This what happened when mine broke
http://youtu.be/7iHr9pvpCFI?list=UUD...do0cAzadZVwKcA

 

crazy. mid turn, out of no where. no impact or rough terrain or anything.

 

Just to give you an idea. That's not my car, but I was the driver. The owner is a friend of mine. The car was built from scratch from different s2000 donors . Yesterday was the FIRST track for this car. The car has tein suspension (if I am not mistaken-with 14kg spring rates), hardrace upper arm, with camber adjuster and js roll center adjuster. My friend told me that the knuckle was taken from an s2000 with 60000km which was sold in parts. I WANT to beileive that the knuckle was slightly cracked, and gave up on the track. I was lucky because the knuckle snapped after a straight line, in a low speed turn and I stopped in 10meters distance. On a quick look at the spot, the only thing was damaged (except the knuckle) is the alloy wheel, which was deeply scratched from the lower screw of the roll center adjuster, other than that all the other parts seems to be ok.

Now the car is in the garage and tomorrow, our mechanic will take out the knuckle. I told him to send me some photos. As soon as I have them I will upload them here

 

overtorquing could lead to bolt failure, not to that area.

 

as I told, I WANT to beileive that the knuckle had a capillary crack, that no one saw it and snapped under track stress. Our mechanic is 52 years old 25 years working as Honda authorized mechanic. He saw many abused s2000s, many ''reasonable'' failures, but that was something that never saw in the past.

 

pretty f@#king scary. i've bounced my car off curbs for a good few seasons. i've yet to crack one, but now i'll be checking mine everytime i pop off a wheel.

i've drifted off 40+ rear tires

 

That's pretty scary. It seems to me that theoretically, with a RCA placing the ball joint farther away from the knuckle, there is an increase in bending stress at that failure point. I wouldn't think it would be enough to cause a failure though, but with sticky tires, who knows...

 

Yikes! Yeah that is a real scary failure! The fact that the knuckle was taken from a parts car though is really going to add uncertainty that can never be answered. My guess is though, that since the basic principles of your setup are in line with most, and this failure has not really been seen from guys who track their cars very frequently, that this is more than just a simple failure. It was caused by something.

 

 

The E36/E46 M3 owners replace their front control arms every 1-2 years, depending upon the track time. The control arms are considered a wear item.