forgive my ignorance. but i have no idea what these are and need descripion. pics would help

 

Weight jacks allow you to control spring height and sometimes stiffness. I'm not too knowledgeable on their operation. So perhaps someone else can chime in.

 

sounds ike the way to go just dont know what they are

 

They are basically SHORT springs that allow you to adjust the ride height of the car, without changing the spring rate any.

And you can EASILY change the ride height when you want to (not on the fly like air bags) when you decide it is too high or too low.

AND.....New springs are cheap & easy to swap out. If you decide it is too soft or too stiff, $100 or less will get you a new pair.

Hell, you could have a set for street & another set for race day at the track. Easy to swap out the day of the day, then back again afterwards.

 

so they are a good idea? and how hard to put on my car? do i need to get new shocks and struts?

 

You'll need shocks and struts if increasing spring rates or lowering the car. So, yeah, it'll be a good idea. If you get the good weight jack package, they mount up just like springs so you won't need to modify the car and it'll be just the same as installing regular springs, but with two pieces to hold onto. I plan to get them for my car at some point. Friend has a similar item on his Acura Integra, and it makes me jelous lol.

This thread will help you out - https://www.thirdgen.org/forums/susp...ght-jacks.html

 

MMM........ I'll try to be brief.
Weight jacks allow you to adust the ride height of EACH corner. The main reason one usually does this is not for the ride height, but for the weight on each wheel. The BEST way to do this is with a set of scales.
You would like to use scales so you don't throw your cross weight way off. You could make your car have MUCH different handling characteristics to the left, as opposed to the right.
With oval track cars, you only care about left turns. IN extremis, eg Midgets, with 65% left weight; a friend told me they would flip if turned right.
This would not happen to us, but if someone took a tweaked car and (unknowingly) put a high or low cross in it, you could oversteer one way and understeer the other.
Scale with your sway bars disconnected.
Be warned, wheel weights can change a lot with not a whole lot of turning on the jackscrews.

 

Drag cars need to be scaled as well but most of us never seem to do it. I can adjust my ride height at the rear easily because I use coil over shocks. I've never had my car on 4 corner scales but should get it done. As mentioned above, by changing the ride height from side to side, you adjust how much weight is sitting on the springs.

When a drag car launches, the right rear tire is trying to lift off the ground. It's usually corrected by using rear sway bars, air bags etc but a simple ride height adjustment can also work.

Think of it this way. All the weight of the car is sitting on 4 tires when the car is at rest. When you accelerate, weight moves to the rear tires, when you brake, weight moves to the front. The same weight transfer moves side to side in cornering.

The car's weight doesn't sit equally on the tires. All 4 wheels carry a different weight. Even something simple as having a different driver behind the wheel will change the 4 corner weights.

The best way to make a car handle is to have equal weight on all 4 tires when at rest. If you jack up the car at one corner but don't lift the wheel off the ground similar to putting a longer spring in, the weight of the car will adjust to the other wheels.

Drag racers usually want side to side weights the same. Front to rear weights change drastically when they launch. Oval track racers will change the side to side weight. Putting more weight on the inside of a turn will make the car heavier to the inside while centrifugal forces are trying to throw the weight to the outside. Even changing one corner can affect an oval car's over steer and under steer characteristics simply by adjusting how much weight is pushing down on a tire.

For the average street or street/strip car, weight jacks are not needed. Like everything else, they're a tuning aid and are mainly a race item. If you autocross regularly, they could be used but without a 4 corner scale to know what the adjustments are doing, you'll never know what you're doing.

 

I don't know how third gen specific weight jackers work, but I have used several different types in race cars with coil springs.

One type has a piece like an upside down top hat with the "head" part, not the brim, pointing down and locating inside the spring coils (from the top).
There is another piece that is usually a piece of round, flat steel plate with a hole in the middle, and a big nut welded to it over the hole.
The round plate gets welded to the top of the front frame rail over the spring. A piece of all thread with either a hex hollowed out of the top end, or a nut welded to that end, gets threaded down through the welded on frame plate and the end of the all thread seats in the "bucket" made by the upside down hat piece sitting in the top of the spring.
When you crank on the top of the all thread it pushes down on the top of the spring and lifts that corner of the car up and makes that wheel and the wheel diagonally across from it carry more of the weight of the car. That's why you here the NASCAR guys talk about "wedge".
You would not be messing with wedge for a street car that needs to handle neutrally. You would want to crank evenly on each side of the car for street use. But you could preload the left side say, for the dragstrip. You usually use a locknut on the all thread to clinch things tight after you adjust the ride height where you want it.
If your car has the shock or strut coming up through the middel of the coil spring, you can't install this type.

The other type I am familiar with are the "cheater" style. They are larger in diameter and have a part that sits down in the spring. They are actually trapped between the underside of the spring pocket in the frame rail and the spring. They are really just a large, round, hollow nut and bolt that can be made taller or shorter by turning the pieces and threading or unthreading them and are locked down with a set screw. You can't see this style when it's on the car, but you can't get at it to adjust it easily either. But the shock can go through the hollow middle of this style.

