Discussion
I'm looking to fit an LSD to my standard 993 Carrera, the ABD is rubbish and the inside wheel spins up really easy in the wet making it tough to handle sideways. Does anyone know which kind i should fit (RS etc) and roughly how much it should cost? (I have oil leaks to fix anyway requiring the gearbox to be dropped) Much appreciated... john c
If you are quick you can get in on the Guards group buy over on rennlist www.rennlist.com 993 forum
John
John
I fitted a quaife supplied LSD to my 1994 C2. I have to say it cured the inside wheel spin, but i got lots of turn in understeer and exit oversteer on slippy roads.... oh and i got high speed oversteer when the rear became partially unloaded... and i eventually side swipped a sign post and parked it on a tree..... then i bought a TT
A limited slip is a double edged sword. It does help by improving traction which is a good thing. But when you finally put enough power down to break both wheels loose the back end will step out very very quickly and you may get spat off the black stuff into the green and brown stuff.
Depending on the diff you will get some understeer as when you go to turn in and the rear wheels need to rotate at different speeds the diff will try to prevent this and the net effect is that the car wants to carry on straight.
Make sure you fully understand the pros and cons of an LSD and even different types of LSD; some are more suited for the road and some more for the track. And if you do get it fitted take it easy at first until you're comfortable with how it's changed your car.
Depending on the diff you will get some understeer as when you go to turn in and the rear wheels need to rotate at different speeds the diff will try to prevent this and the net effect is that the car wants to carry on straight.
Make sure you fully understand the pros and cons of an LSD and even different types of LSD; some are more suited for the road and some more for the track. And if you do get it fitted take it easy at first until you're comfortable with how it's changed your car.
phelix said:
A limited slip is a double edged sword. It does help by improving traction which is a good thing. But when you finally put enough power down to break both wheels loose the back end will step out very very quickly and you may get spat off the black stuff into the green and brown stuff.
Depending on the diff you will get some understeer as when you go to turn in and the rear wheels need to rotate at different speeds the diff will try to prevent this and the net effect is that the car wants to carry on straight.
Make sure you fully understand the pros and cons of an LSD and even different types of LSD; some are more suited for the road and some more for the track. And if you do get it fitted take it easy at first until you're comfortable with how it's changed your car.
The car I bought in December has got a Porsche factory fitted LSD, and frankly it starts to scare me reading this, as I don't have any feel or experience as to when or where the thing will kick in.
I understand the dynamics of the car, I am used to the limits and effects of the PSM unit, but without understanding at what point and how the LSD acts, track time and experimenting seems to be the only way to get a feel for the thing.
It seems to get people out of corner quicker, but it also seems to come with a bit of a health warning....
Gulliver said:
The car I bought in December has got a Porsche factory fitted LSD, and frankly it starts to scare me reading this, as I don't have any feel or experience as to when or where the thing will kick in.
I understand the dynamics of the car, I am used to the limits and effects of the PSM unit, but without understanding at what point and how the LSD acts, track time and experimenting seems to be the only way to get a feel for the thing.
It seems to get people out of corner quicker, but it also seems to come with a bit of a health warning....
In most cars LSD's and stability control are mutually exclusive; what car are you referring to?
Adding an LSD to a car that didn't have one is probably where the biggest driver adjustment is required. Without an LSD excess power causes one wheel to spin; in a corner that'll be the inside wheel which isn't contributing a huge amount of the cornering forces and little oversteer will occur. Take the same car and the driver that's used to that behaviour and add an LSD and the tendency will be to think "oh great, I've got loads of rear wheel traction now; I'm going to give it some major welly cause I can put all my horsepower to the ground now". But now the outside rear wheel which is providing the majority of grip at the rear spins as wheel and you suddenly have unexpected rear wheel steering.
If the car has an LSD right from the start that you'll get familiar with this trait as you get familiar with the car.
LSD's aren't bad things; you just need to treat a rear wheel drive car with respect in slippery conditions. Slightly more so with an LSD. And a bit more still if it's a 911.
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