New Guy needs direction

[fngearhead]

Hi folks,
New Subie owner here. I bought a '91 Legacy L 5spd AWD a year ago as a daily driver. I have a project '89 Cherokee and now it appears I have a project Subaru as well. All I've done so far is an air intake and WRX wheels and tires. I tried lowering it when I replaced the beat struts this spring, but the H&R springs were completely wrong for the rear. I'm ok with the height but I'd really like to stiffen it up. Could you guys point me in the right direction for swaybars and maybe lowering coils that fit? Fresh canvas here, help me out...

Brian

[THAWA]

As far as sway bars go you're pretty much stuck with two choices. A turbo legacy oem bar, or a whiteline bar. Whiteline actually makes two bars, one 18mm (same size as a turbo leg) and an adjustable 18mm-22mm.

I wouldn't say the springs were completely wrong for the rear. They were just wrong for the stock setup. You need non-tapered top hats to use the wrx springs. A serach should yeild most of this information. Someone actualyl went and found out what's compatible between the first gen chassis and the second gen chassis.

[fngearhead]

The H&Rs were actually too large in diameter to fit the rear. The stock rears are pretty narrow.

[THAWA]

Yeah, too large at the top. That's because they're not tapered like your springs.

[Legacy777]

the adj whiteline bar is 20-24mm

As hardy mentioned, you need new strut top mounts to use the non-tapered rear springs.

Here's some pics of my whitelines and sti top mounts. Notice the taper on the rear springs, and smaller top mounts for the rears.

The larger rear top mounts have a separate top mount piece and spring keeper. You'll need both to use the H&R's

http://www.main.experiencetherave.com:8 ... pring1.jpg
http://www.main.experiencetherave.com:8 ... pring2.jpg
http://www.main.experiencetherave.com:8 ... pring3.jpg
http://www.main.experiencetherave.com:8 ... pring4.jpg
http://www.main.experiencetherave.com:8 ... pring5.jpg

[professor]

Flame me if you must but I just did the following to my '92 L wagon:

New AGX struts
Replaced lateral arms with fresh Impreza arms with sway bar mounts
Fit WRX wheels and tires
Installed Whiteline 18mm rear bar, and freshened links
Cut the rear springs 1/2 coil off bottom and contoured to fit spring perch
Energy bushings in front A arms and sway bar links

This lowered the rear about 0.75 inch, increased spring rate about 10-15% by my calculation. The WRX wheels now look "right" with an even gap all around, rather than a larger fender gap at the top. I started the rear AGX adjustable struts at "4" out of eight but backed off to "3". Four was a bit stiff unless my kids were in the car. Fronts are "2" out of four

I have been unhappy in the past with H&R springs and other aftermarket, they often don't fit as well as I like, lower the car too much, or sag eventually.

I really like the results I have gotten, ride is much more firm without being ridiculous. This is not a track car but a daily driver that looks and handles quite a bit nicer than stock.

I spent under $700 for the total suspension job including wheels and tires.

[JasonGrahn]

Cut the rear springs 1/2 coil off bottom and contoured to fit spring perch

increased spring rate about 10-15% by my calculation.

Please share how you came to this calculation, and how did you go about "contouring" the spring i'm curious. Did you cut the factory springs?

[fngearhead]

In this photo http://www.main.experiencetherave.com:8 ... pring1.jpg I'm assuming the springs on the right are the rears. In my kit from H&R, all 4 coils looked like yours on the left of the photo. My car would probably be lowered right now if the H&Rs had been cone shaped. But I think I don't really want to lower it after all since I play off-road now and then. So, stiffer suspension at stock height...possible? Who sells Whiteline stuff? Website?

[THAWA]

the adj whiteline bar is 20-24mm

maybe ther's two, doesnt dave have the 18-22? Or had I should say.

[JasonGrahn]

In my kit from H&R, all 4 coils looked like yours on the left of the photo. My car would probably be lowered right now if the H&Rs had been cone shaped.

So close but so far. All you needed to do is change the top hats.

[jamal]

Cut the rear springs 1/2 coil off bottom and contoured to fit spring perch

increased spring rate about 10-15% by my calculation.

Please share how you came to this calculation, and how did you go about "contouring" the spring i'm curious. Did you cut the factory springs?

Yeah, I don't understand that. They're the same spring, they just have less travel. I don't see how that has anything to do with the spring rate. In fact, by shortening the distance the spring has to compress, it will take less force to bottom out the suspension.

[BAC5.2]

Energy bushings in front A arms and sway bar links

GD bushings?

I wanna replace all factory bushings with Energy bits. I'm very satisfied with their products so far. I just want to know what bushings will fit.

[professor]

I bought the whole kit for the WRX. Energy isn't very specific about what WRX but there is some reference to 2002, which is still not terribly specific since there were different models around that time Japan, US.

In any case, the kit came with new sway bar link bushings that fit the stcok front and back "C links correctly. The sway bar mount bushings, one set appears to be 17mm and one 20mm, so the 17mm fit my front bar fine and the 20mm is too big, but I had the ones from my Whiteline 18mm rear bar anayway. So 3 out of 4 items for sway bar.

