What have you done with or to your M3 today?

[Freiheit]

Originally Posted by pbonsalb

Why did the factory use solid bushings on the next generation M3?

Based on the sound that car made, I'd say its part of their new agenda of actively hating their customers.

j/k

Maybe.

[Freiheit]

Originally Posted by DrFerry

Yes there is; that being a solid mount cylinder surrounded by nylon. Check these out at the link below.

http://alekshop.com/products/aleksho...ngs_bmw_e9x_m3

.

Thanks for the link. Those look like a possibility for me.

Originally Posted by DrFerry

When designing and producing a mass market road car, automotive manufacturers make compromises. These are quite often done for cost, but let's consider other examples. Consider that the vibration transfer path for road noise and tire resonance (tire cavity resonance) has to be damped before entering the passenger cabin. In this way the amplitude of road noise sound waves can be reduced especially if the chassis has its own natural resonance at or around similar frequencies generated by the road surface(s) and tires. I have no idea if the E9X chassis has such resonances.

Based on my own personal experience, I would say there is a chassis/cabin resonance. A lot of aftermarket exhaust for the E9x M3 show a primary harmonic at 3k or close to it. Offhand you might say its just an exhaust artifact, but since it shows up across a wide variety of boxes and pipes I'd say its a chassis characteristic, whether structural or related to cabin volume. If that resonance found a similar wave coming in from the road... hoo boy would that be unpleasant. Even worse, if the cabin wave and the road wave were a few hertz off from each other, the resulting FFR could be a major problem.

Originally Posted by DrFerry

However, the prior generation E46 M3s also used rubber sub frame bushings yet the F8X series M3/M4 uses solid bushing mounts. Hence, the F8X series made a either a different design compromise choice OR the chassis is less sensitive to harmonic resonances. What I am talking about are NVH subtleties typically at the level of a trained test driver skilled at discerning NVH differences and not necessarily most of the general public. I used the Alek Shop nylon encased solid sub frame bushings and was barely able to notice any difference in NVH on most road surfaces. However, I have no experience with the 100% solid aluminum type.

While I'm nowhere near a pro driver, I'm sensitive to certain frequencies. The resonance I experience at 3k in my car fills my sinuses and makes it hard for me to hear the person in the passenger seat talking, yet they can hear me just fine. I've also been in small rooms where I can hum a particular frequency and I get the same response. I'm also noise-compulsive; creaks and rattles in any vehicle, especially if they demonstrate a regular pattern/rhythm, will aggravate me to the point I'll trade the car in or at least park it and not drive it as much. My M3 has zero cabin rattles, and I'd rather not introduce any, which is why I'm thinking I'll just buy the Lemforder kit for the subframe and differential bushings. But I'm still open to hearing from people who have tried different bushings. Maybe the perfect one exists that will unify the rear subframe into a perfect working entity while keeping my OCD happy.

[Davisca455]

Originally Posted by Helmsman

Simply stunning mate. Cleaned "only" or painted as well?

Cleaned only.

Pressure Washer to get the looser dirt off.
Compressed Air to dry.
Then a wipe down with some bicycle cleaner.


The cleaning tools:

[Denny347]

Got up this morning and decided to install my Active Autowerk exhaust that I bought used. Very straight forward. I have a Quickjack but it was easier to use ramps for just this. I will say that this exhaust is down right good looking and very well built. Sound great as well. Still running stock X pipe.

[irokwrx]

Installed Dinmann wheel and do88 oil cooler....D day!

[Redd]

Originally Posted by Freiheit

But I'm still open to hearing from people who have tried different bushings. Maybe the perfect one exists that will unify the rear subframe into a perfect working entity while keeping my OCD happy.

Like you, I'm OCD and sensitive to noises. I've spent a ton of time/money chasing down mice and crickets in the cabin (another story for another day). But I also enjoy a firm confident chassis. There is no such thing as a unicorn bushing - any time you stiffen something up, a new noise may appear. Compared to solid bushings, PU may squeak over time and I assure you that will be much worse than resonance. If cabin NVH is of utmost importance then you might be better off with stock rubber.

That said, I did not notice any new noises from the solid subframes. There is a wee bit of additional ride stiffness but its not harsh. I have a loud exhaust and did not notice any additional noise/drone in the cabin (or maybe it's because of the loud exhaust that I did not notice any. Lol.). The solid subframes impact to ride quality is much less than getting new springs or sway bars. Heck, even my Dinan toe links added more stiffness than the subframe bushings. You may notice a wee bit more transfer of force into the chassis if you hit a large pothole but that's to be expected. The benefits of the solid subframes far outweigh the cons - installation hassle included. One drive in it and you'll wonder why it didn't come from factory like this.

But ultimately its you're call if this is right for you.

[Davisca455]

Progress Report:

Good day today.
Getting close, but taking a little break.
Still on the Todo list for tonight, install mufflers, install rear calipers.
Tomorrow I'll bleed the brakes, get it on the ground and torque the sway bar end links, upper control arm, upper and lower trailing arms.
Then I'm gonna attempt my first string alignment.

