Swapping in a 210mm Euro Evolution differential

[sandford]

so pretty much all you need to do this swap is the diff and to modify the subframe? do you have to get the evo diff or can you use any 210 diff?

[DaveAZ]

so pretty much all you need to do this swap is the diff and to modify the subframe?

You would need the differential, the rear boomerang and the front bolt mount. (See my first post in this thread for the official BMW names.)

Do you have to get the evo diff or can you use any 210 diff?

I don't know the answer to this. That is the major reason I went into extreme detail in the photographs. I have only personally seen two BMW 210mm differentials, and they appeared quite different. It isn't just ANY 210mm diff, but it could be one from a specific vehicle unknown to me.

It would not surprise me if there is another BMW that uses a similar differential housing and only needs the front bolt mount, back cover and/or the rear boomerang mount, but I have no idea if the differential housing is the same as any other vehicle or is actually unique.

The main reason I suspect this is not a unique differential housing is that this housing needs extra pieces to be adapted to mount into the rear subframe, yet the 188mm differential does not.

If there is a problem with 188 diffs it's heat .. not torque.

This may be true. A major reason behind bigger brakes is heat dissipation and it is always misenterpreted by the end user as being able to stop faster, despite the tires being a greater weakness than the rotor/pad size. I don't know every reason BMW used the 210mm on a 3-series, but I know mine. I'm willing to take all the added benefits.

[bmxcm]

wow lots of good info here DaveAZ, i was looking to do the same when I broke my subframe but the info could not be found and I wanted my car back on the road ASAP. as GMW364i the issue is not w/the diff but w/the inferior design of the mounting points. so in my opinion that is reason enough to swap it out. the US diff is basically bullet proof tho, although I have seen a stock car break one (pinion failed)...take that as you will.

I have produced a set of reinforcement plates for the subframe (evo and normal) after 20k miles and many trackdays and abuse. I've finally got the subframe to stay straight. These are laser cut plates and consist of 34 pieces that are welded on the subframe.
Paul

any more info you can give us on these plates Paul? 34 pieces sounds pretty labor intensive tho

[JETninja]

I'm just pointing out the fact that the differential that is factory equipped in the US M3's is pretty much bullet proof.

Except for the '95 3.15's that left the factory with no Locktite on the LSD Carrier Cover Plate. (bolts back out, bounce around and get eaten between ring & pinion. On my original LSD, 5 of 8 bolts were out! 2nd 3.15 had no Locktite either. Got a 3.23 from a '97 now and it's bullet proof for my use) And note, I'm an old dude (47) and never did any donuts / burnouts till 2 weeks ago (great drifting car! jeeze it was fun!) and that was with my 3.23 that I've put a good 15K since I installed it.....


And early cars had solid axles, later years had larger diameter hollow ones. They are interchangable and not much difference strengthwise IIRC......

[DaveAZ]

In response to the PM's I have been getting about this I have begun doing a little reaseach in the direction of using a US 210mm differential in place of the evolution. (I am simultaneously trying to source an inexpensive ring & Pinion in the ratio I am considering.)

E32 differentials and E34 Differentials have the same back cover. That means the boomerang rear mount from the Evolution should fit. The front bolt mount will need to be fabricated, as the bosses for the bolts are in different locations. This will not be a huge issue since the front subframe mount point will also have to be fabricated.

I don't yet know if the locations of the input and output flanges will line up. No one I spoke to who sells used differentials was willing to entertain my requests to measure them for me. I may need to see one in person to take measurements to get my answers. When I have a chance I will measure the Evolution differential that I have and post the measurements here.

If everything lines up this could be something that could be incorporated into the LS-1 kits by their makers. If I need to buy a complete diff to scrounge my ring & pinion I may give the install a try for the sake of knowing if it can be done as easily as I imagine.

E34:




E32:



1995 740

[328iJunkie]

interesting

[vjlax18]

Gear sets from E30's, E28's and E34's are available in a multitude of ratios in 188's. The Euro M3 halfshafts are the same as the US. People run 2.93's who have turbos... it's quite common.

Cool project, not really needed though, but thanks for all of the documentation.

[DaveAZ]

Gear sets from E30's, E28's and E34's are available in a multitude of ratios in 188's. The Euro M3 halfshafts are the same as the US. People run 2.93's who have turbos... it's quite common.

Cool project, not really needed though, but thanks for all of the documentation.

over 13,800 posts?

