Suspension up grade

[Laurenzo]

Chaps I am about to change my suspension set up from the standard preset dampers to fully adjustables on my FD. I have noticed that one or two suppliers are offering different spring rates to suit different applications.
 
I have expiriance on several cars changing from one system to another, and know first hand the pit falls, So my question is, does anyone know what the standard spring poundage is for a UK car, as this will give me a datum point.

[MaLicE]

not got a clue sorry, but can say go careful which manufacturer you go with, some of the cheaper kits say they offer height adjustment however they offer adjustment by dropping the lower spring platform to lower the height but that takes the preload off the spring... if you want propper height adjustment the units alow the bottom mount to be wound up and down to provide height adjustment, i know the cheaper teins use the first method.

got ohlins on mine and they are by far the most comfortable coilovers i have driven with.

[marco]

ok, i am probably having a brain fart, but can someone explain the whole preload jobbie to me?

[MaLicE]

ok the spring is on a platform and has a top mount on top, you wind the bottom platform up until the spring doesnt move about freely... preload is then determined by how much the bottom platform then compresses the spring, im running 10mm preload on my ohlins.

[marco]

but wont the spring just compress the amount due to the weight of the car?

[MaLicE]

but if you have no preload when you go down a road and there is no compression on the spring the car handles bad and the spring becomes unseated... and allows sag on the suspension so when it is compressed if you have no preload the shock will be compressed too much,

http://www.ntnoa.org/suspension_preload.htm

thats about bikes but means the same have a read

[marco]

i still dont get it, the spring is compressed by the weight of the car, the only way you could increase the amount of compression would be to wind in that seat the spring sits on until you topped out the damper and so it had something solid to compress against surely?:Hammer

[Laurenzo]

Marco, perhaps I can help you out here, if you simply drop the platform height on a standard spring, then the spring is too short to touch top and bottom seatings when the car is either lifted, or under high speed cornering there is a gap, and that is highly undesirable. In a road going car it will fail the MOT and then you find yourself having to buy spring assistors to take out the slap (gap).
 
Malice, thanks for the imput, and yes I do have an understanding, it just worries me when one of the leading brands is offering spring rates from less than 400 to over 800lbs that is just crazy and could lead to serious problems. The spring rate on a uk spec car is very good, that is why it would help me to select a near enough replacment without the need to buy several sets of springs to find the ultimate one for my needs.
 
Open question to those that do trackdays what makes are you running, and are you happy with them.

[marco]

ah thanks, i think it was the terms that were confusing me, basicly you are looking to ensure that the spring stays under compression troughout the range of travel the damper is going to see? I will go away and try to translate some stuff I found into ideas I can understand. i am guessing that for 99% of people though the standard coiloever kits that lower using the spring perch will suffice?

[AtomicRex]

Laurenzo
 
If you want to give me a buzz...we specialise in the Nitron Dampers. They will certainly give you the best compromise between road feel, drivability, and comfort. We run 550/500lb springs for the road, and 800/600 for the track.
 
Well worth getting the helper spring upgrade, to get over the issues of pre-load also.

[Laurenzo]

Thank you Atomic Rex!
 
Thank you for the response, yes I do know the Nitron\'s I had them fitted to a Chimera, I had them fitted by a "racing garage" which just thought the idiot behind the wheel wouldn\'t know if it was a good setup or bad, so as you have guessed it was a bad set up.
 
But to their defence once I had taken the principle for a demonstration ride :Laugh he fitted me into a race testing day where they were set up properly!!
 
So Nitrons, yes, I am OK with that brand, I will give you a call and arrage a meet so we can discuss what is best for me, and the car.
 
Kind regards
 
Laurenzo

[MaLicE]

ah thanks, i think it was the terms that were confusing me, basicly you are looking to ensure that the spring stays under compression troughout the range of travel the damper is going to see? I will go away and try to translate some stuff I found into ideas I can understand. i am guessing that for 99% of people though the standard coiloever kits that lower using the spring perch will suffice?

aslong as when you come to MOT that when they jack the car up the spring doesnt come loose and move around... and some people will say if they do move that cable ties are ok to hold them in place this is rubbish its still a failure...

laurenzo - if you go nitrons and want fully height adjustable you need to specify that as normally they only allow for preload adjust and some places will adjust the height with the preload and tell you its fine, if you want the best compromise get the preload and height adjust ones.