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clownkiller
clownkiller Dork
1/24/23 8:25 a.m.

I had a 2011 328ix and loved the car. If it was stick and rwd I would have kept it. We sold it last year with 140k for 7500$

I would absolutely buy that car. 

dyintorace
dyintorace GRM+ Memberand PowerDork
1/24/23 9:25 a.m.
RyanGreener (Forum Supporter) said:

Finally, let's talk mods. I want to make this an OEM+ style daily driver. I notice that the M3 suspension mostly bolts on so I might just go with that. Are there any improved rubber/"softer" poly bushings for the differential/rear subframe? How about engine/trans mounts? I hear these are weaknesses on this car and at this age/mileage, it may be time for a refresh anyway.

Another mod our 128i has is the 3-stage intake manifold upgrade. That, plus a tune, picks up pretty great HP. Read more here:

https://www.thedrive.com/guides-and-gear/i-installed-a-major-junkyard-upgrade-on-my-bmw-128i

You can also search for other articles by the same author. He's done a ton of work to his 128i, pretty much all of which would apply to your future car. :)

RyanGreener (Forum Supporter)
RyanGreener (Forum Supporter) Reader
1/24/23 9:59 a.m.

Loving all the feedback here. Seems like I should definitely go with my gut to buy this thing assuming reasonable pricing! Just time for the waiting game though because its not for sale until the summer...will keep everyone posted!

Driven5
Driven5 UberDork
1/24/23 10:16 a.m.

In reply to SKJSS (formerly Klayfish) :

It's not the strut tower that gets drilled out on the Dinan plates, but the alignment pin on the strut mount or 'guide support' as BMW likes to call it.  So without any irreversible chassis changes, it has the same camber adjustment range as only removing the alignment pin from the stock mounts, just with an extra -0.7* camber,

Dinan Fixed Camber Plate Installation Instructions

Driven5
Driven5 UberDork
1/24/23 10:29 a.m.

Regarding the rear subframe bushings: Yes, the inserts are a cheap and easy improvement for stock spring rates. However, if you are willing/able to get/make the bushing removal tool, there is zero functional reason not to go straight for the 2-piece Polyurethane or UHMW bushings. The more you to up in rate, the more important it is. I have a set of never opened inserts if anybody wants them though.

RyanGreener (Forum Supporter)
RyanGreener (Forum Supporter) Reader
1/25/23 7:32 a.m.
Driven5 said:

Regarding the rear subframe bushings: Yes, the inserts are a cheap and easy improvement for stock spring rates. However, if you are willing/able to get/make the bushing removal tool, there is zero functional reason not to go straight for the 2-piece Polyurethane or UHMW bushings. The more you to up in rate, the more important it is. I have a set of never opened inserts if anybody wants them though.

Interesting on the UHMW bushings (it appears to be Delrin). How do they effect the NVH if used in the rear differential/subframe? They're probably the closest thing to being solid without being solid.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
1/25/23 9:14 a.m.
Driven5 said:

Regarding the rear subframe bushings: Yes, the inserts are a cheap and easy improvement for stock spring rates. However, if you are willing/able to get/make the bushing removal tool, there is zero functional reason not to go straight for the 2-piece Polyurethane or UHMW bushings. The more you to up in rate, the more important it is. I have a set of never opened inserts if anybody wants them though.

I'll take 'em!  My car is 100% stock and will remain that way.

Driven5
Driven5 UberDork
1/25/23 1:28 p.m.

In reply to RyanGreener (Forum Supporter) :

While both are white thermoplastics well suited to a number of overlapping applications, they actually have some substantially different properties. Delrin is a trade name for an Acetal homopolymer, while UHMW (Ultra High Molecular Weight) is a type of Polyethylene. But yes, I believe the only stiffer available are aluminum and require full subframe removal to press them in.

TLDR: The UHMW subframe mounting bushings significantly reduced uncontrolled (undamped) compliance with no noticed degradation in NVH.

