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-   -   Just to clarify- xDrive is a full time awd system (http://www.bimmerfest.com/forums/showthread.php?t=427207)

X3emist 01-19-2010 02:45 PM

Just to clarify- xDrive is a full time awd system
 
I have seen posts here numereous times that refer to the X3 xDrive system operating in RWD under normal conditions and only switching to awd when slippage is detected. I also have seen where some here think that the dash indicator means the awd system is kicking in. This is not true. xDrive is ALL TIME AWD per the following quote from BMW's techincal features page located at- http://www.bmw.com/com/en/insights/t...icle=mm_xdrive

Another key point is that the 4x4 dash indicator has nothing to do with the awd system, it indicates that DSC has kicked in and is modulating the engine power and the brakes to help stabilize the trajectory the vehicle is in and prevent the rear end from swinging out. Here is the quote from the manual itself-

Indicator lamp
The indicator lamp goes out shortly
after the engine starts.
When the indicator lamp flashes:
DSC is controlling the drive and braking forces.
When the indicator lamp stays lit:
DSC has been switched off with the button.

Quote from link above-

xDrive is the permanent all-wheel drive system from BMW: under normal circumstances, it distributes driver power between the front and rear axles in a 40:60 ratio, and changes this figure variably when the road surface or overall driving conditions change.

Acting virtually instantaneously and a manner so subtle as to be go virtually unnoticed by the vehicle's occupants, xDrive can direct up to 100% of drive forces to one axle. Enabling the driver to start up effortlessly even on slippery surfaces or steep hills, xDrive routes all power to the axles with the greatest traction. When parking, the system reacts to the need for high manoeuvrability at low speed by opening the clutch completely so the powertrain functions optimally.

At the first sign of understeering, drive power to the front axle is reduced. If oversteering is detected, xDrive directs more power to the front axle. Thanks to this dynamic redistribution of power, vehicle stability returns to normal even before the driver notices anything amiss.
Driving on a winding road or taking a fast bend in dynamic style is particularly enjoyable with xDrive: you feel as if your BMW is being guided along the curve. xDrive ensures that none of drive power is wasted on a loss of traction: every kilowatt of power is effectively brought to bear on the road.

xDrive is regulated by Dynamic Stability Control (DSC) and uses information from the latter system's sensors to monitor road conditions. In addition, brake force courtesy of DSC is used when there is traction difference between the two sides of the vehicle and wheel spin is likely.

BM2W 01-19-2010 02:56 PM

True dat. X-Drive is quite transparent most of the time, but it will make itself know in the slop or on slippery surfaces. It is much fun when pulling away from the unknowing RWDers on wet off-ramps . . .:D

jimsteph12 01-19-2010 07:47 PM

Interesting. Funny, I asked that very same question to the salesman at the BMW dealer and was told that it's RWD and only AWD when slippage occurs.

Thanks for the clarification.:thumbup:

1972ford 01-19-2010 09:37 PM

Quote:

Originally Posted by jimsteph12 (Post 4861917)
Interesting. Funny, I asked that very same question to the salesman at the BMW dealer and was told that it's RWD and only AWD when slippage occurs.

Thanks for the clarification.:thumbup:

ha, funny when I talked to a subaru dealer about their AWD system, the salesman in the showroom had the wrong answer too.

x3man 01-21-2010 04:08 AM

Salesmen are not to be trusted. They will say anything to make the sale. It is rare that one is truly knowledgeable about the product they are selling. They do exist but rare.

iamthewalrus 01-21-2010 07:44 AM

Quote:

Originally Posted by x3man (Post 4866164)
Salesmen are not to be trusted. They will say anything to make the sale. It is rare that one is truly knowledgeable about the product they are selling. They do exist but rare.

Then why on earth do we have to deal with them? Why can't I go to www.bmwusa.com, configure what I want and submit a deposit? I do this with a Dell or Apple computer, so why not a car?

