First of all sorry for the delay. I ended up paying (with beer, lol) a mechanic friend of mine to do the job. I could have been able to do it, but something told me to get someone who had previous experience in case anything came up, and something came up.
I finally got the car back last week, and have been driving around before writing in order to tell you guys my opinion on driveability/performance.
Basically the the swap CAN be 100% "bolt off and bolt on swap", but that will depend on what you are willing to change. I will write what happened in my case, if you have done this before and disagree with what I had to do in order to get this swap don correctly feel free to comment.
I will divide this into two sections, the swap, and my opinion on driveability.
Note:
My car is a 2003 zhp 6MT. Parts came out of a 2003 M3 convertible SMG. Just in case.
Ok,
The swap:
1- Driveshaft, diff, carrier, and suspension all bolts back up perfectly. As if intended by BMW to perform this swap.
2- Exhaust (I have UUC by Corsa TSE3-L, with stock resonators) fits pefectly. If you have either stock or aftermarket you will not have a problem. I say this because someone told me that maybe I would have to delete one of the resonators in order for the exhaust to clear the larger carrier/diff. No problem here
3- As you may be wondering, yes I had issues with axle-shafts/trailing arms. Good news is that you have two options on getting this solved. First of all, when I was doing my research everyone told me that I would not have to change the trailing arms, only the axle shafts. Well, that is incorrect. When we tried that method we found out that the M3 axle-shafts would be about 1.5 inches too short and would not get to the diff. We started wondering how could this be since the trailing arms are supposed to be "identical" in measurements (as I was told). We took one of the 330 trailing arms down to compare it with the M3 ones that I had. THEY ARE DIFFERENT! I mean, they can be swapped without issues but the M3 ones will get the M3 axles the 1.5 inches in to the diff.
So, thats when we started to figure out what our options were. I initially said, "well, I'll have to spend more money on more parts" since I would have to service the M3 rear brakes. But my mechanic and I insisted that somehow members in other forums had been able to do it without changing the trailing arms. Well, they are correct, kinda. You can use your stock 330 trailing arms, but you will need to reuse your 330 axle-shafts. That way the shafts get to the diff perfectly. By now you may be thinking that the bolt pattern on the shaft and flange are diffrent, you are correct. Only 3 bolts match.
Ok, so we have two possible solutions, either you change the trailing arms and axle shafts (and that would require getting new abs sensor, new brakes if the ones you got are worn and rusted like mine, new hub, new bearings, etc. All this to do a proper job.) or reusing the 330 parts. If you go with the 330 parts you would have the take the axle-shafts to a machine-shop and mill three additional holes to get all six bolts to "bolted" tho the diff flange.
I decided to simply go all out on this and got new rotors, pads, abs sensor, hub and bearings. And damn M3 parts are expensive! Twice or triple the price vs non-m parts. BTW - abs sensor changes, not getting into details, they just change.
My mechanic told me that most probably the people who say that they did not change the trailing arms, probably they took the car to an indy shop and the shop either used the 330 axles with 3 bolts, or drilled additional holes. But they definitely did not use the M3 axles. The 330 axle flange are forged, and it would not lead to problems if drilled properly and then use the M3 reinforcements.
4- I had originally said that you also need some rods (as illustrated in realoem.com). I bought them and they are not needed. They cost me $220 for both of them and you do not need them. They are only for structural reinforcement. I did properly weld two brackets to the body of my car in order to use these "rods", part numbers 33312229295 and 33312229899, since I had already paid them. And its probably a good mod.
All in all, it is not a cheap alternative as previously thought. I mean, I paid $500 for the diff, drive shaft, carrier, axle-shafts, trailing arms, and calipers. Then about $700 for all new screws, bolts, diff fluid, sway bar, rods, bushings, etc. Since I decided to do the M3 brake service about 500$ more on all that. Plus, all the beer, food, tools, and stress to get this done properly.
Total, $1,700 with free labor. You could spend upwards of $2,000 with labor. If you go the cheap way with 330 trailing arms and drilling the 330 axle shafts you could be just below $2,000, but not by much. And all that is because I got a great deal on the diff, carrier, etc.
It is probably cheaper and easier to get your stock diff an aftermarket LSD and gearing. But that is up to you. My best way was to do it like I did, since I was able to pay most of the things in cash and not all at the same time; gave me time to pay some parts first, then a couple of weeks later other parts.
Now to another subject equally important, and equally questioned.
Is if worth it? LOL! Its absolutely awesome!!!
Some of you guys have questioned whether the 3.62 gear ratio is too short for our cars. In my opinion, NO. My car drives perfectly fine for daily use. I cant feel a difference from stock when driving around the city. First gear is not that short and gear changes come with enough time between them. I mean, yes you do notice a difference, but its not that big of a difference. At highway my car is at around 2,600 rpm at 60-65 mph. At 70 mph Im at 2,990 rpm (lol, it just not 3k but almost there). At 75 mph its just above 3k rpm. And I even think my cars has better MPG's in the city.
Took the car for a 2 hour drive the weekend and it was a blast!! Had my dog with me so I did not have many spirited driving on the way to my destination. But on the 2 hour drive back, my wife took the dog on her car, and did a lot of different driving styles.
Is the 3.62 good for drag? I dont think so. I dont like drag so I dont care. But at WOT first gear is short. LSD does a fantastic job though.
How about in track like conditions? It is superb for track. Someone here (cant remember the username) was talking about Laguna Seca, it should be the best mod for that track. The car just goes on any gear, very alive. Third gear is a blast! The handling of the car is SO MUCH BETTER!! The new M3 front and rear sway bars I installed also help here!
My two hour drive was to a track day. I only did a few laps since all I wanted was to test the diff. I have new tires which I did not want to wear too quickly.
On the way back, as I was saying, I would put the car in 6th gear and drive at 65mph (2,700 rpm), then if I need to change lane all I would have to do is press the gas a little and thats it. The car felt like it was on 4th gear. So amazing how the car responds. Then I slowed down a little to 55mph downshift to 3rd, and WOT the car flies!!
Back to the city, and the car now responds like a normal car. If you have ever driven a R53 Mini Cooper S (the 2005 that had a tranny with shorter gears) you know that that car has really short gears, very fun btw. My car is not like that. As I said, my car drives more like stock, yeah with shorter gear but not that dramatically shorter.
Would I recommend this mod to anyone? ABSOLUTELY!!!
If you want a zhp that feels more alive this is the mod for you! If you want the advantage of an LSD on the track, this is the mod for you! If you ever wanted a e36 M3 but went with a newer car, this is the mod for you! There is no excuse (other than financial reasons) for not doing this mod.
I will be installing headers and shark injector soon. I have them here with me but want to do one thing at a time in order to feel the difference each mod makes.
After all this writing I cant remember if Im missing something. Feel free to comment and I will gladly help. If you want to email, text or call me I will leave my info here. If you call me and I dont answer please send me a text, because sometimes I cant answer. But I always answer text, and then call you back.
email - JLAstor@acemergencypower.com or juanluisastor@gmail.com
cel. - 787-221-8777
Hope this helps anyone!
Juan Luis
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Originally Posted by Jlastor
