It's been slightly over 700 miles since I've had O.S. Giken TCD LSD installed along with solid diff bushings and M3 sub-frame bushings. VAC Motorsports built the diff for me.
During this period, I've had the chance to test things out during several track days and AutoX events. Here are my impressions:
1. The rear end of the car no longer feels wavy and disconnected. I get almost direct feedback from the rear wheels through the chassis, through the seat and into my spine. It's uncanny at first, but now after I've re-learned the car, I can say that this upgrade should have been the very first thing I did on my car.
2. The traction is crazy. I am now considering going with slightly narrower tires in the rear because there is so much more grip compared to the front.
3. Accelerating from stand still is now completely predictable. The rear is not longer waving back and forth unpredictably. The car goes in a straight line.
4. On the track and AutoX events, I no longer have to wait for the car to get completely out of the corner and settle down before I give it full power. The O.S. Giken does tremendous job keeping me stable mid corner, whether its under power or not! This is where the O.S. Giken shines compared to the rest of the diffs. You get lock during acceleration AND deceleration. This becomes really useful when trail braking into a corner.
Another difference is that if I change my mind mid corner and I let off the gas, I no longer get this unsettling of the rear end. Instead, I feel the diff unlocking and re-locking again in a split second as I lift off the throttle. It's kind of difficult to explain, but it works wonders for increasing the driver confidence in the car mid corner.
5. NVH. There is a faint whine during acceleration and deceleration. It is more prominent when the diff oil is cold. O.S. Giken make their own gear oil and on the bottle it is stated that optimal performance is achieved at 100C. The diff definitely quiets down once the diff fluid is warmer. The whine is a result of the solid diff bushings.
Today, I've spent a good portion of the day draining the fluid, lowering the diff housing and removing the diff cover. I wanted to inspect the condition of the oil and the ring gear after 700 miles of break in.
Here are some pics:
![Click here to enlarge]()
![Click here to enlarge]()
Notice how the fluid looks like graphite. This is after 700 miles of break in. The new fluid is clear with a faint yellowish tint. The viscosity is unchanged compared to new fluid, so this tells me that the diff fluid is managing the heat quite well even during track days.
This should also serve as a reminder to change your diff fluid!
During this period, I've had the chance to test things out during several track days and AutoX events. Here are my impressions:
1. The rear end of the car no longer feels wavy and disconnected. I get almost direct feedback from the rear wheels through the chassis, through the seat and into my spine. It's uncanny at first, but now after I've re-learned the car, I can say that this upgrade should have been the very first thing I did on my car.
2. The traction is crazy. I am now considering going with slightly narrower tires in the rear because there is so much more grip compared to the front.
3. Accelerating from stand still is now completely predictable. The rear is not longer waving back and forth unpredictably. The car goes in a straight line.
4. On the track and AutoX events, I no longer have to wait for the car to get completely out of the corner and settle down before I give it full power. The O.S. Giken does tremendous job keeping me stable mid corner, whether its under power or not! This is where the O.S. Giken shines compared to the rest of the diffs. You get lock during acceleration AND deceleration. This becomes really useful when trail braking into a corner.
Another difference is that if I change my mind mid corner and I let off the gas, I no longer get this unsettling of the rear end. Instead, I feel the diff unlocking and re-locking again in a split second as I lift off the throttle. It's kind of difficult to explain, but it works wonders for increasing the driver confidence in the car mid corner.
5. NVH. There is a faint whine during acceleration and deceleration. It is more prominent when the diff oil is cold. O.S. Giken make their own gear oil and on the bottle it is stated that optimal performance is achieved at 100C. The diff definitely quiets down once the diff fluid is warmer. The whine is a result of the solid diff bushings.
Today, I've spent a good portion of the day draining the fluid, lowering the diff housing and removing the diff cover. I wanted to inspect the condition of the oil and the ring gear after 700 miles of break in.
Here are some pics:
Notice how the fluid looks like graphite. This is after 700 miles of break in. The new fluid is clear with a faint yellowish tint. The viscosity is unchanged compared to new fluid, so this tells me that the diff fluid is managing the heat quite well even during track days.
This should also serve as a reminder to change your diff fluid!