Clutch Spring Assist 35 lb/in 2015/6

Your 2015-2017 Mustang comes with a 185 lb/in clutch assist spring installed from the factory. This high-rate spring is what causes such a vague and disconnected clutch pedal feel. The clutch pedal travels in a circular arc, with the spring assist in the middle of that clutch pedal travel. The middle of that motion compresses the spring initially and then allows it to extend after the first 30 degrees of travel. The combination of a high-rate assist spring and motion of the pedal during engagement causes a non-linear and sometimes confusing pedal feel. Having a non-linear pedal feel makes it hard to modulate the clutch on your Mustang GT, EcoBoost or V6.