Ground Control weight jacks
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jul 2006
Posts: 1,132
Likes: 12
From: Aloha, Oregon
Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Ground Control weight jacks
So, I guess it's safe to say "I'm low."
I just got finished with the installation of my Ground Control weight jack kit on my car a few minutes ago. I ordered 800lb up front and 200lb springs out back. I have KYB select-a-ride shocks my my car right now. The installation of everything went pretty smoothly, taking out the old springs was the difficult part. It took me nearly an hour and a half just to bang the ball joint out of the spindle. After that I actually ended up never using the spring compressors. I just wrapped a heavy duty chain around the spring and yanked them out. They weren't loaded enough to make them shoot out anywhere. putting the new spring in the front was a breeze.
The rear went fairly quick, probably only took me 20 minutes. I did notice however that on my car you cannot just hang to rear unloaded and pull the springs out. They were still seated. They were very easy to take out though. I do have one concern though. the rear weight jacks are apparently designed to sit inside the spring perch, however on the drivers rear spring perch, the weight jack cannot seat all the way down because there is a brace directly underneath it, bracing the panhard bar mount. I ended up having to compensate this by adjusting the drivers to sit lower to make up for it. has anyone else experienced this problem?
I was able to take my car for a very brief test ride, I can actually make it out of my driveway without any angle at all, I doubt if I can fit a piece of paper under the front lip while doing it though, it is very close to scraping. I didn't have as much luck with the speed bumps though, I have to take them at an extreme angle to prevent any scraping on the Y-pipe. I also noticed that my shocks are adjustable. Apparently they've always been at their softest setting so I adjusted them to the "3" position in the fronts. I have no clue how one is supposed to adjust the rears though. I rode down the bumpiest road in my area that is filled with pot holes and was extremely impressed. I secretly thought that the spring rates I chose would be almost too stiff to drive comfortably on the street. I was wrong. They are not "bone jarring" to any extent, it's actually very nice, I was quite surprised. I'll find out how my car handles tomorrow when I take Germantown road to work
.
As my car sits here's the measurements that I've taken so far.
24.75" from the ground to the front fender lip.
27" from the ground to the rear fender lip.
4 7/8" of ground clearance to my front GFX lip.
My Y-pipe sits at 3.5" off the ground and there's a measly 3" of breathing room for the cat.
I forgot to trim my bump stops but I never noticed any bottoming out yet. Ironically I have no rubbing when turning lock to lock now. I never noticed any rubbing with my fender liners either, I'm going to roll the fenders just to give myself some assurance though. Overall I am extremely pleased with my Ground Control weight jack kit. two big thumbs up and one never ending grin on my face.
The rear went fairly quick, probably only took me 20 minutes. I did notice however that on my car you cannot just hang to rear unloaded and pull the springs out. They were still seated. They were very easy to take out though. I do have one concern though. the rear weight jacks are apparently designed to sit inside the spring perch, however on the drivers rear spring perch, the weight jack cannot seat all the way down because there is a brace directly underneath it, bracing the panhard bar mount. I ended up having to compensate this by adjusting the drivers to sit lower to make up for it. has anyone else experienced this problem?
I was able to take my car for a very brief test ride, I can actually make it out of my driveway without any angle at all, I doubt if I can fit a piece of paper under the front lip while doing it though, it is very close to scraping. I didn't have as much luck with the speed bumps though, I have to take them at an extreme angle to prevent any scraping on the Y-pipe. I also noticed that my shocks are adjustable. Apparently they've always been at their softest setting so I adjusted them to the "3" position in the fronts. I have no clue how one is supposed to adjust the rears though. I rode down the bumpiest road in my area that is filled with pot holes and was extremely impressed. I secretly thought that the spring rates I chose would be almost too stiff to drive comfortably on the street. I was wrong. They are not "bone jarring" to any extent, it's actually very nice, I was quite surprised. I'll find out how my car handles tomorrow when I take Germantown road to work
As my car sits here's the measurements that I've taken so far.
24.75" from the ground to the front fender lip.
27" from the ground to the rear fender lip.
4 7/8" of ground clearance to my front GFX lip.
My Y-pipe sits at 3.5" off the ground and there's a measly 3" of breathing room for the cat.
I forgot to trim my bump stops but I never noticed any bottoming out yet. Ironically I have no rubbing when turning lock to lock now. I never noticed any rubbing with my fender liners either, I'm going to roll the fenders just to give myself some assurance though. Overall I am extremely pleased with my Ground Control weight jack kit. two big thumbs up and one never ending grin on my face.
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
Don't forget to get a front end alignment, once you settle on where you want the jacks set at.
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jul 2006
Posts: 1,132
Likes: 12
From: Aloha, Oregon
Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Ground Control weight jacks
My measurements for my springs are:
F:9 1/2" 800lb
R:10" 200lb
