Should I go coilover?

[Cletonius]

I'm looking to refurbish my entire suspension in the spring, I've got worn bushings and this ridiculous clunk from the rear when shifting. In the past I have competed in autocross regularly but had to stop after I got the E30 as I knew it would need a suspension refresh first. I'm hoping to get back into autocross this season and will be dailying my car as well as driving to/from events. Car in question is a 01/90 325is with a 5-speed and 3.73 gears. Stock motor.

I will be running stock 14" weaves for the forseeable future. Any tire size recommendations? I'm running the stock 195's now.

I'm going to do revshift 80a bushings for everything except tabs, those will be solids or delrin. I'll be doing all the mounts (engine, trans, diff) as well as a fuel tank, flex disc, and maybe shifter bushings if my cash flow allows. New ball joints will also be pressed in all around.

Anyways, I'm tossed up on suspension. I like how h&r races look with e90 hats but since I daily my car I'm concerned about driving in the snow while being that low. I like the sport cup kit but haven't seen many pics of how it looks, nor can I find good subjective feedback from owners.

I like the adjustability coilovers offer but there are so many to choose from. I'm leaning towards the $1500 kit from GC that has all the goodies but that puts me up around $2k for just parts. I have no problem with having to cut/weld my housings, but I will be doing all the work myself so less labor = win.

For about the same money I can do the fixed height with sways.

Help me out guys:

*How's my bushing choice?
*Can I run GCs with stock sways?
*Would a fixed suspension with sways be a better spend?
*What will be better suited to all season driving with snow?
*Will the adjustment collars corrode in winter? If so, how do I stop this?

edit: Also, any input on spring rates?

[bmwguy325is]

If you want to autox the car you need to figure out what class you want to run

[Cletonius]

class is not really as important as the fun factor. They can put it in whatever class it fits into. I used to run a Hotchkis equipped dakota in HS.

[jlevie]

I have a Spec E30 race car that is barely street legal and a fully restored bone stock 87 325is (okay it needs paint). The comparison between the two is remarkable. There is no way I'd want to daily the Spec E30, or anything similar. On the street the stock 87 is a dream and a joy to drive.

You can have a daily driver, or a race car. Pick one!

[einstein57]

*How's my bushing choice?
*Can I run GCs with stock sways?
*Would a fixed suspension with sways be a better spend?
*What will be better suited to all season driving with snow?
*Will the adjustment collars corrode in winter? If so, how do I stop this?

edit: Also, any input on spring rates?

I would never put delrin or urethane bushings for the engine, trans or diff. Too much buzz for a street car IMHO. I use urethane trailing arm, subframe, and RSM only. Everything else is factory. I do thing delrin shifter carrier bushing would be nice.

You can run stock sways. The vert front sway is a thrifty upgrade.

If your perfectly content with the height and rates of a particular conventional spring then go for it. I loved my H&R races but they were too high for my early model so i went coilovers.

You can pick up cheap second hand 7" springs to swap out for winter use.

KW makes a protection spray. I use pledge but i don't have to deal with road salt. Just sea air from being near the coast.

300-450f and 450-650 rear depending on your preference. Picking spring rates is like picking a bed. Whats "right" varies from person to person.

[FredK]

I would personally avoid using H&R Race springs in winter. They really drop the car down low enough that I'd worry about ground clearance. It's not a big deal to swap springs back to stock iS springs for the winter, though. That's what I do.

H&R Race paired with aftermarket sway bars would be a pretty decent autocross setup. It would keep your car's attitude flatter which it seems you realized with your Dakota's setup. Without aftermarket sway bars, your margin of error will be reduced on the autocross course, as the car will definitely pitch side to side.

Of course, if you are a great driver, you can overcome a lot of these obstacles. If you're a rather slow autocrosser like me, mistakes can't be hidden as easily with softer springs.

[Cletonius]

I have a Spec E30 race car that is barely street legal and a fully restored bone stock 87 325is (okay it needs paint). The comparison between the two is remarkable. There is no way I'd want to daily the Spec E30, or anything similar. On the street the stock 87 is a dream and a joy to drive.

You can have a daily driver, or a race car. Pick one!

Eh, I've heard this comparison for years. I agree for the most part but at this stage of my life I do not have the space or desire to have a dedicated race vehicle. I would like to have a sporty daily driver that I can take to the track with minimal hassle.

For comparison, my dakota had the hotchkis spring package, quickor sways, solid body mounts, urethane suspension bushings, and bilsteins. Daily driven for 125k miles that way. snow, ice, whatever. The E30 is soft by comparison and I'd like to get some of that road feel back.

