Help me plan out my 2002 suspension

I'm planning to tear into my 2002's suspension over the winter. I've owned the car for 24 years, and the last time I went through the suspension was probably 20-22 years ago, so I figure it's time. When I put it together I was using it for autox, and I was a lot younger and more tolerant of abuse. I'd like to make it a little happier on longer drives. Not stock, but not quite so harsh. I'd also like to dial in a little more front camber if possible, but that's not a major consideration.

The current setup is Bilstein Sports, stiffer and slightly lower springs of unknown origin (I was told Eibachs, but they don't look like Eibachs to me - no markings or paint left on them, but they're linear, not progressive), 25mm F and 19mm R bars (rear adjustable), polyurethane bushings all around. The bars and springs came with the car; I put in the Bilsteins and bushings.

One of the springs is sagging, so those are being replaced. Eibach makes a set of progressives that seem suitable, so that's where I'm going. Everything else is up for grabs.

I'm thinking putting in new poly bushings isn't a bad idea; the old ones seem OK, but they've been in there a long time. I've considered going back to rubber, but it's hard to argue with the ease of poly. I'm sure rubber would take a bit of the harshness out, but I'm not sure how much. And I dread having to replace them again down the line - I'm still scarred by trying to coax the originals out all those years ago.

The shocks & struts are the big question. I've got a set of Bilstein HD rears on the shelf, but the fronts have been unavailable for a long time. Way back when some people recommended Sports in the front and HDs in the rear, and I suppose trying that is the easiest option. In fact I should probably just throw the rears in now so I can drive the car and see how I like it. If it's still too rough, I'll have to see if I can track down from front HDs, but even then I don't know if they will do the trick.

That said, the other option I'm considering is making the switch to Koni. I can get a set of Koni Sports (yellow) and Eibach springs for under $700, which seems a pretty decent price. I've never had Konis, so I'm not really sure how they differ in terms of feel. I've read a lot about the technical differences, and some users suggest they are softer over smaller imperfections than the Bilsteins, but it's hard to translate that information into something as subjective as road feel.

So: rubber and Koni, rubber and Bilstein Sport/HD, rubber and Bilstein HD, poly and Koni, poly and Bilstein Sport/HD, or poly and Bilstein HD?

Bonus round - adding front camber. After putting M3 control arms that add 0.75deg of camber in my 128i and liking the effect, I started thinking about doing that same in the 2002. Camber plates are available, but good ones are expensive and there isn't a lot of range of adjustment with stock springs (I really don't want the complication and cost of switching to coil-overs). Fixed camber plates seem like they might be a good option, and are in the same range of camber as I have in the 128i, but the only ones I can find don't have a great reputation from what I've read, and also lift the front end a bit. The only other choice is an offset spacer that bolts under the ball joint and moves the steering arm out, giving about 1.7deg of negative camber. This seems like a lot for the street, but I like the ease of mounting, especially since I'm doing the ball joints anyway. Is 1.7deg too much? Are there any other ways to achieve this I haven't thought of? Is it even worth the trouble?

I will get the HDs in the rear this week and report back on my findings, but I'm interested in opinions on any of these points.

Starting at the front, the inboard control arm bushings should remain rubber/stock.  The range of motion and vibration with ploy bushing is a track/race car  application, in my experience. I would use the poly strut rod, that you want more fixed/solid feel. 

Depending on what size rims and their off set you use, now you can add camber.  You are correct, the stock front OD springs will give you very little room to work with, the top spring hats take up that much space.  That said you can bend the strut housings, a little.  Call Jeff at Ireland Engineering, they do it and it works.  Then the fixed upper camber plates for on top. If you can find the off set spacers for the bottom of the struts they return the front control arms to a more stock bump steer. I'm not sure anyone is still making these at this time. 

Are you adding fender flairs?

In the rear, it starts with the differential. Use the poly bushings.  Then on the rear sub-frame, use the Ireland bushings. The trailing arms, that would be your call.  Street car, use the stock rubber.   

Chiming in since this thread is very relevant to my interests. I'm very interested in having a street oriented setup that still feels tight and responsive.