The manufacturers should do build to order with no inventory, or hold very limited inventory in1 or 2 locations nationwide. Scattering thousands of cars across hundreds of dealerships is wildly expensive. Personally, I have no problem waiting 4 months to have the car built to my specifications. I have to do that anyway since I drive manual and most dealerships stock very few manuals.

Think how much money we'd all save!
1) Holding all that inventory is expensive. The dealership is paying the bank ~5% for the loan to hold onto all of that inventory. A $50K car sitting on the lot for 4 months adds $50K*5%/3 = $833 to the cost.
2) Dealers need to inflate prices to keep a cushion so that they can make a deal with the guy who wanted silver but settles for white, because white's on the lot. You're also paying more because at the end of the model year the dealer has to drop prices to move the old inventory. If they pooled their inventory in 1-2 centralized locations nationwide or had perfect forecasting, you wouldn't have this over/under inventory situation.
3) You're paying for multi-tiered advertising: ever see those really cheesy, low quality BMW ads on TV? That's because you local dealer is also advertising in addition to BMW's national campaigns. But, the dealer's ads aren't relevant nationwide, so they get limited local runs which are less efficient than leveraging the manufacturer's ads nationwide. But, you're paying for that.
4) You're paying for the dealership itself, the lease, insurance, employees, benefits. Working directly with a website is much, much cheaper.

Lastly, service and sales do not need to be bundled. The fact that they've been bundled historically is not a reason to keep it that way going forward. When my Audi was out of warranty, I took it to a great, high-quality, local (walking distance) independent German car garage. It was great. As soon as my BMW goes off warranty in 2012, I will go back to FatCity here in Seattle.

People say, "The majority of people aren't yet willing to buy online." Well, I bet if word got out, that you got a great price, a really hassle-free experience, and avoided clueless salespeople by shopping on www.bmwusa.com, I bet that would change. Who had heard of Amazon.com ten years ago and look at them now!

So, imagine an experience like Apple's stores: you go in, there's a showroom for you to play with select models. But most purchases, particularly those that require configuration are ordered online and shipped to you. www.DWR.com works the same way. You go to the showroom to buy a $5K couch; you sit on similar couches and then custom order the combination of fabric and options you want. But there's no bargaining. There is only one price. You don't come onto boards like this and ask, "Did I get a good price?"

Why isn't this happening? Politics. The North American Dealers Association (NADA) has strong political clout and is lobbying against online car sales to "protect the consumer." They also have language in their contracts with the manufacturers to prevent the manufacturer from going direct and leaving the dealership with "stranded costs".

The first manufacturer to go out and acquire all of its dealerships and go direct could do incredibly well. Note that Tesla, which is starting a car dealership from scratch, is NOT building a dealership network. They're doing manufacturer-owned stores/showrooms (like Starbucks and Apple) and a built-to-order model (like Dell). Once they get big, they're going to have a $2K/car price advantage on every other manufacturer. There's a lot of cost built into the current supply chain. And as all of you know from WalMart, Amazon, Dell, etc. tightening up your supply chain is a huge opportunity.

This might seem revolutionary today, but think about when my 5-year-old niece goes to buy her first car 15 years from now. "What do you mean I can't just buy it online? I buy everything else online!"

-James
Seattle, WA

1972ford 01-21-2010 08:23 AM

Quote:

Originally Posted by iamthewalrus (Post 4866385)

This might seem revolutionary today, but think about when my 5-year-old niece goes to buy her first car 15 years from now. "What do you mean I can't just buy it online? I buy everything else online!"

-James
Seattle, WA

Although I do agree that dealers will be more sparse (they already are) as a result of online shopping, the ability to test-drive a vehicle, and have warranty work done, are both strong reasons dealers will always be around with at least SOME vehicles on the lot, for better or for worse, from a consumer standpoint.