Here's a pic: http://omg-stfu.com/temp/dak.jpg (you may have to copy/paste, I don't remember if I put this site in my access list)

I would never put delrin or urethane bushings for the engine, trans or diff. Too much buzz for a street car IMHO. I use urethane trailing arm, subframe, and RSM only. Everything else is factory. I do thing delrin shifter carrier bushing would be nice.

You can run stock sways. The vert front sway is a thrifty upgrade.

If your perfectly content with the height and rates of a particular conventional spring then go for it. I loved my H&R races but they were too high for my early model so i went coilovers.

You can pick up cheap second hand 7" springs to swap out for winter use.

KW makes a protection spray. I use pledge but i don't have to deal with road salt. Just sea air from being near the coast.

300-450f and 450-650 rear depending on your preference. Picking spring rates is like picking a bed. Whats "right" varies from person to person.

What exactly does the diff bushing do? The diff is bolted to the subframe too, I'm guessing the bushing takes the load? (Maybe this is my rear end clunk when shifting?) I can do OE engine/trans mounts, they're time tested. I only went urethane in my truck becuase it was less expensive than the stock replacement.

Have you heard good experiences with the protection spray? One of the reasons I'm considering coilovers is so that I can slam it down in the summer and jack it up for winter. The guy (trevor?) I spoke with at GC said that if I sectioned an inch from my housings I would be able to get back up to within half an inch of stock height.

I've heard that about spring rates. I'd like something firm but not so much where I feel every ridge in the road. Why are the rears stiffer? There's less weight back there so shouldn't less spring be needed to keep it in check?

I would personally avoid using H&R Race springs in winter. They really drop the car down low enough that I'd worry about ground clearance. It's not a big deal to swap springs back to stock iS springs for the winter, though. That's what I do.

H&R Race paired with aftermarket sway bars would be a pretty decent autocross setup. It would keep your car's attitude flatter which it seems you realized with your Dakota's setup. Without aftermarket sway bars, your margin of error will be reduced on the autocross course, as the car will definitely pitch side to side.

Of course, if you are a great driver, you can overcome a lot of these obstacles. If you're a rather slow autocrosser like me, mistakes can't be hidden as easily with softer springs.

Negative on spring swapping. I live in a condo and will be doing the work at my parents house 4 hours away. They have an extremely large climate controlled garage that's brightly lit, where all work will be taking place. It's against the bylaws to do any car work in the parking lot at home, and they have begun fining for as much as possible now that taxes went up... One of my neighbors got a warning for topping off his washer fluid.

I was hoping that the stiffer springs would help the sway bars work, or is that not how this works?

I wouldn't say I'm a great driver and I'm not competing for points, more for the fun of it. I'm pretty solid in the middle ranks. Besides, the E30 is nothing like a 4500 pound V6 powered truck. It's going to be comical the first run I'm sure. The truck only put 128HP to the rollers, I'm sure the E30 puts down more than that...

[M-technik-3]

I have a Spec E30 race car that is barely street legal and a fully restored bone stock 87 325is (okay it needs paint). The comparison between the two is remarkable. There is no way I'd want to daily the Spec E30, or anything similar. On the street the stock 87 is a dream and a joy to drive.

You can have a daily driver, or a race car. Pick one!

Not true some of us don't mind suspensions that are stiff on the road. Spec-E30 is pretty mild for many here.

I get out of my kart (no suspension) and into an E30 with J-stock and the thing feels like a pig. Just depends on what your used to I guess.

Coilovers are fine for street depending on dampening rates and spring rates also helps the quality of pavement is decent and not say Bosnia-Herzegovina bomb blasted ruins.

[einstein57]

What exactly does the diff bushing do? The diff is bolted to the subframe too, I'm guessing the bushing takes the load? (Maybe this is my rear end clunk when shifting?) I can do OE engine/trans mounts, they're time tested. I only went urethane in my truck becuase it was less expensive than the stock replacement.

Have you heard good experiences with the protection spray? One of the reasons I'm considering coilovers is so that I can slam it down in the summer and jack it up for winter. The guy (trevor?) I spoke with at GC said that if I sectioned an inch from my housings I would be able to get back up to within half an inch of stock height.

I've heard that about spring rates. I'd like something firm but not so much where I feel every ridge in the road. Why are the rears stiffer? There's less weight back there so shouldn't less spring be needed to keep it in check?


I was hoping that the stiffer springs would help the sway bars work, or is that not how this works?

The bushing dampens rotational torque on the mounting point

Them make spring sleeves if your really worried about it. Its goes on the outside of the springs to prevent mud, snow, dust from collection in between the coils and contaminating the strut seals.

Leverage. The e30 rear suspension is like a walnut cracker.

The suspension works as a system. Everything needs to complement each other to work in harmony. Stiff springs and stiff sways make for a poor street car. You'll be happy with a vert front and stock rear.