jaholmes

I have a set of JIC already installed. I want to tone down the springs, they are way too heavy now - F-10k R-14k.

I would rather not take them completely off so i'm wanting to see if I can take the top nut off and give enough clearance to pull them out. The front's look like they may come out the top, the rears may be a different story.

Talking with JIC, they said the top nut is set by an impact gun at a certain setting, but I forget now. Maybe the impact gun keeps it from spinning.

Any help would be great.

Bill Verburg

I doubt that you will be able to change the springs inthe car. But it's not a big deal to pull them as long as you have a spring compressor and a good air gun.

I used an air gun to get the top nut off, but to change springs the camber plate and 2 lower bolts come off.

10/14 is certainly stiff for a streetable car., I used 7/10 at first but now have 8/12. It's too new to evaluate, but initial impression is favorable.

jaholmes

Bill, how did you swap out your springs. Did you take the entire coilover out. I am just trying to avoid the alignment cost. I know you can mark the rear eccentric bolt.

My plan was to move my 10k's to the rear and get a set of fronts.

BTW, what do you have the JIC set to as far as rebound. Maybe that's my issue.

Bill Verburg

You shouldn't need an alignment. The camber plates and bottom bracket bolts are fixed and not adjustable as part of an alignment.

Tom W

If you make a big change in spring rates, the ride height will change a bit due to how much compression the spring sees due to the weight of the car. This will have some impact on alignment settings as toe and camber change with suspension travel.

I'm not a mechanic and my JICs are modified a bit, but it took about 30 minutes for two mechanics to swap my rear springs between track sessions without any spring compressor needed. We moved the suspension height back to where it was by adjusting the perches a couple turns.

Bill Verburg

The car height and corner balance are independantly adjusted on the JICs.

The upper collers under the spriings adjust the corner balance, the ride height is adjusted by spinning the lower body, ~2mm/turn.

When you change springs the length of the installed spring is measured and kept contstant. The heavier spring will affect corner weights but as long as all the springs are changed proportionally corner balance should still be ok.

jaholmes

Thanks everyone. The ride height / corner balance points are very helpful.

So if I am just swapping springs I need to get the camber plate out and the top nut. Or just the top nut to get the shock body separated.

Will the shock just tip out enough to pull the spring. Or do you bring it straight out the top hole.

The front's are not a big deal because I don't think there is any alignment settings up there.

Bill Verburg

An older JIC disassembled, the gold colored bush is for a Mode monoball and needs to be machined a bit to seat on the shock rod




Here's the JIC mount, on the right is the red top spring perch again the gold colored bushes ctr right are Mode parts, the JIC are all clustered on top of the mounts, the nut is an odd size, 21mm as I recall.


here is the JIC spread out in assembly order, the topnu/bush goes through the monoball hole and the silver ring is the bottom seat, then the spring perch. You can also see the larger washers and bolts that I used to prevent loss of camber

Tom W

What I was trying to say said another way ... using simple numbers that are not "real life"

Assume you have a car with 500 lb springs in the rear and the corner weight for each is 1000 lbs. This means the springs will be compressed 2 inches when the car is just sitting. If you swap those springs for 1000 lb springs, the new spring will compress only 1 inch. This will raise the ride height 1 inch unless you compensate with the appropriate adjustment to the ride height collar (down 1 inch). (Or am I just nuts?)

Bill Verburg

Not so much on the JICs, the main springs don't change very much at rest, the tenderspring is what does the bulk of the at rest settling or rising.

Tom W

Ok, that's why mine is/was different. My JICs were modified to be able to accept other springs and no longer have a tender. It's all moot for me as after almost 5 years I'm switching from JIC to a KW 3-way adjustable suspension.

viperbob

Tom, get Motons... Don't do the KWs. Who sold you the JICs in the first place that have been working pretty well for you? How are things BTW??

You need to get the stack heights of the springs from JIC so that you have the correct bump and rebound available... They will normally give you the height of the compressed helper spring.

Tom W

Bob: You know full well what charlatan sold and installed the JICs I still have a few photo's of your feet sticking out from under the car when the suspension and brakes were installed (I think that was back in '03 or '04). They have served me well over the years but I'm looking for more than they appear to be able to provide. I have MoTeC with shock sensors to help get 'optimal' adjustments but the adjustment on the JICs is pretty limited.

I'm going with KW instead of Moton's on the advice of the shop and external pro racer advice. The shop has a good relationship with a couple pro race teams that use KW suspensions and can be used for additional advice if desired - so basically it's buying the suspension that I think will be best supported in my case.

My little turtle is a bit different than the car you and I started to modify (and that I swore I would never turn into a 'GT' class car). I've learned a bit as a driver over the years too and can now pedal the Turtle around Thunderhill in about 1:57 - a slight improvement from the original 2:14. You should come back for a visit some time.