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#9: 01-30-2013, 02:35 PM
 
 BAC5.2
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Title: OTM Dir. of Engineering
Location: Automecca
Car: Rental cars
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Quote:
Originally Posted by Impatient View Post
come drive it
I'm not sure I would want to. There are a LOT of reasons to not cut a spring.

Quote:
Originally Posted by Impatient View Post
Mount them on the car, loaded down, things obviously change: the JDM's are the tallest, then OB, then HD (shortest). I THINK the JDM's are tallest, not because of the strut body length, but because of the gas pressure (in conjunction with the fact that the strut CAN extend further), and the HD's have lower perch and shorter travel, but gain back a bit because of the Spec B tophats. I never mounted Legacy struts, but assume the shortest of the bunch mounted, in actual use. I would have thought that JDM's would have equalled stock OB, since lower body is identical SIZE (although smaller perch...no "basket"), but they extend further and weight of car doesn't comepletely negate Bilstein gas pressure.
Gas pressure in the shock/strut doesn't impact the "stiffness" of the strut. The gas charge really only acts to prevent foaming of the oil. Remember that the gas charge is on TOP of the oil, but the strut is controlled by the motion of a piston IN the oil.

The height difference is almost entirely related to the fact that the Bilstein is an inverted strut vs. the standard strut that the OB comes with. That means that in the Bilstein, the piston rod is pointing downward, and the oil is in the upper portion (the exact opposite of the stock setup).