Last post on Feb 08, 2012 at 7:57 AM
You are in the Sedans
What is this discussion about?
BMW 3 Series, Audi A4, Volvo S60 R, Subaru Legacy, Audi S4, Mazda MAZDASPEED MAZDA6, Sedan
#478 of 857 Re: AWD conundrum [shipo]
Sep 11, 2007 (11:36 am)
"Thats because it wasn't deigned in. A Subaru Legacy sedan is 3325# while the Accord EX is 3349#."
Oh come on, that's just silly. If the Suby had its AWD components removed it would be lighter, being "designed in" is irrelevant.
Its still lighter than the class benchmark in FWD. The weight associated with AWD can't be that big of a penalty.
"But in an AWD car, that powering force is split between more contact patches. If one contact patch is needed to turn, then the power can go to the other, shifted to help the car turn (like the Honda SH or just about any active diff car)"
So what you're saying is that an AWD car will turn itself into a RWD car when turning otherwise the front wheels will lose traction. I say, "Why bother?" and start with a RWD car to begin with
Except then you only have 2 contact patches instead of 4. A limited slip or active differential can push the outside tires though a turn.
"How so? Both mid-size cars, about the same amount of power, about the same weight, the Volvo had snows, the Subaru didn't at first but got them the same winter."
This is silly too. I mean come on, my 1970 Challenger was about the same size and weight as my 2002 5-Series BMW, had about the same amount of power, both had manual transmissions and both were RWD. That said, they sure as hell didn't drive the same way, on the snow or off.
But a midsize sedan and a midsize sedan are in the same category. Its not like I am comparing a Lotus and a VW bug or something.
#479 of 857 Re: AWD conundrum [lilengineerboy]
Sep 11, 2007 (12:16 pm)
"Except then you only have 2 contact patches instead of 4. A limited slip or active differential can push the outside tires though a turn."
A popular misconception of what AWD can and cannot do. No further comment.
"But a midsize sedan and a midsize sedan are in the same category. Its not like I am comparing a Lotus and a VW bug or something."
I used those two cars to illustrate a point, a point that suggests that comparing a Subaru to a Volvo was silly and you reject it even though those two cars have more in common from a mechanical perspective than the two you compared. Disingenuous at best. The fact is that unless you're comparing two otherwise identical cars such as A4 FWD vs. A4 Quattro or 328i vs. 328xi or G35 vs. G35x, any comparisons are Apples to Oranges. Like it or don't.
#480 of 857 Re: AWD conundrum [shipo]
Sep 11, 2007 (12:43 pm)
To be quite honest, that simply doesn't make any sense.
It makes sense because you can feel the slip, the light comes on and then control returns. It's not huge but you can detect slight loss of traction.
I didn't imagine it it happened. The car did not loose control put the tires definitely were loose before TC/DSC engaged.
#481 of 857 Re: AWD conundrum [shipo]
Sep 11, 2007 (12:52 pm)
"Except then you only have 2 contact patches instead of 4.
Subaru AWD Defined
Because you never know what’s on the road ahead, Subaru engineers developed Subaru All-Wheel Drive, a system that not only is capable of powering all four wheels, but also automatically varies the amount of power sent to each wheel at all speeds.
A limited slip or active differential can push the outside tires though a turn."
A popular misconception of what AWD can and cannot do. No further comment.
Oh, please, allow me to comment:
"ATTS, during a turn, transfers power (torque and speed) to the outside driven wheel of the car. The effect of the system reduces understeer and pulls the car around the corner. It's an active system that uses dedicated hardware (electronics and clutch packs, etc) to do the transferring. Don't confuse ATTS with a limited slip differential (ATTS is not an LSD), which is a passive device (there are many different designs) that reduces the tendency of the engine power to escape through the wheel with the least resistance (normally the inside wheel during a turn)."
#482 of 857 Re: AWD conundrum [lilengineerboy]
Sep 11, 2007 (12:53 pm)
Sounds like marketing bilge to me.
#483 of 857 Just out of curiosity
Sep 11, 2007 (2:50 pm)
Have any of you AWD advocates added up what it costs, not just in the obvious up front price premium, and in the lower fuel economy, but also in maintenance and potentially expensive out of warranty repairs? Seriously? Give us the numbers, if you have.
The advocates here seem to be hell bent on proving SH-AWD, Quatro, Subaru's system etc. are great technological advances. That's debateable, IMO. But what isn't, is the added cost. Acura has a very checkered history with something as relatively simple as an automatic transmission (well documented premature failures on the TL and previous MDX). I would not bet that the SH-AWD system wouldn't have a hiccup or two over the course of the 155k miles I put on my dinosaur 1995 Maxima. As a matter of fact, our neighbor with a 2005 RL has had it back to the dealer twice for "computer control" problems, in one case it was out of commission for two weeks and would have cost $2,500 out of warranty. Another friend had a Mercedes S430 4-matic that, over 100,000 miles he figured it cost him $4,000+ more in maintenance and fuel costs than a RWD would have (and that was with an extended warranty that covered a couple repairs).
As with transmissions, I can drive a stick, have done so for 25+ years in DC traffic and if I burn a clutch, I know who to blame. The latest SMG and DSG technology may look great on paper when you are reading Road and Track sitting on the toilet. But tell that to a friend of mine who paid $5,500 in repairs on his demonically possessed M3 SMG at under 70,000 miles. In 30+ years of driving high performance cars, he never had to replace a single clutch.
Having grown up in snow country (120 inches annually) and still having a second home there, I concede that I would want to have a AWD SUV for the really serious stuff. But I wouldn't feel the need to encumber my family sedan with AWD and sure as hell wouldn't put it on a sports car.
There is a cost benefit tradeoff to consider - and it seems that some AWD advocates are a little light on their cost ledger.
#484 of 857 Re: Just out of curiosity [habitat1]
Sep 11, 2007 (5:17 pm)
So our '07 Honda Accord EX gets just under 32 mpg average with 166 hp 4 cylinder 5 speed manual FWD drivetrain. Our '05 Subaru Legacy gets just over 30 mpg with a 165 hp 4 cylinder 5 speed manual AWD drive train. That means my cost is 1 mpg. Based on 12k miles a year, the Subaru will use an additional 25 gallons of gas $3.00 /gallon we will say $75/year additional. The Subaru is also on higher performance tires than the Honda so switching to something like a MXV4 would likely make the fuel economy savings even smaller.
#485 of 857 Re: Just out of curiosity [lilengineerboy]
Sep 11, 2007 (5:21 pm)
"So our '07 Honda Accord EX gets just under 32 mpg average with 166 hp 4 cylinder 5 speed manual FWD drivetrain. Our '05 Subaru Legacy gets just over 30 mpg with a 165 hp 4 cylinder 5 speed manual AWD drive train. That means my cost is 1 mpg."
Apples to oranges again. What you don't know is how good your mileage would be if the Subaru didn't have AWD. Comparing it to the Honda and trying to extrapolate what your mileage might be like is completely irrelevant.
#486 of 857 Re: Just out of curiosity [shipo]
Sep 11, 2007 (7:54 pm)
They are two cars in the same segment. They are comparable, in the mid-size sedan forum they are both listed. The Accord doesn't come with AWD and the Subaru doesn't come without it, and yet the Subaru with the same weight and power gets about the same mileage. I think that blows the theory.