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      02-14-2013, 10:41 AM   #7
CJ421
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Drives: 2011 E92 335i
Join Date: Feb 2011
Location: PA

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2011 BMW 335i  [4.66]
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Quote:
Originally Posted by Techevo View Post
All good info, but rebound adjustment has far more effect on handling than compression, and is more critical to get in the sweet spot. This is the reason that 1 way damper adjustments change mainly rebound, with slight compression change.

I normally adjust compression to the softest I can get away with in respect to travel and bump absorbance. I personally think in some applications, too much bump damping is used to compensate for too soft spring rates or anti-roll bars.
Respectfully I disagree. Using a lot of rebound damping in an attempt to improve handling is a 1960s/1970s plan of attack. Quite frankly you're wrong to set compression to the softest, if good handling is your goal.

Good compression damping prevents the unsprung weight from getting to higher velocities than desired; high unsprung weight velocities translate to bad handling. The damper should prevent the spring from absorbing more kinetic energy than necessary; and a well designed damper will counteract any suspension movement immediately, not after the fact. The most effective way to accomplish that is in the compression stroke.

Regarding using bump damping as a compensation for spring rate (bump = compression for others joining in on this conversation) - depending on the damper, it's a valid way to add to the spring rate, especially in race classes where you can't change spring rates. High gas pressure dampers do so with great effect, and there's more benefit to high gas pressure than just assisting spring rate. Regardless, I concede there's no substitute for properly matched springs and dampers. I have doubts about race teams that can't calculate that correctly.
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2011 BMW E92 335i, 6MT, Le Mans blue - Quaife LSD, JRZ RS Pro, JRZ camber plates, Eibach ERS, full M3 susp, custom toe arms, Powergrid end-links, SS brake lines, brake ducting, Michelin PSS, UUC SSK, ETS FMIC, ER CP, Perf. Exhaust, VAC RSIK, Sparcos; work by VAC Motorsports in Philadelphia
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