I work at a marina where we sell outboard motors; people come in all the time with their internet research done, and want us to order just the motor they want (we keep a very small inventory). After the purchase, we may or may not ever see them again, unless a warranty or recall item comes up, but it allows Honda to be assured that the customer has a good experience with their product, and spreads the word or buys again.

iamthewalrus 01-21-2010 09:06 AM

Quote:

Originally Posted by 1972ford (Post 4866491)
Although I do agree that dealers will be more sparse (they already are) as a result of online shopping, the ability to test-drive a vehicle, and have warranty work done, are both strong reasons dealers will always be around with at least SOME vehicles on the lot, for better or for worse, from a consumer standpoint.

I think we're saying the same thing. Ever been to an Apple store? They have plenty of models on the floor to "test drive". But when you buy, particularly if you want any customization, you order it and it's shipped to you. The Apple store is *Apple*, not some third party. With BMW dealers, you're not dealing with BMW North America, you're dealing with some local business owner whose quality varies greatly. That's the key. The dealership model introduces a middle man over which the OEM has little control.

As for warranty work, this is a question of insurance. BMW could "certify" multiple repair shops to do warranty work. You bring your car where you want to, and they submit to BMW for reimbursement. It's just like healthcare: I pick my doctor, and my doctor bills my insurance company. In this case, I pick my mechanic, and my mechanic bills BMW. There's no reason that sales and service need to be bundled at the same location.

noego 01-21-2010 09:12 AM

selling cars of any brand has become so promotion oriented that all the sales people want to discuss is their deal because the 'deal' is what they know. product knowledge is secondary. pressuring a potential buyer to buy now because an offer expires soon is just as much of an element of current BMW sales strategy as it is of any other manufacturer.

my wife wanted a Highlander...thank goodness she test drove an X3 first...because a friend had one and my wife liked it. the Toyota salesman, who had just finished a cigarette and had that appealing stale cigarette smoke aroma, stated that the dealer's policy was to have a sales person accompany customers on all test drives rode in the front passenger seat. the guy did not know sqadoosh about the Highlander, and didn't seem particularly embarrassed by his lack of knowledge - but he did know about the Toyota Sell-a-thon and called us non-stop with updates as the promotion wound down.

our BMW sales person (Mike Plohr with Isringhausen Imports) knew everything about the X3 just as he did about the newly introduced Z4 that i bought from him in '03.

anyhow, this is an interesting topic.

jman103099 01-22-2010 07:04 AM

Quote:

Originally Posted by noego (Post 4866659)

our BMW sales person (Mike Plohr with Isringhausen Imports) knew everything about the X3 just as he did about the newly introduced Z4 that i bought from him in '03.

anyhow, this is an interesting topic.

Isringhausen to me is like a 30,000 sq. ft candy store to a child. I have two BMW dealers closer to me, but still take my car there for many reasons, one being their knowledge.

Also, I just told someone that my vehicle was RWD and the X only kicked in when needed. Jeesh, I thought I knew it all... :tsk:

noego 01-22-2010 08:38 AM

Quote:

Originally Posted by jman103099 (Post 4869552)
Isringhausen to me is like a 30,000 sq. ft candy store to a child. I have two BMW dealers closer to me, but still take my car there for many reasons, one being their knowledge.

Also, I just told someone that my vehicle was RWD and the X only kicked in when needed. Jeesh, I thought I knew it all... :tsk:

yes, Isringhausen is always worth the trip just to see what exotics are there.

when we bought the X3 we had done a fair amount of research and had a good idea of what X-drive was all about. our sales person, Mike, gave us more information and explained when it was useful and when to disable X-drive to put the X3 into 4 wheel drive. that input from him has been useful to know.

a couple of years ago there was a Ferrari of some sort :) in their show room with 1200 miles on the odometer. a person from St. Louis had ordered the car from Isringhausen, put up serious money to secure his order and waited a long time for the car to be built and delivered. he got so paranoid over the attention the car got when he drove it that he brought the car back to Isringhausen to sell for him...and lost tens of thousands in the process.

enamoured 01-22-2010 10:17 AM

1 Attachment(s)
This PDF has been posted earlier in this forum, but here it is again.

X3emist 01-23-2010 08:39 AM

Do What???????
 
