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FWD, AWD, RWD and the Luxury Performance Sedans

102 messages,  Last post on Mar 24, 2008 at 10:20 AM

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What is this discussion about? Acura RL, Audi A6, BMW 5 Series, Cadillac STS, Cadillac CTS, Infiniti M35, Infiniti M45, Lexus GS 300, Lexus IS 350, Sedan

Messages Page 4 of 11

#27 of 102 Re: "adverse roadbed conditions" questions [markcincinnati] by jimbres

Jul 30, 2006 (5:52 am)

Replying to: markcincinnati (Jul 25, 2006 7:51 pm)
Odd remarks, yours, about RWD's purported "tail wagging" tendency. I've driven a BMW 330i (sport pkg & 5-speed manual) under all sorts of conditions & have never experienced this. (I do not, though, go out in this car when snow or ice is on the road; I have a 4WD vehicle for that sort of thing.) Moreover, I've been frequenting these boards since 1998 & can't recall anyone describing a "tail wagging" incident. Have you personally experienced this? If so, please post the details: make & model, road conditions, etc.

#28 of 102 Re: "adverse roadbed conditions" questions [jimbres] by wwest

Jul 30, 2006 (10:11 am)

Replying to: jimbres (Jul 30, 2006 5:52 am)
What's he's pointing out is that if you get heavy footed with a RWD on a low traction surface the rear end WILL try to LEAD. Generally a quick flick of the stearing wheel will prevent this, or bring the car back into line.
 
ALL RWD vehicles have this unavoidable heavy throttle tendency, some more than others, the earlier 911's in particular.

#29 of 102 Re: "adverse roadbed conditions" questions [wwest] by jimbres

Jul 31, 2006 (4:50 am)

Replying to: wwest (Jul 30, 2006 10:11 am)
Understood, but it seems to me that he's trying to say more than that RWD cars tend to oversteer. He describes "tail wagging" as a form of oversteer & hints that it's potentially lethal. This leaves me scratching my head, because I've never encountered this.
 
Now I've read & enjoyed Mark's posts for years, & I know that he's an AWD evangelist. My own view is that AWD confers no significant benefit once the temperature is above freezing & the roads are clear of snow & ice. Under these conditions, I'd rather not carry AWD's extra weight around with me.
 
That said, I think that the war is over & AWD is the winner. Not because it's better but because it's now so cheap that few buyers will decline it, given a choice. Back in late 80s, BMW offered an AWD variant of the E30 325 for an additional 20%. At that price, there were few takers, & BMW stopped offering AWD when it introduced the E36. Today, the AWD premium is less than 5%, based on MSRP for a 530xi. The result: in my neck of the woods (a NYC suburb), I see at least 4 530xi's for every 530i. Will BMW still offer the 530i 5 years from now? I wonder.

#30 of 102 Re: "adverse roadbed conditions" questions [jimbres] by markcincinnati

Jul 31, 2006 (5:25 am)

Replying to: jimbres (Jul 30, 2006 5:52 am)
You've made my point.
 
And you are, apparently, a prudent driver in that you recognize the issues that a low-er coefficient of friction causes in a RWD car. But before you say "yes but," read the next paragraph.
 
The lower coefficient of friction that rain, snow or ice causes, merely brings out the inherent characteristics of the vehicle in question at a lower speed. I.E., if you can induce "tail wagging" at 30kph on packed snow with car "A" and it is 45kph on packed snow with car "B" this simply permits a slow-motion (relatively) demonstration of what would happen with car "A" at 120kph and with car "B" at 160kph, on dry pavement. Most of us would rather get the sense (the feel) of an out of control vehicle and the skill required to get it back into control at the lower speeds rather than the higher speeds (hence Audi's safety training is almost always conducted on a 1.5 mile square sheet of ice.)
 
If you really want to demonstrate this and you have the facilities and the access to cars, try this:
 
Get three cars of similar characteristics (size, weight & power) one RWD, one FWD and one AWD.
 
Go to a snow covered or ice covered (snow would be prefereable and less frustrating) parking lot (empty)
 
Drive each car in a circle -- pick a small enough circle so that you can avoid any light poles, buildings or other potential metal bending objects.
 
Drive each car faster and faster and faster until it begins to "break away."
 
The car that will lose control first is: RWD, then FWD, then AWD. When the RWD car breaks away, it will be "fish tailing" -- the FWD, by contrast, will simply begin to turn wider and wider and to a point will respond by applying further lock on the steering wheel, until it no longer can continue in a circle -- a let up on the gas or a poke at the brakes will immediately correct its "wide steering" behavior. Conversely a poke on the brake in the RWD car will almost immediately cause a "360" or what we love to call a "donut!"
 
 
 
Please remember I am talking about the sub 9/10ths driving activities most of us undertake daily on Primary, Secondary and Tertiary roads -- not race courses. I am also talking about the skills that most folks might have learned in the "normal course" of high school driver's ed and a few years of driving in "weather" and with the common drive lines that have dominated our highways for some 20+ years.
 
