Alternator Options

[old///MFanatic]

I don't know how long the M3 brushes will last, but on my 2000 323iT with 180K miles the brushes were still good for up 200k.

2000 323iT uses a unique and different regulator than our M3s.

[D-O]

Doing a little digging it seems like the plugs on the back are slightly different. I believe you can just swap plugs but would need confirmation with someone who has done it already. I did end up ordering the 140a X5 alternator last night so we'll see what happens when it comes in tomorrow.

Pics of 120a (OEM e46 m3 alternator) vs the 150a (OEM z4m alternator)

Thanks for investigating. I am in for the results as well.

D-O

[bigjae46]

I don't know how long the M3 brushes will last, but on my 2000 323iT with 180K miles the brushes were still good for up to 200K miles. The best way to find out is to remove the regulator/brushes and check the protruded brush length: Just replace the brushes or the whole regulator (with brushes) if they are less than 4mm. No reason to replace the whole alternator as long as the brush slip rings are in good condition. I don't trust re-manufactured alternators.

If you go to the trouble of removing the regulator...why not just replace it.

[sapote]

If you go to the trouble of removing the regulator...why not just replace it.

I don't replace thing unless I know it will break down in near future. By checking the brush length, I have a good idea of how many more 1000s miles I need to replace down the road. Removing the alternator is not a big deal.

[sapote]

2000 323iT uses a unique and different regulator than our M3s.

Both have similar design if not exactly the same, so the brush checking is similar.

[old///MFanatic]

Both have similar design if not exactly the same, so the brush checking is similar.

No they are not. M52TU uses a different one from M54s and also S54s.
Besides that, there are so many variables in use of E46s that would change dramatically the use of the alternator. One who drives to work every day at night, in traffic with seat heaters (multiple accessories) simple example. That’s not even factoring extreme heat/cold climates.

[sapote]

No they are not. M52TU uses a different one from M54s and also S54s.
Besides that, there are so many variables in use of E46s that would change dramatically the use of the alternator. One who drives to work every day at night, in traffic with seat heaters (multiple accessories) simple example. That’s not even factoring extreme heat/cold climates.

Ok, so even if the regulator/brushes are different across the different models, why does this affect the brush length checking method? IOW, why the brush length method works for M52TU alternator but not for S54?

[old///MFanatic]

How many miles/years are you guys seeing the original alternators lasting on these cars?

..on my 2000 323iT with 180K miles the brushes were still good for up to 200K miles.

There are many variables in use of E46s that would change dramatically the use of the alternator. One who drives to work every day at night, in traffic with seat heaters (multiple accessories).

Ok, so even if the regulator/brushes are different across the different models, why does this affect the brush length checking method?

It would not be similar enough to use a 323it as a basis for average mileage was the point.
Sorry, yes you can remove and inspect the brushes. But brushes are only one of several things that can be reason for an alternator to fail.

[sapote]

It would not be similar enough to use a 323it as a basis for average mileage was the point.
Sorry, yes you can remove and inspect the brushes. But brushes are only one of several things that can be reason for an alternator to fail.

OK, we're on the same page now.
I still think short worn brushes is the root cause of most alternator failure after 100K miles. Most people just replaced the failed alternator instead of investigate the root cause. I have not seen any reports of either spun bearings, seized bearing, burnt rotor/stator coil, damaged brush slip rings, or damaged rectifier diode bridge.

[whoissuprme]

So finally was able to tackle the x5 140a alternator install tonight with some help from a couple of buddies. Great news... It bolts right up! All you have to do is swap the back covers and you are good to go!! this seems like a great alternative.

bigjae46

0-60motorsports

PSUEng

D-O

Here are some pictures

This is the new 140a X5 alternator. As you can see there is a port for cooling


Back of the OEM 120a alternator


X5 alternator inside the engine bay with the e46 rear cover on.

[0-60motorsports]

So finally was able to tackle the x5 140a alternator install tonight with some help from a couple of buddies. Great news... It bolts right up! All you have to do is swap the back covers and you are good to go!! this seems like a great alternative.

bigjae46

0-60motorsports

PSUEng

D-O

Here are some pictures

This is the new 140a X5 alternator. As you can see there is a port for cooling


Back of the OEM 120a alternator


X5 alternator inside the engine bay with the e46 rear cover on.

Thats Awesome! Thanks for trying it out. I might go this route in the future.

[Shonky]

But then no cooling port?

[0-60motorsports]

But then no cooling port?

There is no cooling port on the Z4M 150amp alternator either. So this should be fine.

[whoissuprme]

There is no cooling port on the Z4M 150amp alternator either. So this should be fine.

Also no cooling port on the OEM 120a either because the power steering lines are in the way.

[0-60motorsports]

Also no cooling port on the OEM 120a either because the power steering lines are in the way.

Correct. Unless going racing and even then no need for a cooling Hose. LOL