What damper rates do you run?
- Thread starter Noddie
- Start date
OP
OP
I what sense Ed?
Road use? Competition?
Standard? Coilovers?
I'd assume most if not all people use whatever damper rate is given by the manufacturer and don't change damper ratessprings are much the same I presume
The bc coilovers i've seen are fixed b/r ratio
Well, the application is designed towards rally but was trying to get an overview. It doesnt need to exact but more of a general idea.
h701micra
Deactivated Account
This is where I complicate it a litte bit
Forest rally? Or tarmac rally? As the setups are very very different.
I'm guessing by impact simulation you'd need weights and approx shock forces? Or is that what you control?
OP
OP
Well, the idea is to simulate hitting a rock or similar (which is when I assume the wishbone would fail), so forest rally I guess.
What would be the softest damper rating (in bump) that you could expect to run? (softer damping means less force on spring and therefore more force on wishbone).
I had a feeling you may be able to help me on this one Andy
Some rough calcs for a damping ration of 0.6 has come up with a damping ratio about 1470Ns/m sound anywhere near right?
What would be the softest damper rating (in bump) that you could expect to run? (softer damping means less force on spring and therefore more force on wishbone).
I had a feeling you may be able to help me on this one Andy
Some rough calcs for a damping ration of 0.6 has come up with a damping ratio about 1470Ns/m sound anywhere near right?
h701micra
Deactivated Account
Rocks are the main culprits for bending emWell, the idea is to simulate hitting a rock or similar (which is when I assume the wishbone would fail), so forest rally I guess.
What would be the softest damper rating (in bump) that you could expect to run? (softer damping means less force on spring and therefore more force on wishbone).
I had a feeling you may be able to help me on this one Andy
Some rough calcs for a damping ration of 0.6 has come up with a damping ratio about 1470Ns/m sound anywhere near right?
I shall do my best to help out
I've got some forest rally data I'll go dig it up. Should help you out more. Force depends on vehicle weight and spring rate too
where's the 0.6 from?
h701micra
Deactivated Account
Good figureI am estimating 400kg over that wheel btw.
Compression vs Rebound I assume in which case I'd use 0.6 as a control figure
Have you any hertz ratios?
Found some data I'll add it in a mo
OP
OP
No sorry, ration of damping/critical dampingGood figure
Compression vs Rebound I assume in which case I'd use 0.6 as a control figure
Have you any hertz ratios?
Found some data I'll add it in a mo
You've lost me a bit here,
What is a Hertz ratio?
And C/R?
(assuming linear damping in my model btw
)
OP
OP
cheers frankjust checked the k11 and corsa rears ed, both 1:1 ratio
Measuring rate is tricky though eh as force is dependant on the speed at which you move the damper, springs are much easier.
h701micra
Deactivated Account
Ah I see. Makes sense nowNo sorry, ration of damping/critical damping
You've lost me a bit here,
What is a Hertz ratio?
And C/R?
(assuming linear damping in my model btw
Hertz is as you know frequency. Frequency of the shocks. I use inches per second
Ratio is the out difference. Between 0.8 and 0.9 usually
Its to do with going over bumps. Front deals with initial bump but rear has to deal with bump and and the effect of front
h701micra
Deactivated Account
1:1?just checked the k11 and corsa rears ed, both 1:1 ratio
frank
Club Member
there are 2 damper rates on every shock tho i believe ed, a fast rate and a slow ratecheers frank
Measuring rate is tricky though eh as force is dependant on the speed at which you move the damper, springs are much easier.
frank
Club Member
aye, equal compression and rebound andy, where-as the k11 and matiz fronts were 1:2 and 1:4
h701micra
Deactivated Account
And they're standard items?
Never ever come across 1:1 in anything. How did you test em?
I could probably guarantee rebound is higher than compression
h701micra
Deactivated Account
(assuming linear damping in my model btw
h701micra
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Ah I seeguestimated innit
Aye there should be but not huge, weight and rate difference usually dictates a softer rear c/r ratio
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frank
Club Member
i doubt that would be realistic personally ed, it does,nt take much of a bump for the high rate damping to come into effect(assuming linear damping in my model btw
h701micra
Deactivated Account
I suppose we can create a dual linear line to represent a rough digressive rate
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h701micra
Deactivated Account
This might help a tad more :/
Its a force vs velocity graph
Goes up in lbs
And across in inches/second
Compression top left
Rebound bottom right
Its a typical road car/tarmac rally setup
Rotate (not flip) 180deg to get an idea of a forest rally setup
Shows you how much compression is added (jacking up setup) along with spring rate
OP
OP
I could write an expression for damping but would need at least a damping curve in order to do this. The simulation is an impact so would just use the higher rate otherwise.I suppose we can create a dual linear line to represent a rough progressive rate
h701micra
Deactivated Account
Like the one I just put up?
OP
OP
arrr, yes, that looks good. what damper is it?
Do you have any exported data from it? .csv? or excel format? or matlab? anything with numbers in really
h701micra
Deactivated Account
Thats a custom bilstein b4 or 7 iircarrr, yes, that looks good. what damper is it?
Do you have any exported data from it? .csv? or excel format? or matlab? anything with numbers in really
No idea that's all computer stuff. I load the program and it shows me that
I can get print outs etc. I'll email it to you?
h701micra
Deactivated Account
Fixedits more of a stepped/2 stage curve, than a truly digressive one eh (so more simplistic for you ed
Didn't think he'd appreciate this
So I put it into erc graph
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OP
OP
Yes please mate! email would be great. Ill pm you my email address nowThats a custom bilstein b4 or 7 iirc
No idea that's all computer stuff. I load the program and it shows me that
I can get print outs etc. I'll email it to you?
What monstrosity is that!?!
Im out!
h701micra
Deactivated Account
Force vs Velocity graph with every single adjustment tested
OP
OP
mostly two stage bump and linear rebound eh? that what they call '3 way adjustable'? I may be wrong but it looks like the thing being adjusted is the speed at which the shock goes from low to high rate? and the low speed rate, but not the high speed rate?Force vs Velocity graph with every single adjustment tested
Also, andy, what would an average spring rate be for a forest micra rally set up?
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h701micra
Deactivated Account
That's a 3 stage shock that one
you can see in the rebound. The low speed is pretty similar throughout. Linear then digresses to a 3rd linear line Its comp and rebound adjustable individually. Then we can alter shock pressure too
Other than the obvious change. Valving pretty much remains the same
Typical rate I'd say would be 140-160lbs/in
