LSD - How Much More Traction
01-04-2021, 01:00 AM
#1
Three Wheelin'
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LSD - How Much More Traction
Has anyone done an update from open to limited slip and can comment on how much traction is gained with a LSD?
I am having issues with hooking up in 1st and 2nd gears (especially when roads are a little colder) and just wondering if an LSD is worth it to get the rear tires to hook.
It seems strange that the tires spin because going straight, I would expect both rears to have about the same amount of traction. Maybe really sticky tires would do more than a LSD?
I am having issues with hooking up in 1st and 2nd gears (especially when roads are a little colder) and just wondering if an LSD is worth it to get the rear tires to hook.
It seems strange that the tires spin because going straight, I would expect both rears to have about the same amount of traction. Maybe really sticky tires would do more than a LSD?
01-04-2021, 11:34 AM
#2
Three Wheelin'
What kind of tires do you have now, and how old are they? Any tire should be replaced after about 7-8 years, regardless of how "sticky" they are. Also, how cold is "cold"? The stickiest of summer tires do not do so well in colder ambient temperatures (<60 degrees F) and need some heat in the carcass of the tire to generate their optimum grip. So, if your main traction issues are occurring on a cold winter's morning, then a "stickier" tread compound might not help, unless of course you are replacing some old, rock-hard tires.
As for the LSD, my '86 951 came with one from the factory, but I have driven numerous versions with open diffs (mostly with stock engines/boost, though), and can attest that the LSD does help a lot with traction out of tight turns. What helped even more, though, was rebuilding my original diff with upgraded internals from Guard Transmission. It still has only a 40% locking factor on acceleration and deceleration, but has more pre-load on the clutches and works a lot better on track. There are also torque-biasing diffs like a Quaife or Wavetrac which are good street/autocross options because they do not lock up during deceleration like a clutch-type LSD, so they do not induce understeer.
Regardless of what sort of diff you end up with, it will likely require "setting" up the ring and pinion of the transaxle, which requires experience and numerous special tools. There is a good thread on this forum about the process.
Good luck!
As for the LSD, my '86 951 came with one from the factory, but I have driven numerous versions with open diffs (mostly with stock engines/boost, though), and can attest that the LSD does help a lot with traction out of tight turns. What helped even more, though, was rebuilding my original diff with upgraded internals from Guard Transmission. It still has only a 40% locking factor on acceleration and deceleration, but has more pre-load on the clutches and works a lot better on track. There are also torque-biasing diffs like a Quaife or Wavetrac which are good street/autocross options because they do not lock up during deceleration like a clutch-type LSD, so they do not induce understeer.
Regardless of what sort of diff you end up with, it will likely require "setting" up the ring and pinion of the transaxle, which requires experience and numerous special tools. There is a good thread on this forum about the process.
Good luck!
01-04-2021, 02:49 PM
#3
Having done before and after an LSD installation on the street and track, I agree that this is where an LSD really shines. It will also help a bit with straight-line acceleration -- if, say, one rear wheel hits a puddle of water, you're less likely to lose the rear end.