confused about diffs!

[Ross]

Expect you're spinning up both inside wheels... With my 428hp coupe I found I'd get wheel spin on the front left off a favourite roundabout, you'd feel the diff push power to the back and she's just bite in and go.

In the wet both inside wheels would slip and it was hard to get the power down. Thats where a Torsten rear diff would have helped. As the corner opened out the car would start to grip and power moved to the rear as the inside got traction, more you get the power down at the back the more it would take - felt a bit RWD.

[DamoM]

On my standard S2 diff on circuit the car would sometimes spin a inside rear wheel under power whereas now I have more power but it doesn't so it. Given my understanding of what the guys have explained here, I would have thought that as the wheel starts to spin (but still has some resistance), the power gets fed to the outside wheel.

or I could still not be getting it!

[Rocco]

I had a rear Torsen diff and never felt any difference

But to be honest I never went to the limits with the 575hp on road curves...

[pasbogdan]

Since we are talking about diffs now I take this opportunity to discuss the V8 diff option. I'm pretty sure it has been done before but I am a tad lazy.

I got a S2 5-speed gearbox and diff, what is the real advantage/ reason I would want a V8 rear diff?

The open needs more grip to one end to get traction at the other output.The torsen concept gets traction with less amount of grip(resistance)at one end.Or it reacts slowly compared to open and it is not spinning only the wheel with no grip instantly.

[pasbogdan]

I was 100% that b2 q's have a torsen with locking rings
Seems it is shaft in shaft concept but not torsen.

[UrS4boy]

What diff is open?

All of the front diffs are open. Otherwise going around corners would be a bit tough.

[Skull]

all 3 in the early urquattros, pre 1988...

[pasbogdan]

On The UR you have a open Diff not torsen unless fitted after-market

What diff is open?

[DamoM]

Since we are talking about diffs now I take this opportunity to discuss the V8 diff option. I'm pretty sure it has been done before but I am a tad lazy.

I got a S2 5-speed gearbox and diff, what is the real advantage/ reason I would want a V8 rear diff?

I actually have one fitted in the s2 rear diff. The traction as castle Combe was incredible.

[quattrostyle]

Since we are talking about diffs now I take this opportunity to discuss the V8 diff option. I'm pretty sure it has been done before but I am a tad lazy.

I got a S2 5-speed gearbox and diff, what is the real advantage/ reason I would want a V8 rear diff?

[DamoM]

Thank you guys! It all makes sense now!

[Zoig]

http://auto.howstuffworks.com/differential6.htm

The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.

However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.

This pretty much sums it up why the broken CV left the car stranded, if the Torsen could sense some torque on the front diff it would sent most of the power to the rear, but since you have open diff in the front it wont happen.

[Skull]

ok so if I my car has one front wheel on ice it will just spin the power away?

yes this is in theory, but also on ice you have "some" grip, almost always enoug to drive the other wheels.

in real life, you are only standing still if one of your front wheels is in the air (no diff lock whatosever).

if it is one of the rear wheels you can just pull the handbrake a little just to block it from spinning, or engage the diff lock.

[Skull]

the torsen drives all the power to the wheel that hass less grip, that is the torsen downside.

if you would block that driveshaft, you would drive away.

[DamoM]

ok so if I my car has one front wheel on ice it will just spin the power away?