difficulty installing Koni race shocks with ground control

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N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

difficulty installing Koni race shocks with ground control

Post by N1gzd »

Hi,
I am having some difficulty figuring out how to install. This is what I bought for my 1995 Miata for track/autocross.
Koni race shocks
ground control kit with 700/350 springs (one was 650 - but I contacted Ground control and they FedEx me the correct one at no cost)
FCM 36/36 shock mount kit w 2.5 Isolator.

My first question is do I need to move the spring perch snap ring on the shocks. The instructions that came with the shocks and the ground control kit seem to conflict with each other and now I don't know what to do?

The second problem that I have is understanding the how to install the Koni shocks using the FCM kit. It took me a a while to start understanding where the parts go (mostly because no instructions came with it). I found some instructions at the FCM web site. The biggest problem that have is reconciling the fact that the special nut that goes on the top of the shocks does not seem to have the same threads as the Koni race shock. I think that it is for some other brand shock. I can't screw it on because it does not fit (do they make more than one size)? It also appears that it is too long because if you hold it up to the shaft that it should screw on to see how far to the top it would come you can see that if it was screwed on all of the way, the part of the shock that the shock adjustment know plugs on to would not be sticking out (so you would not be able to attach the knob).

Another question I have is about how to tell the difference between the upper and lower NA bushings. I am installing with the 99-05 spring sheet/mount (because I am lowering the car).

Also another question, in the instructions that I found it said that it is necessary to enlarge the hole in the red aluminum washer. However, without enlarging it I can already slide it over the threaded part of the shock shaft (such that it sits on the shoulder just below the threads). Do I still need to enlarge the hole as it says in the FCM instructions?

Please help, particularly about the FCM shoulder nut not fitting. I am running out of time and need to get this sorted out or I will miss the first race of the season.

thanks,
Rebecca
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

I now understand that I need to modify the plastic shock adjustment knob using the supplied plastic part.
However, I am still having trouble with the other issues:
1) apparent wrong size for custom bolt that goes at the end of the shock to tighten everything down (wrong threads).
2) to what position do I move the shock spring perch spring clip?
3) I want to be absolutely sure that I will not bottom out, damage the shocks or have clearance problem. This was sold to me for my application: gc 700/350 with fsm 36/36 and car lowered as much as tolerable on street (car is for track).

Is 350 spring rate in rear too low for these shocks? I was told that it will be fine but I want to be sure that I am not going to have traction problems on the track or autocross.

Thanks,
Rebecca
Brian
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Re: difficulty installing Koni race shocks with ground contr

Post by Brian »

Hi Rebecca,

I have an email into FCM about rushing you a set of those shoulder bolts in correct thread. For those shorter race shocks you can leave the clips where they are, and still have plenty of lowering ability. That rear spring rate is not too low, lots of really fast drivers in STS and STR class using similar in the back and finding it fast.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

Brian,
Thanks for the quick response. I hope they can them to me by next friday so will get it installed by my first race.

Rebecca
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

I have another question:
How do I adjust the CG spring perch when the spring is loaded (such as if the car is on it or if it is tightened up against the spring on the bench. I was not able to crank it up more than 9 turns in the rear (too low still). I set it at 16 turns in the front (so far).

Do I need to use a spring compressor while I am turning it (otherwise the threaded tube spins).

Here is a picture of my right rear:
http://www.pangalacticconsortium.com/te ... 18-177.JPG

I have not succeeded in installing the left front yet because the original lower shock bolt is stuck to the metal shock bushing. I managed to get the nut off but I cannot tap out the bolt because the sleve is stuck to it (and rubber is not helping me get enough shock to tap it). I tried heating it but it did not help. Perahps I need to heat it some more and completely burn all of the rubber out so that it won't cushion the blow. Does any one have a a better solution? Do I need to get out the whiz wheel?

thanks,
Rebecca
Brian
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Re: difficulty installing Koni race shocks with ground contr

Post by Brian »

Hi Rebecca,

You don't adjust the GC collar with the car on the ground. Need to jack it up and pull a wheel to make height adjustments with the suspension fully unloaded (having load and trying to adjust against it can damage the GC aluminum threads and perch). When we have the car on the scale we also have the sways disconnected. What height are you at in the rear? You can add FCM's riser in the rear (link HERE).