I'm not sure where you were going with the ratio availability of the 188mm.
The discussion is about the 210mm differential. The point to me isn't if the gears are "available" as much as it is about if they are economical and worth the price when compared to other options. Do some price comparisons to see what I am talking about. With a little shopping you can buy a used 210mm differential fully built with the ratio you want for less than half of just a 4.33 ring & pinion set for a 188mm.

I'm not sure what to make of the Evolution tubular half shafts. The forums in Europe said they are stronger and lighter, but I have also heard the weakest point is the same in both. If they will both break under the same stress I don't see the need except for weight savings. I won't explore this unless I eventually start breaking them.

As Paul said, once the car has enough power the subframe itself will be a new weak link. I'm sure there are other new weaknesses in the E36 once equipped with an LS1/T56 that I have not considered yet. Hell, I tore the rear subframe out of the unibody itself in my E36 325...

As far as "not really needed," I really don't understand the criticism. You could have saved BMW some money by telling BMW it is "not really needed" before they built the M3 Evolution in Europe with it in the first place. Just for kicks, lets say the engine puts out 750 hp and the car is used for endurance racing or drag racing. Now is it needed? It is all about the intended use of the car.

I know installing a 210mm diff in an E36 isn't for everybody and may even wind up being "overkill" for me. I think it will cost less than "good enough" with a 188mm. To me this is also about the simplest and least expensive way to get to the end result desired.

I know I am going to inspire more people who feel the need to tell me the virtues of the 188mm differential by doing this, but here goes:

The issues people have expressed with the 188mm differential in the M3:
1. Weak front bolt mount
2. Gets too hot
3. 1995 M3 manual transmission (my car) self-destruction
4. Overall strength in very high torque applications, especially launches
(#4 can be argued because other components will typically break first, but why not make it stronger for the long run?)

Do any of these 4 major issues apply to the 210mm differential?

To "bulletproof" the situation in a 188mm differential:
(not addressing the strength issue)
Active Autowerke differential support bracket $200.00
Ring & pinion polish $200.00
Finned cover $450.00
Accusump & oil cooler $450.00

Assuming you are starting out without a differential in the first place, add the cost of a LSD differential with your options of choice:
Adding clutches, variable ramp, Quaife or Kaaz...
Ring and pinion in ratio of your choice.

The 210mm differential came from the factory in many ratios and there are plenty of LSD units floating around for very low prices. It is all about supply and demand here- nobody is buying them and lots are out there.

When I have some time I will add a DIY writeup to this thread that was given to me by a guy in England explaining how to increase the lock ratio in the 210mm.

[=BA=]

Pro's and cons. The EVO diff has a larger oil capacity and will run cooler. The cars which are used in motorsports usually suffer from this if you don't apply extra cooling.

One other concern for going with the 188 with finned cover is the weight of the whole assembly, you gain a good bit of weight by swapping to Type 210.

I replaced my gearset with that of a E46 M3. A lot of 5 and 7 series are actually Type 215, so not sure if you can use them. They are available through BMW motorsport however.

[vjlax18]

over 13,800 posts?

Your point is?

I'm not sure where you were going with the ratio availability of the 188mm.
The discussion is about the 210mm differential. The point to me isn't if the gears are "available" as much as it is about if they are economical and worth the price when compared to other options. Do some price comparisons to see what I am talking about. With a little shopping you can buy a used 210mm differential fully built with the ratio you want for less than half of just a 4.33 ring & pinion set for a 188mm.

I also did reasearch on the Evo differential and found that I could swap internals with any other 210mm diff. The gear ratio options are plentiful and inexpensive.

188's are easier to get then you think. E46 325's had 3.07, 3.15, 3.46. E36's had 2.93, 3.15, 3.91. E30's had 3.73, 4.10. I just gave away a 3.46LSD from an E34. Much easier to find 188's...

I'm not sure what to make of the Evolution tubular half shafts. The forums in Europe said they are stronger and lighter, but I have also heard the weakest point is the same in both. If they will both break under the same stress I don't see the need except for weight savings. I won't explore this unless I eventually start breaking them.

Same P/N as US M3.

As Paul said, once the car has enough power the subframe itself will be a new weak link. I'm sure there are other new weaknesses in the E36 once equipped with an LS1/T56 that I have not considered yet. Hell, I tore the rear subframe out of the unibody itself in my E36 325...

M3's had subframe re-inforcements for a reason.