[fs34]

Originally Posted by Davisca455

Progress Report:

Good day today.
Getting close, but taking a little break.
Still on the Todo list for tonight, install mufflers, install rear calipers.
Tomorrow I'll bleed the brakes, get it on the ground and torque the sway bar end links, upper control arm, upper and lower trailing arms.
Then I'm gonna attempt my first string alignment.

Props for tackling this. Looks like you are on the homestretch. Gives me confidence that I can tackle this at some point. And damn it’s clean under there!

[E90325M]

anyone know the general labor cost for install solid subframe bushing?

[Vedubin01]

Originally Posted by irokwrx

Installed Dinmann wheel and do88 oil cooler....D day!

Love that wheel and the stitching around the airbag!

[slcook54]

Originally Posted by E90325M

anyone know the general labor cost for install solid subframe bushing?

I was quoted $1,700 out the door, parts, labor, everything.

[_X]

Originally Posted by E90325M

anyone know the general labor cost for install solid subframe bushing?

I was quoted $1,368

[SGM_E90]

Installed Dinan exhaust today. Very tame but sounds great.

[jvictormp]

Originally Posted by Davisca455

Progress Report:

Good day today.
Getting close, but taking a little break.
Still on the Todo list for tonight, install mufflers, install rear calipers.
Tomorrow I'll bleed the brakes, get it on the ground and torque the sway bar end links, upper control arm, upper and lower trailing arms.
Then I'm gonna attempt my first string alignment.

I know that feeling. Seems like it's never gonna end. Worst, but I think you already passed that step, there's a regret that pursuits you and try to convince you should never have started that.

F***king desperate feeling!

So many systems involved in that job, so many possibilities to fuck things up.

But man, it's soooo rewarding when you drive the car after that.

If anyone wants to try, don't feel afraid. Do things slowly, don't rush. It will come out nice.

[Siajoon]

Originally Posted by SGM_E90

Installed Dinan exhaust today. Very tame but sounds great.

Just axle back installed? are you paired with oem x pipes?

[Davisca455]

Originally Posted by jvictormp

I know that feeling. Seems like it's never gonna end. Worst, but I think you already passed that step, there's a regret that pursuits you and try to convince you should never have started that.

F***king desperate feeling!

So many systems involved in that job, so many possibilities to fuck things up.

But man, it's soooo rewarding when you drive the car after that.

If anyone wants to try, don't feel afraid. Do things slowly, don't rush. It will come out nice.

I never really felt desperation or pressure, but I absolutely understand why you did.
I think my only two negative thoughts were, "Wow, this is a LOT of work to install $275 worth of parts." and, "If I can't figure how to return the ebrake service latch to its normal position, I'm going to lose my mind."
I'm lucky enough to work in a factory that has multiple hydraulic presses (4X 6 ton, 1X 12 ton, 1X 20 ton, 1X 55 ton), plus I have lathes, mills, TIG welder and materials, all to use any time I want.

You were having to design and fabricate your own hydraulic press in addition to all of the other work that comes along with this DIY.
What you did, was very inspirational, and pushed me to give it a go.
Hats off to you jvictormp!!!

[Davisca455]

Brakes bled, wheel bolts torqued, coming off the jack stands!

[Redd]

Originally Posted by Davisca455

Brakes bled, wheel bolts torqued, coming off the jack stands!

Let's get some feedback on the solid subframes!

[Davisca455]

Originally Posted by Redd

Let's get some feedback on the solid subframes!

I used a sharpie to mark the Toe and Camber setting prior to disassembly.
I lined up the marks during re-assembly and when I checked the Toe and Camber using Longacre Toe plates and Camber gauge, it worked better than I had a right to hope for.

Front Toe: 1/8 In
Rear Toe: 1/8 In
R-Rear Camber: -1-1/4
L-Rear Camber: -1-5/16

With the OEM setup, there were two scenarios that creeped me out:

1) Straight line max acceleration upshifting would cause the rear of the car to have significant (unnerving) lateral movements.
2) On track, in high speed kinks, the rear of my car would display some very unsettling lateral oscillations.
(I'm old school, DSC is always off)

These behaviors were so noticeable, that I decided to invest all of my free time this week installing $275 worth of parts.

After checking the alignment and torquing the non adjustable control arms and sway bar links (at ride height) I just got back from a couple of HARD straight line pulls thru the first 5 gears.
The first pull went so well that I was able to do the second pull with cell phone video in the left hand (not gonna share it).
WAY more stable!
There is no way I would have attempted a max acceleration pull one handed with the OEM setup.

Zero clunks or other noises.

The Jury is out on the Powerflex Purple diff bushings though.
The diff noise is noticeable, but only with the windows up and on smooth pavement.
On coarse asphalt, windows up, the tire noise completely cancels the diff noise.
I will give it some time to try to get used to it, but it's a possibility that I may be headed under the car again...

[Redd]

Give the purple diff bushes some time. Your ears automatically tune them out 90% of the time after a while. A least it did for me.

[DirtyM3]

Nothing really done to the car. Just took her out today to take some photos.

Enjoy

[DL335D]

Amazing car, beautiful pics, but dirty tips! 😂