High-amp Alternator Upgrade on E30?

[hozzziii]

Hi
I have an '85 316 and I'm going for a 2 liter turbo project.
The factory alternator on my car is a 65amp Bosch. I think it was 80A on 318i maybe. I've also noticed this alternator looks very much like the one used on the M20.
The thing is, I already have a 1200w amp and stereo on the car, and I'm also going to be getting a standalone ECU, EDIS, heated seats, electric windows etc. and right now I'm worried the current alt is not going to cut it.

So I went on qualitypowerauto(dot)com and put the numbers in, and it said I need 224 amps to be sure.
Then I thought ok I'm not gonna buy a custom alt for $400-600, so I thought ok let's look what BMW puts in their cars, let's see if I can find something used for a better price.

The closest one I found was on the N20 engine used in 328, 428, 528 cars which is rated for 210amps.
Mounting seems a bit tricky but I think I can manage with maybe some custom brackets and such.
My problem is BMW at some point started using this IBS or BSD system or whatever, for changing voltage and checking battery charge and a lot of stuff that I don't know.

So on this particular alt there's another connection:

That I don't know what to do with.
So I asked on Bimmerfest in the F10 section, they said that's for the IBS, then I asked well do I leave it? do I connect it to something? Someone said it's probably not going to work.

So, I'm not sure what to do right now.
I want a high-output alt to be safe, this was the closest I could find for an affordable price.

I know some members have swapped a 140 amp on their M20s, I think it would be low for my particular project.
So what do you think?
How can I fit an alt that can output north of 200amps that works fine on E30?
Any advice would be very appreciated, thanks.

[roguetoaster]

I think you might want to check your calculations on needed amperage and safety limits. Seems like 200A+ is very high, but I didn't do the math.

That said, if the alternator doesn't have a simple voltage regulator you will probably struggle to control it.

[e30davie]

yer do the math properly, 1200w amplifier means nothing. At normal listneing levels its probably drawing less current than a headlight.

ECU, EDIS, electric windows are largely irelevant. and unless cars that were optioned with heated seats had a larger alternator I would say thats irrelevant too.

in saying that 65amp is a little on the small size. an m20 alternator is 80amp apparently. can you fit one of them?

if i was going down the alternate alternator (hehe) id find an old dumb one that is internally regulated. wiring is very simple. main power and the exciter bulb and thats it. anything modern is going to be too complicated with complex pwm control or simliar.

[hozzziii]

I think you might want to check your calculations on needed amperage and safety limits. Seems like 200A+ is very high, but I didn't do the math.

That said, if the alternator doesn't have a simple voltage regulator you will probably struggle to control it.

Well, the one I mentioned above has an internal regulator.

From what I've read about this Intelligent Battery Sensor is attached next to the battery and doesn't really tell the alternator what to do, rather takes data from the alternator (like percentage utilized or power draw, temperature and whatnot) and also checks the battery voltage if it's full or not and then the dme can turn stuff in the car off to sort of make room for the battery to get charged maybe? I am not claiming to understand this system at all, just taking from what I've read people are saying about this system on their cars.

Also I've found that BSD stands for Bit-Serial Data, and it's just a bus between several engine components (like oil level sensor, alternator etc.) and the dme.

So, overall it seems the alternator doesn't necessarily need this IBS or BSD system to produce charge, rather it seems the newer cars use it to take information from components like the alternator to just assess the health of the system maybe?
I mean if the alt is regulated internally, doesn't sound like with ONE terminal there is much the dme can change on the alternator, it can however control other stuff on the car though.

Also I went on summit's website, and just filtered some search on alternators that were used by BMW, internally regulated, high output as much as possible, as old as possible to avoid these new systems.
And found that the E46 has one on their M50 engines, one that makes a healthy 150 amps.
So does the E46 have any of this Intelligent Battery stuff? Maybe that's simple enough?

[hozzziii]

yer do the math properly, 1200w amplifier means nothing. At normal listneing levels its probably drawing less current than a headlight.