On that stuck right front bolt, I asked Rocky here, and his response: They corrode in there and get stuck, I usually spray penetrating oil and let it set for a little while. But since they heated it up that makes it worse so they may have to cut it off and get a new shock bolt.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

Brian,
I understand that I need to adjust the spring height with it unloaded. I was not able to screw the threads in more than 9 turns on the bench without butting up against the spring. It is too tight to screw it in any more than that. I was able to screw the front ones in a lot more before hitting the spring.

I did try lots of penetrant soaking followed by trying to shock it free before deciding that I am going to have to cut it.

Rebecca
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

more details:
I originally set the shocks to this height on the bench:
http://www.pangalacticconsortium.com/te ... 18-173.JPG

Then after I tried lowering it after installing the right front (it is the left front that has the stuck original shock) I discovered that it was too low and had to remove it and reset it on the bench. I changed the right front shock to this height on the bench:
http://www.pangalacticconsortium.com/te ... 18-184.JPG

(by the way, why does the new shock have that threaded extension welded to the shaft? The original one did not have it).

I then installed this right front and found that I was able to lower the car without it being too low (just in the ball park, do real adjustment later). After that I tried setting the two rear springs to this height. I was assuming that to make the car the same height all around that the spring perch should be about the same on all corners to start. However, the rear spring is longer (because it has a softer spring rate) so there was not enough adjustment range. In stead of 16 turns I was only able to turn it 9 turns (and I had to try pretty hard to crank it that far).

Am I correct about these two things:
1) you should never try and screw it beyond the point that it buts up against the spring (in other words, you can only screw it into the available extra space between the spring perch and the spring up to the point at which the spring fits exactly in the available space? I tried cranking it beyond that point (which means I should loosen it a little). This did not happen in the front because the spring is shorter.
2) Since the rear spring is a lot softer than the front spring, it will not be necessary to screw it the same number of spring perch threads to get it to the same height. If the spring rate is half as much, I might only need to screw it half as many threads because the car will sink further down as the softer springs compress under the weight of the car. This means that if the front is screwed in 16 threads that I might only need 8 threads in the rear to get it to the same height. I think that I tried to make them the same which does not make sense unless the spring rate was the same. Is this correct?

You can see from this picture of the right rear shock drooping, that at 9 threads there is no extra room (I have already torqued it tight against the threads - probably need to loosen it a little so that i don't damage the aluminum):
http://www.pangalacticconsortium.com/te ... 18-177.JPG

this is not a good picture but you can see what the height looks like in the rear:
http://www.pangalacticconsortium.com/te ... 18-181.JPG

This might not be a useful picture because the left front still has stock springs which will make the right side a little low.

Rebecca
N1gzd
Posts: 10
Joined: Sat Mar 10, 2012 5:31 am

Re: difficulty installing Koni race shocks with ground contr

Post by N1gzd »

If I use an FCM riser in the rear do I sacrifice shock range (will bottom out sooner?).

I am hoping that my theory is correct (as described in my previous post) and that I can find that I can do the following:
back off one thread in the rear so that it is 8 threads instead of 9 (so that it is not too tight when there is no load). Then this will be the lowest that the rear can be.
Then lower the front a tiny bit more (so that it is very slightly lower than the rear).

After I finally replace the left front so that it sits down at the correct height, the right side (especially right rear) will come up a tiny amount.
I have looked at pictures of other cars to see their height (but some of these might have had stiffer springs) and they don't look lower than mine.

I know that I can't do this by sight but I wanted to just eyeball it to see if I am in the ball park.

Rebecca
Brian
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Re: difficulty installing Koni race shocks with ground contr

Post by Brian »

When you say car is too low, how low is it as measured from center of wheel straight up to fender lip?
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
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