Best vehicle for bad weather conditions

[JCH13]

Like I've said, AWD control systems like that are very impressive in how they can let the average driver approach the limits of the car. They can also make up for chassis deficiencies that cause the car to be imbalanced. I'm not arguing that point.

However, if you can explain to me how being on-throttle on a skid-pad relates to off-throttle (sometimes on brakes) in slippery road conditions and how that gives AWD vehicles and advantage over 2WD vehicles, please do explain.

Oversteer happens once you've exceeded the grip of the rear tires, the whole point in these systems is to use that grip up to the point where you haven't exceeded it. You don't need to have oversteer to use the rear of the vehicle to help bring it through a corner. What the system is doing is transferring more torque to the outside wheel to help bring the car around the corner, the inside rear wheel doesn't travel as fast when going around a corner and by shifting that additional torque to the outside wheel and overdriving it compared to the inside wheel, it helps bring the car around. This is all done without oversteer, you don't want to slide the rear of the car around, you want to use the outside wheel to help bring it around without exceeding the limits of your tires.

Increasing the torque at the outside wheel (different from "overdriving") creates a yaw torque about the car, encouraging the car to turn. However, unless some wheels are slipping, the car cannot turn more quickly than if no wheels are slipping. If you can explain how torque vectoring allows a car to turn more quickly than it's ideal ackerman turn (no wheel slippage) without slipping any wheels, I'm all ears.

 

[slatr]

Unless that's in the snow, that has nothing to do with the topic at hand...

an sti can keep moving and even accelerate in the snow. A mustang/rwd car would be backwards or in the ditch.

 

[jlee]

an sti can keep moving and even accelerate in the snow. A mustang/rwd car would be backwards or in the ditch.

That's funny, I drove Crown Vic/Chargers in snow for years and never ended up in a ditch.

 

[ND40oz]

Like I've said, AWD control systems like that are very impressive in how they can let the average driver approach the limits of the car. They can also make up for chassis deficiencies that cause the car to be imbalanced. I'm not arguing that point.

However, if you can explain to me how being on-throttle on a skid-pad relates to off-throttle (sometimes on brakes) in slippery road conditions and how that gives AWD vehicles and advantage over 2WD vehicles, please do explain.

In slippery conditions, when I'm taking a turn, I'm on throttle, so it's still working for me. With the SH-AWD system it's only working on throttle, if you are doing something off throttle then it's no advantage. But with the ZF system, if you're off throttle, it's still vectoring torque as the engine decelerates.

Increasing the torque at the outside wheel (different from "overdriving") creates a yaw torque about the car, encouraging the car to turn. However, unless some wheels are slipping, the car cannot turn more quickly than if no wheels are slipping. If you can explain how torque vectoring allows a car to turn more quickly than it's ideal ackerman turn (no wheel slippage) without slipping any wheels, I'm all ears.

If you're not vectoring torque when taking a turn, you'll reach the adhesion limits of the inside wheel before you reach limits of the outside wheel. To get to the limits of the outside wheel, you either need to overpower the inside wheel causing wheel spin, brake the inside wheel like some traction control systems do or vector torque to the outside wheel. It just allows you to use more of the traction you have available to you across the axel before overpowering both wheels instead of just overpowering one.

 

[slatr]

That's funny, I drove Crown Vic/Chargers in snow for years and never ended up in a ditch.

I didn't end up in the ditch in my mustangs either when driving in the snow. I drove very slow and did not accelerate on turns ect..

Drive an STI or EVO back to back with a Mustang, Camaro etc in the snow or wet conditions. I don't think anyone can deny the difference in control.

 

[JCH13]

In slippery conditions, when I'm taking a turn, I'm on throttle, so it's still working for me. With the SH-AWD system it's only working on throttle, if you are doing something off throttle then it's no advantage. But with the ZF system, if you're off throttle, it's still vectoring torque as the engine decelerates.



If you're not vectoring torque when taking a turn, you'll reach the adhesion limits of the inside wheel before you reach limits of the outside wheel. To get to the limits of the outside wheel, you either need to overpower the inside wheel causing wheel spin, brake the inside wheel like some traction control systems do or vector torque to the outside wheel. It just allows you to use more of the traction you have available to you across the axel before overpowering both wheels instead of just overpowering one.

Again, you make points that are correct, but do not explain how any of this helps the car to turn. It definitely helps the car accelerate, and maybe accelerate during a turn, but none of it shows an advantage for AWD in simply turning.

 

[ND40oz]

I've always considered being able to accelerate out of the turn part of turning, these systems assist you in doing that.

 

[jlee]

I didn't end up in the ditch in my mustangs either when driving in the snow. I drove very slow and did not accelerate on turns ect..

Drive an STI or EVO back to back with a Mustang, Camaro etc in the snow or wet conditions. I don't think anyone can deny the difference in control.

I owned a Forester XT with STi stuff on it and now own a CTS-V. I am familiar.

Nobody's arguing control - I believe the current argument is grip during turning.

 

[BurnItDwn]

I would recommend against a convertible, but anything with a hardtop that doesn't leak should work me thinks.

 

[_Rick_]

I believe the current argument is grip during turning.

I would go even further and say, the argument is higher controllable maneuvering speed. Equip your vehicle with magical thrusters, and go around corners with no grip at all :awe:.

But yes, under braking the advantages of AWD are minimal. At best you can benefit by accelerating a stopped/blocked and skidding wheel back to the speed of the other wheels, so it regains traction quicker, than just releasing the brake as ABS would do.

Still, going round a corner where an FWD or RWD car would understeer or oversteer into the ditch due to a local spot of ice, should be manageable, if an advanced, intelligent diff is used to vector power around. Of course, with 4 wheel steering we're even better off

Relatively to the effect of putting on the right wheels/tires for the situation though, the impact of 4WD and even intelligent torque vectoring is small.

Better to invest the money into integrated jacks, wheel gun and an extra set of wheels in a roof rack. Because Dakar.