Love that fresh new fcab smell! :biggrin
Sent from my SM-G955U using Tapatalk
Printable View
Love that fresh new fcab smell! :biggrin
Sent from my SM-G955U using Tapatalk
You mean RTAB? :cool
Installed an M3 rear end over the long weekend...Approximately 134,500 miles. Didn't take many photos besides this one;
Attachment 35366
A few notes;
- If you do this, plan on spending at least TWICE as much time as you think it will take. My car has been a New England car all its life, so there were plenty of rusted fasteners, two of which snapped and had to be drilled out.
- I can't imagine doing this swap without a lift. If you have access to one, definitely make use of it.
- The axles and driveshafts are different lengths than the ZHP. I read somewhere that the driveshaft was the same if you have a 6-speed, but this is not true. I forgot the exact dimension but the ZHP driveshaft was at least an inch too long. The M3 diff is not only wider, but longer, so the input flange is closer to the transmission. The M3 axles still work with the ZHP RTA's though. The difference in length is due to the differential being wider. The ZHP axles can not be used with the M3 diff, due to the length and the bolt patterns being different.
Differential comparison:
Attachment 35367
- The upper / lower control arms and rear trailing arms are interchangeable, but if you use the M3 RTA's, you need to use M3 brakes because they're different mounting points than the 330i, and the rotor offset / dust shield location is slightly different than the ZHP. I chose to re-use the ZHP arms because I had already installed a set of SDW RTAB's in them, and the P/O hacked the M3 RTA when he removed the bushings so there were significant gouges in the housing. The driver's side axle bearing on the M3 RTA was also in need of replacement and I didn't feel like dealing with that, plus I read that the bias with the M3 brakes changes the braking dynamics, causing some rear lockup under hard braking.
- The ABS sensor needs to be reset at a shallower depth in the RTA because the M3 axle diameter at the ABS ring is larger.
- E-brake cables are different lengths... I found this out after I got everything buttoned up. :facepalm Grey goes on the right, black on the left (Driver's side.) They actually still work, but the PS cable is about 1" shorter now and barely engages the threads at the e-brake handle, while the DS cable threads are about 1.5" too long.
- It's important to note that the differential can't be removed without dropping the entire subframe/carrier. The rear differential bolts won't come all the way out because they're too close to the trunk/spare tire well. The control arm bolts also won't come out of the carrier because they hit the differential, but it is possible to loosen the differential and slide it rearward to gain clearance. As a result, everything has to be bolted into the subframe prior to lifting it up into the body. All assembled, this thing weights at least 150lbs, so there is no way you can install it without a jack. It is a significantly easier task with two people. I managed to do it alone by some miracle. As I type this, I realize it may be possible to drill a couple of holes in the trunk/spare tire well to access the rear diff bolts. I'll probably do this at some point if I ever need to remove the diff.
Attachment 35375
Attachment 35376
- Lastly - the ZHP exhaust doesn't clear the M3 half shaft/diff output flange. Mine made contact so I just cut it and installed some temporary dumps after the second resonator. I'll be taking it to an exhaust shop soon to fab up a fix.
Driving impressions;
- The car definitely has noticeably better pickup, but I haven't pushed it too hard yet because I want to make sure there aren't any issues... Plus I haven't had the car aligned yet. Hoping to do that tomorrow. Haven't noticed any difference due to the LSD just yet, but again, I haven't pushed it hard so I can't comment on that aspect. I'll update this post once I have more opportunity to drive it.
- The P/O installed solid aluminum subframe bushings and poly diff to subframe bushings. I would highly recommend NOT doing solid bushings because there is a significant amount of gear whine in the cabin. I'm going to swap them out for either poly or OEM rubber. I don't see any performance benefit from the solid bushings in a daily driver, and the gear whine is annoying.
That's it for now... Will update later.
Great work, thanks for the tips/learnings from your process!
Also, I'm very envious of your 4-post lift...
I wanted a lift for the longest time, but could never justify the cost. Then a fellow car guy offered it up for $750 delivered - it was a no-brainer. It makes a huge difference in maintenance. My ceilings are pretty low so I can only get the car about 36” of the ground, but even that is a huge benefit.
Glad the swap worked out okay Chris!
Damn, $750! That's a helluva deal, sweet score! I think the safety aspect of it is worth it's weight in gold.