Suspension / ChassisQuestions about your suspension? Need chassis advice?
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Lowering 101
--Last updated: Dec. 29, 2008.
Want to lower your car but don't know where to start? Read on for a guide on how to lower your 3rd gen. There are several options for lowering, and we'll try to go over as much of them as possible. As with all lowering options for our cars, the air dam will be the most effected, so keep an eye out for roadkill and other things that could rip up the air dam while driving.
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1. Lowering Springs
Lowering springs are by far the most popular method used to lower a car. Springs are easy to come by, and are relatively inexpensive and easy to install. The downside of lowering springs is that they can put the a-arms in a position similar to that of loaded/compressed suspension, which often yields negative camber (depending on how low you go), causing premature front tire wear and handling problems. When lowering, there are several other suspension components that you will need; adjustable panhard bar, LCA relocation brackets, and an adjustable torque arm. An adjustable panhard bar is a must and will allow you to keep the rear axle centered after lowering, as the stock panhard bar is not adjustable. Lower control arm (LCA) relocation brackets will give the LCAs the proper angle after lowering (which moves the axle up). An adjustable torque arm will allow you to adjust the pinon angle, which will change with lowering. There is a hidden cost with associated with lowering, but these parts will help ensure that your car still handles well. Lowering springs are installed just like new springs...
Front Springs
Jack up the car and support it on jack stands. After removing the front wheel, rotor, and caliper, use the jack to lift up on the inside (pivoting side) of the a-arm to unload them slightly. This will take pressure off of the two pivot bolts that allow the a-arm to pivot against the k-member. If possible, insert a spring compressor and tighten it down so that the spring stays in a compressed state. The only compressor I've found worth using is an internal coil spring compressor, like a KD Tools #3450. The other two I've used (external type and compressing fork) just don't fit. Remove the two nuts from the pivot bolts, pull the bolts out (you might have to wiggle the a-arm), and then use the jack to slowly unload and let the a-arm down. Remove the stock spring. At this point it is very helpful to have an extra jack that is supporting the hub (before you remove the pivot bolts), because it will help keep the whole setup from kicking out, and will help protect the strut from overextending, due to the weight of the spindle & a-arm after you remove the pivot bolts & the spring. Installation is in reverse order. You might want to compress the lowering spring with a spring compressor, but it depends on how stiff and long it is. Index the new spring with the a-arm by aligning the un-tapered spring end in the a-arm notch, and then place the jack under the pivoting side of the a-arm, slowly jack it up and place your pivot bolts. Re-tighten and you're good to go.
Rear Springs
Jack up the rear of the car and place jack stands under the LCA mounting points (subframe area). Unbolt the rear shocks and remove the old panhard bar. Lower the axle with a jack and remove the stock springs. Install the lowering springs (make sure they line up with the grooves of your isolators if you still have them) and then jack the rear end back up and bolt up your rear shocks, and install the adjustable panhard bar. Unbolt one LCA at a time and bolt in (or weld in, depending on your style) the LCA relocation brackets to the axle. Reattach the LCA and move to the other side. You can do both sides at the same time, but the axle moves around without LCAs and it makes it a little more difficult. To adjust the panhard bar, drop the car off the jack stands and measure the horizontal distance from the outside of the wheel (not the tire) to the inside fender lip. Adjust the panhard bar until the measurements of both sides are equal, and lock it. You're done!
Cut Springs
Cut springs are a mixed bag; some people like them and some don't. I did an LSx swap and wasn't sure what lowering springs to use to get a slightly lower ride height. So I decided to purchase new springs and cut them with a cutting wheel as an experiment. I bought stock replacements (Moog 5662 fronts, 5665 rears) and cut the non-tapered ends 14" and 7" (the length of a string wrapped around the outside of the coil, so that I could get equal reduction on both springs), respectively. The car rides great, and is about 0.75-1" lower up front, but I could have gone to 9-10" on the rear springs to drop it another 0.5-0.75". The springs are only temporary, as I'll be installing drop spindles next.
