LSD in rwd cars

Ralphh85 · Post by **Ralphh85** » Mon Jul 14, 2008 2:37 pm

i have herd 2 main things said about having a LSD in rwd (an rear engine in my case) cars, some say they are great an give more traction, others say they are dangerous as they make the back end more likely to go as you will spin both wheels not just the inside one.

any one have experience??

Ralph

Post by **katanaman** » Mon Jul 14, 2008 3:25 pm

Both is true, if its set up for the car properly they help a lot in the dry but in the wet they can make the car more twitchy/tail happy. If they aren't set up properly for the car they can be a total mare in all cases.

Ralphh85 · Post by **Ralphh85** » Mon Jul 14, 2008 3:28 pm

the diff in question is a torsen diff, so not a plate type, there is no ajustment on them.

i have one in the front of my car now as its fwd and its fantastic, transformed the car from a crasy wheel spinnign car to a well behaved car.

but now im putting engine int he back (and using same gearbox) i donno if i should put in an open diff.

it will be appart anyway as i want to put in higher gear ratios for the low revving V8.

Ralph

kiwicar · Post by **kiwicar** » Mon Jul 14, 2008 4:11 pm

Torsen diff in the back of a mid engined car should give you the best results possable, the torsen diff has a maximum torque load across the diff that limits its effect, if you jack one wheel up so it is in the air it will act as an open diff, it needs about 15% resistance to spinning wheel (relative to the one still on the deck) on the lightest loaded wheel to transmit torque to the other wheel, this makes it behave in a much more docile fassion than nearly all other types.
Mike
(hope that makes some sense

)

kiwicar · Post by **kiwicar** » Mon Jul 14, 2008 4:13 pm

Hi Ralph
What are you building??
Mike

stevieturbo · Post by **stevieturbo** » Mon Jul 14, 2008 7:22 pm

Torsen here....no problems as far as I am concerned.

mgbv8 · Post by **mgbv8** » Mon Jul 14, 2008 7:42 pm

I use a crude locker on mine and I think its great.
No more turning out onto a main road and having the inside wheel spinning up while traffic is catching up. Mine just hooks and gets me moving.
It can be a bit twitchy in the wet, but you just get used to how the behaves once you have driven it for a while.
Its even more fun in the dry though.

Ralphh85 · Post by **Ralphh85** » Mon Jul 14, 2008 9:11 pm

my car was... 143bhp VVC K series metro, i converted it from the old A series engine so its an old mk2 not the newer Rover metro.

and im converting it in to a V8 mid engined RWD metro, still a normal road car, will enclose engine in and make it as standard looking at i can. as its a road car not a rally car. engine mounted transversely on a PG1 gearbox in a metro front subframe in the back.

the current box (PG1), has full steel caged bearings and a torsen type A diff, which has the higher torque bias but is weak, so i may change it for a type B since people seem to like them.

i have tried to avoid using the word metro because most people dont like them an say why dont i have a mini instead.

Ralph

Post by **katanaman** » Mon Jul 14, 2008 10:44 pm

sounds like an 8r2 to me

Ralphh85 · Post by **Ralphh85** » Tue Jul 15, 2008 7:56 am

yup, however its not goign to be a rally car of any sorts, tho car already has coilover suspention ont he frotn and i will be fitting it to the rear, all round vented discs, so should be alright!

Ralph

ian.stewart · Post by **ian.stewart** » Tue Jul 15, 2008 1:40 pm

Is a tight diff in a small short wheelbase rear engined car a good idea????, I would think once the car starts to get away its going to be a real problem getting it straight again without a massive lift off, then you have the problems of it facing the wrong way when it gains traction, Personally, I would be looking at a plate diff for street use, or can the diff be sent back to quaife so the slip rate can be changed. or am I just getting old and soft???

kiwicar · Post by **kiwicar** » Tue Jul 15, 2008 3:04 pm

I still think the action of the torsen diff will be the easiest to live with, anything with a short wheel base and a V8 will bite you on the bum one day. You can get them "softened" by changing the pitch of the teath on the "worm" planetry/cage gears. (They were efectivly open in the tanks these things originated in)
Mike

Ralphh85 · Post by **Ralphh85** » Tue Jul 15, 2008 3:52 pm

kiwicar wrote:anything with a short wheel base and a V8 will bite you on the bum one day.

just the inspiration i needed

stevieturbo · Post by **stevieturbo** » Tue Jul 15, 2008 5:06 pm

A Torsen is probably one of the more user friendly diffs out there...

I know I have no problems with mine, and even under sustained loss of traction, its very easy to keep the car in a straight line. So far...it has rarely done anything stupid on me.
I find it very controllable, all things considered.

minorv8 · Post by **minorv8** » Wed Jul 23, 2008 6:53 am

I have a Quaife ATB (basically a Torsen) in my Morris Minor and despite being a short wheelbase vehicle it is quite controllable. In the wet it is a question of balancing your right foot against the grip but as long as you don´t do anything silly it is not a problem.