The only thing I can really be of any assistance for is to recommend you look at AKG for the strut spacers. They seem to have them in stock and they do quality work. https://www.akgmotorsport.com/product/bump-steer-strut-spacer-set-for-bmw-2002/

They also make one of the most badass shifters for the '02, the tunnel mounted shifter, which doesn't really fit the brief of your build. 

In reply to jr02518 :

So rubber for the inner control arm bushing and trailing arm bushings. Poly for both ends of the strut rod? I've got newish stock rear subframe bushings with poly inserts waiting to go in.

No plan to add flares. Wheels are 15x7 running 195/55-15. I have considered throwing a set of 185/70-13s on one of my sets of 13" wheels, which would certainly offer a more compliant ride. I'm not sure I want the trade-offs in handling, however.

Ireland lists both the offset spacers (the AKG ones linked to above correct bump steer but are not offset and do not add camber) and the fixed plates. I'd rather not have to send off parts to be modified if I can avoid it. I don't need both certainly, so it really comes down to one or the other. Not sure how much camber I want for this sort of setup.

Wow, I could have posted the identical thing about my Alfa GTV, including the number of years we've owned it.  Ok, it's actually 23 years and not 24.  But it, too, spend most of the last two decades autocrossing and tracking.  And now looks to have a more comfortable retirement.

After some consideration, I'm leaving the poly bushings.  Like you, putting the original ones is seems traumatic remembering taking them out, and noting how they are generally loaded, I don't think they are the major adders to harshness of the current ride- that would be more the tires and the springs.  

I have red Koni's on my car- and avoided the yellow ones, as they were harsher ones to start with.  More adjustments in the yellows, for sure.  But what I need is not too much compression damping and reasonable (my mind just went blank on the opposite)- which they already have.  That way, progressive bumps will not force the car into low stances.  But I may send the shocks to a Koni rebuilder just to freshen them.   If you are looking for more road driving, you may want to look into your choice of Koni yellows.  

Spring wise, I have some mild upgraded springs for a Spider- and I need to slightly cut down the rear spring to get the ride height even.  Otherwise, I'm looking for more comfort than stiffness, and I do want to raise up the car a little- Alfas all have sump guards that I don't ever recall seeing on BMWs, and I'm pretty tired of it hitting things.

The one thing you've not brought up are tires.  While I've had a great relationship with autocross tires, finding good street tires has not been fun.  You have a tougher start with 13" wheels, whereas my stock wheels are 14" - but it's really hard to find good tires.  My last set were Pirelli Sport Veloces, and they were neither sport nor veloce.  So I'm *probably* going with Vredestein Classic tires.  Look right, and have modern rubber compounds on them.  For sure, I don't need the ultimate grip of R compounds, and they will certainly be better than the Pirelli's that I still have.  So the Classics seem like a great choice will look cool on the original Campy mag wheels.

Your camber issue is way different than my car, so no input there....

In reply to alfadriver :

My car isn't so low that it bottoms out, so I'm not too worried about the lack of a sump guard. I wouldn't be going any lower than it already is.

The only quality damper options are the Bilsteins (Sport or HD) or Koni Yellows. I would anticipate setting the Konis at or near full soft.

As far as bushings, I understand both arguments. jr02518's recommendations put rubber where the suspension is designed to use the bushing to help damp movement, but squeezing them in there is sort of a pain, and if I ever have to pull them out...ugh. My lazy self likes the idea of just sliding in new poly and calling it a day, but it does likely compromise the ride quality some.

With my 15" wheels tire selection is a little better. I've got BFG Sport Comp 2s on there now (correction to the above: they are 195/50-15, not 195/55), but they'll be replaced in the spring. Bumping up to a 55 sidewall may help a little; I haven't decided what tire to put on yet. Going to 13" would change a lot, but not all for the good, I fear.

"So rubber for the inner control arm bushing and trailing arm bushings. Poly for both ends of the strut rod? I've got newish stock rear subframe bushings with poly inserts waiting to go in."

That would be a "yes" to both ens of the strut rod.  You will feel it under breaking, it firms up the suspension from toe in.  The inserts in the sub frame bushings and the poly differential poly bushings. Is your diff. open or a LSD?

