Reinforced Subframe EPIC Failure - Page 9 - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Go Back   E46Fanatics > Tuning & Tech > Forced Induction Forum

Forced Induction Forum
Discuss supercharging, turbocharging and even nitrous and water injection here.

Reply
 
Thread Tools Search this Thread Rating: Thread Rating: 33 votes, 5.00 average. Display Modes
Old 05-06-2015, 03:47 PM   #161
mgp333
Registered User
 
Join Date: May 2015
Location: Connecticut
Posts: 6
My Ride: E46 M3
Quote:
Originally Posted by Rob43 View Post
The less damage you have, the simpler it becomes. So "IF" you have no damage on the underside (cracking or tearing), no reinforcement plates would be needed with a Bolt Through design.


Rob43
Thanks for the reply!

Gotcha. I read that the front mounts are pushing up instead of pulling down. Is this stress not an issue? Or is this taken care of by full reinforcement of the rear
mounts?
mgp333 is offline   Reply With Quote
Old 05-06-2015, 04:08 PM   #162
Rob43
Registered User
 
Join Date: Oct 2009
Location: Richmond VA
Posts: 8,016
My Ride: 03 331Ci 5spd R1200R
Quote:
Originally Posted by mgp333 View Post
Thanks for the reply!

Gotcha. I read that the front mounts are pushing up instead of pulling down. Is this stress not an issue? Or is this taken care of by full reinforcement of the rear
mounts?
Since the fronts almost never see a failure, it's virtually never an issue. Inspect ALL, but concentrate on the rear.


Rob43
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



Rob #43 ITS/ITR/STU, BMW 325I, STU LAP RECORD
SUMMIT POINT WV 1:24:229 SCCA
(DynoDynamics
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dyno Video)
"Chance Favors The Prepared Mind"

I BUILD SUSPENSIONS (Consult) FROM MILD TO WILD FOR RWD & Xi E46's
Quote:
Nitrous is a little trickier than boost, but it's not the spray that kills motors, it's STUPIDITY!!
I Know How To Fix The Rear "Bouncing" Problem On Your Cheap Coilovers Like: Jom RL FK SE & RK.
Rob43 is offline   Reply With Quote
Old 05-14-2015, 12:30 PM   #163
mgp333
Registered User
 
Join Date: May 2015
Location: Connecticut
Posts: 6
My Ride: E46 M3
So it sounds like a lot of people have claimed to have done this bolt through design but no one has posted any pictures!

Anyway, I'm trying to plan all of this out. The nice thing about this design is that you won't actually have to drop the subframe to have it reinforced right? However, it appears that in order to drill up from underneath one will have to remove the exhaust to get access to that driver side rear subframe mount. And when drilling up through the threads, it seems like one will have to be careful not to drill on the sidewalls of the bushing itself.

I'm still a little worried about the front mounts. I have seen a couple posts and pictures about cracks/failure on the front subframe mounts. I'm just wondering if there is anything additional I should do while I have it in the shop and they are going to town welding everything. Thoughts? 02PRUV mentioned that he seam welded a 5mm plate across the width of the floor for the fronts, but this is unclear to me.
mgp333 is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 05-15-2015, 11:53 AM   #164
ShakotanRon
Registered User
 
Join Date: May 2014
Location: Kissimmee Fl
Posts: 80
My Ride: 2000 323i
If you see failure in the front, it will mos likely be on the passenger side. the front of the subframe is forced upward, while the rear is forced downward, and torsional load will make the effect different left to right also. I went with a bolt through on the front, because my car is a drift car, and pulling the ebrake at 70+ mph puts huge downward stress on the front mounts.

Last edited by ShakotanRon; 05-15-2015 at 11:55 AM.
ShakotanRon is offline   Reply With Quote
Old 05-15-2015, 11:57 AM   #165
mgp333
Registered User
 
Join Date: May 2015
Location: Connecticut
Posts: 6
My Ride: E46 M3
Did you have to delete the rear seat in order to do the bolt through? I'm thinking of doing a bolt through on the front mounts connected to a couple small reinforcement plates so that I can still keep the rear seat. I'd like to brace it along the width of the car but don't see how I can while keeping the seats.

Got a pic?

Last edited by mgp333; 05-15-2015 at 11:59 AM.
mgp333 is offline   Reply With Quote
Old 05-16-2015, 07:26 AM   #166
ShakotanRon
Registered User
 
Join Date: May 2014
Location: Kissimmee Fl
Posts: 80
My Ride: 2000 323i
Quote:
Originally Posted by ShakotanRon View Post
for anyone looking to do a bolt through, on the front mounts of a 4 door, with the trunk barrier, here are some pictures, of were the bolt is, from the top, its actually quite easy to find. There is a bracket on the vertical portion of the seat pan. basically start the cut an inch to each Side of this bracket, and 2 inches above the bracket. Then peal back and you will see the front mount. Once peeled back, if you choose to cut this rectangle out, as I did, cut about a half inch under the bracket. The bolt in the picture is my hardware, not oem. The oem harware size is m12x1.5 x140mm you will need a longer bolt for bolt through. And if you plan to use an m12 bolt, you will need to drill the threads out. I am using 7/16 right now which is roughly 11mm, because it is what is available to me, I will be upgrading to a 1/2" bolt, aswell as reinforcing the top side, when I take the car down for the engine swap. The rear has already been swapped to 1/2" hardware. I do not think that 1/2 is particularly superior for this purpose, I believe that m12, is sufficient. But again, this is what is available to me on a budget, and once my hp figures grow exponentially, the 1/2" bolts may be beneficial, since these bolts I BELIEVE are beeing placed in shear, with these bolt through modifications, especially, when reinforced, top side with a much stronger material than factory. But truthfully, I would rather place the bolt in shear, and hopefully make that the fail point, rather than my chassis.

