Where to start with suspension?

[1more1]

Hi, this is my first post here. I'm driving a 2009 128i 6MT Base with 160,000 KM. I've been driving it for 2-3 months now and so far so good! I am only planning to DD the car and maybe take it to some autox eventually.

I want to start improving the car; I'm not happy with the suspension as it stands. It's pretty squishy. There seems to be quite a bit of body roll and understeer in long sweeping bends at high speeds. These are the two things I'd like to correct first.

Regarding the understeer; I understand that adding a bit of negative camber to the front wheels should help. I can do the alignment pin mod to get started but am also considering purchasing M3 control arms.

The car is starting to get up in miles so I was also thinking that the best place to start is with new struts and springs. Something with adjustable dampening and mild lowering (I have to winter drive this).

Lastly, I realized that my car doesn't come with a rear sway bar. I was thinking of putting one in (15mm or 20mm) to help stiffen the rear end. I also understand that I have to drop the subframe to do this and at that point I should also put in the M3 RSFB while I'm there.

Given that I plan to DD this car where would you guys recommend I start? What is the best bang for my buck. I only want to do one of these three mods for now. I will do the work myself so I'm not worried about excess labour form doing the work separately but I don't want to pay for too many alignments either.

Thanks for the tips in advance! I hope to be able to contribute more and more to this active forum as I learn more about our cars.

Edit: Oh also if some Canadians could chime in on where to source performance parts? I've been looking at ECS and Turner but I'm wondering if there are better options living North of the border.

[Suprgnat]

Originally Posted by 1more1

Hi, this is my first post here. I'm driving a 2009 128i 6MT Base with 160,000 KM. I've been driving it for 2-3 months now and so far so good! I am only planning to DD the car and maybe take it to some autox eventually.

I want to start improving the car; I'm not happy with the suspension as it stands. It's pretty squishy. There seems to be quite a bit of body roll and understeer in long sweeping bends at high speeds. These are the two things I'd like to correct first.

Regarding the understeer; I understand that adding a bit of negative camber to the front wheels should help. I can do the alignment pin mod to get started but am also considering purchasing M3 control arms.

The car is starting to get up in miles so I was also thinking that the best place to start is with new struts and springs. Something with adjustable dampening and mild lowering (I have to winter drive this).

Lastly, I realized that my car doesn't come with a rear sway bar. I was thinking of putting one in (15mm or 20mm) to help stiffen the rear end. I also understand that I have to drop the subframe to do this and at that point I should also put in the M3 RSFB while I'm there.

Given that I plan to DD this car where would you guys recommend I start? What is the best bang for my buck. I only want to do one of these three mods for now. I will do the work myself so I'm not worried about excess labour form doing the work separately but I don't want to pay for too many alignments either.

Thanks for the tips in advance! I hope to be able to contribute more and more to this active forum as I learn more about our cars.

Edit: Oh also if some Canadians could chime in on where to source performance parts? I've been looking at ECS and Turner but I'm wondering if there are better options living North of the border.

Rear subframe bushings.

[John_01]

I suggest to do the rear subframe bushings. While you are there you can install a rear sway bar. Either go for 15mm, or you may be able to find a used 3 series rear sway that is almost always 13mm.
20mm rear sway bar is likely to be too big for use with an otherwise stock setup - It will make the car feel unsettled and may cause traction issues.

For the front, I suggest the M3 front arms for more camber. E92 M3 front sway bar is also a good upgrade for use with OE style springs and shocks.

I agree with Sprgnat that the rear subframe bushings are the single most important item.

[1more1]

Originally Posted by Suprgnat

Rear subframe bushings.

Originally Posted by John_01

I agree with Sprgnat that the rear subframe bushings are the single most important item.

I've read that when it comes to the RSFB the difference is more noticeable on a car with more power. Even with a stock N52 it's still better than replacing tired soft suspension? Keep in mind my car did not even come with the factory sport package.

Also yes I had a feeling 20mm would be too large. I like the idea of getting a E9X sway as it would be much cheaper. If I find one at a pick and pull I could even get a practice run at dropping the subframe too aha.

