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Discussion Starter #1
So, I have installed MM COP-5 coilover kit with 250 lb springs on my 2003 GT. I have set the ride height back to where it was with the old Eibach sportline springs, 26 9/16" (measured from ground to center of arch sitting on 255/40-17). Now, my Koni SA shocks are compressed to the bump stops (see picture). To get this ride height I had to drop the perch almost to the bottom of its travel (see picture).

Is anyone else running this kit that can tell me what your shock compression and coil over compression look like?

Obviously, something is not right...
 

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The bumpstop probably has not been pushed up into the upper spring perch yet. Drive the car over a large bump quickly. This will compress the shock, pushing the bumpstop all of the way up. After that, there will be more gap between the top of the shock housing and the bottom of the bumpstop.
 

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Discussion Starter #3
Thanks for the reply. I am pretty confident that the bump stops were up as far as possible. I had noticed that they did not sit all the way in cups when I assembled so I trimmed around the top so that the bump stop would sit flush to the bottom of the cup. Then, I took care to ensure that the cup sat properly to the welded stop on the shock piston then ensuring that the bump stop was fully seated.

I don't know if you have ever seen this before but I think that the Hypercoil springs have to settle over time (or I have some binding in my system that I wasn't aware of..).

So the car had been parked since last Wednesday. I hadn't had a chance to get back to it again until this last Sunday (yesterday). Took my measurements again and noted that it had dropped about another 1/4 inch. Raised the perches again until I got back my original ride height. Took it out, did some figure 8's, bumpy road, etc. came back and measured. One side now higher then when started and one lower. Let car sit for an hour or so to get lunch. Measure again. The side that measured high went back to where originally started and one side still low. Re-adjust and repeat drive. Now both sides are within 1/16 of each other (PS: 26 9/16 DS: 26 1/2). Let car sit overnight and just went and re-measured now. Now, passenger side remained the same but drivers side has dropped another 3/16. You will see from the pictures I have attached that I have at least some shock travel now and you will also see how far up the perch has been adjusted. I don't know how much travel there should be between the bump stop and the top of the sleeve as the original configuration of the Koni had the protective dust cover that obscures the bump stop and the shock piston.
 

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I have the exact same setup on my 03 Mach1 and had similar concerns (similar ride height as well). Like Dr Hidley mentioned, the bump stops end up pushed up after a few drives

I would double check the upper spring perch is sitting flush with the under side of the rear shock mount (the delrin bushing). I double checked mine by ensuring both sides had the same amount of thread sticking up past the nut that secures the shock to the shock mount (in the trunk)

Hope this helps,
 

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Discussion Starter #5
g0max, with your suspension all settled, how much clearance do you see between the bottom of the bump stop and the top of the coil over sleeve? Is it approximately what I am showing in my last pictures?

Out of curiosity, when you reassembled your coilovers, did you trim the top of the bump stop to fit the upper cup like I did (trimmed at approx 45* just around the very top)? If I hadn’t done this, the bump stop would not seat all the way to the top.

Hopefully, I’ll have time to play with this some more this weekend.

Now, I have my front LCA’s and coil over kit to install.
 

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SilverGT1, the clearance I have is less. The lower spring perch is about 1" lower and I didnt trim the bump stops

That being said, the bump travel of the koni shocks hasn't caused any issues with ride quality (and I have hit some good bumps). Just had the car on a drag strip and road course last night, works very well

Did you just put a PHB in as well ? I just did the same and it made a HUGE difference in the way the car handles and launches

Be cautious with the front coil over kit, check the clearance between the upper spring mount and the bolts on the caster camber plates (I hope your using MM CC plates).
 

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Whatever you do, don't trim any material off of the tapered end of the bumpstop. After driving the car at the ride height that you want it at, if you are absolutely sure that it is too stiff from bumpstop contact, trim material off of the square end of the bumpstop. Start by trimming only 0.25" at a time. If you have installed a coilover kit in the rear of the car, the wheel rate is quite a bit higher than it was with the springs located on the RLCAs and therefore the vertical suspension motions will be smaller.
 

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Discussion Starter #8
g0max, Yes, I installed the PHB at the same time. I was just getting the suspension set so that I could install the actual panhard bar. I also have a torque arm in the box that will get installed next. I also have the front LCA's and coil over kit ready to go. In addition, I still have my strut tower brace and lower chassis brace to install. More parts then time right now....

Jack Hidley, I understand your point. I haven't trimmed any length of the bump stop. Only have trimmed the top diameter so that it fit the cup properly.
 
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