E46 Fanatics Forum banner

XI Suspension Guide

205K views 283 replies 104 participants last post by  minengr 
#1 · (Edited)
I'm sick and tired of seeing thread after thread on suspension so read this first. If there are any changes needed to this guide please let me know.

First statement: RWD suspension is NOT the same. If you read in the general forum that H&R springs are super comfortable or Eibachs will slam your car, that is NOT true for the Xi. Xi models have less suspension travel than the RWD models and therefore have different ride comfort characteristics. This also means that you CAN NOT use parts (none of them so don't ask) from a RWD car on an Xi. They have different suspension geometries and dimensions so please confirm any advice you get in the General E46 forum before you buy stuff as it's likely wrong...or just read this guide. With me so far? Ok, read on.

In general you have three options:
1.) Replace your suspension with an OEM replacement. This will be the most expensive option and will not lower your car at all. Depending on how long it has been since your last suspension replacement, it may even raise your car. This set up will have a very soft ride with quite a bit of body roll but will be able to go over any obstacles that may come your way. It also makes it quite a bit easier to jack your car up since you won't have to drive up on 2x4s to get the jack under your car. Remember that you can replace the shocks/struts with aftermarket components and still use OEM springs if you should desire.

2.) Replace your suspension with aftermarket shocks/struts and springs. This option is the cheapest way to go and will lower your car a moderate to high amount depending on what spring you buy. The shock/strut has very little to do with the ride height so we'll start with springs. There are, in general, two options for springs on the Xi. Eibach springs lower the car a moderate (0.75"-1" ) amount while retaining much of the comfort that OEM springs would give you. This seems to be the best option for many people on the forum because we daily drive our cars. This will be similar ride height to a RWD sport package. If you don't and want more performance, H&R is the next set. H&R springs lower the car a high amount (1.5"-2" ) but substantially degrade the ride comfort that you would get out of your car. This ride height will be similar to a RWD ZHP. This option is good if you autocross/track the car and don't use it for your daily driver or if the roads where you live are flawless (but then you wouldn't have an Xi anyway right?). For shocks/struts you, in general, have two options. Koni shocks/struts are the most expensive choice but they are adjustable and the rear ones tend to be a bit more reliable than the Bilsteins. If adjustability is what you're looking for, look no further than the Konis. I personally have them and love them. Konis are ok for cars lowered a lot to not lowered at all. The second option is Bilsteins. They are cheaper and not adjustable but the rears tend to leak. There are reports that running E36 M3 rear shocks will solve this problem but that increases the cost. (Thread: http://forum.e46fanatics.com/showthread.php?t=830014) Bilstein shocks come in both "Sport" and "HD". The "Sport" models have a shorter stroke and are better for cars that are lowered a lot. The "HD" models have a longer stroke and are better for cars that are moderately lowered or not lowered at all. There are other shock/spring manufacturers out there but I cannot vouch for them nor have they been vetted by the forum. If you are someone who has experience with other manufacturers, please let me know and I will update this.

3.) Replace your suspension with coilovers. If you want to go this route, ensure that you get a kit that is designed specifically for the Xi models. Coilovers provide adjustment in ride height on the fly and also provide the most substantial ride height reduction (yes you can "slam" your car with this). However, they do tend to be uncomfortable and more jarring than any other option and also have a tendency to wear through CV boots quickly causing potential front axle failure. They are more expensive than shocks/springs but cheaper than OEM. Also consider that you might need camber plates and arms to compensate for the drop unless you don't like even tire wear.

Please, please, please, please do NOT buy Raceland coilovers or any other cheap shiity parts you find on eBay. They are cheap for a reason and I really would NOT buy crappy parts when it comes to the only thing that's holding your car up. There have been documented failures on these parts and they pose a substantial safety risk to yourself and others if you install them. That said, if you still feel as though you want to buy and install them after this warning, then it's your car and up to you.

Some people have asked if they can combine aftermarket and OEM components for their suspension and the short answer is that it depends. The long answer is that if you want to replace your springs and run OEM shocks/struts then you'll have issues. The OEM shocks/struts are not valved appropriately for the aftermarket springs and will wear out quickly. If your question is how quickly, I don't know as that depends on a lot of things. If you want to run aftermarket shocks on OEM springs, go for it as long as the stroke of the piston is long enough (Bilstein HD works great).