[chris_flies]

Just as a reference, check out my build thread linked in my signature.

I daily it; rain, shine, snow (weeee!), etc. It's driven (172k miles). I also participate in a good few track days locally, though I want to start into AutoX-ing for the lower costs...

You could probably do without camber plates and M rear arms for a total DD, but I think I've got what you're looking for...

EDIT: Car started as a total baser, the only option was Heated Seats (perfect)

[1more1]

Any thoughts on the Powerflex RSFB inserts?

[Suprgnat]

Originally Posted by 1more1

I've read that when it comes to the RSFB the difference is more noticeable on a car with more power. Even with a stock N52 it's still better than replacing tired soft suspension?

I regard the RSFBs as a fundamental flaw of the suspension, and as such feel they should be fixed ASAP. Not upgraded, tweaked, or modded. Fixed. They were crap from new, and only worse with age. Yes, refresh your suspension, but fix it first.

Inserts are better than not doing anything and I have the ///M bushings, but as I've said before "If I did it again, I'd go solid aluminum."

[1more1]

Originally Posted by Suprgnat

I regard the RSFBs as a fundamental flaw of the suspension, and as such feel they should be fixed ASAP. Not upgraded, tweaked, or modded. Fixed. They were crap from new, and only worse with age. Yes, refresh your suspension, but fix it first.

Inserts are better than not doing anything and I have the ///M bushings, but as I've said before "If I did it again, I'd go solid aluminum."

Thanks for the push Suprgnat! The more reading I do the more people praise this mod and the plethora of problems that it fixes.

I think given my setup, the price and time of install I'll start with the inserts and upgrade them to a full bushing if I feel the need down the line. I think that should take the car to where it should have been from the start.

[NorthernDancer]

Hello! With 160K kms, I think you should be doing struts and shocks first. Then good tires.

[Tommm]

My 08 is the same car as the OPs. I replaced the dampers at 53k with Koni sports. I also replaced the bearings, etc. I got a set of 135 springs for next to nothing so i used them (i was hoping to find a high mileage 128i with a shot suspension for my daughter and install my old parts. Found a low mileage E46 323Ci instead).

I am now installing the dinan plates, M3 arms, and whiteline rear bushings.

I am out the $60 i paid brakes plus for the suspension 7,000 miles ago, and an afternoon or two of labor doing the job twice.

OP, if you have the time to work on the car (i shouldn't have the time), you may want to do something similar to what i am doing. I should have done it at once, but the car is depreciating in value, and the track car is getting tired, so i am slowly moving to make the 128i more of a DE/DD

[ShocknAwe]

Dampers and whiteline rsfb inserts. You can always change the springs later if you want. I'd go step by step so you don't overdo it, or end up with a car that far outshines your abilities.

[Gangplank]

I feel like it's Groundhog Day. Lol

RSFB
Rear Diff Brace
Front M3 control arms
Upgrade struts, and springs if you can afford it, or go coilovers if you can afford that on top.

[John_01]

Originally Posted by 1more1

I've read that when it comes to the RSFB the difference is more noticeable on a car with more power. Even with a stock N52 it's still better than replacing tired soft suspension? Keep in mind my car did not even come with the factory sport package.

The stock rear subframe bushings are really horrible. It doesn't matter if the car is 4 cylinder or whatever, they still detract from the handling. I have replaced the rear subframe bushings in my 325i sedan and it made the handling a lot more precise even though the car is otherwise stock. Cornering and braking loads cause the subframe to deflect as much as acceleration does. I suppose if you are attempting to drift a high powered car, then that's another matter. However with the number of km on your car, I would expect a big improvement from upgraded subframe bushings.

I assumed you would want to replace the shocks and springs, since you mentioned that in your post. BMW performance springs with Koni struts and shocks will be good. Also compare the cost with a set of KW V2 coilovers. The coilovers will be more suitable if you actually want to autox your car.

[chris_flies]

Originally Posted by Gangplank

I feel like it's Groundhog Day. Lol

RSFB
Rear Diff Brace
Front M3 control arms
Upgrade struts, and springs if you can afford it, or go coilovers if you can afford that on top.

