needforspeed
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| posted on 26/10/11 at 08:49 PM |
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suspension gurus
hi, basically ive just bought some re conned nitron 3way coilovers for my indy r. i dont need anywhere this much adjustablility but they were too
cheap to pass up! thing is where do i start setting them up? the car they came off was 300kg heavier than mine so will i need to change spring rate?
and how about dampening set them all half way?
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snapper
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| posted on 27/10/11 at 02:26 AM |
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Spring rates as normal for your kit but the adjustability will be about a third or less from the soft end.
Start with all three the same.
Find some racers who use them and talk to the manufacturers for a starter setting.
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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phelpsa
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| posted on 27/10/11 at 07:07 AM |
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Send me a U2U with all the damper details.
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MikeCapon
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| posted on 27/10/11 at 07:37 AM |
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Hi,
The damping rates (and adjustments) are driven primarily by the spring rates rather than the weight of the car. The weight of the car will have an
impact on the required spring rates but a car that is double the weight of another will not automatically have double the spring rate. Factors
including the ratio (wheel/shock movement), the type of tyre hence grip level, any aero effect, the car's capacity to carry additional weight
will all have an impact on spring rates.
The spring preload will be determined as usual, ie by ride height and corner weighting. MK should be capable of giving you the correct spring rate for
your Indy R.
The damping adjustment is a little more complex. A monotube shock such as a Nitron will be fitted with two or three stacks of shims, chosen to offer
optimum damping for a certain vehicle and spring rate. These shim stacks are fixed. In other words you cannot alter their characteristics without
dismantling the damper and altering the shim stacks by changing shims.
While the shim stacks fix the basic damping the adjusters are there to offer a limited amount of change, within the different phases. I imagine that
your 3 way adjusters are, Low Speed Rebound, Low Speed Compression and High Speed Compression.
My recommendation would be to reduce all three adjustments to minimum and increase as required taking care at first although if the dampers are valved
for harder springs you should not be too underdamped to start with.
The difference between high and low speed damping is best expressed as follows
Low Speed - When the chassis moves around such as roll on turn-in
High Speed - When the wheel moves and (hopefully) the chassis does not such as hitting a bump at speed
One thing that would be useful would be to establish the spring rate change. In other words the percentage difference between the springs that were
fitted originally and the 'new' Indy R rates. Quite how much of a difference the Nitron is capable of handling I do not know and I suspect
that calling Nitron will result in them asking you to send the shocks back for a revalve.
All things considered it must be worth a try to see if you can use the adjustment available to get an acceptable result.
I hope this helps.
Mike
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procomp
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| posted on 27/10/11 at 09:07 AM |
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Hi
If you fancy the trip to Brum you can run them on our Damper dyno and see exactly what the adjustment range is and if they are balanced or even in the
ball park for your setup. That's FOC Just give me a few days notice.
Cheers Matt
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MikeCapon
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| posted on 27/10/11 at 09:50 AM |
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quote:
Originally posted by procomp
Hi
If you fancy the trip to Brum you can run them on our Damper dyno and see exactly what the adjustment range is and if they are balanced or even in the
ball park for your setup. That's FOC Just give me a few days notice.
Cheers Matt
^^^
This is the ideal plan. And Matt is the best man for the job. Worth the trip IMO.
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phelpsa
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| posted on 27/10/11 at 10:14 AM |
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Bite Matt's hand off  that is by far the best idea. If that's not possible I might be able to find out more info on the shimming with
mote details (i presume you've spoken to nitron direct?).
[Edited on 27-10-11 by phelpsa]
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Sam_68
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| posted on 27/10/11 at 12:11 PM |
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quote:
Originally posted by MikeCaponThe damping rates (and adjustments) are driven primarily by the spring rates rather than the weight of the
car.
That's a little misleading and, strictly speaking, incorrect.
The coefficient of critical damping is related directly to sprung weight and spring rates.
Of course the corner weights of a typical Locaterfield don't vary that much, so if you do work on the basis of calculating damping rates
purely on the basis of spring rates, then for a given type of car (ie. a Locaterfield, in this instance) you won't be dramatically wrong,
but don't go thinking that you can work calculate the damping of anything from a BEC to a Range Rover purely on the basis of spring rate and
still expect it to work.
[Edited on 27/10/11 by Sam_68]
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needforspeed
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| posted on 27/10/11 at 05:18 PM |
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thanks for all the replys, matt that would be absolutely fantastic thank you very much! il be in touch! 
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eddie99
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| posted on 27/10/11 at 05:31 PM |
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Talk to Guy at Nitron and explain the situation. They have calculations and experience that will be able to help determine if the valving is in the
right ball park. Nitron will no doubt dyno them FOC for you too.
There are few things to be careful of when you play with Monotube style dampers and when testing them on dynos that is a little different from twin
tubes. Things to look out for etc as well as the adjusters interact with each other, gas pressure etc.
The adjusters work very differently to a twin tube like a protech and Nitron are the best people to help you out properly.
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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ffrgtm
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| posted on 31/10/11 at 01:18 PM |
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quote:
Originally posted by Sam_68
quote:
Originally posted by MikeCaponThe damping rates (and adjustments) are driven primarily by the spring rates rather than the weight of the
car.
That's a little misleading and, strictly speaking, incorrect.
The coefficient of critical damping is related directly to sprung weight and spring rates.
Of course the corner weights of a typical Locaterfield don't vary that much, so if you do work on the basis of calculating damping rates
purely on the basis of spring rates, then for a given type of car (ie. a Locaterfield, in this instance) you won't be dramatically wrong,
but don't go thinking that you can work calculate the damping of anything from a BEC to a Range Rover purely on the basis of spring rate and
still expect it to work.
[Edited on 27/10/11 by Sam_68]
Actually it's related to unsprung weight, not sprung weight. The damping ratio of a 2nd order differential eq (mass spring damper system) is
equal to (b/(2*sqrt(k*m))) where b is the damping coefficient and k is the spring rate.
The m is the mass is is actually damping (the unsprung mass) while the inputs from the road would be the forcing function in the regular old D.E.
(laplace transforms so I don't have to write out the derivatives) : (ms^2+bs+k)X(s) = F(s)
For someone to give your dampers a rough valving all they should need to know is...:
Wheel rates (meaning you need your spring rates and your motion ratio... don't forget to square it)
They will need the motion ratio of the dampers.. just use the same motion ratio you used to calculate your wheel rates in your case.
ARB wheel rates (best to measure this directly if you have them)
Unsprung weight (including your damper and control arms/linkages divided by 2)
They will literally only need these THREE things... everything is totally indepedent of your vehicle mass/weight distribution.. ect. The magic of math
P.S. if they ask you for more info than this you should go else where as they probably don't know WTH they're doing.
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phelpsa
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| posted on 31/10/11 at 01:24 PM |
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That would depend on what mode you're looking at 
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ffrgtm
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| posted on 2/11/11 at 03:39 AM |
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Ok fair enough
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