jeromio Posted May 3, 2000 Share Posted May 3, 2000 Anybody have any info or opinions to offer on coilover conversions? I am completely re-doing my suspension - tearing it all apart and replacing everything but the tubes, arms and spindles. I am interested in the ride height adjustability as well as the increased clearance for wider wheels. So far one person has suggested that given 2 Z cars at the same height, the one with coilovers will have less suspension travel. Is this true?Also, people seem to keep saying that coilovers are a race car only kind of deal, but they don't really explain why. The car is a daily driver, but I am a tinkerer and I want performance. Plus, I don't like having to do things twice - as in, some people are saying just go with sport replacement springs and then go to coilovers if those don't cut it. But I'd rather take everything apart once. One thing I have learned from past projects is to do it right the first time - it sucks tearing down something that you've already worked on (and spent money on) to upgrade to the parts that should have been used in the first place. Also, I have heard good things about Ground Control - but is the extra expense worth it? Other vendors (MikeG and Arizona Z) sell conversion kits for substantially fewer dollars (40-50%). Thanks. ------------------ http://240Z.jeromio.com Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 3, 2000 Share Posted May 3, 2000 OK, lets think about the advantage of coil overs.... They offer ride height adjustment per corner... that is the PRIMARY advantage... and they also allow for an easier swap of different springs, and to fit more tire under the car without fender flares. Are they a race only application? NO. Here is the big issue though...its in the spring. how you mount it has little relivance. Progressive rate springs I think are the way to go IF you can find them for coilover apps. Straight rate springs are more of a race only application that some people live with on the street. My 1st Z project had 600# springs front and rear, they were free and I figured "Why not".... I was 24 at the time and my back wasn't hammered to death from years of mountain bike racing, like it is now. I drove that car for two years set up like that, and it was increadible on the offramps and zipping thru traffic, but it would get old on a road trip. I swapped to a set of eibach springs (Progressive rate)and Boge struts and W-O-W!!!! I had suspension travel again, and all the squeeks and rattles went away. That was my 1st lesson in what works on the street. With a V8, I'd think a little stiffer spring rate all around would help, but in a progressive rate it would still make daily driving much better, just make sure you have a good transition ratio from one weight to the other... For those who don't know what I'm talking about.. Progressive rate springs have lighter weight (More comfortable) at the top end of the spring load (Less load on the spring and easier to compress thru the 1st 1/3 of the travel) for daily "regular" use. However, as you hammer it into an off ramp, the more the spring compresses, the stiffer the spring gets, which means you get more performance from the spring as load is applied to the springs (2nd 1/3rd is transitional from the lighter to the stiffer weight), which helps with individual tire performance as well. Progressive rate springs will have two weights associated with them vs. one on a straight weight spring. This is of particular help on the street where road surfaces are much more unpredictable, with manhole covers, potholes, and bridge seems. This allows for better suspension performance at each corner, allowing each tires to responde to the patch of asphault in its direct path. I have used progressive rate springs to autoX on and they work well. True, straight rate springs are nice for racing, but we aren't talking money here, and I think for day in, day out use.... Go with progressive rates... And with coil overs, swapping springs in doesn't take very long, so for my own application where I'll be trecking out to Timbuck 2 to do high speed runs, I can run a 300+# spring all around for the race, and then swap my daily driver springs back in for daily living. And with my back... THATS MUCHO BETTA! Later! Mike Kelly ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 3, 2000 Share Posted May 3, 2000 Mike, great post! jeromio wrote: quoteSo far one person has suggested that given 2 Z cars at the same height, the one with coilovers will have less suspension travel. I hope my recent post on how I fit the larges possible wheels on the rear of the z and it needing stiff springs was what lead you to that conclusion. I did that to get that last bit of clearance for the wheel. If you don't run up against the edge of wheel fitment and go with a 17x8.5 or less, the spring perch of the coilover should not lessen the travel. The thing that lessens travel is to addition of "lowering" springs without taking some section length of tube out of the strut and use shorter cartridges. This does take away from the available bump travel. The same would be true if you used coilovers with the collars adjusted to lower the car by 1.5 inches or more, or lowering springs that lowered it very much over stock. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@tidalwave.net">pparaska@tidalwave.net - Quote Link to comment Share on other sites More sharing options...