As far as "not really needed," I really don't understand the criticism. You could have saved BMW some money by telling BMW it is "not really needed" before they built the M3 Evolution in Europe with it in the first place. Just for kicks, lets say the engine puts out 750 hp and the car is used for endurance racing or drag racing. Now is it needed? It is all about the intended use of the car.

I know plenty of clubracers putting down serious power and they've been using the 188 because it's lighter.

I know installing a 210mm diff in an E36 isn't for everybody and may even wind up being "overkill" for me. I think it will cost less than "good enough" with a 188mm. To me this is also about the simplest and least expensive way to get to the end result desired.

Notice the thank you statement for the documentation of it?

I know I am going to inspire more people who feel the need to tell me the virtues of the 188mm differential by doing this, but here goes:

The issues people have expressed with the 188mm differential in the M3:
1. Weak front bolt mount
2. Gets too hot
3. 1995 M3 manual transmission (my car) self-destruction
4. Overall strength in very high torque applications, especially launches
(#4 can be argued because other components will typically break first, but why not make it stronger for the long run?)

Do any of these 4 major issues apply to the 210mm differential?

3 of the 4 do and do not. Weak front bolt is the only problem listed that's specific to the 188. 210's will get too hot too just like any diff in a racing situation. 3 has nothing at all to do with diffs. 4 is also a problem in ALL diffs.

To "bulletproof" the situation in a 188mm differential:
(not addressing the strength issue)
Active Autowerke differential support bracket $200.00
Ring & pinion polish $200.00
Finned cover $450.00
Accusump & oil cooler $450.00

DSB isn't needed with proper bushings and it just weighes more. You'd have the 210 R&P polished too. Finned cover only needed in racing along with the oil cooler too... which would both be needed with the 210.

Assuming you are starting out without a differential in the first place, add the cost of a LSD differential with your options of choice:
Adding clutches, variable ramp, Quaife or Kaaz...
Ring and pinion in ratio of your choice.

The 210mm differential came from the factory in many ratios and there are plenty of LSD units floating around for very low prices. It is all about supply and demand here- nobody is buying them and lots are out there.

When I have some time I will add a DIY writeup to this thread that was given to me by a guy in England explaining how to increase the lock ratio in the 210mm.

You can find any 188 R&P you want for $200 and any E36 188 LSD for $200. There's $400. Have them rebuilt $800. Install proper bushings $200. Sell stock M3 diff -$400. So there's $1000 spent. And it'll weigh less...

So again, thanks for the write-up. And again, who cares about my post count?

[DaveAZ]

I replaced my gearset with that of a E46 M3.

Old 210mm thread

I considered getting the E46 M3 variable lock. What differences are you noticing?

[=BA=]

Faster acceleration but I haven't swapped the LSD unit. It is possible but I only fount out it was after I made the swap

[DaveAZ]

Just to clear up a few things for vjlax18:

"3. 1995 M3 manual transmission (my car) self-destruction" refers specifically to the differential. The factory did not use loctite on internal bolts which eventually come loose and destroy the differential. It is mentioned a few times in this thread already so I didn't get into the details again.

I was shopping for an E34LSD to get the 3.46 a few years ago when I was driving the 325IS and I had problems tracking them down. I found that all 188mm LSD differentials went high on ebay and were pricier at the recyclers because there is more of a demand for them. I think there are less with desirable ratios floating around, too. I can't find the 188mm prices you quote at the bottom of your post anywhere. We just have different shopping experiences.

You are looking at the wrong year for the part number of those Evo axles. The earlier years are the same as the USM3. They switched to a tubular style in later years. Scroll down to post #21 where I posted a picture of the two, side by side.

In my opinion, those M3 subframe renforcements should have been in all the E36 6 cyl. cars. My 325 only has about 200hp and a stiff suspension. It now has a new unibody panel where the diff mounts in to it in front and M3 subframe renforcements. (I will post a writeup of that nightmare eventually- I took pics.)

The 210mm differential weighs approx. 13 lbs. more but is exponentially stronger and has a greater oil capacity. There is greater surface contact, but I'm betting it stays cooler than a stock 188mm with the same ratio at the same speeds. With the LS1/T56 188mm I'd want a diff cooler for insurance. I don't feel the same way about the 210mm. This is a bench guess; I may change my mind when I actually have the car together.

You can't compare this to clubracers with regard to strength. They aren't running LS1/T56 and don't have the instant torque of that combination. They aren't twisting their subframes. It isn't a fair comparison.

I was only teasing about the thread count- is your laptop in your car?

