BMW M3 Forum
BMW M3 Forum BMW M3 Gallery BMW M3 Reviews BMW M3 Social Groups BMW M3 Chat M3Forum Sponsors >>
Loading


Mobile M3forum
Go Back   BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X) > BMW M3 Discussions > E46 M3 (2001-2006)
Tire Rack Buy Winter Tires Now!
Not a member? Register Now!
Register Gallery All Albums Garage Search Today's Posts Mark Forums Read Calendar FAQ

E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


Reply
 
Thread Tools Display Modes
Old Thu, Mar-02-2017, 02:46:21 AM   #31
J05M3
Registered User
 
Join Date: Nov 2016
Posts: 62
Reputation: 0 J05M3 is on a distinguished road
Location: Kansas City

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by Newswartz View Post
I thought I had it all figured out. I even ordered solid. AKG emails and says they don't recommend it and now this thread. Now I feel like going 95a
I feel ya. I was going solid now its back to oem.
Jump to top J05M3 is online now   Reply With Quote
Sponsored Links
Register now and remove these ads
Old Thu, Mar-02-2017, 02:46:34 AM   #32
EricSMG
40 something
 
Join Date: Nov 2008
Posts: 10,471
Reputation: 0 EricSMG is on a distinguished road
Location: San Diego

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by J05M3 View Post
Isn't that a separate part of the issue though. Yes the RACP wants to rip out because of the forces applied to it, but there is also cracking that happens directly where the front oe bushings makes contact with a spot weld. Two different symptoms of the same problem.
Absolutely! But I'd say that the fronts are minor relative to the pulling away issue. Either way, you're right - and plates should solve that.

Also - I think the fronts are highly affected by driving style. Someone dumping the clutch and/or SMG launch control (PO ow my grey car) will toast the right front mount. Plate it and then don't do that and I'm thinking the fronts are a non-issue.
__________________


'04 SG/Black 6MT || '04 JB/IR SMG
Jump to top EricSMG is offline   Reply With Quote
Old Thu, Mar-02-2017, 02:49:43 AM   #33
J05M3
Registered User
 
Join Date: Nov 2016
Posts: 62
Reputation: 0 J05M3 is on a distinguished road
Location: Kansas City

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by EricSMG View Post
Absolutely! But I'd say that the fronts minor relative to the pulling away issue. Either way, you're right - and plates should solve that.
I feel like I have accomplished something today.......I made up my mind........again.
Jump to top J05M3 is online now   Reply With Quote
Old Thu, Mar-02-2017, 03:02:19 AM   #34
AussieE46M3
Registered User
 
Join Date: Nov 2015
Posts: 143
In the garage:
Reputation: 0 AussieE46M3 is on a distinguished road
Location: Gold Coast

Australia




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
I'd say that the fronts are minor relative to the pulling away issue.
I'd agree with Eric. Having analysed the forces, Both the torque about the engine and resultant torque about the wheels apply an upward force into the chassis on the front right mount.
A quality repair plate that supports up both the vertical and underside faces should be sufficient for the majority of people. Adding a brace over the rear mounts to the chassis rails will prevent the majority of potential secondary failures.

The 'pulling away is most significant on the rear two, more so the left. BMW added extra spot welds on all models in 2001, M3's had more again to stop the mount insert ripping out entirely. This is why in the early days they repaired the top welds however, like most M3 guys find, theirs are often intact and fine.
Jump to top AussieE46M3 is offline   Reply With Quote
Old Thu, Mar-02-2017, 03:06:46 AM   #35
Drewster
Registered User
 
Drewster's Avatar
 
Join Date: Aug 2014
Posts: 2,395
In the garage:
Reputation: 0 Drewster is on a distinguished road

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by J05M3 View Post
Isn't that a separate part of the issue though. Yes the RACP wants to rip out because of the forces applied to it, but there is also cracking that happens directly where the front oe bushings makes contact with a spot weld. Two different symptoms of the same problem.
To clarify the terminology, the Rear Axle Carrier Panel (RACP) is the chassis assembly. The bolt carrier is inside, which allows you to secure the subframe to the RACP.

Yeah, it's all a bit of a mess, but the real nasty pictures of gaps you can stick your finger into usually come from the rears trying to rip out. Adding plates is, I would argue, what keeps those fronts from cracking under pressure. Foam, external support, etc. are what I would personally trust to keep the carriers from ripping out.

Regardless, 95A bushings are still pretty damn hard - you'll still get some whine from the diff etc. I (personally) would still prefer a flat polyurethane face pressing against the RACP rather than the limited surface area of the aluminum ones.. but that's more of my take on it.
Jump to top Drewster is online now   Reply With Quote
Old Thu, Mar-02-2017, 03:34:29 AM   #36
AussieE46M3
Registered User
 
Join Date: Nov 2015
Posts: 143
In the garage:
Reputation: 0 AussieE46M3 is on a distinguished road
Location: Gold Coast

Australia




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

I too get diff whine. I did urethane diff bushings when I was repairing the RACP a couple years ago. I now believe it wasn't necessary to upgrade them.

I hope you guys don't mind me posting this but Jo5M3, you said you're considering future RACP/chassis reinforcing kits?

If you or any other members on this post have any questions about the kit I offer let me know, always open to discussion and willing to help out wherever I can with this issue.

