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Thread: First timer for coilovers/shock adjustment advice

  1. #1
    Join Date
    Aug 2017
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    Hendersonville, TN
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    1997 328i Sport

    First timer for coilovers/shock adjustment advice

    Been doing HPDE and TT for two years now. Just had ISC track coilovers installed/aligned/corner balanced by former SCCA professional road racer. He left the shocks set at 16 out of 32 for me to adjust to my liking but I’ve never done this. My home track is NCM and I’ll be doing TNiA at Nashville Superspeedway next month.

    What’s my approach to how to setup my shock adjustments? Leave them in the middle and adjust up/down and front to rear based on over/understeer? Full soft and adjust? Thanks for the advice!


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    Mike
    1997 328i Sport, 5 speed
    2013 X5

  2. #2
    Join Date
    Dec 2020
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    San Jose, CA, USA
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    1994 "532i6", 1998 528iT
    You'll need some time to burn. I would set the dampers to full soft, go around a grippy, consistent corner you know you can safely push and see if steering inputs can cause the loaded side of the car to "pogo". It should.

    My working definition of pogo is any more oscillation than the following pattern: down, up a bit, level. If the suspension oscillates more than this, it would be considered underdamped for most on-road usage. If it doesn't come back up at all, you are at or past "critical damping" and that's generally considered a bad thing.

    So you're basically hunting for this pattern: adjust the front dampers, take a hard turn, give yourself honest feedback for how the front end is moving. You should be able to find a happy medium. To confirm, run the car over a bumpy road and confirm that the front end neither pogos (like blown shocks) nor skips over bumps ("feel every pebble bruh"). That's a semi-decent front end baseilne.

    People will have varying opinions on the rear. Since it's harder to instigate the rear to pogo, I usually rely on bumpy roads only. Once again you want to slowly raise the stiffness (from soft) until the rear end feels like it's not blown, but not skipping over bumps. You want the car to feel soft and supple without pogoing.

    That'll usually get you 80% of the way there, of course the dampers should be further optimized on-track. If one end needs more grip, you can soften the dampers to the point just before it starts pogoing again. If the car's response is too slow, you can stiffen the dampers on the end that needs to respond faster. If you're keeping time, the stopwatch/Aim Solo is king so you can really just brute-force the science experiment with that feedback as your guide.

  3. #3
    Join Date
    Feb 2007
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    louisville ky
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    87 325
    Mike, I am in Louisiville, KY. Hope to run across one day at NCM.

    Medium is ok I think for street, but I would at full soft and work your way up 2 clicks at a time, something more noticeable. You're look for a feeling that both front and rear of the car or transitioning with each other. Then each axle dependent of handling. Usually full soft rear rain, few clicks front. You'll never be able to set it up for every corner, sometimes it a give or take.

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  4. #4
    Join Date
    Aug 2009
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    Lake Arrowhead, CA
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    75 BMW 2002, 82 320
    My reference point is my retired 1988 NASA GT2 BMW325 that is no longer a race car, but being refreshed to get back on the track. I would say seat time, in any format is the key. I have driven in numerous auto cross events and solo1 events and learned lots about the car and potential track set ups. And the parts that need to be added to the refresh list, it is a never ending learning curve.
    Auto crossing a road race car is not a perfect solution but the dynamic of the car are magnified, yes no straights but its all about corner in/corner out. Getting the front to turn involves weight transfer and understanding the feel of shock compression and rebound.
    I also benefit from learning how much I can toss the car and stay between the cones. My car is producing 180hp at the rear wheels, it weights 2340. I do not want to cut the fenders so I am running 15x7 rims. The car was raced with 225 Toyo RA-1's, a very stiff side wall tire, in it's day. I pulled the warn 4.10 LSD and I am currently running a low milage and tighter 3.73 LSD. The front Bilsteins are adjustable, the rears should be but I for the like of me I can not figure out the way to make this happen. The car was last "raced" in 2010, this combination is not currently in production. The rears are a coil over combination, no spring at the rear a-arm.
    Learning to drive a race car is a constant curve of learning, figuring out the subframe bushings are going bad, priceless.

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  5. #5
    Join Date
    Aug 2012
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    Central, MD
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    1995 M3
    Single adjustable I assume?
    For track adjustments, in order of importance of getting what you want; spring rates, driving style, roll bar rates, damper settings. Tire pressures are in there somewhere.
    Expect the middle settings (I'd expect from about 8 to 24) to not do nearly as much as the softest and firmest end of the settings. 8 clicks in the middle may not do as much as 2 clicks at either end. (Typical of dampers in that price range, but I have no personal experience with the ISCs). So don't get too discouraged if you go from 16 to 20 and feel no difference.

    You won't find nirvana in one weekend, so take notes.

    Pick one corner to adjust to. One corner. Use any of the myriad of charts available online to adjust for entry, mid, exit characteristics (oversteer, understeer, neutral). I'd recommend picking an average mid-speed turn with between ~70-90 degs direction change. Pick a corner that you think represents most corners at the track, but not something off-camber, a 180, or a slight kink or such. Your driving style makes a huge difference in car dynamics, so be consistent and run several/many laps before adjusting again.
    Change one end at a time.

    Good luck.

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