LSD

[944 man]

A mechanical LSD was option M220; but relatively few 944s of any type have one. A new differential (either mechanical or torque sensing) will cost more than many 944s are worth, so its seldom a worthwhile upgrade.....

 

[ratboy_944]

Hi guys, new here but just picked up my first 944 today! shes a beauty 1983 2.5 non turbo. can't believe how well it handle's and how evenly balanced it is! awesome car. only thing is it has no LSD, had a quick scan on ebay and theres a few being broken but which models came with one as standard? also does anyone know where the best place to pick on up from is?

thanks in advance

josh

 

[Neil Haughey]

Given that you don't really need one in an S2 unless looking for the last 1/2 a second you certainly will not need one in an 8v.

 

[DivineE]

As said above you probably don't need one. I once had an argument with a tuning shop which ended with me doing a doughnut in their carpark in my 8v lux to prove you could do it with no LSD.. But if you really wanted one your best (read most economical and plausable) bet would be to get a relitively common 1986 220 turbo gearbox (non LSD) which all have the oil cooler you need for a LSD and retro fit a quaiffe unit. They do one for this box. p.s. Obviously if you can find an LSD option box, on a car being broken, with a good diff in it still then that's fantastic but I've been there twice and ...well good luck is all I can say!

 

[Jonny944CS]

I'd second Neil's comment. Initially I was curious too. I fitted a second hand turbo LSD (40% plate style) that I managed to snap up from ebay for £150 some years back. The unit is getting on for double the weight of the open diff (but the part numbers for the friction plates do start 917 XXX XXX XX [] )

Anyway, the first thing that stuck me was how by just changing the diff a nice neutral handling car had now developed a strong leaning towards understeer. Also, up to a point, it became less 'playfull' around roundabouts. On the track it gave the car rock solid stability on turn-in and exit, but after a while I found that a little dull to be honest. One thing I would say, is that it was fantastic on track in the wet. It gave loads of confidence and predictable understeer, allowing you to commit without fear of getting into a tankslapper. After a bit of fiddling I've found a better balance in the dry by running the rear arb much stiffer, though I get the feeling I’m papering over the diff characteristics, rather than improving the car over the open diff starting point. In conclusion I would say the 160hp of the 2.5 isn't quite sufficient to make best use of an LSD. I tended to notice more of the downsides than the upsides.

 

[djaychela]

As said above, an LSD will really change a car's characteristics - and indeed, it really may not be something you need. Certainly in my other car if you go on/off power mid-corner (as you have to on the road with things such as on-coming cars) then the steering changes characteristic completely. It's never a problem on a stage (as you are far more committed), but for an everyday drive it wouldn't be what I'd like; while an open diff doesn't give the ultimate in traction, it is nice, calm and predictable. Plus you will need to do more servicing on a plate diff to keep it operating properly, depending on how much you abuse it, of course.

 

[sawood12]

An LSD was high on my wish list but I elected to go for the KW instead which increase grip so much I never had a problem with the inside rear wheel spinning up so the LSD came off the wish list. You'll get far more bang for you're buck by upgrading your suspension. LSD is just icing on the cake.

 

[Lowtimer]

Having an LSD on my tuned Turbo I welcome the traction, but it does mean you have to manhandle the car into the corners a bit more, and if I were in an S2 or Lux I would have an open diff for sure.

 

[Neil Haughey]

ORIGINAL: Jonny944CS After a bit of fiddling I've found a better balance in the dry by running the rear arb much stiffer, though I get the feeling I’m papering over the diff characteristics, rather than improving the car over the open diff starting point. In conclusion I would say the 160hp of the 2.5 isn't quite sufficient to make best use of an LSD. I tended to notice more of the downsides than the upsides.

That would be what I expect TBH you would have little choice but to adjust the suspension setup after fitting an LSD, perhaps increasing the rear spring rate substantially. The problem then is that you have to change how you drive the car not just to make it work well but to get the most out of the car. Certainly talking to those racers who have a broad experience across both say a non LSD S2 and a 968 fitted with an LSD is that the cars are surprisingly different to drive.

 

[Jonny944CS]

I get the felling that if I were to switch back to the open diff with the same setup, the back end would be much looser (so to speak [&:]). With the LSD I could be more agressive with trail braking and picking up the throttle early. Great for the chicanes at Castle Combe, not so good for the long fast sweepers of Silverstone. Maybe what I need is a MAGIC PADDLE like Mr Schumacher, then I could adjust for every corner... Intersting that the new Mclaren road car doesn’t have one fitted, relying instead on clever application of the rear brakes to control traction.

 

[Neil Haughey]

Probably change the rear toe setting as well then. On my S2 without LSD I already found the rear end a bit to lively under braking even with quite a lot of toe so now it has loads of toe in and felt fantastically planted last time out. I guess with the LSD you wouldn't need so much rear toe in to stabilise the car under braking and turn in and thus may as a result pick up some speed on the straights as a result of reducing the tyre scrub. Some drivers though like the car to move around a lot I don't. If your suffering under-steer just after the apex you can tune that out by increasing the rebound on your front shocks, I am thinking the corner your referring to is something like Copse where its very easy to run out of track. No doubt about it though its not as simple as just putting an LSD on a car.

 

[Jonny944CS]

Very interesting, thanks for the tips.

Probably change the rear toe setting as well then

Something I'd like to try - though I find changing the rear toe/camber in my garage can be akin to pushing poo uphill with a small stick... I'm currently running with virtually zero toe at the rear, would adding lots of toe not increase tyre scrub on a permanent basis?

If your suffering under-steer just after the apex you can tune that out by increasing the rebound on your front shocks, I am thinking the corner your referring to is something like Copse where its very easy to run out of track.

Yes, Copse and also Stowe in particular. Definately one to try during the 944 group meeting/track evening on June 20th. http://www.porscheclubgbforum.com/tm.asp?m=623728

 

[Neil Haughey]

Whilst I played about with front camber and toe at home personally I wouldn't mess with the rear end. If you have close to 0 on the back end already then you probably don't have any scope left to reduce rear toe. Your right in that loads of toe in on the back end will be scrubbing the tyres all the time however for most of us we don't have much choice in that area. Sacrificing a bit of straight line speed is well worth the extra stability under braking and turn in.

 

[tr7v8]

If you really want an LSD I have a S2 box here with LSD for sale

 

[DivineE]

ORIGINAL: tr7v8 If you really want an LSD I have a S2 box here with LSD for sale

That would be the perfect option I reckon as you'd get the shorter ratios.

 

[944 man]

An LSD is always going to make your car push, but you can reduce this to a large degree by opting for a diff that doesnt act as much on the over-run, as it does under power.