john stephenson

23K miles

NoSubEDU

n00b question:

Can I install an LSD on a 993 that didn't come with the LSD from the factory?

I have noticed that the inside wheel lights up with this fairly stiff suspension. Might have to wait a while to install it, but wanted to know if I had the option to do so.

Thanks guys.

Mark in Baltimore

Sub,

Yes, you sure can.

NoSubEDU

Thanks Mark. Apeeshiate it.

MD355

So here is an update from my car !!

I just installed a rebuilt original factory Porsche LSD (25/65 GKN) on my '95 Porsche 993 Carrera 2 Manual Euro (G50/21) car !!

AMAZING results !!!
I love the way the car accelerates straight line, with full power on both rear wheels...
And when it comes to corner and roundabouts, it is so much more fun !! \
Before with the open differential, it bothered me when the inside wheel spun and was unpredictable... Now the car is 100% predictable... It just drifts !!! LOL

I used to own a Porsche '95 993 C2 when I lived in Boston, MA many years ago... It had option 220 LSD and ABD, but the gearing, especially 2nd and 3rd, was too long !!
I always seemed to lose power between 2nd and 3rd gear swifts...

Now I live in Europe and my Euro 993 with the added LSD is the best combo !!!

Question, what exactly do the numbers 25/65 mean (I believe acceleration and deceleration lock, but I don't understand why you need more lock under deceleration.. ) Anyone can explain ? Thanks !!

trophy

You have it correct, 25% Lockup on Acceleration and 65% on Deceleration

As you have experienced these cars dont need much accel lockup to change the character of the car.

The Deceleration lockup essentially "Locks the rear wheels together" increasing braking stability under heavy braking. It can make huge difference to laptimes because of the added confidence that comes from the stability under braking, the back end doesn't wiggle around as it can with an open diff or an LSD with worn out plates.

MD355

I did some driving today and I see your point !!

When accelerating, sure you want lockup to distribute the torque evenly between the rear wheels...

But when you lift the throttle and the car is decelerating, it is even more important to distribute the engine braking between the rear wheels in order to keep the balance and make the car more predictable !!

Either way, LSD is the way to go !!! It COMPLETELY TRANSFORMS the car !! You can literally "throw the car around" like a go-kart !!!! So much fun !!

NYC993

Trophy has all valid points. But there is a difference under acceleration as well. 993 might not produce huge wheel spin (really none in dry) but even little slippage will cause power loss out of the corners.
When I replaced the stock worn out disks, I felt the difference even on the street. It sure can be my imagination, but I was making longish slower turn at 25-30mhp where I punch it at the end while still in turn, and you could feel the diff locking up.
On a track with slower corners I was able to keep up with new cayman S out of the corners (I'm 200lbs heavier and 50hp less)...part might be shorter stock 2nd gear in my car, but part that he is slipping under full throttle.
But also on the track, LSD made the car under-steer quite a bit...I'm working on adjusting my corner entry speed now so I can be harder on the brakes to get the rotation going.

samurai_k

Besides the cost of procuring a LSD, approximately what labor is involved to remove the stock one and replace it? Can it be done DIY?

NYC993

If you have OEM LSD (M220 option)...it's 500-600 in labor. You rebuild OEM LSD.
It's very simple to remove but, I think you just need to make sure you can set the new ramps/plates so might need special tools.
If it's 2WD with M220 I think you just need the clutch pack, which is cheaper and probably even easier to replace. I have C4 so my kit was 1600 with new ramps and clutches.

If you don't have LSD, then it's much pricier operation.

samurai_k

Thanks.

I have a C2 without the 220 option so will be a retrofit job. From my understanding you can drop the transmission and pack it in one of those igloo coolers and ship it to a transmission wrench for the job.

I was thinking of doing this when I get around to my LWFW/clutch job eventually.

Does anyone have any recommendations for a reputable shop?

Hobbsie

I have a 1990 C2 with Limited Slip, that I just discovered (in a sand pit). I don't know if it's the same for 993 or if it's appropriate to ask some questions about it here. What say you?

Bill Verburg

964 except for RS and turbo used a symmetric 4 plate nominal 40% lsd, Seems to me that I was told that they can't use the GT plate rebuild option as can be used w/ 993 lsd because of room constraints

GTgears

ZF versus GKN. Porsche transitioned to using GKN somewhere in 1995. We don't service anything ZF anymore.

knorrena

I read that the lsd out of a 996 gt3 and a 997 gt3 will fit. I s this true? I found a 996 gt3 lsd at a reasonable price. Can I reuse my stub axles? what other parts would I need?