Quote:

Originally Posted by noego (Post 4869776)
yes, Isringhausen is always worth the trip just to see what exotics are there.

when we bought the X3 we had done a fair amount of research and had a good idea of what X-drive was all about. our sales person, Mike, gave us more information and explained when it was useful and when to disable X-drive to put the X3 into 4 wheel drive. that input from him has been useful to know.

a couple of years ago there was a Ferrari of some sort :) in their show room with 1200 miles on the odometer. a person from St. Louis had ordered the car from Isringhausen, put up serious money to secure his order and waited a long time for the car to be built and delivered. he got so paranoid over the attention the car got when he drove it that he brought the car back to Isringhausen to sell for him...and lost tens of thousands in the process.

If he told you that he does not know what he is talking about. You can not manually disable the 4x4 system. You can disable the DSC however. You need to read up on this thread so you are up to speed and don't do something potentially dangereous to yourself and passengers.

new2u 01-23-2010 09:47 AM

Quote:

Originally Posted by enamoured (Post 4870204)
This PDF has been posted earlier in this forum, but here it is again.

Interesting article.
Thx for sharing. :)

noego 01-23-2010 12:50 PM

Quote:

Originally Posted by X3emist (Post 4872997)
If he told you that he does not know what he is talking about. You can not manually disable the 4x4 system. You can disable the DSC however. You need to read up on this thread so you are up to speed and don't do something potentially dangereous to yourself and passengers.

i misspoke, X3emist, and lighten up

foxwalk 01-25-2010 08:27 AM

I have to say that link to BMW doesn't say "it's in all wheel drive all the time" .. it said it is in 40/60 ratio which means 60% of the power is on the rear wheels and that ratio adjusts when road conditions require it.

So a salesman saying that it's RWD and then it transfers to AWD when road conditions require it is pretty close to the truth, it's just dumbed down for the average consumer. This happens a lot in sales. It could also be the forgetting of certain facts and the salesman's memory degrading a little and then saying what he thinks is true. With BMW this is not exactly deception that is to their advantage in selling a vehicle. They would be a lot better off saying it's AWD or 4x4 all the time than saying it's RWD until the roads require AWD (I would think anyway)

Also I posted in a previous post about this stuff that when you turn DSC off that it disables MOST of DSC and then the X3 is in mostly AWD mode all the time.. This I got from the OWNERS MANUAL describing what the button does :)

X3emist 01-25-2010 10:07 AM

Here is a visual explanation
 
http://www.youtube.com/watch?v=eT8nN...om=PL&index=44

vrooom3440 01-26-2010 12:34 PM

Quote:

Originally Posted by X3emist (Post 4860888)
...Quote from link above-

xDrive is the permanent all-wheel drive system from BMW: under normal circumstances, it distributes driver power between the front and rear axles in a 40:60 ratio, and changes this figure variably when the road surface or overall driving conditions change.

I have always wondered at that 40:60 ratio. It sounds good but just how does it do that?

Looking at the hardware, the system is locked up or not. There are no fluid couplings or anything like that involved. Cannot really run any kind of gear ratio in the transfer case without causing lots of binding.

Which leaves freewheeling differentials in front, rear, and middle and application of brakes to transfer power from one wheel to another.

So that 40:60 ratio suggests to me that the front brakes are always being applied to shift 10% of the power to the rear. Does not sound very fuel efficient to me.

foxwalk 01-26-2010 12:48 PM

vroom3440: did you watch the video? it isn't using the brakes to do that.

Thanks for posting that video, it was really awesome.

Kamdog 01-26-2010 01:19 PM

Quote:

Originally Posted by x3man (Post 4866164)
Salesmen are not to be trusted. They will say anything to make the sale. It is rare that one is truly knowledgeable about the product they are selling. They do exist but rare.

