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      02-13-2013, 02:35 AM   #1
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Question on KW v3...

Hey guys,

I have been running the recommended setting on the KW v3 since the first day I got my coilovers.
And I am going to do a HPDE next month. Want to kind of adjust a little bit on my coilovers.
After I read the manual from KW (not very detail in the manual tho), I understand the rebound rate which is adjusted on the top on the shock, and it is about the stiffness of the suspension. It can decrease the body roll at the high speed.
But I still don't understand what the compression/bump which is adjust at the bottom of the shock is for.... Can someone explain it??
Please correct it if I am wrong, and if you guys would like, please share your KW v3 setting on the track!

Thanks!!
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      02-13-2013, 09:50 AM   #2
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The compression stroke is where the piston is going into the damper body, and rebound the opposite.

Damping is reducing the energy of motion to acceptable levels over a certain suspension travel distance, so that the forces acting on the car don't disturb handling or put excessive vertical loads on the car and driver.

Compression damping controls the unsprung weight of the car (wheels/tires/brakes/half the suspension). The suspension will travel more than necessary if there's not enough of it, resulting in bad handling. Getting compression damping right is over and above more important than rebound for good handling.

There needs to be just enough rebound damping to not convert more energy than necessary. Translated - too much rebound means the spring cannot extend itself quickly enough; the tire will not be in firm contact with the road. A tell for too much rebound damping is a rough ride where it feels as if you are being launched out of your seat going over a bump. On the track, too much rebound will result in the car feeling unstable under braking or entering corners, and a tendency to oversteer out of the corner.

When adjusting a damper with more than one setting, make ONE adjustment at a time. I would start with both rebound and compression on full soft, and increase compression first. Go up a few clicks at a time, ride around the block, and keep doing that until you reach a point where the car feels good (each driver has a different preference, regarding suspension stiffness). Then adjust rebound and stop when you have a smooth ride. I imagine you won't go more than 1/4 - 1/2 the way towards stiff with rebound.
My preference is to keep the rear suspension settings a few clicks softer than the front; there is some benefit to rear body roll (especially if you do not have an LSD).
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      02-13-2013, 10:42 AM   #3
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Wow, awesome post, thanks for sharing your knowledge!

Quote:
Originally Posted by CJ421 View Post
The compression stroke is where the piston is going into the damper body, and rebound the opposite.

Damping is reducing the energy of motion to acceptable levels over a certain suspension travel distance, so that the forces acting on the car don't disturb handling or put excessive vertical loads on the car and driver.

Compression damping controls the unsprung weight of the car (wheels/tires/brakes/half the suspension). The suspension will travel more than necessary if there's not enough of it, resulting in bad handling. Getting compression damping right is over and above more important than rebound for good handling.

There needs to be just enough rebound damping to not convert more energy than necessary. Translated - too much rebound means the spring cannot extend itself quickly enough; the tire will not be in firm contact with the road. A tell for too much rebound damping is a rough ride where it feels as if you are being launched out of your seat going over a bump. On the track, too much rebound will result in the car feeling unstable under braking or entering corners, and a tendency to oversteer out of the corner.

When adjusting a damper with more than one setting, make ONE adjustment at a time. I would start with both rebound and compression on full soft, and increase compression first. Go up a few clicks at a time, ride around the block, and keep doing that until you reach a point where the car feels good (each driver has a different preference, regarding suspension stiffness). Then adjust rebound and stop when you have a smooth ride. I imagine you won't go more than 1/4 - 1/2 the way towards stiff with rebound.
My preference is to keep the rear suspension settings a few clicks softer than the front; there is some benefit to rear body roll (especially if you do not have an LSD).
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      02-13-2013, 10:41 PM   #4
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Quote:
Originally Posted by CJ421 View Post
The compression stroke is where the piston is going into the damper body, and rebound the opposite.

Damping is reducing the energy of motion to acceptable levels over a certain suspension travel distance, so that the forces acting on the car don't disturb handling or put excessive vertical loads on the car and driver.

Compression damping controls the unsprung weight of the car (wheels/tires/brakes/half the suspension). The suspension will travel more than necessary if there's not enough of it, resulting in bad handling. Getting compression damping right is over and above more important than rebound for good handling.

There needs to be just enough rebound damping to not convert more energy than necessary. Translated - too much rebound means the spring cannot extend itself quickly enough; the tire will not be in firm contact with the road. A tell for too much rebound damping is a rough ride where it feels as if you are being launched out of your seat going over a bump. On the track, too much rebound will result in the car feeling unstable under braking or entering corners, and a tendency to oversteer out of the corner.