Honestly I wish I would have specified that I was lowering my car that way they would have sent me slightly shorter springs because I had to adjust the weight jacks to their lowest setting in order to get my desired ride height. However I can't imagine how anyone could go much lower. I am almost sitting on the fender liners. The only reason why it's drivable is because my wheels are tucked enough. For reference my car is sitting as low as crazyhawaiian's '91 Z28 was.
Front end alignment is coming in a couple weeks. My front tires are already F'd from autocross and such. I'm just waiting for my new tires to arrive then I'll put on my new wheels. I also need to either rebuild or get a new steering box, mine has a substantial leak.
I really need some help ASAP with my driver rear spring perch problem. I don't know if I should just clearance that brace with a grinder or what.
F:9 1/2" 800lb
R:10" 200lb
Honestly I wish I would have specified that I was lowering my car that way they would have sent me slightly shorter springs because I had to adjust the weight jacks to their lowest setting in order to get my desired ride height. However I can't imagine how anyone could go much lower. I am almost sitting on the fender liners. The only reason why it's drivable is because my wheels are tucked enough. For reference my car is sitting as low as crazyhawaiian's '91 Z28 was.
Front end alignment is coming in a couple weeks. My front tires are already F'd from autocross and such. I'm just waiting for my new tires to arrive then I'll put on my new wheels. I also need to either rebuild or get a new steering box, mine has a substantial leak.
I really need some help ASAP with my driver rear spring perch problem. I don't know if I should just clearance that brace with a grinder or what.
Joined: Aug 2006
Posts: 12,812
Likes: 110
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: Ground Control weight jacks
cant you just grind down the parts of the rear adjuster thats hitting the brace?
I have the GC jacks as well and love them, ended up with 1050lb fronts and 250lb rears, though i couldnt use GC's rear parts because im using rear coilovers and conventional springs wont clear my wheels. Even these rates are quite reasonable as far as ride quality.
Im quite happy with them as well, i have my car sitting pretty low, not as low as you, but i cant go much lower before i start scraping my bellhousing. The fronts can be adjusted a little over an inch more down, which would sit my front tires on the fender lip
I have the GC jacks as well and love them, ended up with 1050lb fronts and 250lb rears, though i couldnt use GC's rear parts because im using rear coilovers and conventional springs wont clear my wheels. Even these rates are quite reasonable as far as ride quality.
Im quite happy with them as well, i have my car sitting pretty low, not as low as you, but i cant go much lower before i start scraping my bellhousing. The fronts can be adjusted a little over an inch more down, which would sit my front tires on the fender lip
Re: Ground Control weight jacks
to have the front that low, did you remove the bump stops, if not, your riding on them. with my front at 26" they were already touching the chasis, i can't even imagine how you got that low
86TA what rear sway bar are you using?
i have run 1,000 fronts and 1,100 fronts the 1000 is too soft and the 1100 to stiff, so i plan running 1050 as well, i have my ride height at 25 3/4", and probably swap the #200 rears for #250,
86TA what rear sway bar are you using?
i have run 1,000 fronts and 1,100 fronts the 1000 is too soft and the 1100 to stiff, so i plan running 1050 as well, i have my ride height at 25 3/4", and probably swap the #200 rears for #250,
Joined: Aug 2006
Posts: 12,812
Likes: 110
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Trending Topics
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
What are good free heights, to go with, to achieve "low-ness" on 17s? Like......
Re: Ground Control weight jacks
what spring rates are you talking about, with the 1000/200 for the front 8" to 9" and the rear 8 1/2" to 9" you will be able to still drop front about an inch an raise it 3" for the rear 8 1/2" should put you maybe 1/4- 1/2" above fully lowered, with about 2" to raise, with around 25" front ride height and a 25 1/2" rear
the rears are the important ones my 9" springs have me 1/4" above fully lowered my car sits 25 3/4" with 275/40 18 tires
the rears are the important ones my 9" springs have me 1/4" above fully lowered my car sits 25 3/4" with 275/40 18 tires
Last edited by 1988-305-tbi; Sep 12, 2009 at 06:13 AM.
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
what spring rates are you talking about, with the 1000/200 for the front 8" to 9" and the rear 8 1/2" to 9" you will be able to still drop front about an inch an raise it 3" for the rear 8 1/2" should put you maybe 1/4- 1/2" above fully lowered, with about 2" to raise, with around 25" front ride height and a 25 1/2" rear
the rears are the important ones my 9" springs have me 1/4" above fully lowered my car sits 25 3/4" with 275/40 18 tires
the rears are the important ones my 9" springs have me 1/4" above fully lowered my car sits 25 3/4" with 275/40 18 tires
I have 1 front set & 3 rear sets to choose from. I think my fronts are 9" & the rears vary from 10" to 11.5". I'll go measure spring length & check the weights of each to KNOW what I have.
Joined: Aug 2006
Posts: 12,812
Likes: 110
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: Ground Control weight jacks
it would a little, obviously a stronger spring wont compress as much as a lighter one would, so installed height would vary.
I never measured the spring that i received, but i can get my car as low as in Stephens last pic that he chopped.
I never measured the spring that i received, but i can get my car as low as in Stephens last pic that he chopped.
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
That is about the same as my RSs were years ago, when I put cut WS6 springs in them.
Last edited by Stephen; Sep 12, 2009 at 01:46 PM.
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
Old pic, but same overall diameter tires, +- 1".
Stock WS6 springs, my car is sitting at

