280z Suspension Upgrade

[rossiz]

been amassing parts for a suspension re-vamp and reading many posts (thanks for the tech tips Blue!) parts list is as follows:

· Eibach progressive lowering springs

· Staag struts

· KYB boots

· Ball/socket TC end upgrage

· New rubber TC bushings

· MSA performance swaybar kit

· Speed-bleeders for the brakes (love these things!)

got clearance to spend the weekend in z-land, and set to getting it done.

car up on stands, wheels off and I figured i’d try to avoid taking off the control arms. front was easy enough, with the sway bar out of the way it was just a matter of disconnecting the tie rod ends, unhooking the brake line clips and i was able to tilt the entire shock assemblies out through the wheel wells. this way i could undo the gland nut and top-of-shock assembly nut without a vice. the hardest part were the tie rod ends – stuck, stuck, stuck. bought a crowsfoot separator, and they popped off with a little help from a 5lb. hammer.

rear was a little trickier, but it just amounted to unhooking the half shafts at the wheel, and one control arm pivot clamp (the rearmost) and loosening the other and the control arm hung down enough to swing the assembly out of the wheel well.

the original struts were toast – no gas left, fluid leaking, useless.

the rear boots were filled with crumbled purple stuff, i believe it was the disintegrated bump pads. the staag struts seem just fine – no, they are not adjustable, track-ready units, but they were shockingly affordable and fit perfectly. the kyb boots were pretty cheap - plastic vs. the oem rubber ones. i actually wound up cleaning and re-using the stock boots on the rear, mine were in great shape.

the swaybars were simple and installed w/little drama – only tricky part was have compressing the pin bushing sandwich enough to get the nut on the end. wound up using a c-clamp to get it done. needed to split the exhaust at the center flange (between center resonator and rear pipe) to get clearance for the rear swaybar removal/install, but no biggie. nice quality kit, very happy with it.

had an “oh, sh*t” moment when i took the eibach springs out of the box – the rear springs are waaaay shorter than the stockers, so much so that they don't even touch the perches until the car is lowered down. i thought i had been sent the wrong kit, but a few looks online and apparently that’s the way they are.

put her all together and was very disappointed to discover the rear was way lower than the front, and the handling was crappy – harsh, jumpy, not good.

so i decided to go the old-school route and cut a couple of coils off the stock rear springs. 5 min. w/an angle grinder and all was good. took me longer to clean and paint them than to cut them.

now she sits level and the feel is perfect for me. the swaybars really help – zero body roll and she just eats up corners now!

while i had the wheels off, i cleaned out my brakes and installed the speed-bleeders. they are bleeder fittings with an internal check-valve, so you can bleed the hydraulics without a helper - i have these on my motorcycles and they literally make bleeding/changing fluid a breeze.

now for the “embarrassing shade-tree mechanic’s story”:

later, when i was fiddling w/trying to get the shock assemblies back in, i unwittingly squatted down onto the can of brake cleaner, depressing the rattle-can nozzle w/my posterior and sending a soaking charge of brake cleaning fluid into my crotch. let me tell you first-hand: brake cleaner to the satchel burns like hell!! i quickly dropped a serious “sag” and waddled into the house to clean off and change hooting like a scorched owl – thank god nobody was around! yikes...

anyway, i'm extremely pleased with the results - the z handles sooooo much better and the ride is still DD comfortable.

anybody looking for a pair of eibach rear springs???

[240260280z]

good stuff!

The suspension will settle after some driving.

[Sean240Z]

Lmao! Great detailed write up.

[Captain Obvious]

the original struts were toast – no gas left, fluid leaking, useless.

Hahahaha!! I get it. "shockingly affordable" :laugh: I bet you didn't even plan that!

So you pulled inserts out? You were thinking that you might have the original factory strut guts, but apparently not. What brand did you pull out? I can't read it on the pic.

After the work, it should feel just a little more solid than mine? I know it's hard to do the comparison without a side-by-side jump from one to the other, but what do you think? I'd love to have mine an inch lower at some point, but first I had to get a good baseline.

Nice VOC in the crotch story! I'm not sure I would have admitted that one!

[Captain Obvious]

Oh and your car is gorgeous by the way. I wouldn't want to have to clean those wheels, but it's beautiful!

[rossiz]

the struts that were in the car had no branding on them - just black casings and a warning about pressurized gas (no longer applicable).

the car feels really nice now: well planted and quite settled. the swaybars make all the difference in the world when cornering (thanks for the tip Blue!) and have all but eliminated body roll - a total transformation from before (felt like a minivan in comparison). the springs/struts seem to do a better job of keeping the car from getting wobbly over bumps... just seems more settled, balanced, with less translated to the steering wheel.

in truth it's hard to say if it's more solid than yours Cap'n, without driving them together on similar roads. definitely less body roll though. if you're going to lower your car, i would definitely recommend cutting coils first, try that before spending the $$ on the spring kit. worked like a charm for me - dropped it down just enough and kept the civilized ride i so cherish on my commutes.

on another note - i discovered that my rack bushings are almost non-existent! with the car up in the air, if i grab a wheel and turn it sideways the whole rack lifts up & down about 1/2" - yikes. the good news is the rack seems totally tight otherwise and the bushings are cheap (already ordered) so i'm looking forward to pulling that slop out of the steering.

[zKars]

I may have discovered your initial "Rear too low, front too high" problem after the initial Eibach install.

The 6203-001 springs are the fronts, the -002's are the rear... The picture you show in post #1 where the 6303-001 part number is visible on the very very short spring next to the stock rears was the clue. Many many of us have been caught by that little detail in the past.

You likely accomplished much the same spring rate by using a shortened rear spring anyway. Someday when you're bored you can switch the Eibachs around and see if you prefer the ride and likely somewhat lower ride height any better. It looks just fine the way it is.

[240260280z]

I find that eliminating the roll makes the car move like a shark finning on the surface. Glad it all worked out. Good luck with the rack bushings!

[rossiz]

oh crap - you mean i now have the rear springs on my front end?!? does anyone know how different an eibach progressive rear spring is from a stock front spring?

the surprising thing is that this arse-backwards setup dropped the ride hight about 1" and seems to be riding really well... but of course now i'm wondering if i should swap everything back out??

what a pain in the butt...

[240260280z]

"Pain in the butt" beats brake cleaner blast

Here are some rates: http://atlanticz.ca/zclub/techtips/springs/index.html

Most seem to have rears at ~ 13% stiffer than fronts.

You are now at front: 212 lbs/inch and rear ~ 151 lb/inch (approximation with the 2 ring cut factored in).

So you are skewed with rears ~ 30% weaker than the front.

It would be good to correct as this may make the car twitchy.

[rossiz]

yes, as annoying as it is to repeat the process, i suppose i would rather tear the suspension apart and re-do it than take another chemical solvent hit to the nards...

[LeonV]

I may have discovered your initial "Rear too low, front too high" problem after the initial Eibach install.

The 6203-001 springs are the fronts, the -002's are the rear... The picture you show in post #1 where the 6303-001 part number is visible on the very very short spring next to the stock rears was the clue. Many many of us have been caught by that little detail in the past.

You likely accomplished much the same spring rate by using a shortened rear spring anyway. Someday when you're bored you can switch the Eibachs around and see if you prefer the ride and likely somewhat lower ride height any better. It looks just fine the way it is.

I was going to say the same. I'd switch them...