If you've ever raced a car with an open differential, you know how frustrating it is to run around the course with that inside tire loosing its mind. You focus on the braking zone, execute the set-up, hit the apex, then mash the accelerator and....nothing. Ok well not "nothing", you car is doing the best it can with its original basic hardware. You have to time your inputs perfectly, be conscious of the surface condition, and wait.....for what seems like forever to go full throttle again. Not only is this slower, but it wears down the tires faster from all the wheel-spin. Super lame.
Now what if I told you it doesn't have to be this way, WHAT IF all you had to do was plant your right foot and steer? Let me share with you a genius product from CuscoUSA.
The RS Model has small coil springs between the pressure rings, constantly applying some pressure to the clutches. This results in a lower break away torque and minimal loss of this initail torque over time due to wear. The benefit of a lower(51-65ftlb) initial torque is a gradual and quicker clutch activation, smoother turn-in, an overal stable operation.
Not only is the RS completely rebuildable, they are also fully customizable! You have the regular options of 1-way, 2-way, or 1.5-way....but there is more! You can have custom ramp-up angles, preload springs, clutch discs, and even have them WPC treat the gears inside! Don't feel like you need to make all of these decisions on your own either, the crew at Cusco is more than willing to evaluate your situation and make suggestions. I've always felt super grateful for their amazing motorsports support, and I let them decide on my settings every time. Not once have I received anything less than a perfect product from them. You will have to re-tune your suspension once you switch from an open diff to the LSD.
The difference between an open differential and the this Cusco clutch-type LSD is like night and day. The first time you drive the car after the install you need to do the break-in procedure, then change the fluid. There is a definative difference in how the car turns while accelerating, you will feel the LSD lock and pull the car in the desired direction. If you decide to stab the accelerator with the wheels turned you better be prepared and have both hands on the wheel, in dry conditions the grip is INSANE! However in icy conditions you will still need to be careful, because you now will spin both front tires...and that means zero front grip.
Autocross is the perfect way to test a car, you have many different elements to master and usually not the most ideal surface. You need to accelerate at full blast through the first element, then a slalomn, throw in some turns and another slalomn...you really NEED both front tires to do their job. Iv'e raced this car the longest with an open differential, and it teaches you to give up throttle in places where the front starts stepping out. Its extremely frustrating, but there is a solution. The Cusco unit is best described as magical, since it effectively eliminates all of these traction issues. You no longer have to be gentle with the throttle, just set the arc and keep the throttle down...seriously. This is why we jokingly say "just mash the gas and steer", because now the LSD is HELPING the car turn.
The grip on a racetrack is a bit easier to manage, with an open differential you can expect to start spinning that inside wheel when trying to drive off the corners. The only thing to do is just make sure you have a good line and be patient, momentum and precision are the game plan. Once you have the Cusco LSD things change a LOT, you still need to set the arc in the turn but this time you get on the throttle right after braking. You no longer need to worry about the front losing grip and sliding, that doesnt exist anymore. Now you can hold the gas down and it actully keeps pulling the front of the car in the desired direction. The game has now changed to " whats the fastest I can enter the turn and not fly off?", because now you wont have to give up speed anywhere else but the entry!
There are many things you can do to a vehicle to make it faster; more power, weight reduction, fine-tuning the suspension....but all of these upgrades will still leave you with a incomplete build. A ton of power doesnt help much if youre spinning a tire the whole time. This is why I am such a gearhead, I've learned how much of a difference gear ratios and a winning LSD make. If you want to know my opinion on what makes the biggest improvement in a race car; hands-down it's having a Cusco LSD. Check out the comparison video below!
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