Frosty
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| posted on 5/5/10 at 11:09 PM |
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quote:
Originally posted by ReMan
Surely this is achieved by the corect spring /damper lenth combo?
Am I missing something? 
Eventually it would be, but you wouldn't want to spend around £500 on gear which might not work. If you find at the target ride height you are
running out of bump travel then shorter dampers will be the only proper solution.
To begin with though, far better to spend a few quid on helper springs and see if you can make your existing dampers work. If you find the car just
doesn't work at the intended ride height then you have lost the cost of the helper springs and a bit of your time 
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MK9R
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| posted on 6/5/10 at 06:15 AM |
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quote:
Originally posted by Frosty
quote:
Originally posted by Neville Jones
Do the job properly, once, and fit the right length springs. The suggestions above fix the symptom, not the problem. When softening the springs, you
often have to go an inch or so longer.
Faulkners list 7", 8",9", 10",10.5", then 12" and up.
Cheers,
Nev.
So then how does the OP achieve the ride height required with a longer spring?
Presumably the reason the spring is too short at full droop is because a longer spring would not allow the desired ride height at its lowest setting.
You have to make the decision to run a shorter spring when the current one is still too high for the desired ride height when adjusted as low as
possible. Going shorter will often leave the spring loose at full droop.
There is nothing wrong with a helper spring. They exist for exactly this problem. A longer spring is not the answer.
I'm so glad you understand this! Spring length has nothing to do with it, its the amount of compression you get from a certain rate of spring.
The only way to aliviate this and still retain the the same amount of droop and ride height (one of the reasons have bought new dampers to increase
the damper range so i could drop the ride height 5-8mm and still have enough bump) is helper springs or raise/lower the chassis/trailing arm pick up
points, but this is major work on a live axel race chassis fury.
I've been speaking to another guy in RGB and he has exactly the same issue and lockwires his springs in place.
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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Neville Jones
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| posted on 6/5/10 at 09:25 AM |
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For starters, 180lb springs sounds high for that weight of car. Without knowing corner weights and installation angles, then I can only surmise.
A Protech damper, 12.5" between eyes, will have a seat to seat max length of about 7.5". With a corner weight of, say, 170kgs(374lbs),
then a 180lb spring @1:1 leverage will crush ~2.1". The overall travel of the damper will be less than 4", so at full extension, an
8" spring installed, will/should never 'rattle'.
The above is dependant on the ride height being correct at damper half travel. Most will have less droop than bump, as is the norm.
But, if lockwire works and fits your operational needs, then do it.
Cheers,
Nev.
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MK9R
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| posted on 6/5/10 at 09:46 AM |
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quote:
Originally posted by Neville Jones
For starters, 180lb springs sounds high for that weight of car. Without knowing corner weights and installation angles, then I can only surmise.
A Protech damper, 12.5" between eyes, will have a seat to seat max length of about 7.5". With a corner weight of, say, 170kgs(374lbs),
then a 180lb spring @1:1 leverage will crush ~2.1". The overall travel of the damper will be less than 4", so at full extension, an
8" spring installed, will/should never 'rattle'.
The above is dependant on the ride height being correct at damper half travel. Most will have less droop than bump, as is the norm.
But, if lockwire works and fits your operational needs, then do it.
Cheers,
Nev.
its a race chassis so sits lower than the usual road car, which allows far less travel on the dampers, something that all Fury lowered cars have to
battle with. The old dampers allowed 55mm compression (with bump stops) and 25 droop, the new ones have given me about 5-8mm extra. The springs are 6
or 7" (can't remeber sitting here at work), and the seats are set very near the bottom. The protechs have been specifically made for my
car so that they can have maximum travel within the constraints. The basic issue is that the pick ups aren't in the correct place for the ride
height as the car was never originally designed to sit that low, so other than making some serious changes, it has to be done with damper and
springs.
Rear corner weights are 140-150kg. The springs are upright with no advatage
I have just dropped the rate of the springs to 180, they were 225 (this is how i bought the car) in an effort to increase rear grip as it was very
flighty. I have been told i can go as low as 120lbs, but to start with i'm giving the 180's ago. I can't go too soft as i will
bottom too easily.
Cheers Austen
RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
www.trackace.co.uk
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JoelP
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| posted on 6/5/10 at 08:55 PM |
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why do you need X amount of droop if its leaving the springs loose when it droops fully?
When messing about with coilovers in the past, ive concluded that, before fitting, you have to have the platform in a position so that the spring is
not loose at full extention. If you then fit them and the car is too high, you cannot just wind back the platform as the spring will obviously be
loose when the weight is off it. You could either get a shorter spring to lower the car, or remove some droop by getting a shorter body. Or, mess
about with tie wraps etc to keep it all in place.
How much droop do you want/need?
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MikeRJ
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| posted on 7/5/10 at 11:47 AM |
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quote:
Originally posted by JoelP
You could either get a shorter spring to lower the car
No you can't, this gives exactly the same problem. Changing the spring length simply doesn't help in this situation.
quote:
Originally posted by JoelP
, or remove some droop by getting a shorter body.
Then you lose suspension travel, and you don't start with much with a 12.5" damper.
quote:
Originally posted by JoelP
Or, mess about with tie wraps etc to keep it all in place.
Or fit helper springs, since they are designed for exactly this situation!
The only way to fully resolve this issue is to change the suspension mounting points, but in this case it isn't possible without a lot of work
on the chassis.
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bigfoot4616
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| posted on 8/5/10 at 02:53 PM |
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quote:
Originally posted by MikeRJ
Or fit helper springs, since they are designed for exactly this situation!
which is what i had to do on the front of my striker.
using 12.5" dampers and 7" 200lb springs.
got some 2" 4lb helper springs from demon tweeks
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