Originally Posted by
Chest Rockwell
1) Reinforce rear subframe. It’s been inspected and has no cracks as of now. What’s the latest on the best way – I’ve seen the bar method and the plate method. Doing a quick look at the E46fanatics DIY this looks like something I don’t want to do and should take it to a shop...
Originally Posted by
BMWCurves
[*]Subframe cracking isn't as big of an issue in late model year E46s. Other members like Peter (username Slater) will tell you that it is inevitable that the subframe will crack and he may be right. It's a matter of risk assessment but I don't plan on doing any reinforcement anytime soon. Peter's much more knowledgeable on the subject, so have a discussion with him.
first off... and i AM going to be picky about this, because, well, correct terminology is important.
it's the floor, or more correctly, 'RACP' (Rear Axle Carrier Panel), that is what cracks and eventually separates from the chassis of the car. the subframe is a replaceable, mostly-tubular metal structure that the diff and suspension bits mount to, which in turn mounts to the RACP.
with that out of the way:
- post-10/2004 E46s had a factory 'reinforcement' piece/panel sandwiched in between the upper and lower panels of the RACP. presumably it is there to strengthen the RACP and prevent twisting, but i've never seen a cutaway of it so i can't be certain. if you remove one of the plugs in the upper section of the rear floor (in the trunk), you can feel it in there. personally, i have not heard of a post-10/2004, non-M E46 having any cracking or RACP failures - and the 3 post-10/2004 E46s that i have owned or currently own (02/2005 ZHP coupe, 05/2005 ZHP coupe, and 10/2004 325iT) were 100% crack free. but that does not mean it is possible.
- all facelifted E46s had additional spot welds in the RACP to help prevent tear-out. i'm pretty sure this actually happened around 2001/2002, but for sure all facelifted cars (that means ours) have them. this has proven to not be enough.
- many factors contribute to RACP failure. worn subframe and diff mounts, and aggressive driving (hard launches, hard throttle on/off, high lateral loads). these are enthusiast cars, so the latter can and should be expected - let's not beat around the bush here.
- my own personal ZHP (06/2004 build date) has a crack in the RACP 'kink' near the left rear subframe mounting point, where they all crack first. the RACP also started separating in the left rear wheel well (definitely more common on M3s, but can happen on non-Ms). i consider myself a very smooth driver (i'm not a clutch dumper), but i did drive the car pretty hard - high lateral loads were not uncommon, especially after installing an LSD.
"so what the heck, man? why are you all doomsday and stuff about this? what do i DO?"
in my opinion, the correct solution is to redirect the load path to the rear frame rails. for some reason - packaging, perhaps - the E46 rear subframe mounting points do not tie into the frame rails (this was subsequently addressed on the E9x platform), and combined with thin sheet metal - well, it just isn't a robust solution. i personally will be installing a 'VinceBar' reinforcement kit in my 325iT (soon to be 330iT ZHP) as that solution, in my opinion, is the correct one for both eliminating the possibility of RACP failure, and prolonging the life of the E46 chassis. the VinceBar does indeed redirect the load path for the rearward mounts to the rear frame rails, and reinforces the frontward mounts. it does all of this without welding, and also without losing any trunk space or usability of the car - it is completely hidden. win/win/win/win/win.
i don't work for vince or anything. i just think his solution is genius. and good things should be praised.
Originally Posted by
Chest Rockwell
Sweet baby Jesus I didn't expect that detailed/quick of a response. Thanks that really helps.
you will find that this community is a bit different than other online forums. there is a lot of brotherly love. and not much pride.
Originally Posted by
Chest Rockwell
10) I NEED BLUETOOTH CELL HOOKUP BADLY!. I do a lot of work calls while I'm driving and would like to have it integrated with the factory radio. I have the HK premium stereo. Do I need the GROM audio bluetooth box or is my case more simple? My car says pre-wired for cellular. I've attached the factory option sheet for reference and also a screen shot of the GROM I'm looking at.
that GROM unit - the BT-3, i think? - is the exact one i am eyeballing. it looks like it does everything needed, all with the factory head unit, which i really like. unless your car has bluetooth from the factory (should be on the build sheet - have you run your VIN yet to get that? check www.bmwvin.com), this should be exactly what you want/need - it supposedly works perfectly with the stock steering wheel controls. but, like of all these things, i think the head unit needs to be in AUX mode for it to work.
oh, and - WELCOME!
peter
2004 330i ZHP
2005 330iT ZHP
2010 328iT M Sport