[BB_cuda]

I've seen many threads where E90/91/92/93 owners swap over to either only an M3 diff in their existing non M sub frame or better yet swap to both M3 diff and M3 SF.

I have an E90 335D diesel so the ratio for me needs to stay close to the 2.81:1. So, I have already went down the Wavetrac route and retained my OEM ring and pinion.

My question is this. Can i swap sub frames and still use my 215 type pumpkin with Wavetrak conversion already done on it? I think it should work because the M3 diff seems to be accepted by my frame. I am not asking if the driveshaft would be altered. I've read many threads you guys wrote about the hybrid M3 back half/335i front half and shortened/ and rebalanced.

I'm asking if the 215 type diff will go into the M3 subframe and i would use my OEM 335d output shafts. It's really a bushings spacing question between the 2 different frames.

I've asked a very knowledgeable forum member/vendor here and was told no. Our conversation was very short so I don't know if he understood my point of view given above.

I have the M3 sway bar, 2 forward links, and lower camber links [none of this is installed on my car]. I understand if i use my frame that i can not use the M3 toe link. I also know if i switch to the M3 frame, i would have to use the M3 toe links or equivalent.
thanks

[feuer]

The uprights/knuckles are different so you won't be able to use non M half shaft and M half shaft won't mate with non M diff. The M subframe is not superior. It utilizes better lower control arm but those are interchangeable and if you change them you will need to change the rear shocks as well. Also, the lockdown kit is not compatible with M subframe.

[BB_cuda]

Originally Posted by feuer

The uprights/knuckles are different so you won't be able to use non M half shaft and M half shaft won't mate with non M diff. The M subframe is not superior. It utilizes better lower control arm but those are interchangeable and if you change them you will need to change the rear shocks as well. Also, the lockdown kit is not compatible with M subframe.

Not doubting you here and thanks for the answer.

Can i talk the converse of this for a minute? If someone changed to M3 diff only and kept the E90 frame, from what i read above, they would have to switch out to the M3 hubs (maybe this is what you mean by knuckle?) because they would have to run the M3 axles.

Back to what feuer wrote, the knuckle is different and i can't bolt the M3 toe link to my E90 knuckle? Am i getting it? The other links interchange just fine so its gotta be the toe link you're addressing.

Thanks for the guidance on having to use M3 specific shocks when i change to the lower camber link. I'd heard that before but reinforcement is helpful.

Lastly, yes i didn't want to have to give up the use of the VWetish lockdown kit. This pretty much cements it for me to stick with my E90 SF.

[feuer]

Originally Posted by BB_cuda

Not doubting you here and thanks for the answer.

Can i talk the converse of this for a minute? If someone changed to M3 diff only and kept the E90 frame, from what i read above, they would have to switch out to the M3 hubs (maybe this is what you mean by knuckle?) because they would have to run the M3 axles.

Back to what feuer wrote, the knuckle is different and i can't bolt the M3 toe link to my E90 knuckle? Am i getting it? The other links interchange just fine so its gotta be the toe link you're addressing.

Thanks for the guidance on having to use M3 specific shocks when i change to the lower camber link. I'd heard that before but reinforcement is helpful.

Lastly, yes i didn't want to have to give up the use of the VWetish lockdown kit. This pretty much cements it for me to stick with my E90 SF.

To me the subframe is different (separate) part from the knuckles. If someone is to buy, let say from EBay, used M subframe, it might come just bare subframe, with out any other parts attached. Then you find out that the non M parts you have aren't compatible. So in order to use non M diff and non M shafts you need M subframe and M knuckles. If you want to keep your own non M knuckles they won't fit because of the toe arm as you concluded. On top the brakes are different and not interchangeable. Regarding diff lockdown they have them for M cars too. But is only for M diff and bolts onto the chassis itself, not the subframe.

[BB_cuda]

Sounds like the sub frame, toe link, and hub are all a matched set whether standard E9X of M3. Once you switch over to M3, I'm afraid the changes would cascade to M3 brakes too (fitting to hub). Too many changes and not worth it. I like the M3 subframe and toe links but not that much. thank you. Used M3 knuckles are going for about $400 each on car-part.com

[k335d]

If you change your mind and move forward with the m3 subframe i have a set of m3 toe arms you can have.