When adjusting a damper with more than one setting, make ONE adjustment at a time. I would start with both rebound and compression on full soft, and increase compression first. Go up a few clicks at a time, ride around the block, and keep doing that until you reach a point where the car feels good (each driver has a different preference, regarding suspension stiffness). Then adjust rebound and stop when you have a smooth ride. I imagine you won't go more than 1/4 - 1/2 the way towards stiff with rebound.
My preference is to keep the rear suspension settings a few clicks softer than the front; there is some benefit to rear body roll (especially if you do not have an LSD).
Where's the LIKE button at?

Well said and explained better than most I've seen.
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      02-14-2013, 01:12 AM   #5
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Quote:
Originally Posted by CJ421 View Post
The compression stroke is where the piston is going into the damper body, and rebound the opposite.

Damping is reducing the energy of motion to acceptable levels over a certain suspension travel distance, so that the forces acting on the car don't disturb handling or put excessive vertical loads on the car and driver.

Compression damping controls the unsprung weight of the car (wheels/tires/brakes/half the suspension). The suspension will travel more than necessary if there's not enough of it, resulting in bad handling. Getting compression damping right is over and above more important than rebound for good handling.

There needs to be just enough rebound damping to not convert more energy than necessary. Translated - too much rebound means the spring cannot extend itself quickly enough; the tire will not be in firm contact with the road. A tell for too much rebound damping is a rough ride where it feels as if you are being launched out of your seat going over a bump. On the track, too much rebound will result in the car feeling unstable under braking or entering corners, and a tendency to oversteer out of the corner.

When adjusting a damper with more than one setting, make ONE adjustment at a time. I would start with both rebound and compression on full soft, and increase compression first. Go up a few clicks at a time, ride around the block, and keep doing that until you reach a point where the car feels good (each driver has a different preference, regarding suspension stiffness). Then adjust rebound and stop when you have a smooth ride. I imagine you won't go more than 1/4 - 1/2 the way towards stiff with rebound.
My preference is to keep the rear suspension settings a few clicks softer than the front; there is some benefit to rear body roll (especially if you do not have an LSD).

Thanks for your detail explanation!!!
Sounds like it is easier to get the rebound rate right than the compression rate. Like you said, if I feel I am launched out from the seat, that means too over on the rebound. But how can I get to the right point of the compression rate??
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      02-14-2013, 01:23 AM   #6
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Quote:
Originally Posted by CJ421 View Post
The compression stroke is where the piston is going into the damper body, and rebound the opposite.

Damping is reducing the energy of motion to acceptable levels over a certain suspension travel distance, so that the forces acting on the car don't disturb handling or put excessive vertical loads on the car and driver.

Compression damping controls the unsprung weight of the car (wheels/tires/brakes/half the suspension). The suspension will travel more than necessary if there's not enough of it, resulting in bad handling. Getting compression damping right is over and above more important than rebound for good handling.

There needs to be just enough rebound damping to not convert more energy than necessary. Translated - too much rebound means the spring cannot extend itself quickly enough; the tire will not be in firm contact with the road. A tell for too much rebound damping is a rough ride where it feels as if you are being launched out of your seat going over a bump. On the track, too much rebound will result in the car feeling unstable under braking or entering corners, and a tendency to oversteer out of the corner.

When adjusting a damper with more than one setting, make ONE adjustment at a time. I would start with both rebound and compression on full soft, and increase compression first. Go up a few clicks at a time, ride around the block, and keep doing that until you reach a point where the car feels good (each driver has a different preference, regarding suspension stiffness). Then adjust rebound and stop when you have a smooth ride. I imagine you won't go more than 1/4 - 1/2 the way towards stiff with rebound.
My preference is to keep the rear suspension settings a few clicks softer than the front; there is some benefit to rear body roll (especially if you do not have an LSD).
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.
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      02-14-2013, 10:41 AM   #7
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You're welcome.
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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      02-14-2013, 10:58 AM   #8
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Quote:
Originally Posted by kelvin2010 View Post
Thanks for your detail explanation!!!
Sounds like it is easier to get the rebound rate right than the compression rate. Like you said, if I feel I am launched out from the seat, that means too over on the rebound. But how can I get to the right point of the compression rate??
You are welcome. Adjust compression (and afterwards, rebound) until you are satisfied with the car's responsiveness AND the ride is comfortable for you. There's a balance between ride comfort and handling, so if it feels too stiff, then it is and you should reduce compression. And if it's harsh, you should reduce rebound. There is a difference between harsh and stiff.

Don't worry initially about 'getting it right' - the dampers are adjustable and you can adjust them at any time. I guarantee your preference will change over time. You won't know what is 'right' (and I say 'right' loosely because as I said, driver preference is key) until you try some settings, go with it for a while, then adjust them again (it's good idea to write the settings down in a notebook - be sure to note your tire model and tire pressures too). The same settings won't be ideal everywhere - e.g. really stiff on a smooth track is great but on the street ... nah.

