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Bump and rebound speed question.

Apr 16, 2008
289
12
I keep doubting myself about what way to adjust the bump and rebound.

In the setup, is 1 fast or is 20 fast?
If you could clearify this a final time, I'd be on my merry way...

THX
 

Neil Gault

1000RPM
Feb 21, 2008
1,463
341
Nice! Been wondering this for ages. V useful :)
np glad i could help, if you want to find out more about setting up your shocks then try this motec guide i uploaded here
but you will maybe have it already as i did upload the same guide to flatout about a year ago i think :laugh2:
 

Joule413

75RPM
May 16, 2008
82
0
Argh, I always keep getting confused about these settings >.<
I try to remember if it's the higher numbers that are faster, or if it's the lower ones, but I always forget...

I'll try to remember going back to this thread when in doubt :p
 
I

Ingo Voellinger

Are you sure a high damper setting is fast/soft and low is slow/hard?
I thought its the opposite.
And a high springs setting means hard springs?
 
N

Nick Price

motec tells me that my dampers are moving faster when set to 1... and slower when set to 20+

if you cant feel the difference when you mess with the dampers in your setups then id leave them well alone and focus more on the basics... :laugh2:
 

Neil Gault

1000RPM
Feb 21, 2008
1,463
341
motec tells me that my dampers are moving faster when set to 1... and slower when set to 20+

if you cant feel the difference when you mess with the dampers in your setups then id leave them well alone and focus more on the basics... :laugh2:
It can be interpreted a few ways but as i understand it then the lower the number then the softer the suspension will be and the faster the body weight transfers, but if the damper is set to a high number then the suspension is harder with slower weight transfer but faster reaction from the shocks. So is setting it to 1 slow or fast? yes it is slow for the shock to react but fast for the body to accept weight transfer.

There was a pdf engineers guide for the original GTR that goes some way to explaining this but sadly i do not think i have it any more but i will have another look tomorrow.
 

Lee Downham

1000RPM
Jun 16, 2008
1,970
1
I am a simple man, so I think of it in simple terms, kind of like ...

Lower settings (eg 1) = dampers offer less resistance so springs are pretty much free to move as they please
Higher settings (eg 20) = dampers will "hold" or the slow springs' movement down and so stop them reacting as fast ...

Or have I got this the wrong way round as its late and I am tired?


Either way, adjusting dampers is a dark art, but when you start to suss it out, I think it can add those final handling characteristics or tweaks to your setup ... but if your base setup is out of whack, then dampers are not gonna fix things, at best they'll mask a bit of the nastier stuff.
 
N

Nick Price

ive always thought at it from a shaft speed point of view...

bearing in mind weve got slow speed and high speed dampers to fiddle with too, high speed ones have little to do with weight transfer though (although i find the high speed settings hardest to set up by feel alone, thank you motec!)
 

Neil Gault

1000RPM
Feb 21, 2008
1,463
341
I am a simple man, so I think of it in simple terms, kind of like ...

Lower settings (eg 1) = dampers offer less resistance so springs are pretty much free to move as they please
Higher settings (eg 20) = dampers will "hold" or the slow springs' movement down and so stop them reacting as fast ...

Or have I got this the wrong way round as its late and I am tired?
about as good a description as i have seen, nice one :clap:
 

Lee Downham

1000RPM
Jun 16, 2008
1,970
1
... seems the Grasshopper (me) is learning ... ahhhhhh sooooo ... one day I too may become a setup master :wink2:
 
Apr 8, 2007
915
13
From GTR2 Engineers Handbook

Fast Bump - Controls the rapid upward movement of this suspension corner following
bumps and curbs. This Bump is described as “Fast” because the damper is moving up
(compressing) in a rapid motion, usually above 100mm/sec (use telemetry). So this adjustment
controls how a tyre conforms to the road as it’s negotiating the leading edge-topeak
of a bump or road undulation. If you find the car pushing to the outside of the track
in a “skating” fashion over bumps, then soften (lower) this setting. If the car floats and
changes direction erratically, then stiffen (higher) this setting. When in doubt, go softer.

Slow Bump
- Controls the mild UPWARD movement of this suspension corner caused
by a driver input (steering, braking, throttle). This Bump is described as “Slow” because
the damper is moving up (compressing) in a slow motion, usually below 70mm/sec
damper speed (use telemetry). Used to affect chassis balance while we are transitioning
into, and out, of the corners. Decreasing this number will speed up how quickly a corner
accepts weight transfer while we are transitioning. Increasing will slow it down.

Fast Rebound
- Controls the rapid DOWNWARD movement of this suspension corner
following bumps and curbs. This Rebound is described as “Fast” because this damper is
moving down (extending) in a rapid motion, usually above 100mm/sec (use telemetry).
So this adjustment controls how a tyre conforms to the road as it’s negotiating the peakto-
trailing edge of a bump or road undulation. If the fast bump setting has been changed,
then it’s usually a good idea to change fast rebound in a similar manner.

Slow Rebound - Controls the mild DOWNWARD movement of this suspension corner
caused by a driver input (steering, braking, throttle). This Rebound is described as “Slow”
because the damper is moving down (extending) in a slow motion, usually below 70mm/
sec damper speed (use telemetry). Used to affect chassis balance while transitioning
into, and out, of the corners. Decreasing this number will speed up how quickly this
corner gives up - or “sheds” - weight transfer while we are transitioning. Increasing this
setting will slow it down.
 

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