Im looking in to going the m3 3.15:1 diff route. Im planning to run a 285/35r19 in the back to make up for the gearing. It will still run about 90rpm at hi way speeds from what i could calculate.

How do you like the wavetrac so far? Me and Yozh talked i bit about it last weekend and he's planning to go that route like you.

[BB_cuda]

Thanks so much for the toe links offer. Pretty sure I will have to step back if a knuckle change is needed. Too many cascading changes downstream if this happens.

I like Wavetrac so far but am leaning toward ediff deactivation. I still have the OEM m-sport suspension so can't fully gage the LSD yet. My 1500 mile fluid change is approaching. Just passed 1000 miles.

[BB_cuda]

I'm a determined individual on wanting full understanding. Let's keep going with my progression. Assume i switch to an M3 sub frame, keep my Wavetrac equipped 215 differential (this has my needed 2.81 ratio for the diesel), and 1/2 shafts that fit my diff. I've already learned above that i need the M3 knuckles for the M3 toe links to fit properly.

Feuer tells me above the knuckles/uprights won't work with my axles. I'm wondering why this is? By the way, Feuer, what do you mean by uprights in the phrase "knuckles/uprights". I'm clear on what the knuckles are. Back to my original train of thought. My guess is Feuer is saying my 335d axles won't fit into the splines of the M3 hubs that are pressed into the M3 knuckles.

Sooooo, what if i get bone yard M3 knuckles and press out the M3 hubs. I would go ahead and get new bearings while I've got them all apart. The 335 and M3 knuckles use IDENTICAL bearings (p/n 33-41-6-775-842)by the way. Described as 45x85x41. Same part # shown on realoem for both 335 and M3 side shaft/wheel bearings page. Press out the old bearings and press in new ones and then use my 335 hubs and install them into the M3 knuckles.

Question 1) Would that solve the 335 axle into M3 knuckles?

I went to talk with service tech friends at local dealer and they all agree the M3 shafts themselves are bigger but are unsure if the splines are any different at the ends. I've been hunting for close up pictures of the splines. I may just have to go to the boneyard and look at them side by side.

Question 2) I will also be wondering if my 335d brakes will go onto the M3 knuckles properly. I have read other places where people put M3 brakes onto 335 but hadn't locked in on a good thread to understand if the M3 caliper carrier is bolted onto the 335 knuckles or what. I'm looking at the opposite here. In other words, will my 335 caliper carrier brackets bolt onto the M3 knuckles where i can run the 335 rear rotors (with em brakes shoes underneath).

Okay veterans of suspension forum, rip me a new one for my newb questions. thanks

[feuer]

Just to be clear, I'n not sure if drive shafts will fit.
They are different:
335d LK=94MM/D=27MM # 33217561789
335i LK=86MM/D=38MM # 33207568730
However the use the same nut # 33411133785 so There is a chance that they will.
Also, the hub seem interchangeable too:
335d #33416783671
335i # 33416760058
because they use the same bearing # 33416775842
When I say knuckle/upright I think of the wheel carrier # 33326783667 and I said that they won't fit because the toe arms aren't interchangeable. You can mount the wheel carrier but you need aftermarket adjustable toe arms.
To my knowledge the non M and M3 brakes are not interchangeable either. Rotors, carriers and calipers are different, only pads are interchangeable. The space out on the mounting tabs for the caliper carrier is different. This is for the front so you can see what I mean: http://www.fluidmotorunion.com/m-sta...r-make-it-fit/

[Yozh]

Thought I'll throw in a few cents in the mix, however, I have no first hand experience.

Based on the fact that a few 135 guys have fitted M3 diff onto their existing subframes and have used their original rear wheel carriers, leads one to believe that wheel carriers are interchangeable sans the brake caliper issue. M3 diff has to use M3 halfshafts and seems they fit.

However, why go through all this pain just to have M3 toe arms, as I understand is the issue at hand. One, there are a few good aftermarket ones. And additionally, there seems to be a solution of using your original ones with spherical bushings pressed in. Bushing part number is: MEY-3147100005 (Meyle).

[BB_cuda]

Thanks fellas. There's a couple other reasons to stay put with the current subframe. My VWetish lockdown will fit and also my uhaul receiver hitch has a place to bolt to the sub frame. I actually would get better neg camber out of the aftermarket adjustable toes too.