[rao]

Interesting thread. I like the idea of using the larger differentials from other US spec car;makes it much more cost effective.

Time will tell as more people put low RPM high-torque through these diffs. After speaking to everyone that I could find that rebuilds BMW differentials; I am going with a rebuilt e36 diff with a 3.46 ratio, it arrives tomorrow .

I am seam welding the diff support brackets, drilling out the front diff bolt hole and using a bracket for the front of the diff to put that joint in double shear. I am also using newly rebuilt stock M3 axles (and everything else under the car is new as well from the bearings to the rear upper control arms).

I will have a decent amount of power but am not going to be using slicks.

[vjlax18]

I do have a laptop in my car with a cell card in it... but I post from work.

I got my E34 one for $150. I bought 2 E46 3.46's (non-lsd) for $350 total. I guess I just get lucky with parts.

My M3 has the larger axles and my 325 has the smaller. Both look exactly like the picture you posted.
realoem.com lists the same p/n for all M3's US or Euro

I understand the strength differences and I've broken diffs before, but that's after 100k miles and probably 100-150 launches at 4250rpm with 275 r-comps on the rear. I'd rather break a diff than a driveshaft or halfshaft.

Do you plan on flaring the rear of the car? If not, the strength of the diff will not matter the least bit. 245's in the rear will not handle the power.

[vjlax18]

Interesting thread. I like the idea of using the larger differentials from other US spec car;makes it much more cost effective.

Time will tell as more people put low RPM high-torque through these diffs. After speaking to everyone that I could find that rebuilds BMW differentials; I am going with a rebuilt e36 diff with a 3.46 ratio, it arrives tomorrow .

I am seam welding the diff support brackets, drilling out the front diff bolt hole and using a bracket for the front of the diff to put that joint in double shear. I am also using newly rebuilt stock M3 axles (and everything else under the car is new as well from the bearings to the rear upper control arms).

I will have a decent amount of power but am not going to be using slicks.

Use powerflex subframe bushings and the turner solid diff bushings and you won't have any problems. I used to break diff bolts all the time, not anymore.

You'll love the 3.46... I love mine.

[DaveAZ]

I will do some homework on that eventually. I haven't addressed the wheel thing yet. I'm up to my ears in BMW wheels right now (4 sets) and none of them will be on the car when it is done.

The Vorshlag thread has been going into detail about that lately. On one of theirs they are using 18x10 D-Force wheels and 285/35/17 R compounds.

I just got my M3 a few weeks ago and I have a lot of other projects to accomplish just to be happy with it before I get too far into the LS1/T56 swap portion.
I was originally going to be using my 325IS, but I went itno that earlier in this thread.

I'm installing E46 330 rear brakes and I need to rebuild the fronts. It still has the 1995 stock suspension so I need to install my suspension components, but I may change a bunch of them once I do the Engine/trans swap. I have a larger radiator/electric fan going in and other random stuff that I pulled off my 325.

All this is happening before the differential swap and I may decide to change the ring/pinion first.

[rao]

Use powerflex subframe bushings and the turner solid diff bushings and you won't have any problems. I used to break diff bolts all the time, not anymore.

You'll love the 3.46... I love mine.

Interesting - the people at Turner told me not to use poly bushings at all

The way I am doing it; the diff case will break before the bolt will break.

[vjlax18]

You have to check the bushings a lot with the poly ones, but again I used to break stuff all of the time. My subframe isn't moving much anymore and the diff is perfect with the Turner bushings.

You must be joking, but why would you want the diff case to break instead of the bolt?

[rao]

You have to check the bushings a lot with the poly ones, but again I used to break stuff all of the time. My subframe isn't moving much anymore and the diff is perfect with the Turner bushings.

You must be joking, but why would you want the diff case to break instead of the bolt?

I don't; the point is that the bolt will no longer be a failure point, the load will be transferred to the whole assembly. I am also running it through the case so it can be easily replaced in the future.

[DaveAZ]

Interesting - the people at Turner told me not to use poly bushings at all

I wonder why?
I have a set sitting on my counter. I was planning to put them in, but the stock bushings are in great shape.

[rao]

I wonder why?
I have a set sitting on my counter. I was planning to put them in, but the stock bushings are in great shape.

I think they would recommend for track use, but I made it very clear that I was putting together a street car.

[95RogueM3]

Most if not all of the 500+whp cars on this forum are still pushing it through the 188 diff... and without issue.

