Torsen twitch?

[David P]

Since installing a Torsen diff, to my N/A auto, and changing the N/S drive shaft and hub.

I have noticed that during hard acceleration when changing up a gear, the car momentarily pulls left, and during deceleration when changing down, momentarily pulls to the right.

 

I have since added the extra TT diff mounting rubber to the sub frame, but this hasn’t cured it?

 

Anyone have any idea what could be causing this?

Edited February 11, 2010 by David P (see edit history)

[trinitom]

have you done the rear wheels alignment after that?

[David P]

No, but nothing was moved that would affect the rear geometry.

[Ian C]

Check your rear tyre pressures, an imbalance can produce that exact result. Might be you only notice now the two wheels are more tightly connected.

[David P]

I control the tyre pressures regularly, and they have been checked since the diff went in, but I haven't checked them this week, I will do so first thing tomorrow.

[trinitom]

Check your tire pressure 1st if the same, try a geo setup.

if the problem persist take the car to a specialist.

don't take chances with this weather.

could be a sticking brake caliper too.

[David P]

Upgraded to U.K. spec discs with reconditioned 4 pot front & 2 pot rear calipers and new pads a few weeks ago.

 

Wheels and tyres are new too.

 

I was planning a suspension upgrade and geometry check after I had finished the works on engine and gearbox, but if the tyre pressure check does not reveal the problem, it looks like this will become priority one.

[Chris Wilson]

Rear toe or camber is out, mismatched tyres, mismatched tyre pressures, suspension play. It'll be one of those.

[David P]

Tyres are new, correct size for wheels and correct and even pressures.

There is however, a very light tapping from the O/S rear when going over sleeping policemen and potholes, this I suspect to be the strut top. Oddly, the tapping can only be noticed for the first few miles, then all is quiet.

To look at the car from the rear, the camber does look a little excessive, but the tyre wear is even and the car handles well.

 

It is starting to look like the camber could be the culprit, but odd that it didn't show up until the Torsen was fitted?

Or maybe the hub was not exactly the same.

Either way, looks like a full geometry check is in order.

Edited February 13, 2010 by David P (see edit history)