The rim width and off set are the next issue.  A 15x7 ET25 fits and the E30 15x7.5 ET25 can work but you will need longer wheel studs.  The split front hub is a pain to upgrade but you are replacing the bearings and seals anyway,  right?  You are correct on the tire size. again the front end is the limiting factor.  If you can find a set of Mahle 13x6 BBS rims and the right tires, that is the ticket, old school style.

I have some 14x6 Mahle BBS ET18 rims for sale, they offer even more tire, newer tire options.

Camber, welcome to the quest. Not going to the coil over set up is only going to net so much.  That and not being able to adjust for any differences from side to side could be an issue.  These cars are not as square as we wish they were. The stock spring hats with the fixed camber plates offer just a little relief. Having the struts bent adds more. If you can find them, the offset bump stop spacers, again even that much more but you have to confirm the wheel fitment. The control arm at the ball joint might not cleat the inner rim barrel.  Not sure about the non off set spacers and the rims.

I can see you're trying to do this without dropping a ton of money. My immediate thought was to call the guys at Ground Control.

Camber plates and spring rates setup exactly for what you want to do. I've had GC stuff on two E30s and my old BRZ. 

Again, based on the age of these cars I would "buy" new control arms for the car.  The chances are unfortunately good that one or both of you current ones is tweaked to some extent. Until you have them off the car and on the bench the extent of their condition is a guess.  If you happen to remove the inner rubber bushing you will find the two pressed steel haves that make up the control arm offer at best a "V" shaped grove the the rubber bushing is pressed into.  A poly bushing is never going to conform to the available space and provide a street quality ride. In a "race car", you can change them as required.

You can locate used control arms, they are out there.  But what you might find only enforce what you already have on your car.

Yes, Ground Control makes a great camber plate.  But you end up with the spherical rod bearing to the shock front end.   

I'd consider getting Fat Cat Motorsports to custom valve some Bilsteins for you. I did that when de-tuning my RX7 from track toy to street toy and the shock valving  are fantastic. Even running the stiffish springs that I do. 
I'm not a fan of poly bushings for the most part because of too much NVH but it can be subjective 

I have never heard of someone wanting to be suspended.  But if you need to, go to the track and act like a jerk and you will get there.

Ohhh.  Suspension!

Never mind.

I appreciate all the suggestions, but I think we're heading a bit further down the path than I'm intending to go. The budget for this is a grand. I'll replace anything I find that's tweaked, but proactively spending $500 on new control arms is not going to happen. I doubt sincerely that coilovers and/or custom-valved dampers are in the budget. Bushings are probably going to add up to ~$200, springs are ~$250, and four dampers (if required - see discussion above) will be $4-600, so even with off the shelf components there's not a lot of room to maneuver. If I add in either fixed camber plates or the offset spacers I'm pretty much maxed out.

The car already has poly in it now. Everywhere. I will either be replacing those with new poly, or using rubber, or some combination of the two as discussed above. The wheels should have plenty of space for offset bump steer spacers - they are a VW fitment and require 1/4" spacers. I have already installed longer wheel studs.

In reply to 02Pilot :

Sounds like you've answered your question on your own a bit. 

Sounds like the Bilstein HD's, fresh springs, and some new bushings are the way to go. In my experience, poly doesn't seem to have as many NVH penalties in the right locations. 

When I rebuilt the rear subframe in my E34, I went with rubber for everything other than the subframe and sway bar bushings. The only real increase in NVH comes from low speed turning which produces a little bit of bushing squeak. Otherwise the car is pretty close to stock comfort from the NVH side of the house.

It really depends on what you want to sacrifice given your budget. It seems like you could probably make sizable gains in ride quality by going back to 13's. You'll add sidewall and with the right wheels you might even save significant rotational mass. Less mass means less inertia for the dampers to deal with all other things equal.

In reply to MTechnically :

Good point on the weight difference between 13" and 15" wheels. I should weigh what I have now to see just what I'm dealing with. I have to be a little careful with 13" rims to make sure they clear my front brakes, which are a good bit larger than stock.

