Assist Springs

[AndreaCivic]

Hi Fellow Enthusiasts,

I ride on a Civic EK4 with skunk2 coilovers with 10kg front and 6kg rear spring rates.

I find it to be too stiff for daily duties. When i'm cruising around with the mrs and family it is always a talking point of how ridiculous the car rides.

This aside I have put up with the car being like this for almost a year now. It is clear that there is a performance gain and i appreciate that, so i guess i'd like to try and optimise it if i can. Maybe find a compromise.

I have a spare set of 8kg springs here as they were previously on the rear. So i wouldn't mind putting them on the front.

I also found these "Assist Springs" refer here (http://www.swiftsprings.com/products-assist_springs.html) and thought they could be just what i'm after.

I would put 5kg/mm assist springs in the front (coupled with 8kg/mm springs) and 4kg/mm assist springs in the rear (coupled with 6kg/mm springs).

I guess, i'd just like to gauge if this would be a suitable setup. Thoughts? Would this soften up my ride yet still be a competent solution for light track duties? My coilovers have preset damping which is very stiff/vicious i'm told. Is it possible I've got a set which cannot be optimised for street duties? Maybe i should look to something more high end?

Cheers for the help

[AndreaCivic]

I suppose I'm asking if softer spring rates will work with my dampers. Anybody can shed any light on what happens to dampers when softer springs than those designed for the coilovers are used??

[curtis265]

Have you tried softening the dampers first? How is the condition of the damper at the moment?

I think it might be OK given the spring rates aren't vastly different. Need a suspension guru here

[AndreaCivic]

Thanks for response.

Dampers can't be adjusted unfortunately. They aren't adjustable. I'm told they are preset to the hardest setting. There seems to be a bit of chatter, like the spring rates are underdamped. But I couldn't be positive as I'm not a suspension guru myself :/

I've written to skunk2 so hopefully they will advise if dampers will work with softer springs!

Cheers

[curtis265]

arrr that's useless isn't it!

hard shocks have no place on the streets, the last thing you want is ur tyre skipping over bumps resulting in unpredictable handling, as well as a generally uncomfortable ride..

If that's the case it might be worth selling off those coils and swapping for a softer, more streetable suspension. pm TbM

[DreadAngel]

As mentioned, even with softer spring rates you can't be sure if the valving of your dampers are correct for them. Being pre-set from factory eliminates pretty much the option to go softer without spending a lot of money dicking around in the hope it doesn't bounce/float...

Like Curtis said, best to sell up and buy something more appropriate ;)


If you want a supple but tight ride without the complaints from the family, best to match your suspension [softer] with good swaybars, bush kit and tires =)

Swaybars will tighten up your ride without forcefully eliminating body roll like what stiff coilovers will do ;)

[AndreaCivic]

It's really not all that bad and when I changed out the rears from 8kg to 6kg the suspension responded really well.

I really dont think the dampers are too bad. Reducing the fronts to 8kg and adding assist springs could be the sweet spot.

But you guys have mentioned I could be wasting my money which I have taken on board.

it's almost like if I do sell up and change then I've lost a huge opportunity to learn and gauge the concept of suspension setup and tuning.

Cheers guys :)

[Riced_Civic]

if u add an assist spring u are still adding extra spring rate overall.

better to swap out ir spring s for softer ones, u usually can swap spring +/- 4kg and your dampers will still be fine.

[AndreaCivic]

if u add an assist spring u are still adding extra spring rate overall.

better to swap out ir spring s for softer ones, u usually can swap spring +/- 4kg and your dampers will still be fine.

Don't you mean reducing spring rate overall?

Thanks for input re: dampers

[DreadAngel]

Not really mate =)

Mucking around with springs in the hope that the setup is what you want is an expensive exercise =P

You'll be learning a lot more about suspension, tuning and selection with you went as I previously mentioned ;)

[Riced_Civic]

A=main spring
B=assist spring

For example,
When Main springs (700 lbs) & assist springs (300 lbs) are combined,

AxB (700X300)
------ = Combined Spring Rate (210)
A+B (700+300)

You get 210 lbs of spring rate until assist spring completely binds.
After that, you get 700 lbs spring rate.

in the end ull still have ur original spring rate when the assist spring is fully compressed.

[AndreaCivic]

Not really mate =)

Mucking around with springs in the hope that the setup is what you want is an expensive exercise =P

You'll be learning a lot more about suspension, tuning and selection with you went as I previously mentioned ;)

Thanks heaps for your advice. Stiff RSB will be definitely on the cards in the future. I have replaced all bushings in my car with polyurethane ones. The car is very tight.



if u add an assist spring u are still adding extra spring rate overall.

better to swap out ir spring s for softer ones, u usually can swap spring +/- 4kg and your dampers will still be fine.

thanks for your input. i suppose the only thing i would say is that with the assist springs, when they are under heavy load then the stiffer spring rate will take over which will be ideal for track.

Almost like a progressive spring.

With your advice i'll probably now go with 6kg assist spring in front & 4kg assist in rear.

The 1.6 inches of travel in assist springs will probably iron out the nuances of street driving to a point where it is bearable.

I don't understand your formula either btw, why is the spring rates multiplied and then divided by their sum?

[curtis265]

thanks for your input. i suppose the only thing i would say is that with the assist springs, when they are under heavy load then the stiffer spring rate will take over which will be ideal for track.

Almost like a progressive spring.


not quite. You'll still have a soft spring rate, the harder spring will only take over once the softer spring is completely squashed.




With your advice i'll probably now go with 6kg assist spring in front & 4kg assist in rear.

The 1.6 inches of travel in assist springs will probably iron out the nuances of street driving to a point where it is bearable.

I don't understand your formula either btw, why is the spring rates multiplied and then divided by their sum?


it's a formula similar to electrical resistance

It's the equivalent of running resistance in parallel (if you put them in line)

If you want more info, http://en.wikipedia.org/wiki/Hooke's_law


if the springrates are k1 and k2, the spring rates (force/displacement, kg/mm etc), the effective combined springrate is

http://upload.wikimedia.org/math/4/a/2/4a26563cf1a57c5a56bf64b4532c80fb.png

that formula is a rearrangement of the one above.