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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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At the end of the day, the Carrera 4 S should suck the the doors of most RWD and ALL AWD street legal cars on a closed course track and spit the rest of the car into the weeds! Just a matter of cash and if you are in proper physical condition to get in/out of the car and can recover after each drive in the salt baths!  On the other hand, it would be nice to have a Bentley Conti. GT for those stiff back days!  Regards, OW
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Replying to: circlew (Nov 20, 2006 10:13 am) Best Regards, Shipo
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Replying to: shipo (Nov 20, 2006 11:10 am) My point is that that the AWD allows faster track time due to the better adhesion. All things being equal, weight/ride height, AWD will win the day. If Audi does this better it is because they are ahead of BMW from longer experience and across many different model classes. I applaud your opinion but let's see if the '07 335xi offers any resistance to your proposed duel. Regards, OW
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Replying to: circlew (Nov 20, 2006 12:48 pm) My point is that that the AWD allows faster track time due to the better adhesion. All things being equal, weight/ride height, AWD will win the day. The think is, all things are rarely equal, and even if they were I would dispute that statement. First off, AWD is heavy and Audi's arguably superior Torsen based system is even heavier than most. In cornering and braking, that extra weight is very much a detriment. Secondly, tires only have so much adhesion on any given surface and when a front tire is asked to both turn and apply power to the pavement, the amount of accelerative forces at any given moment directly and proportionally reduces the ability for the tire to provide lateral grip. So, while two otherwise identical cars, one RWD and one AWD, might have steady state similar cornering abilities, start applying power and the AWD car starts loosing front end cornering ability. True there are some cars with AWD that will outperform a competitors’ similar RWD car, however, is it the AWD system that is the differentiating factor or is the AWD car simply a better designed car? Regarding the Audi A4 versus the 330i (roughly an apples to apples comparison) the following would most likely be the results at a closed course track: 1 - BMW 330i SP 2 - Audi A4 3.2 Quattro (with Sport Suspension) 3 - BMW 330i non-SP 4 - Audi A4 3.2 Quattro (without Sport Suspension) 5 - BMW 330xi SP 6 - Audi A4 3.2 FWD (with Sport Suspension) 7 - Audi A4 3.2 FWD (without Sport Suspension) Best Regards, Shipo
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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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