E34 Alternators

[Grrrmachine]

The M20B25 for my engine swap is from an E34. As such, it's got an alternator with a massive air vent in it, since it's a 115A unit.

Is this going to be an issue in an E30? I know the E34 used a big plastic intake pipe for this thing, and I have no idea if it'll fit in an E30 engine bay, and without it will there be any risks?

I still have an E30 80A alternator, but the mounting bracket on the block is completely different, so swapping them over is a no go, and I've got nowhere to get a replacement bracket from

[Brianmoooore]

Leave the E34 unit in place. It'll only produce the power that's required, and in an E30 application, won't need the air ducting.

[Grrrmachine]

Is there not a risk of water entering the alternator without the rubber hose Brian? It does look fairly exposed as it stands.

[Brianmoooore]

if any water gets in there, it'll get sucked straight out again by the alternator fan. Ducting is missing on my own E34, but I've never seen any trace of water in there.

[Grrrmachine]

Excellent news, cheers.

So it seems E34 engines will drop straight in to E30s, with the only mods being the engine mounting arms. I'll be confirming that the E34 sump works in due course.

[Grrrmachine]

New issue with using the E34 alternator...



Now the airbox doesn't fit! Only found out after fitting the engine

[Brianmoooore]

Cut the rear ducting off.

[aimlessrock]

or you could use a K&N induction system....

[Grrrmachine]

Brian? Advocating an angle grinder? To a BMW part??