True. I have buying new cars since 1970, and I remember one salesman who truly knew the product.

x3oiler 01-27-2010 03:41 AM

Funny about this split front to rear. I had Subarus for many years and the auto subies are 90% front and 10% rear until things start slipping and yet what is advertised? symmetrical all wheel drive lol . . . yes the MT is locked 50:50 but not the autos . . . still to this day cannot fathom that logic in the Subaru advertising. So the point of this post - at least BMW advertise the truth.

foxwalk 01-27-2010 05:38 AM

I shared that video on Facebook, and a friend of mine said "My 1947 Jeep does that." and no I don't think it's true. but I don't know anything about 1947 jeeps.

vrooom3440 01-27-2010 01:00 PM

Quote:

Originally Posted by foxwalk (Post 4881374)
vroom3440: did you watch the video? it isn't using the brakes to do that.

Thanks for posting that video, it was really awesome.

Yes I have watched the video and yes they can and very likely do use the brakes to do that. The last bit with the Quattro and Xdrive on the rollers is very telling. The Quattro does what I would expect of an open differential and just spins the rear wheels. The Xdrive gives the rear wheels a little bit of spin at which point the computer notes a mismatch between front and rear rotational speeds and applies the rear brakes to slow that rotation down to match the front. The affect is that the rear wheels become harder to turn, the front wheels easier relative to rears, and power gets transferred to front.

X3emist 01-27-2010 01:52 PM

Brakes, come on
 
watch the video and LISTEN to it. There is, as many cars now have, a viscous (spelling) clutch that "slips" for a better word power to the front or to the rear.

The DSC uses the brakes to control under/over steer and keep the rear end from swinging out such as if you enter an off ramp to fast.

Here is a better explanation of it-

Both the new X3 and X5 use an innovative all-wheel drive system called xDrive.

Rich Brekus, manager of product planning and strategy, says, "Most companies show you how their four-wheel-drive systems go through the mud. We show you how well ours goes around corners."

With xDrive, driving torque is always transmitted to the rear wheels, while the portion sent to the fronts is controlled by a multi-disc clutch that can be fully open, fully engaged or at any level in between. Engagement pressure is applied by a servomotor through a linkage of levers, a ball ramp and a disc cam, directed by an electronic control system receiving inputs from the DSC via sensors for the rotational speed of each wheel, steering angle, vehicle yaw, lateral acceleration and the brakelight switch.

In normal driving, the split ranges from a nominal 40/60 to a maximum of 50/50 front-to-rear. In tight curves (including parking maneuvers) with low to medium torque, during heavy understeer and when antilock braking is active, the system is 100 percent rear-drive. Conversely, the rear proportion approaches zero when both rear wheels have near-zero traction. The DSC's traction control can reduce engine torque and apply individual wheel brakes to achieve maximum possible force to move the vehicle.

Transparently to the driver, xDrive also optimizes handling agility and stability on any surface by adjusting the torque split to correct for understeer or oversteer by directing more torque to the non-slipping wheels. It also increases torque to the rears under heavy acceleration and decreases it for light acceleration. All this happens so quickly (reaction time from sensing to control actions) that the system almost operates pro-actively, BMW says.

The system operates seamlessly. We drove an X3 on a stretch of undulating, twisty mountain roads outside of Carefree, Ariz. When the vehicle was pitched hard into a tight corner, the expected understeer wasn't there.

The vehicle also showed remarkable balance while driving on loose gravel roads, correcting steering input and keeping the vehicle going in a straight line.

While xDrive can handle torque split front to rear, side to side duties are handled by the DSC which is electronically linked to xDrive.

The xDrive system is manufactured by Magna Steyr and is available on both the X3 and X5. Though no official announcements have been made, BMW engineers say that the system is easily adaptable to any vehicle in the BMW line-up.
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COPYRIGHT 2008 Gale, Cengage Learning

foxwalk 01-27-2010 02:58 PM

yea that's why I asked "did you watch the video" because I thought it explained that the split power to the wheels isn't being applied by braking.


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