ECU, EDIS, electric windows are largely irelevant. and unless cars that were optioned with heated seats had a larger alternator I would say thats irrelevant too.

in saying that 65amp is a little on the small size. an m20 alternator is 80amp apparently. can you fit one of them?

if i was going down the alternate alternator (hehe) id find an old dumb one that is internally regulated. wiring is very simple. main power and the exciter bulb and thats it. anything modern is going to be too complicated with complex pwm control or simliar.

So this is a spreadsheet I made off the top of my head.
I first used some of the numbers from this site:

https://www.onallcylinders.com/2015/03/27/alt-text-5-things-you-should-know-before-using-a-high-output-alternator/

then wrote what I thought, again off the top of my head.

AC	20
Amp	20
Fan	30
Defroster	15
Headlights	20
Horn	10
Foglights	10
Heated Seats	10
ECU and Ignition	30

The sum of these is 165. I will admit I won't be using them all at once.
So maybe a 150 will do? I found an E46 alt with 150amps which is internally regulated.
You think that will fit?

[e30davie]

Google suggests e46 alternator is ribbed belt, does that suit your chosen engine? can you make a bracket? if so then it will fit:)

Those loads wont be all maximum and all the time so its not its realistic to just add them all up. unless you hold the horn down the whole time you are driving? Power systems study must apply load factors or utilisation rates to the loads to estimate how often they are used else you will never get realisically sized equipment. Utilisation rate of a horn might be 2%

Dont forget the fuel pump, that is one load that will be all the time. and that could be 8-10amps on its own with a utilisation factor of 100%

And remember a land cruiser Prado only has a 130amp. 150 in a 2L 80s bmw seems massive over kill.

[hozzziii]

Google suggests e46 alternator is ribbed belt, does that suit your chosen engine? can you make a bracket? if so then it will fit:)

Those loads wont be all maximum and all the time so its not its realistic to just add them all up. unless you hold the horn down the whole time you are driving? Power systems study must apply load factors or utilisation rates to the loads to estimate how often they are used else you will never get realisically sized equipment. Utilisation rate of a horn might be 2%

Dont forget the fuel pump, that is one load that will be all the time. and that could be 8-10amps on its own with a utilisation factor of 100%

And remember a land cruiser Prado only has a 130amp. 150 in a 2L 80s bmw seems massive over kill.

Well I'm not worried about the ribbed belt pulley. My M10 uses v-belts. It's fine I'll just make a pulley at a machine shop and zinc plate it. I'll even have to account for the pulley ratio on the E46 engine and probably make the new pulley with the same ratio to my pulley just to keep it operating at an rpm that it's designed for.
I'm even prepared to modify the mounts on the casing to a point, to fit it on my engine.

And I don't hold the horn down the ENTIRE time I'm driving, just most of it ;)

I do agree about the fuel pump, forgot about that.

I prefer overkill than on the limit honestly.

My main concern is just about the wiring; can I wire up the E46 alt to my E30? I only have power cable and an exciter bulb cable.
Does the E46 have this IBS or BSD system or is it just a simple dumb alternator?

[hozzziii]

I went and talked to a guy that has a shop and has access to BMW's manuals on newer cars, was a website like ITAS? I'm not sure.
He wasn't really into it and I didn't ask him to just let me sit behind the laptop so I could browse the manuals to find out exactly.

But he confirmed that the newer cars have that system and the DME tells the alt when to go full send or slow down and said the alt can actually disconnect and had an alt in his shop and took the plastic cover off the pulley and showed me it has a bearing in there which means that there's a clutch in there. I even spun the pulley by hand and stopped and I could feel the clutch rubbing and the rotor kept spinning a little bit. So yeah there's a clutch.

Basically he said that an alternator from a 2010 or newer car is a no-go.

I asked him about the E46 alt, he just showed me a picture of an E46 alt and pointed that the pulley doesn't have a bearing, therefore is dumb simple alt that is internally regulated and said I should be fine with that.
But unfortunately he had to work on a car so I didn't get to see the E46's wiring diagrams to know for sure if the E46 alt has the same function as an E30 alt so I would know which terminal I should connect my cables to.

