Moook

Hi Folks
Can anybody tell me why Porsche put the oil cooler pipe onto the transmision.???

Was it becaue the LSD in the box got too hot + expanded etc.???

I cant understand why it was done ... As on pre 88 boxes with LSD,s, there wasnt any cooler.???
Ive heard different "stories/ theory,s" as to why they did it....+ just want to get to the bottom of it all...

The reason also for the ? is i have a 944S2 which i use on track [ DE,s etc] BUT i use it hard...
Ive come across a Turbo S trans, with LSD + cooler. [ At the right price ]...I now want to fit the LSD into my S2 trans, BUT b4 doing so i just want to find out wether to fit the cooling pipe also....So i dont destroy my "new" trans....
Hope somebody can help....???????

UK952

deja-vu

UK952

from the other forum

I imagine, and it is purely guesswork, it was just a relibility measure. 88 On cars were 250BHP with an increase in torque and a bigger step between off boost and on. I expect that during testing this was found to place extra load on the box. The cooler is there to keep the temps lower and the oil in the optimum temp range. On a turbo you also have a very hot (hotter than the na) exhaust pipe running past the other box, though there is a heat shield as well.

The LSD is a friction device so I believe it also generates heat. Can't see any harm in fitting the cooler, but if it is going to be an expensive option changing to a synthetic oil and changing it regularly might be fine. Probably worth discussing it with whoever is doing the work.

Tony

hosrom_951

86 951's came with tranny oil cooler as well.

016R 5P code

Olli Snellman

Cooler was a standard on 1985-1986, 1988 250hp, 1989 and 1990-1991 with LSD. The only model years it was an option were 1987 and 1988 220hp versions (at least in Europe)

If you want to install a cooler to non cooled transmission, you will need a side plate as well. Non cooled trans side plate does not have all necessary things for cooler piping and oil pump. Also transmission end in non cooled trans does not have necessary fittings for cooler

If you are building a "combo" S2/951 S transmission with the cooler. You need to have transmission case from 951 S trans. I am not sure does it fit with S2 internals, because there is a slight difference with transmission case lenght (few millimeters).

in these pictures you can see a non cooled non LSD 1988 trans and cooled LSD 1986 trans

Oddjob

Turbo S and S2 trans cases have the identical part number, so they should be the same. Only different internal parts are the ring and pinion and the 5th gear set. Everything should be interchangeable.

jim944s2

Since you have the 951S trans, you should put your S2 ring and pinion in that tranny, I understand they have a hardened 1st and 2nd, -and you could keep the cooler. If you don't keep the cooler, the drive gear for the cooler pump is different w/ lsd vs non-lsd, and for that's an expensive and hard to find gear when adding lsd to a coolered transaxle.

Oddjob

Actually the S2 input shaft is the same part as the Turbo S input shaft, so it also has the same hardened 1st and 2nd gear teeth.

If you put the S2 ring and pinion in the Turbo S trans, you also get the shorter turbo 5th gear. Which many prefer on track S2s for better acceleration.

Moook

Thanks a lot folks.
A lot of my questions have been answered...

The trans i have, has the holes for the cooler, although i dont actually have one,, BUT i have access to one at a "reasonable" price...

BUT as my S2 trans has only recently been refurbed,, ie new seals + bearings etc. I think ill stick the LSD into it..
The Turbo trans has an unknown history, so would probably need looking at b4 being used....at more cost..$$$$,££££...
Im also thinking of the extra weight the cooler will add to the car incl oil...

Thanks also for the pics ...

Thanks....