|Tech Article Title
|Quattro -vs- Front Wheel Drive
||Performance Car Magazine
Originally posted in the A4 Forum by MichaelB on January 21, 1998. Data came from Performance Car Magazine (February '98).
Bought a copy of Performance Car magazine which tested a '98 A6 Quattro vs. a '98 A6. The results were very interesting. I know someone else posted on this, but here is a more detailed summary for those who cannot find this UK mag at their local newsstands.
First off, there were a few differences between the two cars aside from Quattro. The Quattro had the SPORT suspension, while the fwd had the std. suspension. Also, the Quattro has slightly lower gearing to make up for the weight difference of 230 lbs. Otherwise, they were identical.
If you want to skip all the details...you can go to the bottom, where the VERDICT (according to the writers) is. My verdict is as follows:
1. Quattro's benefits are extremely slim in a 190hp car in both wet and dry conditions (snow and ice is a different story).
2. Article shows benefits of quattro, which we knew of, but shows how very capable the fwd version is as well.
3. For acceleration in wet or otherwise slippery conditions, the Quattro offers the most significant benefits. However, this will not make it stop any quicker.
4. Although the fwd is quicker, the Quattro's launches would even things out in quick stoplight to stoplight type runs. The fwd would pass at some point however.
5. Results on the track may have favored the fwd if it also was equipped with the sport suspension.
Here were the track results:
Q: 24.2 sec
F: 23.9 sec
(Time Exposed to Danger) Emergency Manuever:
Q: 5.6 sec
F: 5.6 sec
Lateral G (note that Quattro has SPORT suspension):
Q: 8.33 sec
F: 8.29 sec
TPR (combined results of above):
Now they went on to test handling on a track, including testing in the wet vs. dry. Keep in mind that the Quattro has the SPORT suspension vs. stock in fwd when analyzing results.
Dry Handling Course (again Quattro equipped with SPORT suspension):
Q: 69.5 sec
F: 69.6 sec
Wet Handling Course:
Q: 39.9 sec
F: 40.1 sec
0-30mph in wet:
Q: 3.23 sec
F: 3.82 sec
0-30mph on simulated Ice:
Q: 7.4 sec
F: 11.94 sec
Some interesting quotes:
On 0-100-0: "The Quattro made its traction off the line count, leaping to 30 mph in 2.1 secs, passing 60mph in a rapid 6.9 sec but then fading slightly to hit the magic 100 in 19.6 secs...but the front-drive SE was marginally quicker to 100 at 19.3 secs. despite trailing the quattro at 30 and 60 (2.7/7.2). Interestingly, the SE had traction control and we recorded our best times with it switched in..."
On Lateral G's: "In theory, there should be no difference...this is a steady-state test using constant throttle opening and both cars have the same size tires, so the quattro doesn't get a chance to show it can redistribute the engine's torque. The reason the quattro is a fraction quicker around the circle is more likely its lower, stiffer suspension."
On wet handling: "You'd expect the quattro to leave the fwd choking in its spray here...the times both drivers recorded for the A6's were within tenths: Barker lapped the quattro in 38.7 secs and the fwd in 39.0 secs, while Strong's times were even closer at 41.0 secs for the quattro and 41.1 secs for the fwd. Barker's best times for the fwd were set with traction control off. It looked less tidy, with plenty of wheelspin, but helped maintain revs out of the tight turns, as on the dry handling circuit. Strong commented that the fwd felt more adjustable, with a helpful degree of tail swing when late braking into the same turns."
Wet lateral g: "Subjectively, the quattro had a definite edge; it seemed to have better bite and more balance, holding its line with less steering lock than the fwd. That said, they both looked impressively rapid around the glassy circle and their lateral g ratings were very close."
0-30 mph wet: "Even with a quarter of an inch of water under its tires the quattro punched off the line almost as well as most fwd cars can manage in the dry. The fwd recorded its best acceleration times with traction control on..."
0-30 mph ice: "This was the only test that proved categorically the benefits of four-wheel drive. "...and the fwd struggled. The revs flared and died as the traction control system went on overtime, and slowly and agonisingly the front-drive A6 picked up speed. By contrast, the quattro dragged itself to 30 mph with ease. There were some unusual sensations as the drivetrain juggled the torque, favoring the front and rear wheels in turn, but there was no denying it was an impressive performance."
VERDICT: "The advantage of 4wd in regular driving is clearly marginal in a 193bhp car. In the dry the front-drive A6 was virtually the equal of the quattro, and even in the wet the quattro's measurable advantage was very slim. The quattro system doesn't increase the cornering grip on offer, it merely allows more torque to be used accelerating out of corners, which isn't the same thing. Nor is it a decisive advantage in this comparison. However, you can't ignore the confidence factor - 4wd can make a car feel more stable - and in snow and ice the benefits of all-wheel drive shine through (though it is worth mentioning that you can't stop a 4wd any more quickly). We're not writing off 4wd. Some cars wouldn't be nearly as effective without it: 911 Turbo, Skyline, Integrale,Impreza. What they have in common is an engine with over 200bhp and a turbo or two, and that's a combination that 2wd has trouble coping with. Four-wheel drive gives the torque unrestricted access to all four tires, and distributes it so that the tires with the most grip get more. That's why 4wd can be brilliantly effective."