[Closed] Engine Braking?

Is this why you often see BMW’s gracefully pirouetting down the road in fairly benign conditions?…though I’ve always expected it’s the big lump of torque from a turbo motor to be the big culprit.

Nope that's mainly people hitting brakes on bends...

I've witnessed a BMW spinning out on a straight dual carriageway with just a light dusting of snow just because he'd accelerated while changing lane in near enough a straight line....the look on his face was one of surprise as he did a few rotations before arriving at the scene of the accident, was a powerful modern 4 series type thing. Seen many a BMW driver hopelessly snaking up snowy hills in an uncontrollable manner, always wandered quite what it is with those cars. In comparison my R56 Cooper S with winters on is great in the snow and will get up snowy hills that defeat 4wd's something to do with 60+% of its weight on the front axle...best drives ever have been on deserted snow covered fell roads making fresh tracks in the pow with the elec systems switched to off, full rally mode.....disclaimer to the fun police, open morland, long sightlines, no inhabitants for miles....

In comparison my R56 Cooper S with winters on is great in the snow and will get up snowy hills that defeat 4wd’s something to do with 60+% of its weight on the front axle winter tires.

BMWs are actually quite capible in the snow on winter tires.

Seen many a BMW driver hopelessly snaking up snowy hills in an uncontrollable manner, always wandered quite what it is with those cars.

It's not the car!

A lot of people buy cars and probably don't even have a clue which wheels the drive goes to, they've just bought it because it looks nice/has lots of toys/is the latest sheep car etc etc

I’ve witnessed a BMW spinning out on a straight dual carriageway with just a light dusting of snow just because he’d accelerated while changing lane in near enough a straight line….the look on his face was one of surprise as he did a few rotations before arriving at the scene of the accident, was a powerful modern 4 series type thing.

That's pretty much what all powerful RWD cars do .... and unless you then keep the power on and worse if you then brake they will do a pretty 360 ...I've driven mine close to 150k now and never had it act unpredictably... My old GTI-6 did a 360 twice... once on a roundabout possibly deisel and once on heavy snow on a French autoroute... but I also had it in winter with studded tyres on frozen lakes and doing hill climbs... (Norway) but once it started to lose it it was a battle.. the BMW I just squeeze a bit more power through the rear wheels... (but mainly avoid the situation ever happening by remembering I'm driving a very powerful RWD car)

Perhaps partly because I'm older but my 330 has more power than the GTi-6 and behaves much more predictably....

Yes...I had a 'possibly diesel' moment too in a 306. One of my favourite past cars, great handling little thing but did like to lift off oversteer very unpredictably....something to do with a generation of Pirelli's that were notoriously bad in the wet perhaps.

Would love to do some frozen lake ice driving....I guess that kind of driving exposes proper chassis handling balance rather than being disguised behind layers of electronics...think the mini could be a riot.

something to do with a generation of Pirelli’s that were notoriously bad in the wet perhaps

P6000's .... ruined the car! The Michelin Pilot's were way better....

Would love to do some frozen lake ice driving….I guess that kind of driving exposes proper chassis handling balance rather than being disguised behind layers of electronics…think the mini could be a riot.

Yep any and all electronics need to be off....

Which brings me back to my question of would something like a Nissan GTR be good or hopeless in the snow/ ice. Given the diff's on both axles are mechanical but any torque vectoring must be electronically controlled then is it the case that the systems aid grip up until point of slip but beyond that it would just be a handful of electronic snatchery....anyone with a fancy Rangey or Audi Quattro know how they drift in the snow...we need to know...

stevextc

P6000’s …. ruined the car!

Yep, the Factory DH of the car world.

We once drove to Chicago airport in snow. It was snowing, not especially cold, a couple of wet inches on the ground - similar to UK snow conditions. Most USA made cars at least until recently are RWD but without fancy electronics; and most people buy tyres with 80,000 mile warranties so they are hard as hell. The road was busy but traffic was moving steadily along at 40-50mph or so. Every few miles there was a car off the road either in the wide central reservation or on the wide verge. I did wonder what on earth they'd been doing until we saw one car about 3 in front spin out. Just driving along in a dead straight line on flat road at constant speed, and the back of the car just drifted out and they spun off the road. I'm guessing it was the snow slowing down on the front wheels that caused the back to spin.

Beggars belief that people design, sell and buy cars like that in a snowy environment but that's another rant for another thread.

Which brings me back to my question of would something like a Nissan GTR be good or hopeless in the snow/ ice. Given the diff’s on both axles are mechanical but any torque vectoring must be electronically controlled then is it the case that the systems aid grip up until point of slip but beyond that it would just be a handful of electronic snatchery

Depends what you mean by any good...
Ultimately if its on the road just drive it well within the envelope. Even my 330D I can drift the back end out anytime I wanted... but I don't and just respect it. I've had it on empty muddy fields and left the traction on and it's handled it well enough... though getting moving was the bigger issue... but IMHO it's more about understanding the car and it's quirks. I think most people just never drive them past the envelope... and especially with something like a GTR rely on something that works until it doesn't then goes completely to hell.

Digby just raised a new question as opposed to brakes vs drivetrain.... How to go forwards, in reverse gear, without the engine turning backwards?

Digby just raised a new question as opposed to brakes vs drivetrain…. How to go forwards, in reverse gear, without the engine turning backwards?

That's where the conveyor belt comes in.

Depends what you mean by any good…

Just curious. Most of the cars I've had the pleasure of exploring the on limit handling traits of on track have been old skool big engineed hairy chested V8's, V12's even, front engined RWD, lightweight, no traction control, no ABS - some of the best experiences ever had, and a rarity these days and going forward.

I have no idea how a modern car with all its complex vectoring do-hickery actually feels like in the chassis at grip limits, but i'd like to have a go. It's sort of related to the fact that most modern cars don't have 'feel', they remove you from the experience and have fancy stuff going on which is why I reckon drivers get unstuck when they encounter something unfamiliar like an icy slope....Most big SUV's have torque vectoring going on and fancy diff's or on a modern Ferrari you can twiddle the dial to select your preferred drift slip angle while turning the wheel with your pinky, or so they say...