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Is it better to have had an LSD and lost than no LSD, at all?
So, here's my dilemma...
(Hi, by the way! I'm Joe from Atlanta, GA, USA. Long time lover of 928's, first time owner)
Since June of this year, I have been the proud and delerious owner of an '87 S4 with 256K mi on the original engine & transmission. This S4 was previously owned by John Pirtle & Clay Zbar, temporarily fostered by Brian Phillips(medipedicman), who then sold it to me. When I bought it back in June for $5K, I knew I had at least several thousands of dollars of "deferred maintenance" to tend to (timing belt, water pump, seals, hoses, brakes, shocks, the usual). She's absolutely beautiful and everything I've always wanted in a 928...
Not only has she been ridden hard, pissing red every which way back there and needs all new seals, but my 928 doctor, Bill Graf, at Classic Imports in Lawrenceville, GA, informed me that she desperately needs a rebuild, which could cost around $2-3K (parts & labor) OR I could replace her with a younger or an already rebuilt tranny for possibly a bit less...
In swoops Richard (richvm) of Garage 928, also a great 928 doctor and ally/support in the metro Atlanta, GA area. Rich gave me a FANTASTIC deal on a used 1988 S4 transmission & differential, ready to plug & play and only 50K mi, guaranteed! Only problem, the diff is NOT LSD.
OK, no worries, we all agree, Rich, Bill Graf and myself, we'll just swap diffs. No prob, easy. It will be fine... Only problem, apparently, trying to get the younger, less abused tranny to work with my original 256K LSD diff could take a very long and expensive "trial and error period" to get the proper flanging and adjustments to make it all work as it should.
OR I could just have the young, supple 50K mile tranny and 50K no LSD diff transplanted and be back on the road again, in no time and for much less $$$...
So, what would you do?
And what will I miss or never get to experience, no longer having a Limited Slip Differential, but instead, driving with a much younger, less worn transmission and differential?
And I know you all like pictures... So here are some pictures of my new tranny and diff. Plus a shot of Rich @ Garage 928, helping me check my trans fluid, since it pisses out at least half a quart per week...
(Also, SHOUT OUT TO ROGER of 928sRus! (ROG100) He also gave me a GREAT deal and consultation on the parts we've used, so far)
Here's the 50K mile tranny I picked up from Rich @ Garage 928, tied down in the back of my truck:
I don't see the problem in changing in your old LSD into the younger transmission.
1. Remove LSD spool
2. Recondition LSD ... almost certainly would need new plates/improvement.
3. Remove standard spool from newer transmission (after measuring existing backlash).
4. Fit reco'd LSD to newer transmission ... replicating backlash to keep the contact pattern matching, and setting factory preload to factory spec.
There isn't any trial and error, as it's just ensuring the LSD is within spec, and that it's installed with correct clearances ... then
Installing the LSD is a very straightforward procedure. An experienced shop should be able to do it in a couple of hours or so. Measure backlash before disassembly and install with that same backlash.
Joe,
Mine does not have an LSD and I can't even get out of my driveway if there is a hint of ice. I sure wish mine had an LSD, but it has minimal options, unfortunately it does have a sunroof! In any case, you do really want an LSD, so go for it!
Hope to see you Saturday at Rich's gathering. The ex-John Pirtle car is a great looking car!
Dave
Setting the backlash is only part of the equation that needs to be solved.
The bearing preload is just as important and must be checked and reset, as the two different carriers are almost certainly different overall sizes from bearing flange to bearing flange.
Don't install that limited slip without taking it apart and inspecting. It will need new friction discs at a minimum, at that mileage.
Irregardless, the entire job is worth about 4 hours, plus whatever parts are needed to freshen the limited slip, so it would be silly to let a limited slip " get away" for that investment.
BTW....a used limited slip, that only needs new friction discs is worth $500 anywhere. The value goes down rapidly, if the friction discs are destroyed and have damaged the thrust rings.
Your used 50,000 mile transmission was your best choice. There's absolutely no way to correctly rebuild one of these transmissions, using quality parts, for $2000. Simply impossible, unless the very cheapest of Chinese parts are used....and even then updating and changing marginal pieces isn't going to happen and the entire differential section is not going to be touched....just removed and re-installed.
You definitely want LSD unless you drive straight lines in dry weather at half throttle. If so, then you don't need it....
OK...I'm Aussie guys so we are blunt and to the point..
HTF! Do Porsche sell a car this expensive ..like the same price as medium house in there day and think to NOT include a LSD diff standard..I'm sorry but Porsche took a **** on everybody! In fact it's bloody disgusting!
when every muscle car came standard with Detroit lockers in the 9" or a " big slip daddy" (to quote the 1960s ..yeah , 1960s! ..in the Beach Boy song) .. Chrysler had the posi track , and others the lsd ...and these guys thought a LSD should be on the option list for a car like this?! ..tell me, to the people who bought a 928 new, did the dealer at least offer a reach around when he ripped you so hard from behind?!
The cars were the most expensive Porsche you could buy in there day right? ..
Not really true, at 99% of the car makers, LSD was an option, (even in the Muscle Car days), back then there were plenty of single tire smokers trying to keep up with other well optioned models.
Just like Porsche it was another option like heated or Sport seats, just as in today's base models, nobody buys the base unless they just want the look or whats on the lot
And Porsche like all car makers are in business to make $, right
OK...I'm Aussie guys so we are blunt and to the point..
HTF! Do Porsche sell a car this expensive ..like the same price as medium house in there day and think to NOT include a LSD diff standard..I'm sorry but Porsche took a **** on everybody! In fact it's bloody disgusting!
when every muscle car came standard with Detroit lockers in the 9" or a " big slip daddy" (to quote the 1960s ..yeah , 1960s! ..in the Beach Boy song) .. Chrysler had the posi track , and others the lsd ...and these guys thought a LSD should be on the option list for a car like this?! ..tell me, to the people who bought a 928 new, did the dealer at least offer a reach around when he ripped you so hard from behind?!
The cars were the most expensive Porsche you could buy in there day right? ..
I find the entire "limited slip/no limited slip" differential question extremery humorous.
All limited slips, after the first few years of production, are what I refer to as "snow/ice" units. These single friction plate (one friction plate on each side) release at such low torque (especially when worn) that they are completely worthless in any sort of performance driving exercise....unless the road is incredibly slippery.
I sincerely doubt if 2% of the people here could actually tell if a car had a limited slip or didn't have one, by driving different vehicles....the rest would just be good guesses.
I considered having some "functional" limited slips produced for "high performance" use in the 928 application.....and I may still do this. However, a "real" limited slip (instead of the exsiting "snow/ice" version) would also require some suspension changes to be made to compensate for the additional "push" that would be generated. (928's traditionally understeer when approaching their limits....a "real" limited slip would increase this understeer tendency under high limit "on throttle" corner exit. (This understeer tendency also makes larger front sway bars, increased rear tire percentage, and increased front spring rate percentage very humorous.)
FRANKLY Porsche never considered drag racing to be racing..... I tend to agree since racing like sex should last for more than 14 seconds. Even specialty hot rods like the 1969 Boss 302 did NOT come standard with traction lock ! The Fairlane Torino Cobrajet 428 demo I drove for several weeks had an open diff in 1969 still ran about 130 mph I did however order in several Drag Pack optioned 428s in Mach 1 s so they got lockers with 3.90 or 4:30 gears. One of those blew off the oil line to the front oil cooler in my driveway on a cold Indiana morning
10-17-2014, 01:36 AM
Is it better to have had an LSD and lost than no LSD, at all?