I am not here to argue against RWD in other conditions (although I might point to the success Audi -- but not just Audi -- have had w/AWD in competitions since a little race called Pike's Peak back in the 1980's.)
 
The tail wagging in a "safe" set of circumstances -- circumstances that dramatically demonstrated what I am talking about -- was behind the wheel of a BMW 3 series (RWD.)
 
Even the traction control and ASR and ESP electronics of modern RWD cars cannot completely eliminate the "fish tailing" behavior of a 2WD car (when those wheels driven are the rears.)
 
If you want to put power down: AWD.
 
If you want to increase control: AWD.
 
Perhaps a controversial statement for some: if you want to win races -- also AWD.
 
My comments, to repeat, however, are from a "real life" perspective -- on the highways and byways of our daily driving (which I submit are rarely, if ever at 8/10's, let alone 9/10's), most folks will find "nothing satisfies like beef," er, AWD.

#31 of 102 Re: "adverse roadbed conditions" questions [markcincinnati] by wwest

Jul 31, 2006 (5:23 pm)

Replying to: markcincinnati (Jul 31, 2006 5:25 am)
Sorry, you're dead wrong, DEAD wrong...!
 
RWD offers the most "benign", "native to your basic instincts", driving experience of all.
 
Having the front wheels/tires "contact patch" DEDICATED to lateral, directional control, and the rear to DRIVE, engine torque, leading or lagging (compression braking) is without any doubt the most optimal configuration overall.
 
Yes, absolutely agree that as long as traction is good or at least reasonable FWD will be the WINNER.
 
AWD, hmmmmm....
 
Which version....?
 
Front torque biased..... absolutely NOT!
 
Rear torque biased...., fixed or dynamic (4runner, Acura RDX, Lexus AWD GS300), agreed.
 
Front torque biased (RX300/330/350, Highlander) NOT!

#32 of 102 PS... by wwest

Jul 31, 2006 (5:27 pm)

I drive a 2001 911/996 C4 and have driven it on the track at Daytona and I cannot say, truly, that I wouldn't have rather had a RWD to push harder.

#33 of 102 Re: "adverse roadbed conditions" questions [markcincinnati] by jimbres

Jul 31, 2006 (7:34 pm)

Replying to: markcincinnati (Jul 31, 2006 5:25 am)
I wouldn't dispute the benefits of AWD on a snowy road. But your post #26, to which my remarks were intended as a response, made no mention of snow or ice. Not surprisingly, I interpreted your post to mean that this mysterious & sinister "tail wagging" could occur at any time - even on a hot summer day. In your subsequent post, you make a more narrowly drawn & thus much less controversial claim: given certain specific road & weather conditions, AWD is safer than the alternatives. If that's the point you wanted to make, I wouldn't argue with you. (Certainly, I'm not crazy enough to drive an SP-equipped RWD BMW shod with "summer" tires under those conditions.)

#34 of 102 Re: PS... [wwest] by markcincinnati

Aug 01, 2006 (5:55 am)

Replying to: wwest (Jul 31, 2006 5:27 pm)
The general driving public is the driver I mostly refer to when I present some of the reasons for one to consider AWD, FWD or RWD. What may or may not happen on a track is NOT irrelevant -- it is, however, for the vast majority of folks, infrequently where they find themselves driving their personal vehicles.
 
Benign is a good word to use to describe the reaction to driver inputs. Car manufacturers have, for years, come to the conclusion that understeer is a good thing, i.e., it is primarily a benign trait (at least modest understeer, I would not urge any manufacturer to continue to increase the amount of understeer using the premise "if a little understeer is good, more must be better".)
 
Yet, a little understeer IS good for most drivers on our Interstates, Primary, Secondary and even Residential highways, roads and streets. A "little" understeer is considered by folks who get paid to opine about such things the MOST benign, i.e.
 
FWD besides its many packaging, weight and cost saving attributes offers (or usually offers) improved control for the driver under public driving conditions and under most conditions ranging from dry pavement to slick pavement.
 
I am not suggesting, however, that it is a wise choice for the high or highest performing vehicles. That can be another discussion another time, i.e.
 
A synthesis of what I assume we MAY both agree with follows:
 
For average drivers (on the public roads), FWD will either appear to be superior, or for practical purposes will be superior and FWD more often than not will have certain advantages in poor weather.
 
However, therefore, notwithstanding, a well set up RWD car with a trained driver is extremely capable in poor conditions when "set up" properly.
 
If we can agree that the above generalizations do apply to the majority of non-professional drivers, then, hopefully my point has been clarified.
 
By the same token, AWD offers (or can) even higher levels of control and -- as it continues to be demonstrated (in the highest performing and luxury performance classes) -- performance.
 
I will so stipulate that I am not discussing some of the many FWD vehicles that have had RWD bolted onto them, but continue to behave 95% of the time as FWD vehicles.
 
