Limited Slip and Automatic

[zerow]

I am slowly bringing Betsy back to life, and with time against me this semester, I am sourcing the last few things for the 610. As you know, I have to run an automatic for the sake of my war injury. I was talking to a friend who mentioned that having the Automatic and wanting limited slip differential would cause the automatic to be less efficient than if I were to run just an open set of gears. I called shenanigans, but maybe he has a point...? I don't want to install the open gears that I have to have to remove them later in favor of the Limited Slip (remember: back injury). Any insight on this?

[hobbes_the_cat]

He might have a point, but I don't think any lost power would be felt when driving the car. Lots a cars come from the factory with autos and LSD. If it was a noticeable power loss thru the lsd people prob wouldn't buy them, and traction is always good (unless your a drifter:rolleyes:)

[DanielC]

My thoughts, and this is a wild guess. A limited slip differential would be very slightly less efficient on dry pavement, with either type of transmission, because power has to be used to overcome the drag caused by the wheels going different speeds going around a corner. If your tires on the back are different sizes, this might be an issue, also. If you never went around a corner, this drag would not be an issue, because the differential is not slipping.

Going around a corner, an "open" differential would just freewheel, and therefore roll easier.

 

However, I believe the slightly greater difference in gas used by a limited slip would be pretty much be exceeded by a wheel spinning the first time an "open" differential got stuck, or one wheel spun without driving the car.

 

With a back injury, can you push a car that is stuck, slightly? Would a limited slip differential reduce the chance of you having to ever push the car?

 

If I were you, I would get the limited slip differential.

 

For what it is worth, My daily driver, a (2 wheel drive) Ford Aerostar has an automatic, and a LSD.

[zerow]

I don't plan to push, but if push comes to shove (pun intended), I could just enough to get out of a "situation".

 

@ hobbes: I would never drift the sedan. EVER. The e-brake on a '73 610 is not conducive to drifting (umbrella handle) and I'm tall (6'-1")...my knee already hits the thing!

 

@ DanielC: She's gonna be a dry pavement car. I like the power that is generated with LSD...positive traction to BOTH wheels. BTW, it will be a daily driver, and more highways than streets.

[Master-O-Turbonics]

In straight line acceleration there will be ZERO difference in drag vs an open differential. Only a little drag in cornering acceleration. (How often are you accelerating through a corner on the street that its going to change your gas mileage???)

 

What rear end does your car have? R180? H190?

I don't know about your particular model... Just 210, 200sx/roadster, and Z car stuff.

[albyneau]

I am slowly bringing Betsy back to life, and with time against me this semester, I am sourcing the last few things for the 610. As you know, I have to run an automatic for the sake of my war injury. I was talking to a friend who mentioned that having the Automatic and wanting limited slip differential would cause the automatic to be less efficient than if I were to run just an open set of gears. I called shenanigans, but maybe he has a point...? I don't want to install the open gears that I have to have to remove them later in favor of the Limited Slip (remember: back injury). Any insight on this?

 

Without going into a physics lesson, the difference is negligible, and the small extra load is gonna be on a clutch car as well. Solid axles (and therefore handling) benefit greatly from positive traction control~ not so much w/IRS. If it makes you more confident behind the wheel~ do you really care if it gets 1/20th mpg less?

[zerow]

The sedan has IRS, so no live/solid rear axle. If opens work, I will run what I brung...3.70s