Guest mattrp Posted May 4, 2000 Share Posted May 4, 2000 Well, I just installed coilovers this weekend. My friends and I took the car apart, ground off the old perches (good excuse for a new grinder), taught ousrselves to weld, and installed the coilovers. I used the ground control setup. I got 175# in the front, 200# eibach in the back, and kyb gas charged struts all around. I can now set the car on the exhaust, or way above stock ride height in ten minutes. It's a long conversion, and the ride is very rough with my springs (like go to the bathroom before getting in), but the results are amazing. I also custom made a rear sway bar so that is part of it, but the handling is excellent. Before, inner wheel spin and lean were annoying, now the tire spins a little, but the suspension snaps back down and off I go. I have it with about 2 1/2" clearance on the oil pan, and still have 2" of adjustment on the coilovers. The exhaust unfortunately is lower, so I cant go any farther. There is absolutely no body roll, and the car is amazing. You just push harder and harder, no roll, no turning transition, and istead of a jerky slide, it just slides sideways when you push too hard. GO FOR IT!!! Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 4, 2000 Author Share Posted May 4, 2000 No, I haven't seen any of your info on coil overs. This bump travel warning was from EricZ in reply to a post I put up at zcar.com. It didn't really make sense to me, but, I have no experience with coilovers and he did, so.... Anyway, I think you guys have sufficiently re-assured me on this point that I'm going to proceed. I'm not planning on being too radical - most likely just 16" rims and only 1 inch lower than where the car sits now. It has a pretty mild L28/SU engine in it right now - my long term goal is to upgrade to L28 turbo. But that's so long term that it could definately change. I pretty much want to do the suspension once and be ready for whatever else I may decide to do with the driveline later. So now I just have to choose a vendor for the kit & springs. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted May 4, 2000 Share Posted May 4, 2000 Matt, you used #175 springs for the front? I just ordered coil overs from Ground Control and they suggested #200 for the front with a V8. Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted May 4, 2000 Share Posted May 4, 2000 mattrp, Quick question on your coil-overs. Did you also install GC's camber plates with your new coil-overs? When I called GC, the person I talked to (can't remember his name) recommended against using them because of the noise they transmit into the car. Thanks Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted May 4, 2000 Share Posted May 4, 2000 If you are going with coil overs, it means you want to lower the car as much as possible (more than a stock set up can handle)right? In this case you will have to adjust camber/caster angles to compansate for lowering, or you will wear your tires. So I would think that coil overs and caster/camber plates should go together. Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 4, 2000 Author Share Posted May 4, 2000 Certainly in my case I don't want to lower the car as much as possible. I merely want the flexibility to set the car up exactly how I want it ride-height and spring rate wise. I don't plan on using camber plates due to both the cost and the lack of rubber. Quote Link to comment Share on other sites More sharing options...
Guest mattrp Posted May 5, 2000 Share Posted May 5, 2000 Nope, no camber plates. I taught myself to weld and was going to make the slotted adjustments on the strut towers. I was then going to add reinforcement plates. Im cheap. I did make custom sway bar mounts from sheet steel remember. Yeah, I thought 175# was too low, but believe me, it is more than enough for a street driven car, with lots of autocrossing in store. Take a dump before you get in. HEHEHE. Matt 72 500Z Quote Link to comment Share on other sites More sharing options...
Mikelly Posted May 5, 2000 Share Posted May 5, 2000 Caster camber plates are absolutely N-O-T needed. However, I would recommend an adjustable lower control arm. You will definately need to compensate for the change in the geometry of the front suspension after lowering the car. Even 1 inch of lowering will require an alignement. Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
jeromio Posted May 5, 2000 Author Share Posted May 5, 2000 By lower control arm adjustment, are you referring to the relocation of the mounting hole in the crossmember? I have read about moving this up 0.75-1 inch to reduce bump steer. Quote Link to comment Share on other sites More sharing options...
pparaska Posted May 5, 2000 Share Posted May 5, 2000 When you relocate that hole up, you can relocate it out also, to add negative camber. I made the position of the pivot holes adjustable. Separate adjustment up/down and in/out. I have no idea whether the adjustment will hold as it gets loaded going down the road. If I find it moves, I'll weld the mechanism in place! Quote Link to comment Share on other sites More sharing options...
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