All of the rear suspension bushings should fit but I installed none since I got recent Impreza arms and the bushings were fine.

The front A arm bushings fit into the arm fine but it was too tight to fit in the mount, so i ground a little away from the center metal bushing, and then it fit fine. The rear A arm bushing had a little slack at the core, the rear of the WRX arm must have a slightly different grind, so I filled the slight gap with JB weld and tightened the crap out of it.

I did all of this with nothing more than a sawzall, torch, large c-clamp, and a decent bench vise.

The kit cost $120 which is less than Subaru rices for the rear A arm bushings alone. I think I priced OEM at nearly $500 for all of these bushings.

As for spring rate, if you cut a spring in half, the spring rate doubles. So with about 4.5 active coils, I took away 1/2 active coil, so +12% or so. I contoured the spring by grinding the cut end flatter on the bottom and tapering out and inch or two so more coil would sit flat on the spring perch. It fit fine and secure in fact more secure than some aftermarket springs I've seen, where there is very little contact and springs jumping off the perch are not unheard of.

BTW the bottom rubber ring spring cushion thing in the old struts was pretty torn up, so I sleeved the spring bottom ends with a piece of thermoplastic rubber tubing, and heat sealed the end so it won't slip off. We'll see if it stays put but so far so good.

[jamal]

As for spring rate, if you cut a spring in half, the spring rate doubles. So with about 4.5 active coils, I took away 1/2 active coil, so +12% or so.

If you had half the spring, you would just have a smaller spring with the same rate, unless the springs are progressive or something. If you use the basic equation for a spring, you'll get this:

For a spring with a constant rate, F=kx, where F is the force required to compress (or stretch) a spring with constant k a distance x.

Assume a spring has a rate k = 150 lb/in and 6" of travel. To fully compress the spring, it will take 150x6 = 900 lb. Say you shorten the spring so it will only have 5.5" travel. Now it takes 825 lb to fully compress.

[scottzg]

Nope. The deal is the amount of compression per coil. So, you have a 10 inch, 10 coil spring. You compress it 1 inch. Each coil is now 1/10th compressed. Now you have a 5 inch, 5 coil spring (you dont wanna lose your coke can under your car) You compress it one inch. Each coil is now 1/5th compressed, twice as much. It took double the force to compress the 1/2 as tall spring.

I could figure out the correct equasion, but i really don't care enough to bother.

[jamal]

Yeah but now you're compressing half the amount of coils twice the distance per coil, so it still takes the same force to compress the whole spring the same distance.

Sorry to turn this thread into an argument about cutting springs, but I think it's important to find out who's right. I spend a lot of time reading this forum and I expect that most of the information I find will be correct.

[vrg3]

Do you not believe that cutting a spring increases the spring rate, Jamal, or are you just trying to make someone explain the concept better?

It's harder to compress a spring with fewer coils. Think of it this way -- If you have two uniformly wound 10 lb/in springs, and you put them in series to make a bigger spring, how much force does it take to compress the entire thing by 1 inch? Well, if you apply 5 pounds of force, each spring will compress by half an inch. So... you've halved the spring rate.

So now pretend your original 10 lb/in spring is really two 20 lb/in springs in series. Cut it in half, and you've got a 20 lb/in spring.

[jamal]

Do you not believe that cutting a spring increases the spring rate, Jamal, or are you just trying to make someone explain the concept better?

I didn't believe that cutting a spring increases the spring rate. I guess that makes sense, though.

[vrg3]

Yeah. It does.

[Legacy777]

In this photo http://www.main.experiencetherave.com:8 ... pring1.jpg I'm assuming the springs on the right are the rears. In my kit from H&R, all 4 coils looked like yours on the left of the photo. My car would probably be lowered right now if the H&Rs had been cone shaped. But I think I don't really want to lower it after all since I play off-road now and then. So, stiffer suspension at stock height...possible? Who sells Whiteline stuff? Website?

yeah the springs on the right are the rears. there's a few different whiteline distributors. www.isrperformance.com www.boxer4racing.com and www.pdm-racing.com to name three

[Legacy777]

the adj whiteline bar is 20-24mm

maybe ther's two, doesnt dave have the 18-22? Or had I should say.

It's possible they did have one in the past, but to my knowledge all that's listed in the application guide is the 20-24mm

[Legacy777]

As for spring rate, if you cut a spring in half, the spring rate doubles. So with about 4.5 active coils, I took away 1/2 active coil, so +12% or so. I contoured the spring by grinding the cut end flatter on the bottom and tapering out and inch or two so more coil would sit flat on the spring perch. It fit fine and secure in fact more secure than some aftermarket springs I've seen, where there is very little contact and springs jumping off the perch are not unheard of.

The only issues I have with this is if there are dead coils in the spring. I don't know enough about coil spring design to give a definite answer, but I would think, depending on where the dead coil is, just cutting it in half would not give you double the rate.