Anybody can help me with coil spring size question ?

[Surya-P]

Hi,

I bought a new coilover set, but its front spring is smaller than the stock one. Diameter of the spring itself and mainly its coiling diameter ( I hope that is the correct term). The spring values is 5kg per mm or 317.5 lbs per inch.
Its a linear spring.

The Ford Racing one I see has progressive spring and only small coiling diameter at the bottom but grow bigger as it goes upward. I don't understand the science of spring to any better extend than a visual note :....." holy cow, how come its so much smaller than the original one"

Its from BC Racing, its Taiwanese.
It is a 100% the same as what is explained on this post :
Megan Racing Coilovers
........which is supposedly a Meegan , a prototype.

I can't get Bilstein built Ford Racing Part in my country, so this BC Racing one is the only one I can get my hands on and more expensive here at retail. No choice. I am usually a fan of Koni and Bilstein.

Attached a photo to compare between standard one and the BC one.
http://api.ning.com/files/vSn44x8JhP...andardvsBC.JPG

Sorry I can't make the photo pop out no matter how I try. Link is the best I can do.

Thanks in advance for those who can assist me.

SP

[Iceracer]

Coil overs usually are smaller in diameter.
One way to get less spring material in a given space, which produces a stiffer spring.
Springs with different coils are usually progressive.

[Surya-P]

Thank you Ice. I always wonder why it is called a coil-over
Coil-over-a-strut yah ?

In a real world work of the suspension, will coilover be more heavy duty than the standard Mcpherson it replaces , say given same engineering level ?

Thanks again.

[Iceracer]

In most cases, the coilover spring will be considerably stiffer than stock but in some cases a lower rate spring is available,
Basically, there two reasons to use coil overs, adjustable ride height and wheel loading.

[Surya-P]

I see Ice, many thanks.

I been reading on the coilover thingy between your reply and it seems best I must get a workshop who has weight scales to get the best result.

I never had adjustable height suspension before. Only adjustable rear damper hardness once in my 1st car.

I been playing with this new rear damper of mine ( since there is no coiling spring around it ). I think the so called adjustment is for how slow the strut recover back ( rebounce ?? ) to maximum long position. Use my body weight to push it down and I do not find any hardness difference between setting of zero (low ) to 30 ( hard ), except when both bottomed out, the setting 30 is like 1 second slower to get back to maximum long compared to the zero setting (low ). This wont define actual hardness wouldn't it ?

I recalled my 1st car 8 stage adjustable rear damper was different, I find it hard to push in the dampers when set at HARD....well that was a very long time ago and I may be sensing wrong when pushing these dampers with my own body weight yesterday.., but the rebounce I done 3 times and the hard setting is indeed slower to recover.

Many many thanks Ice.

Regards
Surya