Coilover springs are adjusted pretty much the same way, but it is all done on the spring/shock unit.

 

There is some really sweet info in this thread.
If you don't mind me adding a few questions I now have...
I understand the ground control weight jacks can be welded in or simply placed in, and held by the force of the spring. What are the odds of a non-weld in weight jack coming out if I use my car for road racing?
If I run an 8 inch spring with weight jacks will it handle worse or better than the same weight spring of say 11 inches? I.e. using a prokit verse a shorter eibach spring?

 

does anyone have pics? i learn good from pics lol

 

http://www.cecoatings.com/images/misc/weightjacks

 

ok that helps alot! so its basicly a screw to adjust the springs. now what i dont understand is the pics were of two things?

 

They are FRONT and rears.
The front just look like screws and plates. Simple terns they compress the spring to lower the car.
http://www.cecoatings.com/images/mis...ightJacks1.jpg

FROM LEFT to RIGHT

Stock Spring, weight jack fully adjusted high. and then fully adjusted lowered

Other picture of the aluminum pieces are the rears.

Look again Ive added a few more pic's. Im diging out more to add also. So keep looking now and then.

 

There were pics in the thread I linked.

 

x2, but never hurts to have them linked here also. So if someone searches and finds this post and not the other one.

 

Now I see how weight jacks for third gens are done. They are mainly used from the bottom of the spring, it seems. The ones I am familiar with work from the top of the spring.

The "cheater" type that I was talking about earlier are made to help entry- level street stock class circle track race cars handle better. Street stocks are not allowed to use many racing parts, but need a lot of help for left hand cornering. When you put the cheater style weight jacks in, you can't see them and nobody knows you are tuning your wedge and ride height unless they crawl under the car and look at things very closely.

So no, they won't fall out when racing. They would be more likely to fall out with the car jacked up with no weight holding the spring tight against the top mount, and on the axle housing. If you were really worried about them falling out, you could drill some holes in the plates and tie- wrap the springs and plates together.

It would probably be best to use shorter springs anyway since the weight jacks will take up some room above or below the spring. And remember, if you cut a spring and make it shorter, it will make it stiffer.

 

That may be true, but unless you keep the exact same ride height after swapping them, you will need to have your wheel alignment checked.

I'm really looking into these for the rear because I hate how high the back of my car is even with the Prokit springs. How much would it cost to do just the back... $150 with springs?

Mike

 

weight jacks can be used on the street but if you do not set them up corectly you will have a car that does not handle and will destroy tires. they are primarly ment for racing (not drag) with the proper set up you can conrtol your cornering.

if all you are going to do is 1/8th, 1/4 do not wast your time or money. if you are going to do some sort of road racing, start racing and have them as a add on for later down the road.

there has been lots posted,.. good info you will have to decided how much work for the pay off vs a conversation piece????

 

Could you use these for daily street/track driving or would it be better just to go with coil overs?

 

Obviously an old thread, but many people are now running weight jacks for both track and street driving. The adjustability is an advantage for both fine tuning the suspension for the track, AND for adjusting ride height for a street cruiser. Ground Control was mentioned in this thread, and I've used them on two Irocs now, but UMI and Detroit Speed both now offer them and I'm sure others will soon. Coilovers do weigh a little less but are a LOT more expensive. Honestly, for OUR cars, I just don't see the need. For the highly skilled/competitive track driver, coilovers may offer an advantage I'm not aware of, however it's not hard to find a fast driver/car using weight jacks.

 

Hey I know this is an old thread but I'm looking to get a set of UMI weight jacks for the rear 175lb because I need to fine tune it. the lowering springs I have don't sit quite equal on each side and I want the stance to be slightly higher and prevent rubbing on one of the tires, and I really want the freedom of adjustability. My main questions are if I should just get a spacer to fix this? And if I go with weight jacks how will the ride quality be? I have Bilstein shocks now so would those work okay or should I get new ones? Thanks!

 

The weight jacks will let you fine tune your ride height where as a spacer will be just that, a spacer. ...and keep in mind adding a .25" spacer on one corner won't necessarily just add .25". Every change will have slight changes on every corner. Lot's of variables. Then it can change again after 20 miles of driving when they settle. Nothing wrong with NOT going weight jacks, but they absolutely make fine tuning ride height MUCH easier. As for ride quality, it'll be the same as any other spring at the same rate. The springs are just shorter, to allow room for the adjustable weight jack, so they can bind more quickly, so you can't go with too light of a spring. 175# springs will be no issue. I ran 150# rear springs on my Ground Control jacks with no issues, though 150# is really TOO light of a performance spring. I just wanted to start low and increase from there. I'm running 175 springs now actually.

 

Thanks a lot for the reply! If you have another second I should also note that I plan on mostly it being a street and daily driver kind of car but I still want to keep good straight line performance Will these affect that at all? And will I need to upgrade shocks for the 175# spring rate?