I favor Proactive AWD, Rear biased AWD and AWD "systems" that marry mechanicals and electronics -- stability control systems, e.g. Nothing less than a 50 50 split will pass muster -- and in an ideal world, the vehicle under scrutiny will be well weight balanced F/R and have at least a slight R/F torque bias.
 
Overall, I am suggesting that the average driver under average conditions, driven at under 80% or 90% of the "performance limits" of the vehicle will find the greatest ease of achieving both control and performance first with AWD, then FWD followed by RWD.
 
We could continue to debate -- and substantiate with many anecdotes and many articles (some biased some more-or-less objective) -- what is best for "racing" or driving over 9/10th's.
 
We could discuss the market penetration and number of models being sold (in several markets, not limited to one or two) that either offer as standard equipment or as an option AWD. We could further attempt to differentiate and discriminate between performance and utilitarian classes.
 
We could look at the "exotics" and the cars made of unobtanium over the years and see the trend in terms of end driven and number of wheels driven, etc.
 
We could look at the hold outs, the purist marquis over a 10, 20 or 30 year period and note the trends in adoption of AWD.
 
AWD's penetration across the board (some great applications some not at all great) continues and continues to accelerate. Not too many years ago, my Bimmer-centric friends would have been in near total denial that their beloved RWD BMW's would ever be offered with AWD.
 
The upcoming 7 series will nearly complete the transition from nearly none (can be had with AWD) to nearly all (can be had with AWD.)
 
The largest BMW dealer in Ohio (which may or may not be significant or statistically important, I don't know) claims that ~40% of the inventory sold is AWD -- and that is inventory constrained, NOT demand constrained.
 
The practical superiority and "benign" nature of AWD is virtually self-evident.
 
Please note the word before "superiority."
 
At this point, debating 2WD vs. AWD beyond its practical and widespread application for the general driving public was never my intention.
 
I know virtually no driver who EVER drives on the track at Daytona or anywhere else on the track for that matter -- the parking lot full of cars at my office, however, tells the tale. There are almost NO RWD vehicles, a few FWD vehicles and at least 50% AWD vehicles.
 
Granted this is an anecdote, granted we live in Ohio which does have "moderate" (modest) winter weather and precip, but this does appear to be a trend, a Mega-trend in drive lines. AWD from several aspects (including consumer demand) is superior and most desirable.
 

#35 of 102 "Moichendizing. . .moicehndizing!" I can get it for you wholesale. . . by markcincinnati

Aug 01, 2006 (7:37 am)

". . .the popularity of SUVs in the 1990s is now driving growth in the high-end features in car-based products as some buyers migrate from SUVs to smaller vehicles. All-wheel drive is becoming a more important factor in consumer purchase decisions.
 
Ford customer research and independent analysis shows that 73 percent of current midsize SUV owners want AWD or four-wheel drive (4WD) in their next vehicle. Additionally, 20 percent of full-size car owners want AWD in their next vehicle. And interestingly, in the large car sample, less than one percent of the owners currently have AWD.
 
The trend is stronger in the luxury market where 18 percent of luxury car owners currently have AWD, but nearly 50 percent say they want it in their next car.
 
In 2003, AWD or 4WD vehicles accounted for 25 percent of the market. It is estimated that number could double to 50 percent of the market by 2012."
 
From "media" press release.
 
Again, this indicates the trend is for AWD. This indicates the "popularity" and increase in demand for AWD.
 
VHS was also more popular as measured by "demand" than Beta.
 
That I happen to think the pros of AWD outweigh its cons . . . is really beside the point.
 
AWD is succeeding in the world of "moichendizing" (Mel Brooks, pronunciation.)

#36 of 102 Re: PS... [markcincinnati] by wwest

Aug 01, 2006 (9:14 am)

Replying to: markcincinnati (Aug 01, 2006 5:55 am)
I think we are in full agreement, for average drivers (95% of the population) on average roadbed conditions FWD will be the most optimal selection.
 
However I think this particular discussion started out being pertaining to driving on adverse roadbed conditions.
 
So, first, tell me what advantage AWD or even a 4WD/4X4 has in these roadbed/highway conditions other than often developing a high level of false, over-confidence, by exhibiting the ease of getting you up and going initially.
 
When things get dicey I want the front tire contact patch dedicated to lateral/directional control and absent a clutch pedal I NEVER want any level of engine compression braking on the front contact patch.
 
Yes, the trend is certainly and clearly toward AWD, but regretably absent driver education we will continue to see those potentially dangerous, unsafe, and even hazardous front torque biased AWD systems predominate in the marketplace.
 
But look at the RDX, GS300, and 4runner AWD systems and you will see yet another trend. AWD systems that dynamically allocate and/or reallocate engine drive or braking torque according to vehicle and roadbed conditions.
 
Basically all of these quickly remove engine drive/braking torque from the front contact patches when conditions warrant.

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