD most probably only takes up a few kilobytes.
 
vladimir
if the load shifts to the back the rear wheels should NOT loose traction since all the load increases grip. the front wheels should spin first since the front gets light.




Epinionator89,

which AWD cars have you tested? the skylines for example have that ETS system so that usally all the power goes to the rear and only when they spin a part of the torque will go to the fronts so giving the car AWD traction with RWD feel.

i have only noticed on my AWD ruf ctr2 with 900hp that the fronts will start to spin first and the car suffers from horrible understeer (and you can't by the VDC for it...damn!)

you also have to think about the weight bias of the car. cars with the engine in the front usually have more weight in the front, thus probably allowing the rear wheels to start spinning before the weight has even shifted (and when they once spin...)


besides, it has nothing to do with the space on the DVD. those physics are only text. the code for the AWD most probably only takes up a few kilobytes.
Click to expand...


In real life, for example, a Subaru Legacy has an all wheel drive system that has 90% torque up front and 10 to the rear. When a front wheel starts to slip, power is then transferred to the rear wheels (that's just one of their AWD systems, remember)

In a Honda Element, all the power is directed up front only until the front wheels spin. In other words, the front wheels should be spinning first before the rears start turning.

To test GT4's all wheel drive system, I usually drive to Laguna Seca's corkscrew backwards and try to start going up the dirt part (on the right if you're going in the usual direction, on your left when driving up the corkscrew). Due to the lowered traction of the dirt, all four wheels have to grip. However, I noticed that power is transferred to all four wheels all the time. The first wheels that spin are the rear ones no matter what car I'm driving--Legacy, Element etc...

On many high powered 4WD cars in the game (like the Escudo Trial Car by Suzuki or even a highly modified Element), I can spin the rear wheels with the traction control off while the front barely spin at all.

What I'm trying to figure out is how exactly GT4's 4WD system works.
 

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