CableSrv Posted May 16, 2005 Share Posted May 16, 2005 I'm posting here cause i'm having the same issue but never heard of this before... this is my first z and I redid my suspension with tokico hp shocks and 225lbs 8in springs all around. but now my back end floats going over bumps kinda like an old buick the other thing that got me is these 225lbs don't feel like 225lbs... I had 180lbs on my 2000 focus and those were stiff compared to the 225's on my z! the last thing that concerned me was when the car is lifted off it's wheels the shock extends so far that the springs are no longer tight and fall down unsprung!! is this natural with 8in springs ? should i worry that at full extend my springs aren't even holding any pressure? this is with it lowered 2in from tire to fender. Quote Link to comment Share on other sites More sharing options...
Here comes trouble Posted May 17, 2005 Share Posted May 17, 2005 John.... here is something out of the 1978 Z shop manual which appears the rear spring constant is 127.7 pounds to the inch at a free length of 15.43 " and the front is 115.4 pounds to the inch at a free length of 15.71" and the damping force is the same for all corners at piston speed 0.3 m (1.0 ft)/sec...... Expansion/Compression : 121 lb/66 lb.....Why the difference in the expansion and compression ?? for oscillation effect Attn: ANON..... I happen to have 4 chrome 12 inch 180 pound Carreras from e Bay that were delivered to the door for less tha $50.00 three years ago (for my 250 GTO project). but would it really matter if we exchanged a pair of them between ourselves to have a 5 pound difference???? I plan to mount them all and hope my fat rump in the weight distribution gives a satifactory oscillation from front to back. Oh that tickles..cheap thrills Quote Link to comment Share on other sites More sharing options...
johnc Posted May 17, 2005 Author Share Posted May 17, 2005 the damping force is the same for all corners at piston speed 0.3 m (1.0 ft)/sec...... Expansion/Compression : 121 lb/66 lb.....Why the difference in the expansion and compression ?? The forces involved and the ride quality designed into the car. Expansion (rebound) is controlling the force of the compressed spring as it is expanding after being compressed by a bump or from body roll. Compression (bump) is controlling the rate of spring compression as a result of hitting a bump or from body roll. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted May 17, 2005 Share Posted May 17, 2005 wow that sucked... I revived the thread only to get my question ignored Quote Link to comment Share on other sites More sharing options...
johnc Posted May 17, 2005 Author Share Posted May 17, 2005 Actually, I did reply but its not here. I guess I forgot to hit a button. Anyway, don't compare spring rates or "feel" from one model car to another. Its irrelevant. Regarding the springs hanging loose, its normal for a coil over setup and is not a problem unless you get the car airborn. Make sure after jacking or putting the car on a lift, that you pause and amke sure the springs are seated int he upper spring perches. You can also buy helper springs that will keep the spring located properly. Quote Link to comment Share on other sites More sharing options...
CableSrv Posted May 17, 2005 Share Posted May 17, 2005 Thanks johnc I appreciate the info and it has allowed me to relax I'm talking with Ross from MM to see if I can get higher springs for the back Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 17, 2005 Share Posted May 17, 2005 Usually the upper perch has holes in it. Just run a couple zip ties around the top coil and through the perch. The bottom will always seat itself. Quote Link to comment Share on other sites More sharing options...
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