Basic Drift Chassis Setup Part 2
By Mike Kojima
In part one of our series we spoke about the importance of good suspension which is probably the first major step in setting up a car for drifting. Although the suspension is really important, perhaps just as important is a good limited slip differential.
To read more on suspension set up and part one, check out this section. “The Ultimate Guide to Suspension and Handling”
One of the most critical parts of a drift car that isn’t really part of the suspension but worth mentioning here is an LSD or limited slip differential. Without an LSD, it is really hard to get a car to drift. An LSD diff is one that locks the two drive wheels together under power. When the wheels start to spin on a car with a regular diff, all of the power is transferred to the wheel with the least grip so only one tire spins, in a turn it would be the inside rear wheel. No power is transferred to the loaded outside wheel and it does not spin. This makes it hard to get the car to slide by using the engine's power.
|The OS Giken LSD is one of the best on the market. It is highly adjustable for locking and initial breakaway. It also has a lot of clutch disks for long life.|
Spinning both rear tires using the engine's power, most importantly the outside tire is an important tool to reduce rear grip and to get the car to oversteer. An LSD allows the driver to throttle steer the car using the engine’s power to help steer that car once it is sideways.
|The OS Giken uses these springs to adjust the slope of the lock curve. The stronger the springs, the more gradual the locking and the more initial bite when the throttle is applied. Cusco diffs have similar adjustments but it works in reverse, the stiffer the spring the faster lock is applied because with a Cusco the springs work on the opposite side of the pressure ring. For drifting you usually want a fast steep slope to the lock curve.|
An LSD locks the wheels together so they both spin, this makes it easier to achieve on throttle oversteer. For drifting most people prefer using a 2 way LSD. This locks the wheels on acceleration and deceleration generally making it easier to keep the car in drift even if the throttle is backed off. A two way diff also allows a drift to be initiated more easily using the shift lock technique where a downshift is done without heel and toe rev matching.
|To adjust a diff, it must be taken apart by removing the housing bolts. Here Billy Johnson disassembles his OS Giken diff.|
When shopping for an LSD a few features are important to look for. You want to get an LSD with the maximum amount of clutch plates, OS Giken, Cusco and Kaaz all have a lot of plates. More plates equal stronger locking and longer wear. Adjustable breakaway torque is also a useful feature as for drifting you want the diff to be pretty solidly locked up compared to grip driving. All of these diffs have adjustable breakaway torque.
|These cone springs control the initial breakaway torque for the diff by controlling the preload on the clutches. A stiff spring has greater initial breakaway than a soft one. Just about all racing LSD's can be adjusted this way. Generally for drifting you want a high initial breakaway torque.|