Firebirds
-Canuk Motorsports, razor ('92 GTA)
-Eibach Sportlines, //<86TA>\\ ('86 Trans Am)
-Eibach Sportlines, nolanr0413 ('85 Trans Am)
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2. Drop Spindles
If one is looking for the best way to lower a car up front, drop spindles have no equal. Drop spindles move the spindle shaft up, effectively moving the wheel mounting point up (and the car down), but allowing the strut and a-arm mounting points to stay the same. This way you can keep the correct suspension geometry of the car, and eliminate the negative camber (and tire wear) that comes with lowering springs. You will need to run stock springs up front, but will still use lowering springs (as well as an adjustable panhard bar and LCA relocation brackets) for the rear axle.
Drop spindles for the '82-92 F-body were first made by Belltech (part #2200, also available was #5200 - drop rear springs to match the spindles), but sales were under target and the company decided to stop making them, ending with the last remaining prototype production pair being destroyed in 2004. Even though Belltech was contacted several times by those on this board about reproducing the spindles, sadly, nothing even came of it.
Recently, two other companies have started to make drop spindles for the 3rd gen. AJE Racing makes spindles which provide a 1.8" drop. The second company is Racecraft, which have a 2" drop.
-AJE Racing Drop Spindles
-Racecraft Drop Spindles
3. Weight Jacks
In a nutshell, weight jacks allow you to run the spring rate & length that you want, and be able to adjust the ride height independently without swapping springs. Weight jacks are very popular with those who road race and autocross, but there are those who have adapted them for lowering for street use. There is a lot of information on weight jacks than can be covered in this post. See Ground Control's 3rd gen parts catalog for more information on what's available.
4. Air Suspension
Air suspension is probably one best ways to have adjustable lowering. Air bags replace your springs (you will still need shocks & struts) but allow you to adjust the ride height any way you want. Drop the car to a certain level for shows or driving, and raise your car to stock height if needed (speed bump clearance is a good example).
Air ride has been installed by a few here on the board, and is probably one of the most complicated and expensive lowering options. You will need air bags, air line, control valves, PSI/valve controller, air compressor, and storage tank, as well as space the mount the air compressor, tank & valves. Air Ride Technologies (ART) makes a kit for 3rd gens (#L1-4350) that includes the front & rear bags, mounting plates, plus everything else to get the system installed and working.
5. More Information
I've tried to be as comprehensive as time permits, but I would still suggest that you search the various forums for more information. There is a wealth of other suspension information that I have not touched on, including spring rates & length, coil-overs, camber & caster plates, etc. There have been some great discussions about handling and suspension by those members who have been around for some time, and I have benefited greatly by their knowledge. It would be a good idea to read up on posts regarding suspension dynamics and handling, as you will gain a better understanding of how your suspension functions.
__________________ KONIs I Eibach Pro-Kit I 36mm/24mm sway bars I Spohn: Adjustable PHB I Wonder Bar I SFCs Custom LCAs I LCARBs I J&M Products Camber/Caster plates I Hawk's Ceramic Pads I 4th Gen 3.23 Posi I LS1/LT1 Brakes
Super Kev - YOU ROCK!
We are always reading your posts and this info is timely as we are finally going to pickup the drop spindles, C-4 brakes and then drop her down - looking at bagging the IROC. Thanks again.
I've read that you could shorten stock springs by compressing them with a compressor to the length you want and placing the whole thing in a 400* oven for about 20min. then let cool slowly to regain temper.
Bad idea. Messes with the temper and the spring rates. Seen the Hondas setting an inch off the ground and bouncing like a baby toy? That's what they did.
I'm sure the fact they were running stock shocks didn't help, but when you heat the springs, it messes up the temper of the spring no matter how you cool it. At least that's what I've observed and read on here.
I must have been misinformed then. All I've ever heard about heating the coils to lower a car is bad. And it still only lowers the car, not increases spring rate. I have seen Hondas that heated the spring, and it did make the car bounce around like a toy (almost a foot of travel from braking) and I know they heated them to lower the car. Might have done it incorrectly or not used shocks.
Well I think the difference is that "heating springs" is usually in reference to some hack job just putting a flame to the spring while its in the car. This results in an uncontrolled and localized reaction.