This is utterly and totally misleading. Most all, if not all, cars pushing ins excess of 500whp have Diffs built by Dan @ Diffs Online, Jim Blanton, or Metric Mechanics. I personally have a 2.93 40% lock in my turbo car. Ive heard of quite a few 3.15s grenading with just north of 400wtq (themadhatter grenaded my old 3.15 with his TTS2 kit) This conversation is comparing stock 188 diffs to stock 210 diffs..we arent talking about built 188 diffs.

[DaveAZ]

My M3 has the larger axles and my 325 has the smaller. Both look exactly like the picture you posted.

A few weeks ago I looked at my 325 & M3 and ran a thread around both. I thought the circumference was almost identical. The big difference between them was at the wheel end- The M3 part is huge there by comparison.

[DaveAZ]

I said I'd add the % lockup information I got from an England site.
This is all cut & Paste, not written by me. Here goes:

I find the % of lock explanations a little misleading; once these units have locked they can transmit 100% of the torque equally across a locked axle.

My understanding is that the % is more representative of the amount of torque that is allowed to slip before the unit locks. (A 25% LSD allowing 75% to slip before locking, which isn't the same as having the ability to redirect 25% of the torque.)

“I am sure Joe has increased the locking effect in his diff by fitting extra discs.”

Fitting the extra clutch packs makes the unit more durable and much more pleasant to use, but doesn't necessarily increase the readiness to lock. (Although it can be used to the same effect as extra 'wavey' washers etc, by increasing the LSD cluster pre-load.)

Ford Atlas (Euro car) axles use the same ZF LSD unit with four clutches as opposed to the BMW's two clutches. A four clutch 'repair kit' for an Atlas axle (£120) can be fitted in to the BMW LSD cluster by machining the housing and leaving out a flat washer from the cluster, if the machining is calculated so that the pre-load is unaffected, the locking % characteristics are also unaffected, but the 'action' is much improved and the unit will last longer.

There are two ways to increase the 'poise'/locking action (readiness to lock) of the LSD unit.

One way as already mentioned is to increase the LSD cluster pre-load, either via stronger spring/wavey plates, or by extra clutches/shims. (Basically changing the height of the cluster so that the unit has extra pre-load). This is the most commonly used method but isn't my preferred choice. (Although I do use slightly increased pre-load to supplement my preferred method in my diff, for gravel use.)

My preferred method for increasing the locking is to alter the pressure ring ramp angles. The pressure rings have opposing triangular recesses machined on the inside edge, when one wheel spins, the shafts that run in these recesses try to climb the ramp, which in turn forces the pressure ring outwards to 'nip' the clutches within the cluster. Altering the angle of the ramp faces makes it easier for the shaft to climb; consequently the clutches are nipped more readily without any increased pre-load inside the cluster.

Another advantage of using the altered ramp method is that the unit can be machined in such a way that it can operate differently in opposing directions. Many track/race drivers prefer a 'softer' unit on the overrun/trailing throttle, to avoid savage lift-off/trailing throttle oversteer on corner entry. Anyone who's familiar with the transmission locking the inside rear wheel with a clumsy downchange, can imagine how disconcerting it could be for the unwary driver, if this caused both rear wheels to lock. (Similar effect to pulling the handbrake on.) The ramps are infinitely 'fine tuneable' to allow different locking in each direction.

A popular choice is to machine the ramps to 30 degrees as opposed to 45 degrees. It is essential that the shaft sits at the same height in relation to the pressure ring when in the 'neutral' position. Because of this, it isn't possible to alter the existing ramps, but new ramps can be machined adjacent to the existing ramps.

Standard pressure ring ramp......

_________________________
Modified pressure ring ramp......

_________________________
Together......




Calculating/predicting the locking % isn't an exact science imo, I've been told that an 80Lb pre-load with standard ramps will give 40% locking in each direction, I've no way of measuring this.

For my diff, I use 30 degree ramps in both directions with an 80 Lb pre-load, this makes a very 'tight' LSD unit and imo this is perfect for gravel use, but in an ideal world the same ramp set-up with standard pre-load might be more appropriate for tarmac use.

It's down to individual preference really, but my guess for a nice sporty road car set-up would be to use 30 degree ramps for power on, with the standard 45 degree ramp for overrun and a fractionally increased pre-load. (Four clutch conversion optional.)

Increasing the pre-load with standard ramps is an easier but still effective method.

Apologies if it sounds complicated. Once you get it apart it'll all become clear, it isn't too difficult.