Suspension Issues from Chile!!... Valving / Spring rate / Sway bar

[neneossa]

I was testing my buggy and I felt the suspension very smooth, especially during the braking (nose dive), acceleration and turning (body roll). I'm in Chile so I have to do the valving myself. ( I have shims and I know how to do it)
I have to improve the suspension so I was thinking in some options:
1.- Change my valving (more compression) becasue the bypases are totally closed and I feel smooth. Coilover are in 10 comp and 10 rebound.. Bypass are in 15 comp and 10 rebound
2.- Change the spring rate but I believe that is right because the car recover his position after braking or turning.
3.- install rear sway bar but I´d rather not do it for now. (maybe is the solution ahhaha) (I don't have any Sway bar)

I need some advice from you to improve the suspension :s

Thanks!!!!

I attached some pictures from today´s test

 

[neneossa]

Well, I think that I found put a lot of answer after my suspension test

1.- I checked the sprung rear weight
Main spring 250 lb/in
Tender spring 235 lb/in
Combinated Spring rate: 121 lb/in
I lifted my buggy then I released the nut spring up to have 0 preload. After that I measured the distance of the length shock. Then I put the car on the floor and I measured the shock length again. The difference between full drop to ride height without preload was 5.9”
Finally, my sprung weight was 715 lb per corner (rear), it math with the value that I had calculated before.
Neither the coilover nor bypass were depressurized so I think that these pressure increase the final spring rate that I measured.

Finally, I put 1.5” of preload that means 9” of free coilover travel equivalent to 60% ride height.

Whit this change, I’ve lowered the CG so I will get less body roll than before.
On the other hand, I’ve decided to install a rear sway bar to control the body roll

Respect to the nose dive, I don’t know how to solve it, may be I’ll put more firm valving in the front coilovers and bypass.
Lowering the rear CG I think will help in the weight transfer so I hope to get less nose dive

 

[partybarge_pilot]

Are you using the secondary stop nut's? In the cornering picture it looks like the rear shock has the top spring almost compressed and the bottom one is not. If you have these set too high you will get a lot of body roll/attitude change.

 

[neneossa]

Are you using the secondary stop nut's? In the cornering picture it looks like the rear shock has the top spring almost compressed and the bottom one is not. If you have these set too high you will get a lot of body roll/attitude change.

I watched the same about the top spring full compressed but I don’t know why. The top spring is 235 and main is 250 so isn’t a big difference between them for this to happen.
The secondary stop nut is installed (look the attached picture) Is is located in the top part of the coilover maybe 2” under the main spring nut.
Maybe I should installed in a lower position to avoid the tender spring bind and to allow that the main spring work with his complete spring rate.
How to know where the secondary nut should be located?

 

[neneossa]

after to see this, I understood that I must lower the secondary nut. I read that it should be located 2" to 3" above the slider. Today I will change this and I will test.
on the other hand, I have the idea that I should have a harder lower spring that I have now. What do you think? I dont have problem to get my ride height

 

[partybarge_pilot]

Move the nut down first, one change at a time.

 

[neneossa]

I moved down the front and rear secondary nuts. In the rear coilovers I left the secondary nuts 3” over the slider at ride height. In the front coilovers I left it at 2”. Also I lowered the front and rear ride height because it was over the designed ride height, that means that I moved down the CG so I will get less body roll than before.
I finished 1 hr ago so I didn’t time to test it.
Tomorrow after my work I’m going to test the suspension again.
Thanks for your advice, was very helpful!
And I agree, one change at a time

 

[partybarge_pilot]

You may have to go closer than that. 3" above the slider will probably = 6" of wheel travel.

 

[neneossa]

You may have to go closer than that. 3" above the slider will probably = 6" of wheel travel.

Perfect, in front is 2” so I think it is ok. I’ll check first tomorrow with 3” rear and then I’ll change to 2” to test Again.

Thanks again!

 

[neneossa]

You may have to go closer than that. 3" above the slider will probably = 6" of wheel travel.

Well, I moved down the crossover ring at 1.5" in the rear coilovers and the car improved a lot!!! less body roll, maybe 60% less than before. After that I moved down again up to the end of the thread and it felt better than before again!.
Also the nose dive improved a lot too but I think I need to work in the front end doing the same that the rear end. ( now the crossover ring is 2" above the slider in front). The handling and traction improved too so it was a incredible change.
My only concern now is my bypass set. Now they are at almost full compression and free rebound. I need to check more.
Anaway, Im going to install the rear swaybar to improve the bodyroll.
If I would like to change the lower spring from 250 to 350... is better try first with the swaybar and then decide or is something necessary?

 

[partybarge_pilot]

I would work on the BP valving before changing springs or adding a swaybar. Also testing in some rough terrain. Driving around a flat lot will not tell you much.

 

[cosmo]

What springs are those (manufacturer)? Looks like you are all most at coil bind in a couple of the pictures. On a flat surface?

 

[neneossa]

What springs are those (manufacturer)? Looks like you are all most at coil bind in a couple of the pictures. On a flat surface?

The springs manufacturer is “Viper”
Regarding with the coil bind, it happened because the crossover ring was in a wrong position. “Partybarge_pilot” told me that I should set properly the crossover ring and after moved it the car improved a lot. Also I don’t have sway bar so the body roll is absorbed by the springs.
I believe that I should change the rear springs but first I will test the car with tat configuration in a rough terrain.
I hope this weekend go to the dunes to test the suspension in the whoops.