BMW xDrive. Would you tick the option box?

[white_goodman]

Just wondered what the PH consensus was on xDrive (haven't driven an xDrive equipped BMW yet), as I know BMWs are very popular with PHers due to being RWD. I can see why they now offer it on most models, as some people appreciate the extra traction and security of AWD in inclement weather and for this reason, many potential customers would have previously bought an Audi (quattro) instead. Modern AWD systems are fairly light and efficient now, so I think the compromise in performance and fuel economy that you get with AWD is less of an issue than it used to be.

I can see why quattro is so popular, as the alternative is FWD but will xDrive be as popular or does it detract from the purity of BMW's RWD chassis? Is this why the M cars (X5 and X6 excepted) are still RWD?

I'm still amazed that a manufacturer famed for its quality engineering (Mercedes-Benz) still hasn't been able to engineer AWD into its RHD cars. Can you get 4MATIC on the new C-Class? Surely if BMW and Audi can do it, Mercedes-Benz should be able to offer it on future new models in RHD markets.

[white_goodman]

EricE said:

I suppose it always depends on where you live, but with the M135i and M135i xDrive I would absolutely go with the AWD version. The RWD version without a LSD would be a real pain in winter here in Austria.
Mind you snow tires are mandatory here but what good is a 320 hp one-wheel drive car on a snowy mountain pass...

I think a lot of people still associate AWD in small cars with the old front heavy implementations with the old versions of Haldex and very "safe" calibrations (Audi). True rear biased AWD like xDrive is a wonderful thing and the newer Haldex (VAG MQB, A45) systems are almost as good now.

This is the last new BMW I really lusted over!



It has all the right ingredients that I associate with BMW:
Conservative but handsome styling;
Revvy NA straight six petrol (surely one of the best engines ever made)
RWD
Manual gearbox

I'm not sure why I've never owned one. Would love an E46 CS or CSL but just had a look at prices and they're more money than I expected for 10+ year old cars! However, a friend owned a "normal" E46 M3 and said it was too fast to enjoy on the road most of the time and promptly sold it and bought a 106 Rallye instead, which he says he prefers!

For some reason, the new M3/M4/M5 just doesn't seem to do it for me (haven't read any reviews on the new M3/M4 yet though)! If I was going to buy myself a new BMW, I quite like the look of the 435i/435d Gran Coupe, possibly with xdrive, as I currently live in Canada where the roads are snowy and icy for 50% of the year and being able to put the power down in those situations without the massive wheelspin that ensued under even modest throttle openings in my relatively modestly powered FWD car last winter. Conversely, on normal tyres, the Jeep we had just gripped and went without any drama. Sadly we don't have the Jeep any more but have a set of winter tyres on my wife's new FWD car, so will be interesting to see how effective they are this winter (never driven on winter tyres before).

Would xdrive be worth it in the UK? I'm not so sure but my Impreza was awesome in the snow on the few occassions that it snowed on "normal" tyres and no less fun for being AWD (but maybe a bit worse on fuel). It's good to hear the xdrive system is rear-biased and hasn't been detrimental to the dynamics from those that have driven one. I expected the usual tirade from the RWD lovers who haven't tried one but it's not RWD, so must be crap! Personally, I have least experience time-wise with RWD (although have owned 3 RWD vehicles) but have also owned AWD/4x4 and FWD vehicles and think that all three configurations can be brilliant if executed well. I didn't realise about the extra ride height though. Not necessarily a bad thing here but if it looks funny that might put me off! I wonder why? Do quattro Audis ride higher than FWD Audis? How does quattro compare to xdrive i.e. what's the torque split/balance? I've only driven the Haldex-type quattro (A3/Golf?) which works OK but feels a bit weird.
Just when you think the front wheels are going to spin as they would in the FWD version, the drive shuffles to the rear axle and rockets you forward but feels like a FWD most of the time. I would prefer a rear-biased system or the Subaru AWD system personally.

I'm torn between a new 435i/435d Gran Coupe and a lightly used A5 3.0 TDI quattro or S5 Sportback. quattro being a no-brainer in the case of the Audi!

[white_goodman]

EricE said:

All of the old VAG Haldex implementations generally put 100% torque on the front axle until some loss of traction occurs. From my understanding they were also relatively slow to react which is how that effect you mentioned occurs.

The newer Haldex gen 5 works a LOT faster and puts more torque on the the rear axle based on other factors like g-force, acceleration, etc. Thats why the calibration makes such a big difference (i.e. Golf R going sideways vs S3 having a tendency to understeer). Still, the torque is on the front axle under normal conditions.
See: https://www.youtube.com/watch?v=ZSkwYwgd3ZI

xDrive works in a very similar way to Haldex but it puts all torque on the rear axles by default which is why it feels so much sportier. It’s a RWD car most of the time until you need the additional traction.

Other Audis (A4 upwards) use a torsen center differential which is a while different thing all together.

The reason why Haldex doesn’t provide a full time 50:50 or 60:40 torque split is obviously fuel economy. A company here in Austria sells a modified Haldex controller for VAG cars with the old Haldex. It’s tweaked to always provide 50:50 torque so clearly that would be possible.

https://www.youtube.com/watch?v=FHa823iSFM4
(seems like they mixed up the top and bottom videos because the bottom one does not look anything like the normal FWD based understeery version)

Thanks for that. xdrive sounds a bit like the 4WD system in the Ferrari FF then, which can't be a bad thing! How does the non-Haldex quattro (torsen diff) system work then?

[white_goodman]

ORD said:

What car is that? Handsome.

E46 M3 CS