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This is kind of my review on the GC stuff. I purchased the entire kit which included the following. Front weight jack with 900lb springs,rear weight jack with 200lb springs, Koni single adjustable rear shocks, Ground Control custom made strut housings with Koni single adjustable strut inserts valved specifically for the weight of springs I'm running (so I was told,no way to tell)
I couldn't be happier with this set up, it performed very well and the ride isn't much harsher than the eibachs that is was running. The bumps are a bit more sharp but to be expected. Install is very easy and quick, rear hight adjustment is super simple,front not bad if you can get a jack under it. If you are thinking about this kit do it! Money well spent in my book. Hung with some of the big dogs at the Optima search for the ultimate street car challenge in Colorado . Took 8th overall in the GT-vintage class.
Looks good. Never seen their struts before. How much did they cost you? and the whole kit?
EDIT: Forgot to ask what the heights of the springs are front and rear? I made my own weight jacks but Im running 850lb fronts and 175lb rears and i hope the ride is slightly softer than the cut moog 5664s I had. I run a 9.5" spring and I couldnt lower it more than 27.5" front... I guess a 8 or 8.5" spring would have been good. But I fixed the issue with 20s lol... mines not a strip car, shows and light fun.
Last edited by customblackbird; 08-25-2015 at 12:48 PM.
Looks good. Never seen their struts before. How much did they cost you? and the whole kit?
EDIT: Forgot to ask what the heights of the springs are front and rear? I made my own weight jacks but Im running 850lb fronts and 175lb rears and i hope the ride is slightly softer than the cut moog 5664s I had. I run a 9.5" spring and I couldnt lower it more than 27.5" front... I guess a 8 or 8.5" spring would have been good. But I fixed the issue with 20s lol... mines not a strip car, shows and light fun.
Not sure never did measure the spring hight, the fronts are very short though. From the ground to the fender is 25" front and 25 5/8" rear. The kit with the strut housings and all new Koni single adjustables was about $1700.
Not sure never did measure the spring hight, the fronts are very short though. From the ground to the fender is 25" front and 25 5/8" rear. The kit with the strut housings and all new Koni single adjustables was about $1700.
Prob 6.5 or 8" springs for the front. The rear is what I'm interested in.
I like the front struts... and at 650 that's not bad when off the shelf koni yellows are about the same. Maybe when I'm happy with my spring rate and I want to upgrade my kyb agx front struts I'll order up a set.
Way to go at the Ultimate Street Car Challenge! I enjoyed seeing the pictures of you and BADNBLK carving it up!
I have almost the same set up and I love it! I started with 850# fronts with koni yellows when I rebuilt my front end in 2013. This spring I upped them to 1000# springs and added Toyo R888's. Made a HUGE difference. The car is down now for LS1/T56 swap and I did put the 250# rear springs in but only with the stock shocks from my '01 SS donor car for budget reasons.
Glad you got the kit. I don't recall that being available when I bought mine. Looks like the way to go for anyone buying them now.
I love the stance of your car. I already have Koni's and was about to order the weight jacks from Ground Control. I think i'm going to use the 900/200 spring rates as my car rode quite stiff from the factory. Do you happen to know your wheel and tire sizes/offsets?
I love the stance of your car. I already have Koni's and was about to order the weight jacks from Ground Control. I think i'm going to use the 900/200 spring rates as my car rode quite stiff from the factory. Do you happen to know your wheel and tire sizes/offsets?
I'm currently running a 285/35zr18 tire,rear rims are 18x10 with a +10mm off set. Same as a E39 BMW.
You and I appear to be the only ones who have GC's new struts. It's good to hear they performed to the task. I Installed mine way back in the summer of 2015 when I did the rest of my suspension/steering overhaul, but I havent driven my car due to other car problems and no funds/little motivation to fix it.
I've found several threads here in TGO that specify Ground Control brand, but why? There are other brands of weight jacks, some of which are better-built and cheaper. Why pay for a name? Is it because they were the first ones tried in TGO?
I've found several threads here in TGO that specify Ground Control brand, but why? There are other brands of weight jacks, some of which are better-built and cheaper. Why pay for a name? Is it because they were the first ones tried in TGO?
