Stiffer Springs or Bushings?

[brian52555]

Hey everyone,

Just got back from my first BMWCCA driving event last weekend - I had a blast. Currently my car is set up with HR / Bilstein sports, UUC swaybar kit, and Sparco strut brace. Handling is worlds better than stock, but there was still a bit more roll than I would have liked on the course, going around the slalom/skidpad.

In any case, this may seem like a dumb question and it might be, but would my money be better spent on stiffer springs (HR Race?) or doing some maintenance stuff like Control arms, bushings, RTA bushings, etc. I have no idea what's been done since the prior owner lost all service records. The front trailing arms and bushings look about done though.

I realize that maintenance should come first but was just wondering from a performance standpoint, which mods would make more of a difference.

Also, at this point I'm not really interested in coilovers - don't want to modify my strut housings... maybe I should just keep the HR Sports until I'm ready to go nuts and spring for AST coils? I wonder how much better handling the HR Races are compared to the Sports.

[bryant.cw]

Bushings make a huge difference.

[Jean]

What model/year car? As a cheap upgrade you can swap swaybars from a cabrio for example. Sports are too soft for autocross if you are looking at anything more than just "having fun".... bushings won't decrease body roll either but obviously fall under maint.

[jlevie]

To reduce the roll, you need stiffer springs. But if the bushings are worn they need to be replaced. If you are going to track the car I'd recommend that you immediately do:

Motor, transmission, and differential mounts
Subframe bushings
Rear Trailing arm bushings
Offset Control Arm bushings

Use 75d poly bushings. The tighter suspension will make the car more responsive and more stable.

H&R Race springs, Bilstein Sport shocks, 22/19mm sways, and camber plates is the Spec E30 handling package. It works really well, isn't terribly expensive, and can be lived with on the street. A car set up this way corners relatively flat.

[brian52555]

Nice. Thanks guys.

Car is an 87 325iS with a 1/4 million miles. I've done a bunch of maintenance since getting it last year - timing belt, brakes, oil pan gasket, clutch master/slave, valve adj, etc etc. She is running pretty well but I think I will need to address a small tranny seal leak eventually.

Motor, transmission, and differential mounts - Did new OEM engine mounts last year. Should I go poly? For the differential, I was told the solid OEM bushing is indestructible. Tranny mounts probably need to be changed - what do you think about the UUC enforcers?

Subframe bushings - Sigh, was hoping to avoid this one. I guess while doing this I might as well go stainless steel brakelines.

Rear Trailing arm bushings - Someone recommended adjustable bushings last weekend, however I've heard bad things about them online. What's the story?

Offset Control Arm bushings - Yes, I'll probably do control arms and tie rods and M3 CAB. Anything else I'm missing in that area of the car? I've got an e36 m3 rack ready to swap in, guess I could just do it then?

[JRKOUPE]

Nice. Thanks guys.

Car is an 87 325iS with a 1/4 million miles. I've done a bunch of maintenance since getting it last year - timing belt, brakes, oil pan gasket, clutch master/slave, valve adj, etc etc. She is running pretty well but I think I will need to address a small tranny seal leak eventually.

Motor, transmission, and differential mounts - Did new OEM engine mounts last year. Should I go poly? For the differential, I was told the solid OEM bushing is indestructible. Tranny mounts probably need to be changed - what do you think about the UUC enforcers?

Subframe bushings - Sigh, was hoping to avoid this one. I guess while doing this I might as well go stainless steel brakelines.

Rear Trailing arm bushings - Someone recommended adjustable bushings last weekend, however I've heard bad things about them online. What's the story?

Offset Control Arm bushings - Yes, I'll probably do control arms and tie rods and M3 CAB. Anything else I'm missing in that area of the car? I've got an e36 m3 rack ready to swap in, guess I could just do it then?

good advice here.......if your sf bushes are good.....leave that one alone....but if u r serious do it!
IE makes really good sf bushes and the yellow poly mtr mounts. i use em. Powerflex makes relly good lcab's....i use em on track and on streets.....


Bimmerworld makes hard rubber tranny mts...and cheap..i use em.

i track my car mainly...but i drive her to tracks!...I run HR race and GC Konis......sooon to do c/o's.....I use all the stuff i spoke of....all great for over yrs of tracking.

and i run oe bars.

e 30s do lean alot....youd need big springs to correct...like 500/700-600/800

[JRKOUPE]

Nice. Thanks guys.

Car is an 87 325iS with a 1/4 million miles. I've done a bunch of maintenance since getting it last year - timing belt, brakes, oil pan gasket, clutch master/slave, valve adj, etc etc. She is running pretty well but I think I will need to address a small tranny seal leak eventually.

Motor, transmission, and differential mounts - Did new OEM engine mounts last year. Should I go poly? For the differential, I was told the solid OEM bushing is indestructible. Tranny mounts probably need to be changed - what do you think about the UUC enforcers?

Subframe bushings - Sigh, was hoping to avoid this one. I guess while doing this I might as well go stainless steel brakelines.

Rear Trailing arm bushings - Someone recommended adjustable bushings last weekend, however I've heard bad things about them online. What's the story?

Offset Control Arm bushings - Yes, I'll probably do control arms and tie rods and M3 CAB. Anything else I'm missing in that area of the car? I've got an e36 m3 rack ready to swap in, guess I could just do it then?

re adjustable rear's.......if your specs are good...Id just do IE poly fixed rcab's..i did. I track her hard and rear is PLANTED w/o adjustability.

Some e30s are just shot in the rear and specs on lowered cars are terrible.

But alot of folks use the adjustables w/ no issues....but you dont NEED them.....if you r car is solid and in spec...


re engine mts...if you run her hard at the track.....id watch the oe mtr mounts.....but go w/ the IE yellows...nvh is not bad at all..and car feels more solid...I love em.

I sheared oe mtr mts in 2 hard track days....but Im guessing they were orig.....90 k miles....and very oily........sheared the oe trans mts as well.........