The last picture, is my current rear reinforcement, executed by the p.o. it will work for now, but will be redone better when the new engine goes in.

This post has 3 pictures of the top side of the front.
ShakotanRon is offline   Reply With Quote
Old 05-16-2015, 09:31 AM   #167
mgp333
Registered User
 
Join Date: May 2015
Location: Connecticut
Posts: 6
My Ride: E46 M3
Quote:
Originally Posted by ShakotanRon View Post
This post has 3 pictures of the top side of the front.
It looks like I could only see a brace for the rear. Did you just have a bolt and a washer for the fronts?
mgp333 is offline   Reply With Quote
Old 04-26-2016, 06:50 PM   #168
2000323AUG
Registered User
 
Join Date: Dec 2015
Posts: 3
hey, does anybody in the Atlanta area do this? I would like to get my stuff reinforced before I end up in a stick'd thread lol
2000323AUG is offline   Reply With Quote
Old 04-26-2016, 06:56 PM   #169
mgp333
Registered User
 
Join Date: May 2015
Location: Connecticut
Posts: 6
My Ride: E46 M3
http://www.m3forum.net/m3forum/showthread.php?t=546116
mgp333 is offline   Reply With Quote
Old 09-22-2016, 03:34 PM   #170
BuzzE46
Registered User
 
Join Date: May 2016
Location: Queens NY
Posts: 11
My Ride: 2006 M3 E46
hey guys, I checked my sub frame, and had it checked, I have 56,900 miles on the car. so far no cracks or anything whats so ever

how much would it cost to do preventative maintenance? only curious bc I don't want to have it cracked down the road and pay a lot
im in the nyc area

any advice would be appreciated
BuzzE46 is offline   Reply With Quote
Old 09-22-2016, 04:17 PM   #171
Rob43
Registered User
 
Join Date: Oct 2009
Location: Richmond VA
Posts: 8,016
My Ride: 03 331Ci 5spd R1200R
Quote:
Originally Posted by BuzzE46 View Post
hey guys, I checked my sub frame, and had it checked, I have 56,900 miles on the car. so far no cracks or anything whats so ever

how much would it cost to do preventative maintenance? only curious bc I don't want to have it cracked down the road and pay a lot
im in the nyc area

any advice would be appreciated

Start reading at post #8, this is one of the best & most cost effective ways to do what you want since you have no current damage.

http://www.bimmerfest.com/forums/sho...d.php?t=920154



Rob43
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.



Rob #43 ITS/ITR/STU, BMW 325I, STU LAP RECORD
SUMMIT POINT WV 1:24:229 SCCA
(DynoDynamics
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Dyno Video)
"Chance Favors The Prepared Mind"

I BUILD SUSPENSIONS (Consult) FROM MILD TO WILD FOR RWD & Xi E46's
Quote:
Nitrous is a little trickier than boost, but it's not the spray that kills motors, it's STUPIDITY!!
I Know How To Fix The Rear "Bouncing" Problem On Your Cheap Coilovers Like: Jom RL FK SE & RK.
Rob43 is offline   Reply With Quote
Old 12-06-2016, 09:16 PM   #172
Z33KLF
Registered User
 
Join Date: Nov 2016
Location: Indy, Chicago, BJ
Posts: 1
My Ride: E46 M3
very interesting thread
Z33KLF is offline   Reply With Quote
Old 03-25-2017, 08:07 PM   #173
gsxspooling
Registered User
 
Join Date: Nov 2005
Location: Maryland
Posts: 14
My Ride: 02 BLK M3
So some of you may have seen my post in the Mid-Atlantic regional section. I'm looking to get reinforcement plates welded and and looking for a reputable shop to do it in the area. since this seems like the goto subframe thread, I thought I'd post here. Any recommendations?
gsxspooling is offline   Reply With Quote
Old 01-22-2018, 03:02 PM   #174
24LemonsE46
Registered User
 
Join Date: Feb 2017
Location: Chicago & Glenview
Posts: 2
My Ride: 2002 E46 325i
I'd like to see if @Rob43 can fab up the x-member for the "bolt through" design. Tried PM - inbox full. I'd appreciate it if someone could PM me his email! As my use-id alludes to - I have a 2002 E46 sedan that I built into a track car for the 24 Hours of Lemons series. I'll tie the x-member into the rear legs of the cage vs the shock towers like Rob pictures but the center section should be the same.

(cosmetics don't matter on this one - just simple/strong!)

Thanks!
Attached Thumbnails
Click image for larger version

Name:	IMG_6473.jpg
Views:	251
Size:	139.8 KB
ID:	722745  

Last edited by 24LemonsE46; 01-22-2018 at 03:02 PM.
24LemonsE46 is offline   Reply With Quote
Old 09-19-2019, 11:42 PM   #175
cosmos328Ci
Registered User
 
Join Date: Nov 2008
Location: Queensland
Posts: 1,466
My Ride: 400+whp. 500.4ftlb
Transmission: 5 Speed Manual
Rear Subframe Chassis Reinforcement

Rear Subframe Chassis Reinforcement
Attached Thumbnails
Click image for larger version

Name:	Rear Subframe Chassis Reinforcement.jpg
Views:	38
Size:	91.9 KB
ID:	784349  
__________________
M54B30, ESS TS2 Manifold, 4" Throttle Body, 108mm pulley - 4.25".
cosmos328Ci is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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 On
Censor is ON



All times are GMT -5. The time now is 03:27 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
(c) 1999 - VerticalScope Inc. All rights reserved.