scoobyboothy

iTrader: (1)

after being blinded with science, and having a slightly crumpled scooby on the drive

what power disrtribution is the MY99 uk model turbo 2000

hodgy0_2

on optimal conditions -- i.e. dry tarmac it is a 50/50 split -- in the same way a standard front wheel drive has a 50/50 split between left and right

but when slip occurs -- as in a front wheel drive, the center diff wheel deliver all the torque to the slipping wheel, so on a MY00 with open diffs all around (some people say the rears are limited slip -- but i,m not sure) -- when one wheel looses all traction, you are going nowhere

but this will happen way after a fwd or rwd has given up

the two questions that you need to ask are

what is the power distribution in optimal conditions?

and what happens when a wheel or wheels loose traction?

vyore980

The new Impreza's my Boxer Diesel one has a limited slip differential viscous coupling type what ever that means I sure it is better then none

BMWhere?

Please correct me if I'm wrong, but I'm not aware of any Impreza that has an open centre diff! AFAIK, all non DCCD Impreza's have a viscous coupled centre diff. With viscous coupled diffs, if traction is lost at one end, then the diff will effectively lock and deliver 50% of the torque to the non slipping end. In order to get stuck, you would need to slip with one wheel at each end of the vehicle with open front and rear diffs. With a rear LSD, then you would need to slip on both rear wheels and one front wheel to loose drive.

hodgy0_2

tbh honest I am not sure if the impreza has an LSD in the centre

I thought it was just open -- but I coul be wrong and you maybe right

but your description of an LSD centre is spot on (and hence the working of an open diff would be too)

I suppose the best way of telling would be to jack one wheel up -- if it turns -open, if it doesn't LSD


but LSD's are only partially successful in really really slippery conditions anyway - thats why "proper" 4X4 off roaders have actual mechanical diff locks

jasonius

iTrader: (1)

Well my 05 wrx has never put all the power to one wheel only..!

On really slippy, compacted snow/ice you can feel the power moving around, but usually all 4 wheels spin.

Even if one front wheel is on ice and the others on clear tarmac, from a standing start the one low grip wheel will not spin uncontrolled..?

One other thing that IMHO can play a part in extreme cold weather: diff/tranny oil will be much thicker, unless you can give the car a decent run up, which in these conditions not being able to use any boost, can be a problem.. Surely this effectively adds more diff lock to viscous diffs..?

rbaz

iTrader: (1)

Yes it will help you stop quicker.
Doesn't anybody know how to drive in snow and ice?
Leave the brakes alone use the transmission to slow you down if you only have 2wd you only have 2 wheels doing the engine braking you got all 4 with AWD

dunx

iTrader: (3)

Transmission is irrelevant when the tyres are the limiting factor, Scoobys sell in Finland but they are LEGALLY OBLIGED TO FIT THE CORRECT TYRES for these conditions. iirc.

Over here this weather is so rare that a set of snow tyres will rot away by the next time you need them. Unless you are lucky enough to live in the high Pennines, Cumbria or Scotland.

IMHO

dunx

P.S. LSD's all round on mine so I can accelerate fine, but I can't stop due to semi-slick RE-070's.

P.P.S. Surely the whole point of a viscous centre diff is that it is open normally, and then locks as slip increases due to the shear forces acting on the viscous fluid....

rbaz

iTrader: (1)

Yes tyres will be a major factor but still better using the transition/engine braking than the brakes themselves.
I did it today (in a 2wd car std tyres with good tread depth) trying to stop going down a hill ABS did almost nothing dropped it into second then first slowed down no problem and stopped at the bottom

You cant expect semi slick to work on snow ice or any wide tires. I wouldn't even try taking it out with RE070s on snow
Get some std alloys stick some new cheap budgets on em will be excellent

BMWhere?

Why would you fit a set of snow tyres? Why is it that when you talk about "WINTER" tyres people always think "SNOW" tyre? Winter tyres are not snow tyres, they are designed to work ALL WINTER and will perform consistently better than Summer tyres (such as RE070's) throughout November to March in any part of the UK regardless of the weather!

That is exactly what a viscous coupling does!

dazmotaz

you should really go down a snow or icey road in first gear if you loose grip give the throttle
a blip to spin the wheels and let off back to engine braking lightly feather the brakes to keep your speed down or drive like a *** and buy a new car in summer lol

scoobyboothy

iTrader: (1)

I did that,b but it didn't work the way it intended. Ended up sliding across the road into a parked car and crunching the corner!!

Big J T

Going back to the original post, this is the first impreza i've owned and is much better in the snow than my 3 series bmw was last year.
The only problem is im worried about spanking it !

BMWhere?

then fit winter tyres!

dazmotaz

think im gonna get winter tyres fitted its the way forward got a 05 merc vito van on road what a sack of ****e that is even gets stuck on flat with a thin slither of snow costing me a fortune driving subaru about everyday think it goes out driving at night on its own like cristine the amount of petrol im going through
it nice been able to go anywere though

TonyBurns

iTrader: (3)

An my00 has a 45f 55r split and a vicious coupling diff, this is NOT an open differential, only dccd cars are equipped with open centre diffs.

As for winter tyres, yes there are benefits to be had but if it snows your still better off with a set of snow chains or tyres (or buy a nice cheap series 3 lanny as a project ready for next year )

Tony

BMWhere?

Snow chains are a pain in the ar$e to fit and remove just to drive down the local untreated roads at the beginning and/or end of your journey, and they're really not necessary in a scooby.

For the last 10 years I've lived in South Germany on the edge of the alps with many ski resorts within an hours drive. If the snow is good, I ski most weekends throughout the winter. Over 10 years driving the scooby here with winter tyres, I'm sure you can imagine I've driven many times on wet, icy and snow covered mountain roads.

I've always had chains in the boot as its a legal requirement to carry them, but I've never fitted them once! On several occasions the police have had road blocks to force drivers to fit chains, but they just see the Scooby and wave you through.

Chains may be good as an emergency back-up, but if you have winter tyres you're very unlikely to ever need them in the UK. As has been said many times, winter tyres are suitable for the whole winter, not just when it snows, so you can leave them fitted from November to March and always have the best tyres for the conditions, whatever the weather brings!