Jump to content

LSD


Recommended Posts

4 hours ago, crafty1 said:

Not yet fitted, I have been struggling to find someone locally to do it at a half sensible price, but hopefully this month I will. Will let you know once done. 

 

I'm surprised it costs much to fit, I'd imagine it would only take a couple of hours and some gearbox oil. What sort of quotes have you been getting?

 

If you give up trying to find someone I'll buy it from you 👍

Link to comment
Share on other sites

I suspect the reason you're getting crazy quotes is because the diff is not a separate unit like in most RWD vehicles.  In the 987, the diff is built into the gearbox:

 

62373d1439706605-pdk-owner-question-othe

 

I suspect that this is causing hesitation and uncertainty on their part and the work required.  It doesn't look that bad, from what I know of the underside.  No subframe to be dropped, which is usually extremely time consuming.

 

I would make sure it's done with someone that has access to Porsche workshop manuals.  This is, personally, not a job I would like someone guessing torque values on.

Link to comment
Share on other sites

The quotes I have had vary from £1k to £1.8k just to fit it. It is a gearbox out job then depending on who you talk to it should require 2 new diff carrier bearings as removing the old ones without damaging is tricky however these don't appear to be readily available from Porsche.

2 new seals either side also and one quote said all new bolts for the crown wheel and new gearbox/lsd oil.

 

The next issue is does it require shims ? Also the backlash needs to be checked or the gearbox can be damaged. All this adds up and the last bit ref checking shims and backlash means it's not really a job for me to tackle myself.

 

Regal Autosport in Southampton are probably the go to guys for Wavetrac fitment and the best quote I had but they are about 125 miles from me and need the car for a few days. 

 

I've checked 2 Porsche specialists locally one didn't want to do it the other never came back so assume the same. My next stop is a local company that prep all sorts of race cars.  

 

Also what has stopped me so far is while gearbox is off should I add in a lightweight flywheel....

Link to comment
Share on other sites

On 24/01/2019 at 03:09, Aaron said:

I suspect the reason you're getting crazy quotes is because the diff is not a separate unit like in most RWD vehicles.  In the 987, the diff is built into the gearbox:

 

62373d1439706605-pdk-owner-question-othe

 

I suspect that this is causing hesitation and uncertainty on their part and the work required.  It doesn't look that bad, from what I know of the underside.  No subframe to be dropped, which is usually extremely time consuming.

 

I would make sure it's done with someone that has access to Porsche workshop manuals.  This is, personally, not a job I would like someone guessing torque values on.

I thought all diffs were built into the gear box. Shows how much I know!

Link to comment
Share on other sites

15 minutes ago, Dougle_turbo said:

I thought all diffs were built into the gear box. Shows how much I know!

 

Longitudinal, front mounted engine with the gearbox bell housing connected directly to it.  Propshaft to the rear diff (mounted between the two rear wheels), then driveshafts to each wheel.

 

Integrated diffs are more common in mid-engined and rear mounted cars (like the Cayman and 911) and, of course, FWD cars.

 

23 hours ago, crafty1 said:

The quotes I have had vary from £1k to £1.8k just to fit it. It is a gearbox out job then depending on who you talk to it should require 2 new diff carrier bearings as removing the old ones without damaging is tricky however these don't appear to be readily available from Porsche.

2 new seals either side also and one quote said all new bolts for the crown wheel and new gearbox/lsd oil.

 

The next issue is does it require shims ? Also the backlash needs to be checked or the gearbox can be damaged. All this adds up and the last bit ref checking shims and backlash means it's not really a job for me to tackle myself.

 

Regal Autosport in Southampton are probably the go to guys for Wavetrac fitment and the best quote I had but they are about 125 miles from me and need the car for a few days. 

 

I've checked 2 Porsche specialists locally one didn't want to do it the other never came back so assume the same. My next stop is a local company that prep all sorts of race cars.  

 

Also what has stopped me so far is while gearbox is off should I add in a lightweight flywheel....

 

Contact the diff manufacturer and ask them to confirm what is required as part of the install?  If anyone is going to know - they are. :) Judging by the various processes and requirements being suggested, I suspect some of them may be unnecessary.

Link to comment
Share on other sites

On 25/01/2019 at 08:32, Aaron said:

 

Longitudinal, front mounted engine with the gearbox bell housing connected directly to it.  Propshaft to the rear diff (mounted between the two rear wheels), then driveshafts to each wheel.

 

Integrated diffs are more common in mid-engined and rear mounted cars (like the Cayman and 911) and, of course, FWD cars.

 

 

Contact the diff manufacturer and ask them to confirm what is required as part of the install?  If anyone is going to know - they are. :) Judging by the various processes and requirements being suggested, I suspect some of them may be unnecessary.

 

I spoke to Wavetrac at the Autosport show, they were of the opinion you can just fit it and that it wouldn't need shims etc. One of the guys on the stand actually have a 987 that they had fitted a diff into and he said he did it himself. Some specialists want to do everything mentioned in the posts above others just a straight swap, so I think some is unnecessary too.

