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How do I know my LSD still works?

eabeukes

Well-known member
Joined
30 Jan 2018
Messages
194
I have an early C2 that came with a LSD - is there any test I can do (other than driving fast sideways) that will tell me if it still works? I don't know if its ever been replaced, but I know the old 'spin one wheel and the other should spin' test might not work on some of the newer systems? :eh!:
 
Be interested to hear answer to this, never quite understood these?
 
Jack the car in the air with both rear wheels. Spin a wheel. If the on other side spins in the same direction, then it works.
If it spins in the opp direction, it doesn't.
 
You could also put the car on a grass surface and accelerate (gently) and check that both wheels are driving from the marks on the grass.
 
Surely an LSD can only be tested at speed/load? Similar to a viscous coupling I would've thought.
 
Mine is pretty worn but I can still feel it working, both when drifting, and when in tighter low speed corners where I can feel the car rotating into the corner in a way that non-LSD cars just don't do.

As has already been mentioned, to check the LSd was still there and the clutch plates in it hadn't already worn away completely I would go somewhere with a loose surface and see if I made No. 11s or No.1s.
 
On a recent edition of Fifth Gear, the beardy presenter fitted an LSD to an old hot hatch, they did a before and after "test" by basically doing a standing start with a bit of wheelspin on a low traction surface ( painted garage floor ), then measuring the rubber laid down. with no LSD one rubber mark was twice as long as the other, with the LSD fitted the two rubber marks were the same length :grin:

Find yourself a nice empty carpark with rubbish tarmac and lay some rubber down :lol:
 
the "car up in the air, spin wheel" procedure surely only works with a gear/torsen LSD, not with a clutch-plated one that's designed to lock only under load?
 
Do all 996 have LSD or was it an option?
 
asterix_the_gaul said:
Do all 996 have LSD or was it an option?

Mine has the option code "224 Limited Slip Diff" :thumb:
 
infrasilver said:
asterix_the_gaul said:
Do all 996 have LSD or was it an option?

It was an option on the early cars and wasn't required on the later PSM cars

I think it was more a case of they couldn't get the PSM intelligent enough to understand what the car was doing when the LSD was 'working'. The PSM would try and override what the LSD was trying to do by applying brakes, adjusting throttle, etc.

The same issue also happens with the 996 C4. When the rears spin, the PSM drops the throttle before there's enough torque to get the VC working.

They overcame this later hence LSDs being fitted to later cars.
 
I just know that I`m going to have to test my LSD at the weekend now :pc:

You lot are a bad influence :hand:
 
Doesn't appear to be a massive amount online about the diff type that Porsche fits to there sports cars but if I recall correctly the diff I ordered for my 981 was described as a mechanical diff ( clutch) and my understanding is that this replaced the early type of diff (Viscous) . Not sure if jacking the car and rotating one wheel to see if the other rotates in the same direction will work as I think that both the diff types that Porsche use only come into affect if one of the drive wheels loses traction when under power.

I am probably wrong but as I say not to much info around.
 

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