Can anyone comment on E70 vs. E53 in snow?

[Pex5]

That was exactly what I was wondering about. I convinced a friend to get an X6 5.0 which he just ordered. He says his current range rover is excellent in snow and asked about the X6 (he will be using snows on the BMW, but didn't on the Rover). I think he is going to be very pleased as long as he can learn to be gentle with the gas pedal.

I got a lot of responses on this post from people who liked their E53s in the snow. That was not really my question. You answered my question as to whether the E70 is better. I realized afterward what my definition of a car that is "good in snow". It is this: The closer you can get on snowy roads to the average speed you travel in dry conditions, the better your car is in the snow. It's not about getting stuck. Its a combination of acceleration, braking and handling on the snow and ice that all combines to give you confidence (or a lack of it).

Thanks again. Enjoy the E71. It was going to be my next BMW until I got my wife the E70.

DRP

[Kungen]

Thanks DRP. You will surely be positively surprised of the capability of the E70 in snow and on ice. The DSC-regulation is faster and less aggressive, which means that you could drive closer to yours and the cars limits with reference to available grip before the system kicks in and when it kicks in it will distribute the torque in a faster and more subtle way than the E53 does wich will make you not only drive faster but also with a better body control.

Everyone telling that BMW does not build capable cars for difficult conditions does not know what they are talking about. I have driven many different cars in severe snow storms and temperatures around -40C. No one of the other brands have been as good and as reliable as the E53 and now the E71. The traction from the xDrive is just superb (with snow tires), the heat from both petrol and diesel are great and the cold start capability is better than any other car I know.

In some winter tests in Swedish and German car magazines the traction from the xDrive models have been found better than the equivalent systems from Audi, Volvo, Mercedes, Subaru, Land Rover etc and equivalent with the mighty Landcruiser (BUT with the possibility to go fast also in the bends...) :-)

So, congratulation to you and your wife owning one of the best winter cars available! Enjoy the next snowfall!

[JCL]

You are comparing the X6 (E71) with DPC to the E53, and drawing conclusions based on the X6 performance. Yes, the difference was noted in a post above, but it is the defining difference in the two models (apart from the E71 engines). The original poster's question was about the X5 (E70). The problem is that as far as I know, the DPC system on the X6 is not available on the X5. BMW is using that traction control system to differentiate the two models. So, it is comparing apples and oranges. The E70 has essentially the same x-Drive system as the post-2004 E53s. We can talk about response times in the DSC system, but at the end of the day, I think it really comes down to tires and weight. Tires can be made to be equal, but the E70 is still heavier, and weight is the enemy.

There is also a comment that the additional ground clearance of the E70 will make it better handling than the E53 in poor conditoins. I disagree. It has a higher centre of gravity, and that will give it worse handling, all other things being equal. The additional ground clearance only matters in deep snow, and it is only marginally different. Snow conditions will matter more than the small difference in ground clearance in my experience.

Kungen, I agree with you on the all-weather capability of the X5. No question in my mind, it is a very capable vehicle with the right tires. Most of the discussion on the limited capabilities of the X5 on this forum and others is about off-road driving, where ground clearance and other issues come into play.

[Markost12]

Originally Posted by Kungen

Thanks DRP. You will surely be positively surprised of the capability of the E70 in snow and on ice. The DSC-regulation is faster and less aggressive, which means that you could drive closer to yours and the cars limits with reference to available grip before the system kicks in and when it kicks in it will distribute the torque in a faster and more subtle way than the E53 does wich will make you not only drive faster but also with a better body control.

Everyone telling that BMW does not build capable cars for difficult conditions does not know what they are talking about. I have driven many different cars in severe snow storms and temperatures around -40C. No one of the other brands have been as good and as reliable as the E53 and now the E71. The traction from the xDrive is just superb (with snow tires), the heat from both petrol and diesel are great and the cold start capability is better than any other car I know.

In some winter tests in Swedish and German car magazines the traction from the xDrive models have been found better than the equivalent systems from Audi, Volvo, Mercedes, Subaru, Land Rover etc and equivalent with the mighty Landcruiser (BUT with the possibility to go fast also in the bends...) :-)

So, congratulation to you and your wife owning one of the best winter cars available! Enjoy the next snowfall!

I took my Volvo XC90 to Nordkapp and had no problems with pirelli scorpions. Now with E70 I would not dare to take this trip with the same tires. My father has a Landruiser and I can tell you that it is the best on the snow among the three.
Just my opinion.

[Kungen]

Well, the FlexRay response time of 2.5 ms is surely contributing to make the feedback of all systems (damping, DSC etc) a lot better. As you know, the enemy of grip on slippery surfaces is not the weight (purely physically) but slow adjustments of the different systems. This is why Volvo with the Haldex III version has no chance against for example the BMW xDrive system. The Haldex system shifts 90% of the torque to the front wheels and is able to theoretically shift over 50% of the torque to the back wheels in 1/8 rotation of the wheels. This 1/8 rotation is a disaster when it comes to grip on slippery surfaces. You can just read all the test of 4wd systems and you will see that they all come to the same result.

