Alternator Options

[Slideways]

ok, I think some non-Ms had a cooling duct from the foglight area. Might have been ZHPs or something. Or maybe auto cars.

Funny enough, the M3 has a molded intake port on the brake duct that has been blocked off. That could have been for alternator ducting.

[heinzboehmer]

Funny enough, the M3 has a molded intake port on the brake duct that has been blocked off. That could have been for alternator ducting.

It's clearly there for making your own DIY brake ducts

[Slideways]

It's clearly there for making your own DIY brake ducts

For only the driver's side? lol

[terra]

...That might actually be that mystery solved. I always wondered what that was for. Sure looks like the alternator ducting would fit there

[ZiMMie]

The problem might be the oil cooler lines it might interfere with the duction maybe not.

[0-60motorsports]

Anyone know if the Z4M alternator will fit on our M3's? Especially the electrical connector( I guess if we change the back cover)?

[Slideways]

Anyone know if the Z4M alternator will fit on our M3's? Especially the electrical connector( I guess if we change the back cover)?

The mount is the same for both cars, but the Z4M is 150A while the E46 is 120A.

Edit: Z4M also has a different connector due to BSD comms.

[AWE46M3]

Bought a Valeo alt in December on Bimmerworld when it was on sale. Installed it last week when my Bosch alt voltage regulator started to fail causing some electrical gremlins to pop up in the car. The Valeo alt started whining as soon as I pulled out of my shops parking lot. My car sounded supercharged...

Purchasing an OEM BMW alternator through my shop and having them install it again. I get a 2 year warranty on the alternator and don't have to pay for labor again. It seems like Valeo and Bosch reman alternators are super hit or miss and it's the luck of the draw you'll get one that works. Paying the OEM tax and going the BMW route with this part.

[0-60motorsports]

It will as the mount on the S54 is the same for both cars. Z4M is 150A while the E46 is 120A.

I just heard from my tech and he said it'll fit but the plug functionality will not work as it uses BSD communication. So it's better we stick to the 140Amp. I really wanted to get the Z4M alternator lol

[Slideways]

I just heard from my tech and he said it'll fit but the plug functionality will not work as it uses BSD communication. So it's better we stick to the 140Amp. I really wanted to get the Z4M alternator lol

Yes, I'd only go with an E46 alternator. I thought the Z4M one could be used in a pinch due to the mounting points being the same but forgot about the BSD functionality.

[0-60motorsports]

Yes, I'd only go with an E46 alternator. I thought the Z4M one could be used in a pinch due to the mounting points being the same but forgot about the BSD functionality.

Yeah I'll order the X5 140Amp alternator as there is no harm using a stronger alternator as shown on the Z4M. Thanks.

[terra]

I just heard from my tech and he said it'll fit but the plug functionality will not work as it uses BSD communication. So it's better we stick to the 140Amp. I really wanted to get the Z4M alternator lol

A lot of the non-M guys have used the BSD alternators on their pre-BSD cars with seemingly no ill effect. I don’t know if those voltage regulators just fall back to the old school mode or what.

[0-60motorsports]

A lot of the non-M guys have used the BSD alternators on their pre-BSD cars with seemingly no ill effect. I don't know if those voltage regulators just fall back to the old school mode or what.

Thanks for that info. I just didn't want to risk getting it then it'll be a paper weight if it didn't work right. I want it to have oe functionality etc with the battery light etc on the dash coming in when it's supposed to come on. I tried tors with an e92 voltage regulator and same thing, if anything is wrong I won't know as the battery light on the dash will not come on..

[bigjae46]

Funny enough, the M3 has a molded intake port on the brake duct that has been blocked off. That could have been for alternator ducting.

That’s exactly what it’s for.

I was thinking about running. 200amp HO alternator in my 330ci to power a massive 25wattsx2 amp that was 44” long. Yup…that amp had unregulated power supplies and was stable to a 1/4 ohm. Almost a short circuit! But I would have needed cooling to run that alternator.


Ultimately I decided to go with more efficient amps.

[Subfra///Me]

Bought a Valeo alt in December on Bimmerworld when it was on sale. Installed it last week when my Bosch alt voltage regulator started to fail causing some electrical gremlins to pop up in the car. The Valeo alt started whining as soon as I pulled out of my shops parking lot. My car sounded supercharged...

Purchasing an OEM BMW alternator through my shop and having them install it again. I get a 2 year warranty on the alternator and don't have to pay for labor again. It seems like Valeo and Bosch reman alternators are super hit or miss and it's the luck of the draw you'll get one that works. Paying the OEM tax and going the BMW route with this part.

As I said before, I went thru two genuine BMW alternators in about 10k miles, so I'm not sure they are any better. They do have a limited lifetime warranty that extends beyond the typical two year warranty, but you have to pay for the labor though. Unless you have some sort of connections.

On a side note, why are people interested in using any other alternator than the one specifically made for the e46 M3? What are the advantages?