Is there an easy way of testing if LSD is functioning?
05-04-2007, 01:48 PM
#16
Burning Brakes
Find a car park, put it in first, put a bit of lock on the steering, get your revs up and then drop the clutch. If it does a donut, then the lsd is working 
05-04-2007, 04:45 PM
#17
Technical Guru
Rennlist Member
Rennlist Member
Originally Posted by Paul902
- put car in neutral
- jack car so one rear is firmly on the ground, the other in the air.
- with a torque wrench rotate the wheel in the air using the wheel lug nuts.
- measure the amount of torque required to rotate this wheel (IE keep increasing torque setting until wheel turns before the torque is reached).
- jack car so one rear is firmly on the ground, the other in the air.
- with a torque wrench rotate the wheel in the air using the wheel lug nuts.
- measure the amount of torque required to rotate this wheel (IE keep increasing torque setting until wheel turns before the torque is reached).
Originally Posted by Paul902
For me I had 17 Nm before the rebuild and 105 Nm afterwards.
05-04-2007, 05:30 PM
#18
Rennlist Member
Thread Starter
Originally Posted by doug751
I suggest that you just take a little bit at first. Get a really good lawn chair, like a Lufuma from France. Then just chill out with a SMALL bottle of water, perhaps a beer if things get too heavy. Just listen to the birds. Avoid TV, motorcars, chainsaws, bummer neighbors, the FUZZ. You WILL know if it is working. If not, you are either too square, or you bought a bad square.
Good luck.
Good luck.
LOL.Harry
05-04-2007, 05:31 PM
#19
Rennlist Member
Thread Starter
Originally Posted by Megatron-UK
Find a car park, put it in first, put a bit of lock on the steering, get your revs up and then drop the clutch. If it does a donut, then the lsd is working
Harry
05-04-2007, 06:33 PM
#21
Three Wheelin'
Originally Posted by JasonAndreas
You really can't get an accurate torque measurement using this method. The only way to do this properly is to disconnect the driveshaft and center the wrench (measure) directly on the transmission's output flange. BTDT with a Snap-On digital torque wrench.
The minimum torque spec range as given by Porsche is 20 - 50Nm (15 - 37 ft.lbs). But I think because your measurement was taken offset to the flange that your spinning torque was probably quite a bit less?
The minimum torque spec range as given by Porsche is 20 - 50Nm (15 - 37 ft.lbs). But I think because your measurement was taken offset to the flange that your spinning torque was probably quite a bit less?
Jason, agreed using the flange is a better method, albeit more difficult to get at. As for the actual torque applied in my case there is a good FAQ on torque wrench extensions here: http://www.norbar.com/faqs.php. I think this decreases the actual applied torque by the ratio of:
(wheel centre-to-nut + wrench length) / wrench length. Thus I was maybe around 12 Nm ( just estimating here)
In any case I know that one of my two plates was worn bald, and the unit had no pretension on it (after removing the ring gear and the three set screws the two halves of the diff housing did not separate under spring washer pressure), and this is bad!
05-04-2007, 07:35 PM
#22
Rennlist Member
I knew mine was working accelerating out of a corner on a mountain road. The road was damp, the rear was starting to break loose when the light came on. Recovered traction and I was on my way.
05-04-2007, 11:37 PM
#23
Burning Brakes
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There's not a better question on this site then the infamous: L-S-D, How do you know it’s work’n!!!
Love it!
Personally, just kick back, park on the beach and wait for the sunset…..! (if it never sets; you know you're good!)
Love it!
Personally, just kick back, park on the beach and wait for the sunset…..! (if it never sets; you know you're good!)
05-05-2007, 03:40 PM
#24
Burning Brakes
Originally Posted by RS man
Would you do that to your car?
Harry
Harry
I'm not suggesting you try for the world record at one handed continous donuts, but seriously, if the back end breaks out then it's working. If only one wheel spins and you just start to turn, then either the LSD is too heavily worn (if a ZF/plate type), it's broken (a hydraulically linked or Torsen type) or you're running an open diff.
It's the simplest and most reliable method.
