Since we had a big snowstorm in the Northeast yesterday, I finally had a chance to drive the Volvo in a good amount of snow. I though I would write a summary of my experience with Volvo's Haldex system vs. the Quattro system in the '09 Audi A4 we traded in back in May. Both cars were on the same tires in similar conditions, not just the same make/model tire, the actual same tire, a Hankook Icebear W300 245/45/17 winter tire, so it gave me a good comparison since it removed tire differences from the equation and allowed the car to be the only factor.
Overall, I prefer Haldex to Quattro.
From a dead stop on a snow covered road, the Haldex exhibited more initial slip in the tires than the Quattro. I believe this is because the Quattro is RWD based (40/60 F/R split), so the weight of the car transferring to the back helps with initial traction during acceleration, where the Volvo is FWD based (95/5 F/R split). That is the only area where Quattro is better in my opinion.
At higher speed, the Quattro always felt a little unstable, meaning the steering wheel would move left/right or the rear would get out of line a little sometimes. The car would always correct, but there was a moment of slight concern. IMO, this is because the Quattro uses its locking center differential to correct slip front/rear and sensors to correct slip left/right through open front and rear differentials, which allow for more wheel spin. When slip occurs left/right it uses the brakes to shift power to other axels with traction, hence the instability feeling in the car. The Haldex is more stable at higher speed and more predictable when you run across say blowing snow covering half a lane. Since the Haldex constantly uses sensors to move the power, I didn't get that moment of concern because the car was always evaluating the conditions.
In low speed turns, the Haldex is better. The RWD bias of the Audi is it's shortcoming in this situation. I learned to drive on a RWD GMC Van, so I am used to the feeling of a sliding rear in snow, however in a $40K sedan I don't like the feeling as much, and Quattro slides it's rear a lot. The Haldex never felt like it was going to spin around nor did the rear end get out of line.
Anyone have any other comparisons from other cars they have owned? I would be curious to see differences between Haldex & X-Drive, 4-MATIC, Subaru's symmetrical AWD etc.
Overall, I prefer Haldex to Quattro.
From a dead stop on a snow covered road, the Haldex exhibited more initial slip in the tires than the Quattro. I believe this is because the Quattro is RWD based (40/60 F/R split), so the weight of the car transferring to the back helps with initial traction during acceleration, where the Volvo is FWD based (95/5 F/R split). That is the only area where Quattro is better in my opinion.
At higher speed, the Quattro always felt a little unstable, meaning the steering wheel would move left/right or the rear would get out of line a little sometimes. The car would always correct, but there was a moment of slight concern. IMO, this is because the Quattro uses its locking center differential to correct slip front/rear and sensors to correct slip left/right through open front and rear differentials, which allow for more wheel spin. When slip occurs left/right it uses the brakes to shift power to other axels with traction, hence the instability feeling in the car. The Haldex is more stable at higher speed and more predictable when you run across say blowing snow covering half a lane. Since the Haldex constantly uses sensors to move the power, I didn't get that moment of concern because the car was always evaluating the conditions.
In low speed turns, the Haldex is better. The RWD bias of the Audi is it's shortcoming in this situation. I learned to drive on a RWD GMC Van, so I am used to the feeling of a sliding rear in snow, however in a $40K sedan I don't like the feeling as much, and Quattro slides it's rear a lot. The Haldex never felt like it was going to spin around nor did the rear end get out of line.
Anyone have any other comparisons from other cars they have owned? I would be curious to see differences between Haldex & X-Drive, 4-MATIC, Subaru's symmetrical AWD etc.
