Mythbuster: continuing project thread of my 1303 '75

[scourtaud]

Hi,

Nice job but before you go any further, are you sure about the oil you put into the tranny?

Usually in a 911 with LSD (old ones), oil is something like 75w140 (not sure about the exact values but sure about the range). I can check if you need the exact values.

Seb

[Wally]

Originally Posted by scourtaud

Nice job but before you go any further, are you sure about the oil you put into the tranny?

Usually in a 911 with LSD (old ones), oil is something like 75w140 (not sure about the exact values but sure about the range). I can check if you need the exact values.

Seb

Hi Sebastian,

Yes, very sure: besides the fact that this is not an old tranny 911 type with porsches' own syncro system (which indeed needs a different oil), its actually counterproductive to use thicker oil or specially formulated LSD oil:
The latter usual has friction modifiers, which reduce the effectiveness of the friction plates. In that sentence alone, you can see/read how weird this is...
Those 'special' lsd gear oils were made because they reduce noise of the friction plates (in slow corners or in the parking lot), which is very liked by the typical Porsche owner who wants a comfortable a relatively quiet car.
I just want performance

[Bruce.]

Good luck with the diff!

I wouldn't go too crazy with the burnouts though. Replacing the clutch pack with "cup spec" (not the crappy road clutches) costs over £600 from Porsche.

[Wally]

Originally Posted by Bruce.

I wouldn't go too crazy with the burnouts though. Replacing the clutch pack with "cup spec" (not the crappy road clutches) costs over £600 from Porsche.

If you hadn't noticed already Bruce, I now have a Guard Transmission clutch pack in there, that's supposed to be better then even the 'cup-spec' clutch disks
Both in performance as in duration

[scourtaud]

Originally Posted by Wally

Hi Sebastian,

Yes, very sure: besides the fact that this is not an old tranny 911 type with porsches' own syncro system (which indeed needs a different oil), its actually counterproductive to use thicker oil or specially formulated LSD oil:
The latter usual has friction modifiers, which reduce the effectiveness of the friction plates. In that sentence alone, you can see/read how weird this is...
Those 'special' lsd gear oils were made because they reduce noise of the friction plates (in slow corners or in the parking lot), which is very liked by the typical Porsche owner who wants a comfortable a relatively quiet car.
I just want performance

Thanks for the intel, I'll pass it along to one of my friends who doesn't really care about noise (1983 RUF SC) and I'm glad I was wrong but I'd rather be wrong than hear about a broken lsd...

Have fun on the track...

Seb

[Wally]

It was great weather last sunday, I'll update later some more. In short I gained a lot on my time and even got a prize!