They are the only company that makes a drop in kit for the 3rd gen. Our font and rear suspension are unique in a way that you can't just bolt in off the shelf parts... will always require fabrication.
I've made Speedway and Afco stuff fit but I wouldnt say it was better/cheaper than the GC stuff thats bolt in ready.
I've found several threads here in TGO that specify Ground Control brand, but why? There are other brands of weight jacks, some of which are better-built and cheaper. Why pay for a name? Is it because they were the first ones tried in TGO?
You always have a better way to do things but never share....
Show me another weight jack setup that's a direct fit for a 3rd gen that's so much cheaper
I've installed weight jackers and use off the shelf universal parts. Requires a bit of work, disassembly of the car (front) to do correctly and is time consuming. Sure its cheaper, but it takes a lot longer and a lot of people dont have access to the tools and equipment to do that kind of work.
First, I never posted anything about direct fit. Good job putting words in my mouth. Way to win enemies, too. Second, noone ever asks for any alternatives.
Third, if you can't be bothered to invest $300 in a Harbor Freight stick welder, rods, gloves, auto-darkening helmet, and angle grinder, that's on you. They will pay for themselves.
When it comes to my cars, I count my labor as free. The same labor I've never sold for less than $15/hr, and currently $22/hr.
So what if another brand requires an hour of fab work, if it's at least $25 less? Plus the result is an exact fit for your specific car.
Bolt-together kits? Anyone can do that. It doesn't qualify as "Built, not bought". Only a fabricator can honestly claim that. And it feels damn good.
So these have me interested as my recent S60 axle change screwed up the ride height of the rear of my car. I have been running Eibach pro kit springs but as you can see in the picture it now sits really high in the rear. Gap is ~1.5" more on the rear then the front. If I remember the pro kit is normally a 1" drop in the rear. The S60 rear perches are apparently much higher from axle center line so now lowering springs aren't actually that low. The GC website says up to 3" drop so if I used ~2.5" of that I would be about level (assuming that 3" value is from a stock height). Would the spring be so compressed at that adjustment that its basically worthless? I could start looking at coilovers for the rear, but just put the koni shocks and struts on it (well full suspension change really) and I don't really love the idea of supporting the cars weight on the rear shock mount area. The car was never really meant to support its weight there. Getting a better spring option for the rear to bring it down is my preference.
Another thing, you probably have variable rate springs and Ground Control sells constant rate springs. Downside is the ride will feel more sharp but the plus side is the suspension will be more consistent and predictable.
I know of no off the shelf lowering kits that use progressive springs or variable at that matter. I would classify both as a spring that effectively uses two or more rates during normal driving. A lot of people think vogtland are progressive but they aren't. Simply use tight coils to take up space during full droop so it stays put. Once compressed they are dead and the actually driving rate never changes. As far as I know no kit offers progressive or dual rate springs including the ebaich kits. I've personally owned sportlines, weight jack style and now vogtland. The rate of a progressive spring is using varying spring DIA or coil spacing. I don't believe the prokits are progressive even though they give you a range of spring rates. They compress to a point and then the spring rate stays consistent or linear.
The S60 I'm sure has massive axle tubes which increase the height of the spring perches immediately. That is probably where you see the ride height increase. Coil overs in the rear... don't even get me started. I got a good spohn kit with the plates and sold it once I mocked it up. Didn't like the angle of the shocks/springs at all. If it can't be modified in the stock locations then buy a different car lol. Weight jacks in the rear will provide a shorter than stock spring and will net you the drop you want. But shorter spring height can affect ride quality and depending how short can limit travel. I think your best bet is to remove the stock rear spring isolator and see what that gets you. Then Trim a 1/4 coil off the rear spring to get your desired ride height. If your not going to constantly adjust ride height then the weight jack is useless once you achieve desired ride height. If your a set it and forget it type of guy trim your eibach spring and enjoy. Another spring to try is the Vogtland... find them to be stiffer than the prokit in the rear and the dead could allow more to be cut for slight decreases in ride height.