Sooner or later you'll understand the setting's effects, and neither I nor anyone else can give that experience to you in text form. Kind of like riding a bike.

Good luck out on the track, be sure to tell us about it. There's usually a ton of knowledgeable and kind people at HPDE events (especially BMW CCA) - get a ride with someone and just have fun.
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      02-14-2013, 07:31 PM   #9
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Quote:
Originally Posted by CJ421 View Post
You're welcome.

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.
I didn't suggest running a lot of rebound, I said rebound adjustment is more crtitcal to get spot-on compared to compression. i.e. your compression damping can be slightly off optimum and it won't have as high an effect, compromising handling and grip than if the rebound adjustment is off optimum.

Thus why 1 way dampers manufactured by Ohlins, Koni, KW, etc have the one adjustment alter the rebound damping with only a very slight effect on compression damping change. If compression damping was more important to get spot-on, this would be the main adjustment of a one way damper.

I don't run the softest compression damping available, I run the softest I can get away with for my set-up and track, sprint or hill climb tarmac conditions. i.e. bump absorbsion without compromising grip.

It's worked for me for the last 30 years of competing and track work.
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      02-14-2013, 08:04 PM   #10
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Quote:
Originally Posted by Techevo View Post
I didn't suggest running a lot of rebound, I said rebound adjustment is more crtitcal to get spot-on compared to compression. i.e. your compression damping can be slightly off optimum and it won't have as high an effect, compromising handling and grip than if the rebound adjustment is off optimum.

Thus why 1 way dampers manufactured by Ohlins, Koni, KW, etc have the one adjustment alter the rebound damping with only a very slight effect on compression damping change. If compression damping was more important to get spot-on, this would be the main adjustment of a one way damper.

I don't run the softest compression damping available, I run the softest I can get away with for my set-up and track, sprint or hill climb tarmac conditions. i.e. bump absorbsion without compromising grip.

It's worked for me for the last 30 years of competing and track work.
Understood and thanks for clarifying.
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      02-14-2013, 10:51 PM   #11
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Quote:
Originally Posted by CJ421 View Post
Understood and thanks for clarifying.
No worries, other than that, you're info is absolutely spot-on, IMHO.
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      02-15-2013, 12:21 AM   #12
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Quote:
Originally Posted by Techevo View Post
No worries, other than that, you're info is absolutely spot-on, IMHO.
Thanks man. I got the mistaken impression you were saying use rebound in situations where I thought using compression was appropriate.
But getting it just right makes a lot of sense. The correct rebound setting range would seem to be rather narrow. Good to know, as I have a double adjustable damper set on order (time to re-learn the car I suppose).
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      02-15-2013, 03:07 AM   #13
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Quote:
Originally Posted by CJ421 View Post
Understood and thanks for clarifying.
One more question. I read the manual from KW, "Before performing any adjustments, the valve must be closed by turning the adjuster in the full clockwise direction. In this position, the shock will be at full hard, or “maximum power”." Does that mean every single time I adjust the V3, I have to turn it to full hard before I start adjusting or I will damage it??
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      02-15-2013, 03:21 AM   #14
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Quote:
Originally Posted by CJ421 View Post
Thanks man. I got the mistaken impression you were saying use rebound in situations where I thought using compression was appropriate.
But getting it just right makes a lot of sense. The correct rebound setting range would seem to be rather narrow. Good to know, as I have a double adjustable damper set on order (time to re-learn the car I suppose).
ot- are you selling the rs1's?
thx for the informative posts btw
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      02-15-2013, 08:49 AM   #15
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Quote:
Originally Posted by kelvin2010 View Post
One more question. I read the manual from KW, "Before performing any adjustments, the valve must be closed by turning the adjuster in the full clockwise direction. In this position, the shock will be at full hard, or “maximum power”." Does that mean every single time I adjust the V3, I have to turn it to full hard before I start adjusting or I will damage it??
That's something I'd have to defer to the KW owners - I simply don't know!
Quote:
Originally Posted by cvc 22349a View Post
ot- are you selling the rs1's?
thx for the informative posts btw
Anytime.
I'm planning to sell my RS1 setup (inc. springs/camber plates) when the new setup gets installed - drop me a PM.
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      02-15-2013, 05:02 PM   #16
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Quote:
Originally Posted by kelvin2010 View Post
One more question. I read the manual from KW, "Before performing any adjustments, the valve must be closed by turning the adjuster in the full clockwise direction. In this position, the shock will be at full hard, or “maximum power”." Does that mean every single time I adjust the V3, I have to turn it to full hard before I start adjusting or I will damage it??
No, you don't need to fully close before adjustment, only the first time so you have a datum of how many clicks open you are. Make sure you write down how many clicks from open you are running front and rear to help you remember your setup and make future adjustments easier.
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