Hi
Has anyone modified the viscous coupling on these cars?
Standard cars have 5percent power on the front until the rear looses tracktion and then it locks up to 40percent i think.

Has anyone tried locking them and creating a 50/50 split on the power distribution?
Or pumping them up creating a more permanent 40/60 split?

pnr: 996 339 021 02 if anyone's curious

 

lol i upgraded to a 100% rwhp w lsd lol. but sorry, i wasn't being facetious. i just never once really saw the wisdom of it. but otoh, the abs/psm during my ( ahem ) "learning curve"? another story entirely!

yeah as i understood it, you're exactly right. at a mimimum it's 5% always, up to a max of 40%/60% frt/rear conditions dependent.

i just wish i had a chance to use it in truly inclement weather, as i'm sure it would be the bomb. on dry desert canyon roads? it was an albatross! i'm glad i yanked it.

 

Tim has been playing with a 997 swapped setup. I might consider that at some point when I've got a standalone bolted in. I don't know of anyone modding the stock stuff presently, it's purely mechanical unlike the electronically controlled 997.

 

Uh, no.

The viscous coupling in the 996 Turbo never locks up.

The only time 40% of the torque is transferred to the front diff is at speeds of 150+mph.

If you encounter a situation where the rear wheels/tires spin you should avoid spinning the rear wheels/tires. This will just burn up the viscous coupling.

The front/rear diffs have to have some fluid coupling between them to avoid problems when turning. The front and rear wheels/tires describe different arcs and the two diffs spin at different speeds.

Even when going straight the front and rear wheels/tires spin at different speeds. It is this difference in speeds that at the viscous coupling heats the special fluid and makes it more viscous so torque is transmitted to the front diff and then on to the front wheels/tires.

 

you have 3 choices,

remove it and go RWD

do a custom install of 997tt front diff and wire it to a switch.

Have a custom front diff made.

 

The thing is i want more permanent power on the front wheels.
I dont like that the car needs to slip on the rears before the front comes properly in to play. so a permanent 50/50 would be best. (not locked, because of what macster replied)

Im considering driving my 996tt in the winter thats why i whant more traction on the front.
And i guess by pumping up the VC which would give more traction to the front, the unit would overheat right?

 

Viscous couplers can be rebuilt and modified to change the lock-up

 

I'm thinking I'd trust the factory split for all weather snow use if I were inclined to drive it in weather like that. Between the PSM and the fact that the car comes fitted to allow a ski rack I have a feeling the car was plenty tested in the snow. Just make sure the tires you choose maintain the stock ratios to ensure it works properly. If you go with a standalone ECU then maybe consider a 997 front diff.

 

I emailed Bara Motorsport in the UK earlier today to see if they had any experience with the porsche vc.
He did the VC in my Ford rally car,so he knows his way around gears and clutches.

I think this mod with some tune will make the car pretty aggressive also on tarmac.
But it would be nice to hear if someone has tried this already.

 

call guards transmissions here in the states, i heard its about 3500$ for a custom diff they have not done one but are willing to make one. i was going to do it but found a different route to try

 

But was this the centre diff or front diff?

 

We're talking fwd right now

 

+1 guard can build anything you need. if they custom spec the rear diff, why not the front?

 

Its the centre VC i want to modify, no need for a uprated front diff when no power comes that way.

Does anyone by any chance have any pictures of the VC unit?

 

theres only one diff / VC in the system, the front diff/VC is all one unit.

heres a a pic from pumalex's forsale thread