Here is what I have to work with.....Stamped metal rings on the middle 2, leaving no doubt as to their lb rating.
The outer 2 were sold to me as 180 rear, 600 front. Rear has NOTHING printed or wrapped on it, front says. 0950.550.650
Which the 0950 makes sense, since it is 9.5" tall. But 550.650? Supposedly a 600lb but?????
Stock WS6 springs, my car is sitting at

Here is what I have to work with.....Stamped metal rings on the middle 2, leaving no doubt as to their lb rating.
The outer 2 were sold to me as 180 rear, 600 front. Rear has NOTHING printed or wrapped on it, front says. 0950.550.650
Which the 0950 makes sense, since it is 9.5" tall. But 550.650? Supposedly a 600lb but?????
Last edited by Stephen; May 4, 2010 at 09:15 PM.
Joined: Aug 2006
Posts: 12,812
Likes: 110
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Re: Ground Control weight jacks
i dont get your height measurments, the stock wheel and tire is 25.7" in diameter, but you have 26 from the ground to the fender and a gap of about 1.5-2" above the tire, that wouled be somewhere around 27.5-28" from the ground to the fender.
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jul 2006
Posts: 1,132
Likes: 12
From: Aloha, Oregon
Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Ground Control weight jacks
So I installed my SS wheels today and the front tires are now perfectly flush with the fenders. They only fit because of the negative camber that was a byproduct of the lowering I did. I had to take my fender liners out or else my tires would be sitting on them. Taking them out gave me more clearance to have vertical travel. I'm going to cut a portion of the old liner and place it back inside the well to prevent debris and water from traveling back towards the door hinges and possibly into the drivers compartment. I also definitely need to roll my fenders. I have less that a 1/4" before they rub on bums. The only place I noticed any rubbing turning lock to lock is on the battery tray. This is probably because I have taller than stock tires. I'll just give it the old BFH mod and call it good. The rears have no rubbing or clearance problems whatsoever so I have no work to do back there.
I also managed to finally lower the rear all the way. I tried several different methods to cut that brace. First I tried using a hole saw. This proved to be almost the most effective method but all efforts were hindered because the actual drill bit kept getting in the way. The grinder almost fit but not at the exact location i needed it to cut at. The pneumatic reciprocating saw did nothing, the blades were too flimsy and were probably meant for wood. I ended up borrowing my neighbors oxyacetylene torch. Two minutes is all it took to cut that brace enough for the weight jack to sit all the way down on the spring perch. It didn't lower it as much as I had hoped. I'm sure it still has some more settling to do but I wish it would go down almost another inch in the rear. I can't remember if I indexed the rear springs though so I going to redo that as well as do some more fender rolling.
I also managed to finally lower the rear all the way. I tried several different methods to cut that brace. First I tried using a hole saw. This proved to be almost the most effective method but all efforts were hindered because the actual drill bit kept getting in the way. The grinder almost fit but not at the exact location i needed it to cut at. The pneumatic reciprocating saw did nothing, the blades were too flimsy and were probably meant for wood. I ended up borrowing my neighbors oxyacetylene torch. Two minutes is all it took to cut that brace enough for the weight jack to sit all the way down on the spring perch. It didn't lower it as much as I had hoped. I'm sure it still has some more settling to do but I wish it would go down almost another inch in the rear. I can't remember if I indexed the rear springs though so I going to redo that as well as do some more fender rolling.
Last edited by DBLTKE; Sep 15, 2009 at 11:13 PM.
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jul 2006
Posts: 1,132
Likes: 12
From: Aloha, Oregon
Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Ground Control weight jacks
I never realized that I didn't post any pics so here they are.
Here they are fully extended on the left and fully lowered on the right

Quite a bit shorter.

Springs installed.
Here they are fully extended on the left and fully lowered on the right

Quite a bit shorter.

Springs installed.
Thread Starter
Supreme Member
iTrader: (1)
Joined: Jul 2006
Posts: 1,132
Likes: 12
From: Aloha, Oregon
Car: '91 Camaro Z28, '85 Camaro Z28
Engine: LB9, LB9
Transmission: T5, 700r4
Axle/Gears: Eaton 3.73 Posi, 3.23 Posi
Re: Ground Control weight jacks


Plenty of ground clearance.


With the SS wheels.


Absolutely no rubbing after some messaging.

Joined: Aug 2006
Posts: 12,812
Likes: 110
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
Banned
iTrader: (12)
Joined: Jul 1999
Posts: 12,212
Likes: 13
From: Bertram (outside Austin), TX
Car: 87 GTA
Engine: L98
Transmission: 700R4
Axle/Gears: Dana M78 3.27 posi
Re: Ground Control weight jacks
Me either, but I bought my set used.
Spanner wrenches are easy to make though, so I wasn't concerned about not getting one.
Spanner wrenches are easy to make though, so I wasn't concerned about not getting one.
Thread
Thread Starter
Forum
Replies
Last Post
eightsixseven
Tech / General Engine
2
Dec 16, 2024 01:50 PM








