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Sedans Ultimate AWD Sports Sedans
828 messages, Last post on Oct 03, 2009 at 9:40 PM
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I have driven an a4 3.2L SP Q on the track, and it had a lot of plow, quite a bit more than a non-SP RWD(*) 3-series. Not sure how this translates to a 330xi, but i wouldn't be so sure that an a4 would win the proposed race. I had been toying with the idea of a s60R as a dark horse for the next davemobile, for AWD turbo goodness, but i can't see why i would with the 335xi now coming down the pipeline.
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Replying to: dhanley (Nov 20, 2006 2:01 pm) Best Regards, Shipo |
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Replying to: shipo (Nov 20, 2006 1:24 pm) I agree your view of all things never really are equal, that is why we seek the best design. Your description of the physical forces makes sense except that I would add it depends clearly on the pavement conditions in the corners, not any given surface. If the approach angle is too sever and you are in a car that tends to understeer, AWD should work for the lateral traction of the front tires to help the car get through faster by pulling the car through after the apex. Perhaps the design is not here yet in the AWD sedan segment that will top your AWD vs. RWD list but I'll wager change is a coming. So, for your ultimate AWD list is: 1 - Audi A4 3.2 Quattro (with Sport Suspension) 2 - Audi A4 3.2 Quattro (without Sport Suspension) 3 - BMW 330xi SP I assume the A4 has a true sport suspension where the Bimmer is lacking. Best Regards, OW
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Replying to: circlew (Nov 21, 2006 5:14 am) I've been hearing the whole "Pull the car through..." thing for years, however, I've never seen any scientific or technical explanation confirming that as a fact or debunking it as a myth. Assuming for the moment that that happens to be true, it would seem logical that an AWD car designed as a FWD (Audi in this case) vehicle would benefit from the AWD application much more so than would a properly balanced RWD (BMW in this case) car which would tend to oversteer at the limit. Still and all, I believe that your 1, 2, 3 list from above is probably accurate as the A4 Quattro is indeed offered with a true sport suspension. Best Regards, Shipo
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Replying to: shipo (Nov 21, 2006 5:47 am) R&T did a test of these cars. The list is auto cross test result times: Autocross Results Subaru Legacy 2.5 GT spec.B 54.9 sec. Audi A4 2.0 T Quattro S-Line 55.2 sec. BMW 325xi 56.0 sec. Infiniti G35x 56.2 sec. Volvo S40 T5 AWD 56.3 sec. Mazda Mazdaspeed6 56.7 sec. Lexus IS 250 AWD 56.8 sec Here are results from an AWD vs. RWD G35 Test: Rear Drive vs. All-Wheel Drive: That Is the Question For fun, we brought a rear-drive Infiniti G35 to our autocross and compared it with its all-wheel-drive G35x brother, in both wet and dry conditions with VDC yaw control switched off. We assumed the rear-driver would be quicker in the dry, given its ability to hang out its tail and help the driver tighten his line. But in the wet, we were confident the all-wheel-driver would have a tremendous advantage, hooking up better out of turns. Here's what we learned: Well, we were wrong on one front, right on the other. Based on group average times on the dry autocross, the awd G35x proved itself faster, surprising us with its rear-biased manners and lapping nearly a second (0.9 sec.) quicker than the rear-drive G35. In the wet the G35x fared even better, 1.3 sec. quicker than the rear-drive G35. Credit goes to the electronically controlled awd system, which maintains a rear-drive bias while endowing the car with improved stability. Don't get us wrong, the G35x still liked to hang its tail out, but the driver didn't need to be quite so careful with the throttle to keep the car's back end in check. In the rear-drive G35, the driver had to be far less aggressive with the throttle (and quicker with corrections) to post respectable times. Wet or dry, the awd G35x was far easier to drive quickly. The G35x's center diff is responsible. From 0 to 10 mph, its electromagnetic wet clutch splits the torque 25 percent front/75 percent rear for good grip off the line; thereafter, the car is 100-percent rear drive until rear-wheel slip is sensed. Then, the diff can send as much as 50 percent of the power forward. Although other awd systems will produce different results, the G35x proves that all-wheel drive, properly applied, can give you the best of both worlds. — Andrew Bornhop Regards, OW
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Replying to: circlew (Nov 22, 2006 10:09 am) - I'm surprised at how well the 325xi did compared to the A4 (in S-Line trim no less) given its lesser suspension and hard and narrow All-Season tires. This is by far the closest test of the two cars I've ever seen. - I'm not surprised that the G35x finished behind both the Audi and the BMW, even with it's significant power advantage. - I am surprised that the "x" effectively stomped its RWD sibling into the dirt. I've seen a few other tests that showed quite the opposite. Without knowing anything more about the cars and the track, I'm highly suspicious of the rubber on the G35. Keep in mind that one of the biggest knocks against the G35 is that it's suspension isn't the greatest. Said another way, I don't think I've ever seen a test where a RWD G35 was capable of beating a fairly anemic E46 325i around a tight track much less a more powerful E90 325i. Best Regards, Shipo