No, that is entirely wrong. Rear springs are almost always progressive rate. I have three sets in my garage (Hypercoil, Hotchkis, Suspension Techniques)
The spring rate of a progressive coil changes with the compression height of the spring, and all coils are active at all times. For example, I think Hotchkis advertises a rate of 100 - 140 lb/in. What you get depends on how far the spring is compressed.
Actually the Ground Control kit isn't really for the purpose of setting ride height, it is for purpose of setting corner weights. That's why it is called a "weight jack". You can change the weight on each tire (and how the car handles) by changing the suspension preload on all 4 corners. People just happen to use it mostly for tweaking ride height because it is really convenient.
I can also with 100% certainty say that your "progressive springs" use tightly wound coils at the top that transition to a wider consistent coil. Their are many forms of progressive springs and the one I just described isn't truly a progressive spring. The weight on the rear cargo never actually changes... just momentum created by the weight of the car being pushed down or up. The top coils are dead during the compression of the vehicle weight which leaves the lower half as active coils. The bottom half is not progressive and it can be seen in the coil spacing and DIA. Companies throw the term progressive around even when they aren't.
My vogtlands look exactly like the eibach and the hotckins and they are not a progressive spring... they are a dual rate linear. True progressive used tapered wire DIA or tapering the spring itself like a beehive... not to be confused with out stock rear spring which is already in a tapered design.
What you have is called a dual rate linear spring, gives the same 140-250lb rate spread as my vogtlands and truly are not progressive the 140lb is the installed rate then u drop the vehicle weight which compresses the top coils thus decreasing the active coil
Spring height and increasing the rate to a stiffer 200or so lbs. . Slicktrackgod needs to drop some more in depth knowledge about the subject if need be.
I know what weight jacks are for, most as you stated don't use them for the intended purpose. Most of our cars don't need performance lowering springs that actually
Do more harm than good without complimenting suspension mods.
What are the spring rates for the GC springs? I assume they are much higher then that of the sportline eibachs since the springs have to be 3" shorter then factory to allow that much drop
*edit: should have re-read first post. It says 200lb, but they offer 3 rates on the website so what is range available?
You can choose springs in 25 lb/in increments. They stock a few choices but most likely you'll have to wait a few weeks for new springs. They will try to match the spring to the rest of your car so best to call them up and have a chat and order through their tech line rather than make your own choice.
Correct. Normally all coils are active and work together until the force on the springs is high enough to fully compress the more tightly wound coils and make it act like a solid piece. At that point only the wider spaced coils are active and the spring rate changes. That's a progressive rate spring like every set I have in my garage. I guess I would counter with this question.... why go through all the extra effort to wind a spring with two different pitch if it isn't intended to be a progressive spring?
I haven't opened a book about spring theory in 25 years so I will say I am pretty rusty on the topic. I did make a mistake earlier when I said all coils are active all the time and changes with compression height. You posted good info to help me better understand it is more of a step change, and I thank you for that!
So these have me interested as my recent S60 axle change screwed up the ride height of the rear of my car. I have been running Eibach pro kit springs but as you can see in the picture it now sits really high in the rear. Gap is ~1.5" more on the rear then the front. If I remember the pro kit is normally a 1" drop in the rear. The S60 rear perches are apparently much higher from axle center line so now lowering springs aren't actually that low. The GC website says up to 3" drop so if I used ~2.5" of that I would be about level (assuming that 3" value is from a stock height). Would the spring be so compressed at that adjustment that its basically worthless? I could start looking at coilovers for the rear, but just put the koni shocks and struts on it (well full suspension change really) and I don't really love the idea of supporting the cars weight on the rear shock mount area. The car was never really meant to support its weight there. Getting a better spring option for the rear to bring it down is my preference.
Another option is to skip the rear weight jack and just get a shorter spring. Suspension Spring Specialist makes a pigtail spring that works in our application. They have the option of 9, 10, 11, 12" free length in several spring rates. My factory springs measured around 15" to give you reference. The only thing is I'd start considering how much travel your shock has left. The koni yellow's might have plenty of travel though, I'm not sure.
08-25-2015, 12:41 AM
I guess I would counter with this question.... why go through all the extra effort to wind a spring with two different pitch if it isn't intended to be a progressive spring?