Feel free to put a post on the thread or contact me via messenger, email, facebook etc.

http://www.m3forum.net/m3forum/showt...=565038&page=7

I'm always willing to help out other forum members and offer a discount for them.

Last edited by AussieE46M3; Thu, Mar-02-2017 at 03:39:13 AM.
Jump to top AussieE46M3 is offline   Reply With Quote
Old Thu, Mar-02-2017, 05:03:06 AM   #37
bigjae1976
Registered User
 
Join Date: Nov 2008
Posts: 5,100
In the garage:
Reputation: 0 bigjae1976 is on a distinguished road
Location: Wichita

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

If you have solid subframe bushings then your diff won't flop around if it has rubber bushings.

The OE diff bushings may need a more frequent replacement interval but I'd rather replace a diff bushing than subframe bushings.
__________________
2013 F30 328i - Melbourne Red
2011 E90 M3 - Monte Carlo Blue
2004 E46 M3 - Imola Red
Jump to top bigjae1976 is offline   Reply With Quote
Old Thu, Mar-02-2017, 07:30:10 AM   #38
BTB
Registered User
 
BTB's Avatar
 
Join Date: Jun 2013
Posts: 1,516
In the garage:
Reputation: 0 BTB is on a distinguished road
Location: Chicagoland

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by EricSMG View Post
This is, and has always been, precisely my line of thinking and is exactly what I did.

Contrary to popular belief, I've never thought the OEM bushings were the problem. Rather, the thin metal and poor load path are the true issue(s). The front OEM bushings' lips only highlight the underlying problem.

Further, logic tells us that while a solid bushing will indeed spread the load at the mounting point, it will also dramatically increase the spikes in load and so this just seems..... well.... like a bad idea to me. You might gain localized strength but compromise the overall structure more. Just conjecture, of course, but food for thought.

Surely with a Vincebar/bolt-through fronts this is probably a moot point, though. But the flip side of that is that once properly reinforced, why go solid at all? Why not enjoy the smooth and quiet OEM bushings that are built like tanks and last forever?
Well part of the point of going solid, as I understand it, is to restrict movement and reduce oscillation (or increase the natural frequency, I guess) in the rear suspension as a whole, eliminating or reducing wheel hop. This won't be addressed by just strengthening the chassis. But if that is of no interest to you than oe probably would be perfect

It seems, then, that solid subframe bushings are likely most effective (or least problematic) when used in conjunction with proper redistribution of the load path of the rear subframe, whether in the form of the vince bar or other. It does seem like using aluminum bushings on a stock, non-reinforced car would be a bad idea... given that other cars feature solid mounted subframes with rubber diff bushings, I wonder what problems could arise from doing the same, other than maybe shorter bushing life...?
__________________
UIUC / TU Munich Mechanical Engineering 2018
2003 ///M3 6MT Coupe Imola Red/Black Napa, slicktop, manual seats
My Journal
Jump to top BTB is online now   Reply With Quote
Old Fri, Mar-03-2017, 03:56:30 PM   #39
albino09
A Yankee South of the Mason-Dixon
 
Join Date: Nov 2014
Posts: 381
In the garage:
Reputation: 0 albino09 is on a distinguished road
Location: Nashville

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

Quote:
Originally Posted by BTB View Post
given that other cars feature solid mounted subframes with rubber diff bushings, I wonder what problems could arise from doing the same, other than maybe shorter bushing life...?
It's a difference in design. The E46 rear suspension was designed with compliant bushing material in mind. Comparing this rear subframe to the later E9X cars where the mounts are bolted to high-strength steel frame rails, it's a comparison of apples to oranges.

I agree with AKG. If you remove play and vibration at one end, it will all end up on the other. The energy has to go somewhere. You'll end up eating up diff bushings faster than you normally would.
__________________

2002 Laguna Seca Blue/Dove Grey...Journal
Jump to top albino09 is offline   Reply With Quote
Old Fri, Mar-03-2017, 03:59:25 PM   #40
Newswartz
Registered User
 
Newswartz's Avatar
 
Join Date: Sep 2016
Posts: 82
Reputation: 0 Newswartz is on a distinguished road
Location: Hudson Valley

United States




Default Re: Ordered AKG solid subframe mounts and they emailed me back......

I told them to switch me to 95a
__________________

Dinan · Samco · RPI · Rogue Diablo · SMG Tune · Csl 255 DME ·ST Coilovers· IForged 19" ·smoked corners/turns · Mason Xbrace · StormMotorwerks · Turner · H&R · Hawk · JBL· Kenwood ·Fan Delete ·Angel eyes · Csl front/rear diffuser · Tint · Polished engine goodies · AKG Subframe · AKG RTAB · Redish Plates · Rogue Pullies
Jump to top Newswartz is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 12:50:11 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
M3Forum.com and M3forum.net is in no way sponsored, endorsed or affiliated by or with BMW NA / BMW AG or any of it's subsidiaries or vendors.
BMW and M3 (E90 M3 | E92 M3 | E93 M3 | E46 M3 | E36 M3 | E30 M3) are registered trademarks of BMW AG.
M3Forum Terms of Service
Copyright ©1999-2017 M3Forum.com
Discussing Ordered AKG solid subframe mounts and they emailed me back...... in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)