Rear Shocks

[FourPoints]

New to me 2000 Z3 2.8 manual, 54k miles, (summer time) daily driver, all stock.
Just had my buddy put it up on the lift and check out underneath, noticed I've got a rear shock leaking which needs replaced.

I don't know much of anything about suspension tuning and options, though I've tried reading through some of the threads out there, I'm just not familiar enough yet to make heads or tails about what advice does or doesn't apply to me.

I would upload a pic of my existing shocks but the image upload tool just doesn't work on this site (and I've tried from multiple computers).

My friend / mechanic is suggesting I just replace the rear shocks with Bilstein B8's, or if I want a sportier ride B4's (I might have that backwards)

I've seen talks about various setups with coil overs and everything, but I don't have that in the rear (part of my confusion). What do you suggest, and what else should I also replace while I'm in there doing them? He looked around but didn't see anything else in need of replacing, though he doesn't know the history of these cars as well as many of you do.

[fmcfad01]

The OEM shocks are Sachs and for what they are, they are very expensive.

Most people go with Koni 'Yellow' or Bilstein shocks paired with H&R springs. I, and most of the people here, have found Koni to be a bit more comfortable.

The next step up from that is to get a coilover kit from TC Kline, Ground Control, etc. They are all going to be more like $1500-$2500 depending on your options.

The rears are not a true coilover, but you can put the spring on a ride height adjuster and get the same effect.

There are some cheaper coilover kits these days, but not much chatter about them on this forum. I think BC is one of the companies. There are probably other options.

[FourPoints]

You're going to have to be simpler for me, I'm still learning... I assume Koni is the brand name like Bilstein, is 'yellow' a specific model? also what company is H&R?

How do you 'pair' the H&R springs to the Bilstein shocks, or do you mean just put them on at the same time? I am inferring that the springs are then a separate non-coil over setup stock on the rear? What is involved with that change?

[MartyBtoo]

You're going to have to be simpler for me, I'm still learning... I assume Koni is the brand name like Bilstein, is 'yellow' a specific model? also what company is H&R?

How do you 'pair' the H&R springs to the Bilstein shocks, or do you mean just put them on at the same time? I am inferring that the springs are then a separate non-coil over setup stock on the rear? What is involved with that change?

Right on all counts. You probably want to look at a website like bavauto.com to get the nomenclature down. I'm not necessarily recommending Bavarian Autosport, but their website helped me figure it out.

Marty

[luciano136]

For what it's worth, I still have a full "stock like" suspension in my garage I need to sell. It consists of Bilstein HD shocks+stock springs in the front and Bilstein sport shocks+M springs in the rear. I ran it for a while and was very happy with it. The only reason I changed is because I needed height adjustment once I went to aftermarket wheels.

PM me if interested.

[Vintage42]

New to me 2000 Z3 2.8 manual, 54k miles... I've got a rear shock leaking which needs replaced... not familiar enough yet to make heads or tails about what advice does or doesn't apply to me... mechanic is suggesting I just replace the rear shocks with Bilstein...

I would not put expensive new Bilsteins on the rear unless you were going to put new Bilstein struts on the front, too. Struts are expensive to buy and install. If you are not going to replace struts now, and if you think the struts still ride OK, I would replace the shocks with Monroe, which are very inexpensive, and whose ride might match the old Sachs struts. The drive until the struts needed replacing, which could be tens of thousands of miles. At that time, you can replace all four corners with whatever your budget and taste wants. I am pleased with KYBs, a nice ride and not too expensive.

[fmcfad01]

Right,
Koni's would be sold by the company Koni:
http://www.koni-na.com/cat_search.cf...X7sSwSObGpJ6bL
They have three types, of which you should select the Yellow ones - which are the 'Sport' shocks. Avoid the FSD model.

You can see here what a non-coilover suspension for our cars looks like. The fronts have a spring perch and the sprint goes over the strut. In the rear, there is a strut and a spring that goes between the sub frame and the rear training arm.
http://www.tcklineracing.com/webdocs...Details122.cfm

Then you have what we call coilovers (or a more general way of thinking about it - ability to adjust the ride height front and rear as well as the stiffness of the shocks)
http://www.tcklineracing.com/webdocs...Details150.cfm

You can see there that the rear springs still don't mount over the shock, but there is a ride height adjuster.