Backgroun: The stock spring rates run around 1.2Hz front and 1.3Hz rear rates. Eibach's raise that to around 1.3Hz front and 1.5Hz rear. Most coilovers reverse the F/R ratio and go for springs rates delivering around 2.0Hz front and 1.8Hz rear. I went with custom tuned coilovers that return it to 1.8Hz front and 2.0Hz rear. Because of the terrible motion ratio on the rear spring, this means running a very stiff spring despite the reasonable wheel/ride rate. I didn't do subframe bushing until after the coilovers. So an unintended side effect from all of this, is that it has helped me better understand the (disappointing) design limitations due to the extensive (excessive) uncontrolled compliance in the rear suspension. 

I installed the M3 front control arms at the same time as the coilovers. So on a front suspension with 5 joints (top mount, and inboard/outboard for each lower), mine went directly from 2 spherical and 3 soft rubber, to 4 spherical and one significantly stiffer rubber. Despite this, the 'road feel' (NVH) from the front suspension increased suprisingly little (non-obtrusive) and the ride quality from the front is actually quite good.

On the other hand, after installing the coilovers the rear developed an rather unsettling (to both the car and the driver) bounciness over some types of bumps but not others. This was not at all present on the front, despite the dampers set at equivalent levels. The bounce was directly correlated to the damping level, with softer bouncing less and stiffer bouncing more. This meant that the bounce was coming from other uncontrolled compliance in the rear suspension, rather than a lack of spring damping. It was bad enough that I immediately decided to scrap my plan for the less effective inserts and go straight to the UHMW 2-piece. The tool I used pulled the stock bushings out like butter and I was able to get the UHMW in without disconnecting the brake line by 'converting' the front pair into 3-piece bushings. If they would shorten the upper half and length the lower half, to more like 1/3 and 2/3) it wouldn't be an issue, but I digress.

After installing the bushings, the uncontrolled (undamped) bounce in the rear was reduced by probably 80% or so. I noticed no degradation in NHV during that time, although it's not to say you might notice a very small amount with a different setup. I do expect that additionally installing UHMW diff bushings would contribute noticeably more NVH from the diff itself through to the chassis, but I can't say just how much since I don't have them.

Much like the front suspension, I'd ideally want to try going as close as possible to full-spherical rear suspension, and just let the springs and dampers do their job. At this point I'm not sure if the remaining (now jut moderately annoying) bounciness in the rear is coming more from the rubber in the upper and/or lower shock mounts or the rubber bushing on the inboard side of the lower control arm ('camber arm') that carries the spring. I have spherical lower shock mounts and stiff upper mounts waiting to go in to find out though.

Even if I wasn't intentionally experimenting with the suspension on this car and just went the Eibach/Koni route instead, I don't see any reason I wouldn't want to stick with the M3 arms and UHMW subframe bushings. As always, YMMV.

 

In reply to AngryCorvair (Forum Supporter) :

Send me your address.

OHSCrifle
OHSCrifle GRM+ Memberand UberDork
2/18/24 10:19 a.m.

In reply to RyanGreener (Forum Supporter) :

Did the doctor sell her car to you?

RyanGreener (Forum Supporter)
RyanGreener (Forum Supporter) HalfDork
2/18/24 2:09 p.m.
OHSCrifle said:

In reply to RyanGreener (Forum Supporter) :

Did the doctor sell her car to you?

Believe it or not, I'm still waiting....she keeps delaying her new car purchase which does work in my favor. I have three cars right now and I'm running out of storage room so I'm figuring out how to shuffle things around.

RyanGreener (Forum Supporter)
RyanGreener (Forum Supporter) HalfDork
3/12/24 9:42 p.m.

So I don't think I'm going to be able to smartly buy this car unless I'm going to have it sit for over a year (I really feel guilty when cars sit around and do nothing). Would anyone else here be interested in buying it if I can gather more details? She's planning on selling it pretty soon based on her progress.

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