1 XL â or EXL, Exploration Licence (United Kingdom), a type of onshore licence issued between the First Onshore Licensing Round (1986) and the Sixth (1992). 2  Xln â Crystalline (minerals). 3  XLPE-Cross-linked Polyethylene. 4  XMAC â Cross-Multipole Array Acoustic log.
When the frequency approaches 120 CPM (2 Hz), occupants perceive the ride as harsh. Consequently, the suspension of the average family sedan will have a natural frequency of about 60 to 90 CPM. A high-performance sports car will have a stiffer suspension with a natural frequency of about 120 to 150 CPM (2 to 2.5 Hz). Originally, human sensitivity to ride frequency was believed to be associated with the natural oscillations of an adult human body during a walking gait.
Rating Newest Oldest. Best Answer: It depends on how loud it is. Federal limit is 95db at 30 feet at 3000rpm. Basically, your car cannot exceed 95db (decibels) from 30 feet away from the car, with the engine at a constant 3000rpm. Some states have more strict laws, CA for example (and many others also) have a 93db limit. I currently have no mufflers on my car, and have not gotten pulled over once for my exhaust.