I bought my koni shocks from a store called ImportRP and they use that as a username on here that you can private message (PM). They had by far the best prices for my e39 M5 when I was shopping around, but things can change.

H&R is a brand. They make sport springs. People tend to use these on our cars. You could also go with Dinan springs or any other brand for that matter.
http://www.tcklineracing.com/webdocs...Details316.cfm

I'm just using TC Kline's website since they have everything in one place. You can certainly shop around and find the best price elsewhere.

The link above to Koni's website says you should buy the following for our cars:
8741 1338LSpor
8741 1338RSpor
2x 8040 1217Sport

The issue a lot of people have with Koni fronts is that you only get the insert. You have to cut open the stock front shock and put this koni insert inside. That can be a pain and intimidating.

Companies like TC Kline can sell you a ready to go koni shock with a spring perch, but you'll pay for the convenience. I'm not sure what shock that is or if it can be bought elsewhere, but i'd imagine TC didn't magically make it themself.

EDIT: looks like Koni is having a 25% off sale.

EDITs Galore: Looks like the 8741 1338LSpor & 8741 1338RSpor may have a spring perch and are not inserts. Not sure when that changed, but that's good news!

EDIT: the front koni's for M's are inserts, non-M cars don't have to worry about that. Here's what I'm talking about:
http://www.koni-na.com/pdf/boltstrut.pdf

[TUD]

Just an FYI, Bav Auto currently has Bilsteins on sale. HD Fronts for $175.00 each & the rear Sport for $75.00 each

[Vintage42]

Some say Bilsteins are stiff.
http://www.bimmerfest.com/forums/sho...7&postcount=24
http://www.bimmerfest.com/forums/showpost.php?p=7408161&postcount=2
http://www.bimmerfest.com/forums/sho...9&postcount=24
http://forums.bimmerforums.com/forum...2#post27342402
I like the softer ride of KYB or Monroe.

[FourPoints]

so I've been PMing back and forth with luciano136 about the ones he has in the garage, and reading the threads linked above and just had this thought, someone tell me if this makes sense, or if I'm crazy.

I am daily driving the car for the rest of the summer as it's, for the time being at least, my only vehicle. I don't want the car so rough riding that it's unpleasant, but at the same time I did buy the car specifically with the 2.8L because I wanted something that was fun to drive and very sporty. With that said, I'm not driving it real hard (that breaks too many things which are expensive to fix), but I do like to get a little spirited with it now and then aka I am seeing the traction control kick in about 25% of the time I shift into 2nd on an interstate onramp (and the tires are not to blame), though that may be partially due to the right rear shock going bad, but around town I drive it pretty casually and relaxed.

So what I'm thinking is that for the front, where I'll find the most potholes, speed bumps and other road irregularities I want a stock ride that is fairly forgiving, but for the rear I want it a bit stiffer to hold the power to the road for those times I want to get on the throttle a little bit on a winding back road or onramp and enjoy the car for what it's capable of.

So, until something needs replaced, I leave the fronts stock, and replace the rear with something stiffer and sportier. When the fronts ultimately need replacing, I replace them with something softer and OEM like (sounds like the KYB might be that eventual solution?)

Does this make sense, or is there some rule that you shouldn't run different types of shocks on the fronts and rears?

[gmushial]

I would not put expensive new Bilsteins on the rear unless you were going to put new Bilstein struts on the front, too. Struts are expensive to buy and install. If you are not going to replace struts now, and if you think the struts still ride OK, I would replace the shocks with Monroe, which are very inexpensive, and whose ride might match the old Sachs struts. The drive until the struts needed replacing, which could be tens of thousands of miles. At that time, you can replace all four corners with whatever your budget and taste wants. I am pleased with KYBs, a nice ride and not too expensive.

+1 have 50k miles on my KYB, and if/when they need replacing, they'll be another set of KYBs... the car is used 95% for touring, 5% weekend corner straight'ng - very happy with them.