We should all put a link to suspension recommendations in our signatures.

I feel ya, it only takes 5 minutes of looking to find this stuff...

(OP, I'm not trying to sound like a jerk, it's just repetitive )

[Tommm]

Originally Posted by Gangplank

I feel like it's Groundhog Day. Lol

RSFB
Rear Diff Brace
Front M3 control arms
Upgrade struts, and springs if you can afford it, or go coilovers if you can afford that on top.

With 160K kms, I think the shocks are about ready. I would be more inclined to go in your order if the shocks weren't so old.

[Gangplank]

Originally Posted by Tommm

With 160K kms, I think the shocks are about ready. I would be more inclined to go in your order if the shocks weren't so old.

The first 2 items on my list are relatively inexpensive and were a HUGE improvement. The M3 control arms are just for added camber and to tighten up the front end.

And I agree with you at that mileage the shocks are done. Time to upgrade them,but do to RSFB & Diff brace if you can...

[Gangplank]

Originally Posted by chris_flies

We should all put a link to suspension recommendations in our signatures.

I feel ya, it only takes 5 minutes of looking to find this stuff...

(OP, I'm not trying to sound like a jerk, it's just repetitive )

Umm... 5 min of searching, 5 hours of reading opinions, 5 days of thinking about it, and 5 months to make the final decision. Or is that just me? Lol!!

[chris_flies]

Originally Posted by Gangplank

Umm... 5 min of searching, 5 hours of reading opinions, 5 days of thinking about it, and 5 months to make the final decision. Or is that just me? Lol!!

That's about it!

For me, it's one minute of searching, one hour to make a decision, one second to regret that decision, one month to re-research it, another month to decide again, and then one second to spring for it and be done.

[1more1]

Originally Posted by chris@strutmonkey

Koni Yellow (adjustable) shocks and Eibach springs... get an assembled kit that includes new strut mounts, spring pads, bumpstops, mounts, etc, etc... so you do it once, and do it right.

Looks like a good kit, I'll check it out!

[1more1]

So in case anyone is interested I decided to start with RSFB. After some deliberation I decided to go for the full bushing given that my existing bushings have high km. I went for Whiteline KDT917 since I could get them the easiest and cheapest off Amazon. They seem like they'll be easy to install. I'm planning to use this method to remove the old ones.

I'll post my thoughts after I get them installed in case anyone is interested.

Thanks for everyone's help!

[1more1]

Update: Finally got a chance to put the bushings in. The technique I planned on using did not work. I borrowed a FWD bearing press from a co-worker and that made the job a breeze. The two larger cups were the perfect size. I needed to get some 5/8 threaded rod a couple washers and some nuts and that was it.

I got the contraption on there and tightened it as much as I could then heated the outside of the subframe with a propane torch and tightened it again until the bushing bottomed out. I heated it one more time and wiggled the rest of the bushing out. This worked on all 4 corners. I didn't need to disconnect the brake lines. Would recommend this method for sure. It worked really well. The Whiteline bushings went in no problem. I had a little trouble getting the front metal inserts in by hand but I just used the sub-frame bolt to press it into position.

First impressions: First of all the car seemed higher in the rear (4 fingers) but after the first drive it settled down to 2 fingers. I'm going to check the torque again later today but everything felt tight on the road.

I'm extremely happy with the performance. Up until now I was disappointed with my 1'er and felt that it was too soft and squishy. These bushings brought the car to my original expectations for sure. Everything people have said is true. The car is more planted overall, especially at speed but most of all I just have so much more confidence being able to feel what the rear end is doing. This was what I expected from my first BMW.

I also heard that some people noticed an improvement with the 1-2 shift and it may be because I'm overthinking it but I'd say the car shifts smoother now. 1st gear doesn't hold on as tight.

Anyways just thought I'd add to the list of people who've done this mod and give my 2 cents (not that it's worth anything).

Thanks for push to do this for my first mod! It was well worth the effort. Next on the list is some fresh suspension.