My streetported and stripped 87 base FC has a few mods. Intake, suspension, wheels / tires, weight reduction, adjustable front camber, relocated battery, and probably some other stuff I can't recall. But it still had the stock "open" differential.

I have learned to stay off the gas when going through the apex of a nice hard curve. Doing a 180 into a ditch on a rainy day due to inside wheelspin makes you get very careful with the throttle.

So I found a GXL at the local Pick - apart junk yard and removed its (strangely, still attached) LSD for a scant $125. The car had ~110k miles on it. I spent four hours today installing it and checked its static differential friction with a torque wrench, and it was about 15 foot pounds compared to less than one foot pound on the open differential (to get the axle pads to rotate opposite each other).

My first impression when driving the car now is that it feels almost sluggish. Turning takes more steering input. This car has a little toe-out in the front wheels and would wander when going down the highway before, but didn't tend to do that as much after the install. The really strange part about the car now that it has the LSD is that it doesn't feel like it will snap (oversteer) at any moment on me like before. I can just gas it right at the apex of a turn and the rear will stay planted. The rear of the car feels like it has some kind of aerodynamic tail fins behind it now or something, because it feels like it "wants" to stay behind the front.

It's amazing what just 15 foot pounds of static friction between the axle shafts did to the car. It feels pretty complete now and more stable whenever power is put down. This was one of the best ways I can think of for spending four hours and $125.

I hope you enjoyed my little story. Thanks for reading.

 

glad it worked out for you in the end

 

yeah, you got lucky.

 

lmao

 

come on kids, it's not like I put an LSD on a snowmobile or something.

Now the only mod left for this car is exhaust, ECU and forced induction.

 

so would say this has made the car faster, or just more predictable. ie been keeping my eyes open to find an lsd diff for my '91 and i was curious as to how much it would help. so does the car feel like its plowing or understeering now? or is it just less likely to snap oversteer (every one with on open diff feels your pain on that one)?

 

Lol
Excluding exhaust, those are the "hardest" things to accomplish, how troublesome.

 

Nice, glad to hear you're enjoying it...I just "found" several clutch-type LSD's and am going to throw one in my 88 'Vert soon, hoping for a similar experience!

 

I'd say it's more predictable and a skilled driver can be faster with it vs. the stock diff, but it won't make the car faster without the right technique. For example, I can mash the gas now to get slightly sideways during a zigzag set of cone gates or slalom at an autocross and cut the cones tighter, because the back end won't be gripping 100% and following the front tires, but slightly drifting. I did this today at an autocross and never would have been able to get away with it before.

Another way it can make the right driver faster is now you can lay down the power a lot earlier when exiting a sharp turn. But no, it is the same NA speed in a straight line as before. This mod is like putting in toe eliminators and setting a fixed rear toe angle. It makes the car more stable so it can be brought closer to its limits when cornering and accelerating w/o risk of losing the car completely in a 180 spin.

Cliff notes - the car is much more predictable now when driven on the edge of traction, but it takes the right driving skill to make anything of it (and I'm still pretty green when driving at the edge of traction).