Preload/Suspension/Ride Height Questions

[Shimadorisanni]

As of now I currently am riding on GP Sport Gmaster coils 10kg/8kg, and am currently maxed out on the rear using the bottom spinning mount. I need to know a way to lower the ride height a bit more while still maintaining similar preload rates. Would Swift Assist springs achieve this? Would it allow me to retain the preload? Or would they actually soften the spring? The other option is a helper spring, which I feel like accomplish the same thing. Also what helper/assist spring rate would be ideal? Any help would be appreciated.

Helper Spring
http://www.frsport.com/Swift-H65-060-030-Coilover-Helper-Spring-2-4--Length-65mm-ID-3-0-kgf-mm_p_62300.html

Assist Spring
http://www.frsport.com/Swift-A65-068-XXX-Metric-Coilover-Assist-Springs-65mm--2-56---ID-68mm-Length-Each_p_13984.html

[derass]

Depends on how much thread distance you have between the lower mount and the spring perch. Those helpers are going to add a few inches to the total spring length. If its too long, you would have to actually raise the car to install the helpers. That wont help you achieve what you're trying to do.

You didn't mention what chassis your car is, but I know S14 have very long rear shock bodies, so there may be enough room for your idea to work.

Either of your options will preload the new spring combination, the assist spring more-so than the helper. The assist spring has stiffer rates and is intended to offer a progressive rate when installed on a coilover with an existing linear rate spring. The helper spring has a very low spring rate and is intended only to prevent the spring combination from becoming loose at full droop, with the weight of the car on them, they will be fully compressed.

Installing helper springs would not affect the overall spring rate. Assist springs, in a sense would soften the spring. This is because the progressive rate ideology behind their use. However, once they are fully compressed (cornering, taking a bump etc.) the spring combination will take on the rate of the original linear spring.

With that being said, I personally would choose to get the assist springs. They would preload the entire spring combination while giving the coilovers progressive rates, making them ride much more smoothly. I would probably get the 5kg/mm rate as I have 6kg/mm currently and find them to be a bit stiff.

Another option would be drop knuckles in the rear.

[Shimadorisanni]

Depends on how much thread distance you have between the lower mount and the spring perch. Those helpers are going to add a few inches to the total spring length. If its too long, you would have to actually raise the car to install the helpers. That wont help you achieve what you're trying to do.

You didn't mention what chassis your car is, but I know S14 have very long rear shock bodies, so there may be enough room for your idea to work.

Either of your options will preload the new spring combination, the assist spring more-so than the helper. The assist spring has stiffer rates and is intended to offer a progressive rate when installed on a coilover with an existing linear rate spring. The helper spring has a very low spring rate and is intended only to prevent the spring combination from becoming loose at full droop, with the weight of the car on them, they will be fully compressed.

Installing helper springs would not affect the overall spring rate. Assist springs, in a sense would soften the spring. This is because the progressive rate ideology behind their use. However, once they are fully compressed (cornering, taking a bump etc.) the spring combination will take on the rate of the original linear spring.

With that being said, I personally would choose to get the assist springs. They would preload the entire spring combination while giving the coilovers progressive rates, making them ride much more smoothly. I would probably get the 5kg/mm rate as I have 6kg/mm currently and find them to be a bit stiff.

Another option would be drop knuckles in the rear.


Sorry, i will take some pictures today of the tread distance as well as the measurement from top of spring to perch. The chassis is an s13, and soon I will be adding subframe risers which i hope will give me a little more leeway. So for an 8kg/mm rear spring I would want a 5kg/mm assist spring setup?

[TheRealSy90]

Adding any sort of additional spring is going to raise your ride height with your current setup.

You could get shorter swift springs to replace your current springs, however, I also have GP Sports coilovers and with the rear mounts fully raised, lock collars removed, and the spring perch drooped all the way to the bottom mount, i'm tucking rim on 17's... So I don't see the need for shorter springs.

Remove your lock collars and droop the rear spring to the lower mount, or as far as you need to go lower.

I'm planning on not drooping the spring in the future, and instead raising the top mounting point higher up inside the car, thus lowering the car. Also, subframe risers will not affect your ride height.

[derass]

I think Sy has the better idea of what you could do. Shorter springs will lower the car further and allow you to retain preload. If you want to have a very low ride height with the frame an inch from the ground and the wheel/tire right against the fender, a softer rate that would result after installing assist springs probably isn't the best idea. Those assist springs will have at least an inch of travel before they fully compress and you would bottom out on the road or your fenders.

[Shimadorisanni]

Adding any sort of additional spring is going to raise your ride height with your current setup.

You could get shorter swift springs to replace your current springs, however, I also have GP Sports coilovers and with the rear mounts fully raised, lock collars removed, and the spring perch drooped all the way to the bottom mount, i'm tucking rim on 17's... So I don't see the need for shorter springs.

Remove your lock collars and droop the rear spring to the lower mount, or as far as you need to go lower.

I'm planning on not drooping the spring in the future, and instead raising the top mounting point higher up inside the car, thus lowering the car. Also, subframe risers will not affect your ride height.


I was going to do that but i was worried as to the effect that it would have after doing that, wouldn't the drooping spring cause some preload problems? I dont need to be frame rails on ground low, as I have BN, but would like to get more wheel under my fender if at all possible.

I thought subframe risers raise the subframe a few cm, allowing the bottom mounting point to be closer (in theory) to the top of the strut tower (coilover mounting point)?

Regardless, thanks for the advice. I will put this to good use. Definitely have thrown assist/helper springs out of the equation.

[Shimadorisanni]

I think Sy has the better idea of what you could do. Shorter springs will lower the car further and allow you to retain preload. If you want to have a very low ride height with the frame an inch from the ground and the wheel/tire right against the fender, a softer rate that would result after installing assist springs probably isn't the best idea. Those assist springs will have at least an inch of travel before they fully compress and you would bottom out on the road or your fenders.


I agree, i would rather retain the same spring rate, while just sacrificing a bit of preload, rather than having more rear travel due to lower rate. Thanks for the help. Ill see what removing the bottom lock collars feel like.

[TheRealSy90]

Drooping the spring essentially would be no pre load on the spring. Also, rising the subframe is only rising up the inside mount points of the suspension arms, it is not raising the knuckle up towards the car, thus not lowering ride height.

[!Zar!]

Drooping the spring and putting a shorter spring on the car is the same thing.

Whoever says otherwise is an idiot.

[Shimadorisanni]

How much revalving would be needed for a shorter spring?

[TheRealSy90]

Drooping the spring and putting a shorter spring on the car is the same thing.

Whoever says otherwise is an idiot.

You can retain preload with the shorter spring, but then again that wouldn't lower the car at all lol.