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Replying to: shipo (Nov 22, 2006 10:38 am) To properly pit these seven all-wheel drivers against one another in a safe environment, we set up a near-1-minute autocross course. Because these cars deliver better traction than a comparable 2-wheel-drive car (see sidebar on rear- vs. all-wheel drive, p. 75), we decided to include a timed wet session after our morning dry running. Best-laid plans sometimes go awry. We quickly found out that the water truck couldn't drop enough wet stuff to achieve standing water, compounded by the extremely abrasive surface of our former Marine Corps landing strip — picture gritty sandpaper. The grippy surface, combined with learning the track more and more as the day went on, resulted in faster times in the wet than in the dry. Maybe we're just unusually gifted rain drivers.... Regardless, the autocross proved an excellent way to find the nuances of each car's handling habits. Stability systems were turned off. "The Subaru proved to be just about every editor's fastest way around the course, ahead of the second-place Audi A4 by 0.3 sec. When watching the Subie round the cones, we were struck by how much dive, squat and roll the car exhibited. But that translated into a forgiving nature, important since it doesn't have yaw or traction control. Its extremely potent engine provides tire-shredding thrust out of corners. And, if really provoked, the spec.B can rotate with drop throttle — not a usual trait for an awd'er. A few of us found that if we got the car to oversteer under braking heading into the big sweeper (see track map), it could be 4-wheel drifted under power all the way through. Fun stuff! "The Audi A4 — like the Subaru and the Mazdaspeed6 — had the advantage of summer tires, and in the Audi's case they were also the widest of the group. What's interesting here is the completely different manner in which the Audi goes about its business than, say, the Subaru. The A4's sport suspension feels composed no matter what type of transition situation you put it in, but the car also has absolutely no inclination to oversteer. It simply claws and scratches for traction at all times, the counterpoint being that low-speed entry understeer is harder to alleviate than in the Subaru and Infiniti. Because of this nature, it's not as "entertaining" as the Legacy or the G35x. But it sure gets the job done. "The BMW was possibly the biggest surprise at the autocross. Not because it didn't win, but because it did so well (third) despite all-season tires and a lack of power compared to the Subie. Precise steering with great feedback helped, as did a superbly confident chassis that could occasionally be persuaded into oversteer, showing its rear-drive nature. The BMW's predictable handling made the course so easy — aided by proper sport seats that hold you firmly in place — that it felt like you were driving slowly. Also interesting to note is that while the Bimmer finished third, the Infiniti and Volvo were nipping at its heels, just 0.2 and 0.3 sec. behind, respectively. "If you're more concerned about having fun than posting top lap times, consider the G35x. Its awd system feels the most like a rear-driver of the group. It responds instantly to drop-throttle (a little more so than a few editors preferred) and is by far the easiest with which to invoke oversteer, powersliding its way through the big sweeper in an easy-to-control drift. The G35x can be steered with the throttle more than the others, but because of its size, weight and less crisp steering response, its times suffered. Which the big power from its V-6 (with a fearsome wail) just couldn't make up. " While the Volvo seemed to be the odd man out for most of this test, it proved it has some abilities as a sports sedan with a very respectable finish in the autocross. This true test of a car's handling showed the Volvo's best traits are its small-for-the-group size, forgiving handling that will never get you in trouble and a broad spread of power from its turbo-5. But numb steering and too much body roll meant the car became vague in the middle of corners, making it feel less like one piece than the others. The S40 is missing the proper sporting "edge" of cars like the BMW and Audi. "The manly version of the Mazda6 proves the saying that "power is nothing without control." Yes, the Mazdaspeed6 has loads of power, but that means little around a tight autocross course where the emphasis is placed on handling. Under-tired for its weight, the Mazdaspeed6 also dives mightily under braking and feels like a larger car than it is. Turn-in is excellent, but there isn't enough steering feel to let you know what's going on after that, unusual for a company that's been turning out cars with great steering of late. A few of us were bogged down by power-steering-pump issues as well, sporadically occuring throughout the day. "Despite Toyota's claims to the opposite, we find its VDIM stability system to be, well, a real killjoy. What's worse, there's no switch to turn it off. So we completely defeated it via a special series of actions with both the brake pedal and the e-brake. Then we found the true nature of the car. Turns out, it's quite fun to drive in this mode, exhibiting large doses of drop-throttle and power-on oversteer. Possibly because the car wasn't designed to be driven with VDIM off, the IS 250's tail-out attitude was not as controllable as the others. We did appreciate its good steering feel and solid structure, though it's under-tired, overweight and underpowered for autocrossing. (end) I'd like to add that the 330 xi with the added power might surprise even more...you just need to experience it to know. Regards, OW
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Replying to: circlew (Nov 22, 2006 11:04 am) Interesting choice of test tracks. Nearly thirty years ago I spent a fair amount of time around the airfields that are (or were) owned by Uncle Sam's Misguided Children. Given how coarse their pavement usually was, I'm not at all surprised that once learned, drivers had no problem generating very fast wet track lap times. That said, I don't really think the track used for this test is a good representation of how those cars will perform against each other in the real world. "I'd like to add that the 330 xi with the added power might surprise even more...you just need to experience it to know." I suppose, however, that same car in RWD trim with the SP will impress a whole lot more.  Best Regards, Shipo
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Replying to: shipo (Nov 22, 2006 11:20 am) Agreed until the time comes when the results show to the contrary. Best Regards, OW |
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Replying to: circlew (Nov 22, 2006 11:04 am)  The volvo dealer near me is selling a two-year old CPO s60R for 27.9K (34K miles). Assuming that they will go down on the price, it seems like a good deal for a 300hp AWD car. But based solely on tests i've seen, it's not in the same handling category as the other cars in this topic. |
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