I understand the appeal of 13" wheels but..... what tires? The 165r-13 is long gone. The 185/70 Tirerack recommends is a bit too tall and the Sprint Classic is a bit too vintage looking for a 2002. The 175/70 are pretty much all garbage. 205/60? If you can find them they are, IMO too wide for the 5" wheels.  185/60 too short. 

I have to import 13" tires from the Europe when I need them for cars at the shop.  On that subject Demon Tweeks is really good about shipping tires to the states. I am ordering 13" A539 Yokos from them for my car.

I would go to 187/70-13" tires for a whole host of reasons; compliance,  weight and feel.

The taller sidewall will significantly add to the ride quality and to my mind is more in keeping with the way the car would have handled originally. All that tire wind-up (for me) makes a car fun.

I don't know the weight of your wheels but in general I'd expect the 13" tire to be 2-3lbs lighter per tire and around the same per rim. So the 13" combo may be as much as 6lbs per wheel lighter, which is pretty noticeable on car with not a lot of power. 

The rubber bushings suck to replace but they do make the car nicer, it's not a huge difference but you do notice.

Now I am biased towards cars with skinny tall tires being more "fun". I race cars with both tall skinny tires and short fat slicks. A car moves around on the tires is more fun as well as being less harsh.

Naturally this is all my very subjective .02

Now I am really torn on the 13" vs. 15" question. Tire Rack doesn't offer much in 13, but other tire sources (Simple Tire and Giga Tire, for example, as well as Amazon and ebay) have lots. Most probably suck, but it's hard to know. I don't really need super sticky (the BFGs on there now are great, but a bit overkill for 99% of the driving I'm doing these days), but reasonably quiet, predictable, and decent wet and dry are important.

EDIT: Just found a General RT43 in 175/70-13 that's probably about as good as it's going to get. Those weigh 14lbs each vs. 20lbs each for the current BFGs, so that's 6lbs lighter already, never mind the wheels. Yowza.

I'm going to see what I have in 13" wheels. I know I've got a set of steelies, but they won't fit over the brakes. I'm pretty sure I've got a set of 13" basketweaves that should fit, but they probably need refinishing before I would put them on the car. I sold my turbo bottlecaps ages ago (that was probably dumb). I might want to track down a set of turbines - I always liked those wheels but never had them.

Won't have a chance to work on the car for a couple days, but when I do I'll weigh the wheels, as well as throwing in the Bilstein HD rears and see what that does.

Minor update: I threw the Bilstein HDs in the rear this morning. A quick test drive suggests that they are a good bit more comfortable than the Sports I had in there, so that's a step in the right direction. Right now I'm thinking my progression is going to be four springs and HDs for the front (assuming I can find them), then see how it feels. The combination of progressive springs and less aggressive dampers may be enough; this also allows me to use the offset bump steer correction spacers. If it's not, the next step will be 13" tires (which would necessitate camber plates if I want more camber). I'm going to inspect the poly bushings and decide whether they need attention (they are 20 years old at this point, so it's entirely reasonable to think that they will). Having just fought with the rubber bushings on my Saab's control arms, I'm thinking that I'm probably going to stay with poly, but we'll see how I feel when I get to that point.

Good deal. From what I remember of BMW days, the Bilstein Sports and HDs have nearly the same valving, but the Sports are shorter to deal with lowering springs. 

Looks like Ireland Engineering has the front HD's in stock. At least according to their site here http://www.iemotorsport.com/bmw/item/02bil023.html. Might want to jump on them.

Seems like  a good starting point. I totally understand the desire to stick with 15's for the moment.

In reply to z31maniac :

That was the rumor, but Bilstein's website suggests otherwise, albeit ambiguously. The B6 (old HD) lists "Parameter 163/76," which I'm assuming are values for compression and rebound, while the B8 (old Sport) lists "Parameter 200/60". I wish I knew more about what those numbers mean, but Bilstein isn't telling.

In reply to MTechnically:

IE seems to be selling gold-plated versions, at least judging by the prices. I think I've found a source that's a bit more reasonable, but I'll know for sure once I place and receive the order.