 

No problem. Weight jacks and 175lb springs are fine for just about anything you're gonna do, and certainly for just being an all around good driving car. You'll see a lot of guys nowadays who are seriously competing in autocross and other kinds of racing, and you can get into the nitty gritty about what's best for that, but there's SOOOOOO many other things that go along with it. For all around driving, which is what most of us do, weight jacks aren't really any better or worse than any other kind of spring set up. Their purpose is technically to help balance each corner for competitive track driving, but "most" of us nowadays use 'em to help fine tune the ride height. Tried and true, they're a great option.

Your bilstein shocks should be just fine, assuming they're in good working order.

 

Thanks once again I really appreciate the helpful info and I think I'll be getting a rear set off these as it seems like the best option from everything I've gathered the shocks are only about 5 years old with about 10,000 miles so they should be okay (if anything my next shocks and struts will probably be koni yellow when I need them). And sorry one more question, will I need to get an alignment or should everything sit right once I do them?

 

Official answer? -Anytime you change ride height, an alignment is a good idea. That being said if it's already lowered, but you're simply going to "fine tune", chances are you won't really "need" an alignment. I've made little changes here and there over the years and typically don't get it realigned. I've lifted both of my last two trucks (GMC and Chevy) and neither changed a whole lot. Leveled my wife's 4Runner and you could SEE it out of alignment it changed so much! ...In your case, I doubt it's necessary.

 

Hey I changed my mind a little bit and I think I will go with the ground control ones now after not hearing great things about the UMI ones. When I contacted them they said 850lb front and 205lb rear. I thought that might be slightly to stiff and not ride as good as I want for the street driving I'll be doing. at least the rears I was thinking 175lb but idk about the fronts if that's to stiff or not.

 

Correct, 850 lb/in makes for a sharp ride, suspension hardly moves just driving down the road. Got to have large cornering loads or be moving VERY fast before you get good motion and the ride smooths out.

 

​​​​​​So what spring rates would you recommend with the ground control setup?

 

There aren't many choices to go lighter, 800 or maybe 750 lb/in if it can even be found. Weight jacks by nature are stiff because the spring is so short; Can't allow much movement or the spring will bind. If you want a smooth ride then go with full springs.

 

I'm running 750# springs (Eibachs I think), that I got from Ground Control. Stiffer than stock, but still a good ride. No hardcore track experience, but plenty of spirited backroad country driving and no issues with bottoming out.

 

​​​​​​are you running 175 rear then? And also do I need to call them to get the 750lb or could I type it in my order? That's probably what I'll go with if you say it's not to bad. And compared to a non weight jacks setup how big of a difference is it really? I know it will be stiffer but is it really that bad? I just want the freedom of adjustability because it would make everything easier otherwise I would just stick with the springs I have now.

 

Depends on the road.
You must have good shocks, Koni yellow minimum. Next level above Koni is very expensive, most of us are using the Koni.

 

Roads are pretty bad here lol. And I do plan on upgrading to koni yellows soon. I can get the rears for just under 300 for both right now so I might do that. And I didn't realize until after I said it but you already said you had the 175lb in the rear Abubaca so my bad. If worst come to worst might just get the set and sell the front ones if I don't feel like I need them and just use the rears as that's where I need the adjustment. So idk if 175 would be an okay rate to mix with the front if I decide to not use them or if I should go down to 150 or not. The springs i have now are BMR. Sorry if I'm getting annoying with all the questions I'm very particular with my stuff and I just wanna make sure I get it right and not spend to much more than I need lol. Thank you for all the info I really appreciate it!

 

BMR, Hotchkis, UMI all have similar spring rates up front but match that with rear springs ranging from 140 - 200 lb/in advertised. Keep in mind a lot of aftermarket springs are variable rate, so that Hotchkis "140 advertised" is actually 100 - 140 lb/in. It rides stock-soft cruising down the road and then stiffens up when pushed harder.

Whereas weight jacks are usually single rate, meaning you are always riding on the same spring rate. So a 150 lb/in weight jack spring in the rear is actually a whole lot stiffer cruising down the road than that BMR or Hotchkis spring. I would lean toward the softer side with a weight jack, and I think the softest Ground Control will give you is 150 lb/in.

 

I'm currently on 750/175, with Koni Yellows. It's definitely stiffer than stock, but.......I mean.....ya gotta pay to play. It's not bad at all, in my opinion, and I'm 48, if that means anything, lol! We have good roads here though, and over bumps and potholes, it's more than I'd want, soooooo, you'll have to make that call. I had 150's in the rear to start, but it wasn't quite enough, PLUS I've got the lowered axle side panhard (parts from Qwiktrip) and that'll put some extra leverage on things, so 150 was NOT gonna cut it. Might even go more, but thus far the combo works and is pretty dialed. Once the LS is in, we can push it harder and see what happens.

You'll have to call GC to get lower than 800. They don't list the 750.