A slow heating and cooling at a controlled temperature is a completely different thing. Still pretty much a PITA and a trial and error thing. If you have a lot of time(and no money) or are confined by some rules it my be a loophole for you.
I just find that buying "lowering springs" is a mixed bag...It may say it lowers the car 1" or 1.75", but which car? Every modded car is different. My car has aluminum heads, no A/C, headers, battery in the rear...I know for a fact that sportlines don't lower my car 1.75"! So I'm looking for alternatives. I'm gonna try the heated thing to "customize" the springs....we'll see!
All that bounce on those slammed imports is usually in the shocks. Most of the time it is worn out stockers still in a set of stiff lowering springs. But a cranked out set of adjustables will do the same thing on a car that is too light.
Heating the springs is an old-school lowering trick, but is usually performed with a torch. It's a fast way to get a car low, and if you know what you are doing the change in ride is minimal. I've got a buddy with a 65 Riviera who's frame sits about an inch from the ground, it is all torched springs and with the 18 inch rims it rides really nice and handles like it is on rails. Can be a b**** to get it flat though.
__________________ Stronger and harder than a bad girl's dream!
I just find that buying "lowering springs" is a mixed bag...It may say it lowers the car 1" or 1.75", but which car? Every modded car is different. My car has aluminum heads, no A/C, headers, battery in the rear...I know for a fact that sportlines don't lower my car 1.75"! So I'm looking for alternatives. I'm gonna try the heated thing to "customize" the springs....we'll see!
I think manufacturers use an average lowering height on otherwise stock cars. You honestly don't expect manufacturers to give lowered heights on every possible mod that can be done on a car. Another thing to consider when buying springs is the spring rate, which I think the sportlines are a horrible choice. Eibach admits the the sportlines are not a performance spring, but they are made "just for looks" of the car being lowered.
I think all in all, lowering the car is really more than just throughing shorter spings on it! There is a lot more to take in account.
I have a question. With the Eibach Pro series lowering kit what all do you need to change? It says the shocks are ok? But what about the other suspensions components like panhard bar and LCA brackets? Do i need them? -Matt
I have a Jamex springs around my car. I am wondering how many inches lowering my springs are for front and rear? Also what is the part number of the springs? Since I want to keep it as a record incase I will change my springs later on.
If you drop the car, the first thing to replace is the shocks. They say the stock ones are ok so they can sale more. In truth, using stock shocks (or replacement shocks) is a bad idea. You need a shock designed for lowering springs. KONIs (Yellow or Red), Bilstein HDs, the nice Tokicos and KYBs. Then getting a set of LCARBs will correct your lower control arm angle and a adjustable PHB will re-center the rear axle after lowering.
__________________ KONIs I Eibach Pro-Kit I 36mm/24mm sway bars I Spohn: Adjustable PHB I Wonder Bar I SFCs Custom LCAs I LCARBs I J&M Products Camber/Caster plates I Hawk's Ceramic Pads I 4th Gen 3.23 Posi I LS1/LT1 Brakes
I just acquired some 1.75" dropzone springs for 50 bucks and they're NEW so i couldn't pass them up.
I think the 1.75 will be too much drop, im looking for somehting like the sportline drop that is 1.6 and 1.3. The front i'm planning on using some thick 5/8 id heater hose to raise it .25~.20 so im at that 1.5-1.6 mark. The rear im planning on doing the heater hose as well, but with .5" id hose it will only raise it .15~.20. What else could i do to raise the rear about a tenth or even a quarter? Thanks
Looking at lowering my 1989 Firebird just a tad. Nothing as radical as the dropped spindle photos posted. My struts and shocks have had it due to age not mileage (car only has 19K). I have a lot of space above the 245/60/16 tires.
I was wondering if the stock GTA springs for a car the same year are shorter than the standard Firebird springs? Any ideas?
Looking at lowering my 1989 Firebird just a tad. Nothing as radical as the dropped spindle photos posted. My struts and shocks have had it due to age not mileage (car only has 19K). I have a lot of space above the 245/60/16 tires.
I was wondering if the stock GTA springs for a car the same year are shorter than the standard Firebird springs? Any ideas?
most likely no
you will have to cut what you have, or purchase lowering springs
