buzzmag

This should draw many comments here.

http://www.popularmechanics.com/cars...lick=pm_latest

iforyou

iTrader: (1)

Most AWD systems are there just to enhance traction when you step on the gas. It doesn't make the car turn better or brake faster.

Torque vectoring helps handling. How much it helps depends on the the system is setup. SH-AWD for instance is helpful if you drive aggressively and step on the gas when cornering hard.

eSH-AWD is another big step forward. It takes away the fuel economy disadvantage. In fact, it improves fuel efficiency. It can apply negative torque so the effect is more pronounced. It also works even when you are stepping on the gas. The system can figure out how fast you are going, your steering angle, and determine how much positive and/or negative torque to apply per wheel. Yes, traction per tire is limited. But such system can maximize the use of all available traction per tire. That's the key point as during a turn, in most cases, not all 4 tires are at their limit at the same time.

CGTSX2004

iTrader: (1)

The article itself is certainly not wrong. The important thing is that the laws of physics and traction still apply, meaning that there is still limited traction. Also, common sense cannot be thrown out the window, as is often the case with people who buy AWD assuming they can pretty much do whatever they want and the car will correct it.

I think the same issue applies to stability control systems. They are able to correct and adjust up to a certain level of stupidity. Beyond that, the systems are just as useless as if they were not there. Both are systems that create a false sense of invincibility in drivers and can lead to even more severe crashes when crashes do happen.

Does that mean we should not sell them? Absolutely not. We just should not throw common sense to the wind because of a false sense of security created by a piece of technology.

JonFo

I found the article to be biased and does not jive with my expereince at all.

I refuse to buy anything but AWD-based cars. Much in the same way I want brakes at all four corners.

I live in the mountains, and wen it gets slippery, only AWD gets you up the hill.

As for handling, my driving experience is that my AWD vehicles hang-on much better in any grip circumstance relative to a FWD system

One of the negatives of the 2nd gen RL AWD system is that it's primarily a FWD car, with the option to send power to the rear. In contrast, my Subaru's (and I've had six) give limpet-like grip whether on the gas or not.

Now I love the SH on the RL, but as noted, the current version only works when under power. I'm looking forward to the new one with the electric torque vectoring, including negative torque (which works under braking or coasting thru a corner).

Ultimately, my ideal AWD is an electric motor at each corner.

CGTSX2004

iTrader: (1)

I think you are subscribing to the fallacy that the article is trying to debunk. Grip can only be provided by the tires. How you utilize that grip to get you moving can be improved by which wheels of the car are driven.

In your example of getting you up the hill, that is an instance when optimizing the available grip provided by the tires is definitely at an advantage with AWD. AWD allows you to keep moving because it allows you to keep building more momentum because you have 4 potential points of power application to the driving surface versus only two.

Once moving, however, AWD cannot improve your grip, it can only optimize it because mechanical grip is a result of the friction of the tire against the road surface. While the article is a little harshly worded, it is really aimed at those people who seem to believe that having AWD makes you invincible to all road conditions.

n-spring

Yes, I always got a kick out of seeing all the 4x4 SUVs in the ditch during the first winter snowfall in Colorado.

JonFo

Oh, agree that the vast majority of idiots in SUV's incorrectly believe their 5K+ pound vehicle with AWD can get them out of trouble in bad conditions.

And that even AWD sedan owners can get overconfident and crash.

However, being a performance driver and knowing a bit about physics and how stuff works, some of us see and use AWD as a performance enhancer, not a band-aid.

When coasting around a corner (or under braking) you are indeed at the mercy of the grip provided by the four contact patches of the tires. Period.

However, those of us who know how to drive an AWD vehicle for max performance rarely coast in the middle of a curve, we're usually on the gas.
because as noted, when putting torque down four is better than two.
And with SH-AWD, you also get toque vectoring steering help as well.

So I know can go around curves much faster with the RL than a FWD car of similar heft. matter of fact, proven it when idiots stay on my bumper going downhill at 55MPH into a 60% corner, I brake right up until I start turning the wheel, then I'm hard on the gas with the MID display giving three to four bars of torque to the outside rear wheel. Meantime, in the rear-view mirror, the RWD Bimmer driver has skidded into the wrong lane and is swerving all over the place.


One great proof-point of AWD superiority is when grip is reduced, such as when raining, it adds a huge advantage. Remember the early SCCA Audi Quattros?
They were nose-heavy understeering pigs in the dry, barely able to keep up with the Caddys and Bimmers. But as soon as it rained, they'd lap the field.

iforyou

iTrader: (1)

I think we are actually on the same page.

1.) Most regular AWD systems won't improve lap times in regular condition

2.) AWD systems with torque vectoring can improve lap times in most cases

3.) Most AWD systems help improve grip when accelerating in any condition and can help one get out of trouble if stuck

4.) AWD systems do not make the car stop faster

5.) AWD systems add weight and most of the time make the car slower