So I guess the E46 alt is greenlit, just need the E46 wiring diagrams. It's progress I guess.

[hozzziii]

Well I can't find the E46 wiring diagrams. And looking at pictures of the E46 alt is also not helping me either.

the little connector above the positive terminal, has two connections inside it.
that makes me nervous. I need the wiring diagrams.

If anybody knows where I can find E46 wiring diagrams, would be very appreciated.

[reelizmpro]

I have cars that run old school sound systems with multiple amps, wideband O2, piggybacks, etc. I run BNR 140A Bosch alternators with high output voltage regulators on my S14's with poly or bosch white bushings, large gauge ground wires and reinforced adjusters. They were around $130 shipped back in the day. If you search Ebay they are now offering 150A Bosch for $325 shipped. You may want to contact them and see what they can do for you. Another thing, old wiring doesn't conduct well so look at upgrading grounds and cleaning up junctions and terminals. 140A with upgraded voltage regulators has been plenty of power for my M3's.

[hozzziii]

I have cars that run old school sound systems with multiple amps, wideband O2, piggybacks, etc. I run BNR 140A Bosch alternators with high output voltage regulators on my S14's with poly or bosch white bushings, large gauge ground wires and reinforced adjusters. They were around $130 shipped back in the day. If you search Ebay they are now offering 150A Bosch for $325 shipped. You may want to contact them and see what they can do for you. Another thing, old wiring doesn't conduct well so look at upgrading grounds and cleaning up junctions and terminals. 140A with upgraded voltage regulators has been plenty of power for my M3's.

Yes I actually saw them on Ebay as well just today curiously.
I was browsing to see what E46 alts cost and yeah, they came up. Which is weird considering I wasn't searching for E30 alts.

And yes, I will be upgrading my wiring with the alt. I imagine that old cables that were good for 65amps back in the day will not be good for 150 today.

I did consider BNR actually, with the same mounting and belt situation it's quite attractive and very convenient.
It's just that I don't live in the US, so shipping will be expensive.
Also with my country's currency, $325 is a kind of a lot.

I can find used alts in my country for less than $200 and negligible shipping cost.
But then we arrive at the situation with the connector.

I might cave and just buy from BNR. I am cautious about their long term support though.
Do they use regular Bosch regulators? I didn't see any names on their regulator in the picture.

I'm gonna go to that guy's shop again and pry him about that E46 wiring diagram.
Been searching online all day and nothing.

If all else fails, probably will buy from BNR.

Thanks man.

[reelizmpro]

The BNR alternators come with generic aftermarket voltage regulators. I upgraded them myself after I got the alternators from them. I understand if you want to source your alternator locally though. Overseas shipping is a nightmare right now.

[ADEN]

Well I can't find the E46 wiring diagrams. And looking at pictures of the E46 alt is also not helping me either.

the little connector above the positive terminal, has two connections inside it.
that makes me nervous. I need the wiring diagrams.

If anybody knows where I can find E46 wiring diagrams, would be very appreciated.

I think these alt. needs 12v switched power on one side of the connector to work and a wire for the lamp on the other side.

[hozzziii]

I think these alt. needs 12v switched power on one side of the connector to work and a wire for the lamp on the other side.

So, 12v switched for the DFM to turn on the alt.
Then the cable from my cluster, which also has power and turns off when the voltage from the alt gets to 12v.

Can you just tell me where you got this information and all?

I just wanna be sure that I'm not gonna burn my car down.

[ADEN]

If you have the alt. just bench test it using only the lamp light 12+ connected see if it works, if it doesn't try puting 12v to the DFM and see. The other connection is for the ms45 the regulator drops the 12V to 8V with pulses to establish a serial connection for the dme for diagnostic reasons.

If i were you i would give it a shot since both wires in the connector are 12V power, You aren't burning anything.