If you are going to be doing a suspension replacement, ensure that you purchase all new hardware to perform the task you are doing. This includes the upper mounting nuts, lower mounting bolts, etc. Also purchase new upper shock/strut mounts and rubber bushings. You can reuse the bump stops however they will need to be cut approximately 0.75" if you are lowering the car.

For more firsthand ratings on what people think of different options, check this link:
http://forum.e46fanatics.com/showthread.php?t=731343

For DIY Instructions follow this link:
http://www.bmw330ci.net/projects/suspension.php
The car is a RWD car but the method is the same.

Parts you will need if you want to do a complete refresh:
07119900402 - Rear Lower Shock Bolt x2 (Required)
33521136283 - Rear Shock Protector Tube x2 (Optional)
33531094518 - Rear Lower Spring Pad x2 (Optional, replace if yours is damaged)
33531136385 - Rear Upper Spring Pad 5mm x2 (Optional, replace if yours is damaged)
33531094754 - Rear Upper Spring Pad 14.5mm x2 (This is the thicker version of the one right above, pick one or the other - Optional, replace if yours is damaged)
33526772864 - Rear Shock Mount Gasket x2 (Required...unless you like water in your trunk)
33531136395 - Rear Bump Stop x2 (Optional)
33521092362 - Rear Upper Shock Mount x2 (Highly suggested)
07119905374 - Rear Upper Shock Mount Nut x4 (Highly Suggested)
31356778832 - Front Lower Strut Bolt x2 (Required)
31336752735 - Front Upper Strut Mount x2 (Highly suggested)
31331091867 - Front Upper Spring Bushing x2 (Suggested)
31331096664 - Front Lower Spring Bushing x2 (Suggested)
31311139453 - Front Strut Mount Cap x2 (Optional, replace if you lost yours)
31336752832 - Front Bump Stop x2 (Optional)
31316769731 - Front Upper Strut Mount Nut x6 (Highly Suggested)
31106774714 - Front Upper Strut Nut x2 (Suggested)

Koni Part Numbers:
8741-1481RSPORT x1
8741-1481LSPORT x1
8040-1343SPORT x2

Bilstein Part Numbers:
24-024532 x2 (Rear HD E46)
24-024532 x2 (Rear HD E36 M3)
22-052810 (Left HD Strut) x1
22-052827 (Right HD Strut) x1
22-052834 (Left Sport Strut) x1
22-052841 (Right Sport Strut) x1

H&R Part Number:
29383 x1

Eibach Part Number:
2089.140 x1

Thanks to Dreamliner330 for the above list.

Vendors for Suspension parts:
Pelican Parts
ECS Tuning
Tire Rack
Your local dealer
The internet

Disclaimer: This post is simply a set of recommendations on what you do with your car. It is still up to you to make your own choice on what to buy and how to safely install these parts on your car. If performing this level of work is beyond your capabilities, please take your car to a professional who can appropriately install these parts for you. The suspension is one of the most important systems in your car and you should therefore not compromise any safety when it comes to it.

Good luck!
 
See less See more
#38 ·
Shawdow, let me know your impressions of the H&R's, I'm going to make the decision in a couple weeks. I have to wrap up doing the DS Tie-Rod as the boot was torn and I had to wait for it to arrive!

Joe
 
#41 · (Edited)
I was pretty set on going with bilstein's and h&r springs when getting to this but only skipped over most stuff but seemed like the prevailing choice of most xi owners.
With that said, didn't know there was a difference with the HD and the Sport. Anyway, to get to the point; define "moderately lowered" vs. "lowered a lot".
Is a lot an xi aspect or is a lot an aspect of coils where the car sits an inch off the ground? I mean I think I'd consider the H&R drop pretty moderate so the HD's should be fine, no?
Lastly, would the choice between Sport's and HD's make that much of a difference with the H&R springs?

Thanks in advance for all the answers ahead of time and this thread! Will surely help a lot of people and I'm sure I'll be back with more noob questions the more stuff I look up...
:thumbsup:
 
#59 ·
I apologize that I missed this before but the actual defined measurements of what "moderate" and "a lot" are in the first post of this thread along with which shocks you should get for which setup.

Feel free to come back with good questions and if they haven't already been answered in the OP, I will add them to the post.
 
#76 ·
Hey I got a question. I have a 02 325i sport package and I am looking into buying the koni fsd kit with the eibach pro kit springs. What are your opinions on this set up and well it lower it fine or will I need to do any modifications to anything?


Sent from BimmerApp mobile app
 
Top