Link to comment
Share on other sites

I had a gripper diff in my 987 race car. Superb bit of kit but probably a bit extreme for road use. IMO an LSD really livens up a Cayman even the tame one in my R! 

Link to comment
Share on other sites

A bit of an update. The biggest issue by far is sourcing new Diff carrier bearings which I think are a must as not keen on trying to remove and reuse the old ones. Porsche do not list them. 

 

More investigation shows that the Cayman (and Boxster) 6 speed Gearbox is a Getrag 466 unit which is the same as those used in Audi's etc. The only place I can find so far which claims to sell the correct bearings on line is here 

 

https://www.oreillyauto.com/detail/b/national-2929/transmission---transaxle-16780/differential-16805/transmission-differential-bearing-12689/b4705f02093e/national-bearing/lm503349a/2553548/2009/porsche/cayman?pos=0

 

So the correct bearing part number would appear to be : 

Part # LM503349A

 

It's probably going to have to be a case of remove the gearbox and diff and check the bearings against this info then order them, being a Getrag unit shared with other manufacturers I think it's unlikely the bearings are solely for Porsche. I guess we will have to wait and see. 

Link to comment
Share on other sites

  • 3 weeks later...

Finally got the Wavetrac installed and very pleased with the results. Only had a short drive on greasy roads but it certainly adds a bit more fun with PSM off...

 

If sideways action out of junctions and some adjustable 2nd gear roundabout sliding is your thing then this ticks the box nicely.

 

Otherwise the stand out feature is how much slack appears to vanished from the drivetrain, not to say my car was bad before but now it feels as the throttle/drivetrain interaction is really sharp and car finds traction where before the traction light would have been flashing. Also under heavy braking the rear feels more planted.

 

In the end I used a local race car prep specialist who did a great job, the diff carrier bearings were in great condition so were reused, no shims were required the backlash was checked, they said it was a quality product and relatively straight forward instal, still cost just over £1k however.

 

Overall well pleased, I am sure it is part of what makes the R standout over the S, it gives the car a more focused Porsche 'GT' feel which can only be a good thing, I can't wait to get it on track again.

  • Like 1
Link to comment
Share on other sites

5 hours ago, Dougle_turbo said:

Who are you going to order it from?

 

Regal Autosport I reckon.  Just about to order a Heigo Roll bar from Stuttgart Classics too.  Both our cars seem to be taking a similar direction lol

  • Like 1
Link to comment
Share on other sites

  • 4 weeks later...

Quick update on the Wavetrac.

Did have a very hairy moment on the motorway with a big patch of standing water which may or may not have been exacerbated by the diff. Cruise control on and speed at 70ish mph, car hit the water (PS4S tyres but my Ohlins suspension is quite hard) and next thing I am basically a passenger in a fairly big tank slapper, all happened so quick and I am not sure if was me or car PSM but it straightened out. One thing for sure now in very wet weather I will not use cruise again but it made me wonder if the diff once sensing the lack of traction started to lock and hence rear slid one way then the other. Anyway lived to tell the tale but I think fair to say these cars don't like standing water especially on the bigger size wheels and tyres !

On the track it's great, started off as very wet and greasy day with limited traction and grip. I had PSM off (off as much as it lets you..) and as you would expect it's playful and easy to get it sideways if you want to but with a lot more control and predictability than an open diff. As the track dried it definitely found traction where an open diff would not and just dug in, corner exit speeds definitely improved and zero understeer to speak of, tail still moves around a little under really heavy braking but less so then before. Overall very happy.

Link to comment
Share on other sites

24 minutes ago, crafty1 said:

Quick update on the Wavetrac.

Did have a very hairy moment on the motorway with a big patch of standing water which may or may not have been exacerbated by the diff. Cruise control on and speed at 70ish mph, car hit the water (PS4S tyres but my Ohlins suspension is quite hard) and next thing I am basically a passenger in a fairly big tank slapper, all happened so quick and I am not sure if was me or car PSM but it straightened out. One thing for sure now in very wet weather I will not use cruise again but it made me wonder if the diff once sensing the lack of traction started to lock and hence rear slid one way then the other. Anyway lived to tell the tale but I think fair to say these cars don't like standing water especially on the bigger size wheels and tyres !

On the track it's great, started off as very wet and greasy day with limited traction and grip. I had PSM off (off as much as it lets you..) and as you would expect it's playful and easy to get it sideways if you want to but with a lot more control and predictability than an open diff. As the track dried it definitely found traction where an open diff would not and just dug in, corner exit speeds definitely improved and zero understeer to speak of, tail still moves around a little under really heavy braking but less so then before. Overall very happy.

 

This has nothing to do with your LSD, the culprit is in the cruise control!  NEVER EVER use cruise control on wet roads!  

 

PS, One thing to check is your rear toe angle as well. Misalignment of it can cause a "floaty" rear end...

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.