Benton

Carl,
It is my understanding that it is preferable to have a higher % lockup on deceleration. I know the factory 993 cups and RSRs have a 45/65 (65% on deceleration) differential. From tracking my car, my biggest qualm was trailbraking into a corner and locking up the inside rear. Are you sure this differential only offers 15% lockup on decel? Many people use a 50/80 even.

I found this thread on a quick search, but I'm sure there's more: https://rennlist.com/forums/showthre...d+deceleration

smiffypr

Porken is right, the 928 LSD is 40% locking in either direction because the ramps are the same angle in both directions. You can "easily" test your locking percentage yourself with two "bendy-bar" torque wrenches and a bit of maths.
I think the reason that racers like/need higher percentage lock up on deceleration is that the torque being transmitted by the diff is small (engine braking versus engine power), but we want a large (torque) locking factor to prevent lock-up due to braking.

Smiffy

Andre Hedrick

So is there an offer for thicker plates here?

Carl Fausett

Adjusting the 8-disk LSD for other performance levels:

Just taking a moment to share how to adjust the lock-up ratios of the 8-disk LSD.

The LSD's lock-up and can be measured out of the car by using the process on page 39-59 of the WSM. Also on that page, there is a hint of how you could raise the lock-up above 40% by using replacement outer plates that are available from Porsche in thicknesses of 1.9, 2.0, and 2.1 mm.

Additionally, by re-arranging the order of the outer plates and inner plates (friction disks) you can also change the amount of surface area available for the outer plates, and therefore the lock-up ratio.

Brett928S2

Hi Carl

I emailed your company as you suggested about shipping costs to the UK....

That was 3 days ago and no answer yet ??

All the best Brett

Carl Fausett

Sorry, Brett

That is unintentional.

I am not logged in to Rennlist often, but I check my email at
carl@928motorsports.com frequently.

Please send me your complete shipping address and I'll get you a shipping quote and a sales order all made up. Tell me too, if you need the 8-disk LSD also or whether you want to acquire one of those locally.

I thank you for your interest and your business.

928@AMG

Hello Carl,

some further questions :
If I buy a good used 8 Disk LSD as advertised on your website , how is the
exact condition ?
I don' t mean the mileage etc, but the condition of the friction disks . Do
you check the friction disks before you sell the LSD ?

If available , it could be interesting to buy an used 8 disk LSD with worn
friction disks for a cheaper price .
Replacing the disks with new ones is an easy job for me :-)

Is it possible to tell whether an early gearbox has a LSD inside by the gearbox number ?

The_Remora

Now this is a product I am very interested in. Will do this conversion asap. maybe this will be my xmas present to myself. to me, this is more interesting than the x-pipe i want. if you can't put power to the pavement, what good is it? Although unintentional smokey burnouts are entertaining at times...
Good stuff you're developing, thanks Carl.

Vilhuer

Yes and no. Number says if there should be one inside or not but its obviously impossible to say for sure without checking.

Carl Fausett

all good questions. I will try to answer:

We inspect the LSD's when we get them and confirm they are in good operating condition. Very rarely are they worn out or damaged - the cars they came from, after all, had 220 to 234 HP and narrow tires. They were not very hard on them.

You can get your LSD anywhere - thats why I prioced the kit with and without.

Generally speaking, most 928's pre-1984 had LSD. It was very common back then. But you have to check to be sure. From this thread:
I do not have any old-wornout LSD's that will go cheaper than this - and yes, it isnt very hard to replace the frictions disks and plates. Expect to spend a little bit on those to Porsche if you go that route.

928@AMG

Hello Carl,

thx for your answers .
If I have an pre 1984 gearbox physically in front of me , then of course I would check for the LSD as quoted.
But if I , for example, want to buy a gearbox from some 100 mls away , I can't check myself. If I ask the seller to check for a LSD as quoted , the seller realizes that he can claim much more money cause most sellers in Germany don't know that there could be a LSD inside.

If I ask the seller for the gearbox number , that's unsuspicious :-)
I think it could be possible to get a pre '84 gearbox with LSD for approx. 100-200 EUR .

riddler777

i have a 90' GT and the stupid psd, that doesn't allow to make nice powerslides, interferes all the time,

question: if this prefacelift 928 gearbox with LSD, can be mounted on 90's chassis, are there any differences, or just straight bolt off, bolt on job?

Carl Fausett

No, the 1985 and up transaxles are slightly longer, and there is a different torquetube (shorter) and transaxle crossmember to match.

In otherwords, when swapping across the Borg-Warner timeline (roughly 1985) you need the transaxle, the transaxle mounting crossmember, and torque tube with shifter linkages to move with the transaxle.

Vilhuer

Wrong. G28/03 is only manual gearbox which uses different longer TT and same rear subframe as automatics. Shifter linkage is only critical outside difference between '80-84 Porsche and '85-95 Borg Warner syncro ring gearboxes. All these gearboxes from G28/05 to G28/57 use similar TT and almost similar subframe. Minor differences in subframe over '80-95 time period were done because of twin exhaust mounting points. Actual critical dimensions are same.

Carl Fausett

I dont think thats right, Erkka. I have done the G28/01 (1978) to G28/11 (1988) upgrade a couple times and the torque tube with shift linkage and crossmember always had to come with the Transaxle.