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Old 09-30-2013, 02:25 PM   #2
Derf00
6th Gear Member
 
Join Date: Feb 2005
Vehicle: '08 S197 GT
Location: AZ
Posts: 9,603
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From the factory Ford will sometimes use different spring rates for vert vs coupe.

http://web.archive.org/web/201210141...ings_calcs.htm

That's because the vert is usually a couple extra hundred pounds heavier from chassis stiffening. Aftermarket spring rates are usually as stiff or stiffer than the more stiff factory version so it doesn't make any difference. Yes, FRPP is considered aftermarket.
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08 S197 GT Auto: FRPP Strut Tower Brace, FRPP Bullitt CAI, Bama 91-P Tune
Pending upgrades: Shaftmasters Aluminum 3.5" DS, FRPP 3.73 gears, Axle back exahust (?)

Quote:
Originally Posted by LostBoyz View Post
if you are getting 29mpg in your 5.0, you aren't driving it correctly
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