I was testing the grip i Sweden this year between a 2004 E53 and a XC90 in different gradients and different friction coefficients between left/right. There were identical set of tires between the cars and the difference was huge. When the XC90 was standing still, spinning, the E53 was gently finding grip in almost any situation thanks to the fast regulating xDrive.

In for example "OffRoad" 2/09, different systems were compared and the X6 had the highest speeds in slalom and exacly identical time in acceleration on ice uphills like the Landcruiser. The Volvo XC 60 (with Haldex IV) and Jeep Cherokee had no chance in any of these disciplines.

Regarding differences between E70 and E53, does not the E70 have a standard setup with 60% torque to back and 40% to front, while the E53 have 50/50? At least this is what I can recall, Audi has followed and changed their successful Torsen 50/50 to 60/40 as well, which gives a lot better drivability on curvy roads (less understeering).

Only my opinion...

[Kungen]

Regarding the increased ground clearance, the improvement was of course intended for deep snow conditions. On slippery roads the increased center of gravity is not making almost any difference for the handling since the resulting force between the vertical force from the car's weight (from center of gravity) and the horizontal force from the resulting friction of the tires will end well within the contact point of the tires and thus not create almost any roll or shift of force between the tires.

On dry roads, where the horizontal force is high it is of course important to have as low center of gravity as possible. It is however the quotient between the distance between the wheels and the center of gravity that is of essence (i.e. the resulting force), not the center of gravity alone.

I would guess that the E70 has a better ratio than the E53 here (wider track and probably not too much increase of the center of gravity), which theoretically would allow higher curve speeds on dry.

[JCL]

Kungen:

You gotta love debating with engineers! Not slamming you, as I am one, as I suspect you are.

While Flexray may be faster, I don't think that the x-Drive E53 had problems with response time. The pre-2004 models did have limitations there. Neither is directly comparable to the Haldex system which is an add-on to a FWD car.

The E53 has a 62/38 torque split. I thought that applied to the pre-2004 models, as well as the x-Drive models, but I could be wrong.

Your comments on centre of gravity are primarily considering static forces, or at least steady state forces, not dynamic forces. Given a choice, a lower centre of gravity is much more preferable, for the benefits in roll centre, transient responses, etc. I struggle to understand how any vehicle with the same AWD system (E70 vs E53) is going to handle as well when it weighs more, and has a higher CoG. You can compensate for it with DSC, but you can't overcome physics. Just my opinion.

Wider track will help in cornering (theoretically) but it doesn't help in braking. Weight and CoG will be the enemy there. Importantly, a driver at the limit is never doing one thing, whether it be braking, cornering, recovering, or whatever. They are usually doing several of those at once. That is why it becomes an issue for dynamics vs static considerations.

We could debate the finer points of the above, but my comments really were that all things being equal, it doesn't matter because tires play much more of a role here than anything else, and the X6 is a different animal because of the DPC.

I have driven in -30C, but not in that much snow (at least in our BMWs). I have pushed snow deeper than the bumper with the E53, and with a 325x. Both had the same (Michelin) tires. The 325xi walked circles around the E53. It simply weighed less. it had far less ground clearance, but that didn't matter compared to the weight issue. Everything else was essentially equal (OK, manual vs automatic).

If we look across the wide range of posts on this board, there are those who are running their tires at 40+ psi to improve handling, and others who are happy with the winter/snow performance of their 20" all season tires. What I am suggesting is that you and I are debating the final 1% or 2% delta, and may be on our own here. Still an interesting debate, though.

[Fraser]

Originally Posted by JCL

The E53 has a 62/38 torque split. I thought that applied to the pre-2004 models, as well as the x-Drive models, but I could be wrong.

Pre X-Drive E53s indeed had a 38% front/ 62% rear torque split. With the introduction of X-Drive the torque distribution went to 50/50. This, of course, only applies on a high-traction surface under normal operating conditions.

[JCL]

Originally Posted by Fraser

Pre X-Drive E53s indeed had a 38% front/ 62% rear torque split. With the introduction of X-Drive the torque distribution went to 50/50. This, of course, only applies on a high-traction surface under normal operating conditions.

I went and looked it up (since my memory may be fading). BMW websites I checked state that it is 40/60 F/R nominal torque split, but variable depending on traction. This preserves the RWD feel.

Do you have a source that states differently?

[Fraser]

I have a BMW tech sheet on the X-Drive E53. However it does say that the 50/50 drive is with the centre multi-plate clutch (which acts as a diff) fully closed. I presume this means locked up. So 40/60 drive is probably right when the centre diff is open. I know that BMW did make a big song and dance about retaining the feel of a rear-driver as much as possible.