Limited slip rear ends

[RedMisted]

Just a question for pondering. Is it true that when upgrading from an open diff to one that has a limited slip that this will cause your car to "push" on corner exit? Will you need to make suspension changes to get back handling balance?

[titanium]

It can create a push, but I have found that it can be corrected by using your right foot to increasing the opening of the throttle.
This throttle-induced oversteer condition, can result in increase rear tire wear and general soreness in the face and jaw from smiling so much.:D

[RedMisted]

Someone said that you can minimize the push by decreasing the size of the front anti-sway bar.

[titanium]

Yes, anything you can do to 'soften' the spring rate of the front will increase the amount of weight transfer to the outside tire when turning.
So, going to a anti-sway bar that is less-stiff, will increase weight transfer to the outside tire.

[88YB1]

Cris,
The primary reason for going to a limited slip or locked rear end is that the inside rear tire is slipping during acceleration coming out of a corner. Body roll transfer weight to the outside wheel lightening the inside wheel. An open diff puts the power to the wheel with the least resistance. IE the inside wheel. To avoid wheel slip you must delay acceleration which cost you time. Especially if the corner leads onto a straight. A limited slip or locked diff allows you to put down power sooner. The increased power of both wheels pulling could lead to understeer. (push)
Some things that can be done to over come the understeer are, run heavier springs on the rear, lower rear tire pressure, higher air pressure on the front, run thicker swaybar on the rear, run a thinner swaybar on the front, move weight to the rear, lower the front roll center.
I would start with a heavier rear swaybar. Reducing roll on the rear may be suffcient to eliminate wheel slip, and understeer at the same time. It is the least expensive and has the most potential for improvement.

Chuck

[billf]

Maybe and addendum to the above: One of the things that happens when adding the LSD, is that the increased traction will actually propell the vehicle to a greater cornering speed, which can open the door to different characteristics than the vehicle ever had. It then should be tailored to the driver.

Do a lot of research before committing to one specific type of differential. Each has a different feel, and especially for a few, wear patterns and life cycles. Something that is effective in drag racing may not work when cornering, or especially corner entry.:eek:

My experiences were with ITB Mustangs, and to a point will apply to a GT (ITE). You will have more options in ITE, such as torque arms and trailing arms. The amount of traction available in ITE configuration is greater (of course), and will give you different results and problems with corner entry AND exit. And other options of crossmember/Lower arms will give you even greater opportunities.

Feel free to e-mail me with any questions you think I might be able to answer.

Good racing.

Bill:024:
[email protected]

[RedMisted]

Thanks guys, for the replies. My car is actually a V6 with the Ford Racing Trac-Loc differential. I've got adjustable RLCAs, and other drivers used to tell me my car handled great when it had the stock open diff. I've not had the new diff under track conditions yet, so my plan is to test the car next week at MidOhio with a local BMW club and then examine my options for dialing out any increased understeer.
A racing acquaintance who wrenches at a Ford dealership installed my unit and tested my car on some back roads afterward. He says it's really sweet and probably shouldn't create too much understeer to really worry about. He's also got a Mustang but races ITS Nissans and Acuras