found 2 m30s! should i do it?!?!

[lukeADE335i]

Start by researching solder vs. crimp connectors. Talk to Luke about that;). Seriously it is a nice swap. You could just do a MarkD chip, flywheel, and 3.46 and be pretty happy is my guess.

Was that post aimed at me, or another Luke? Anyway - yes solder your engine loom, don't use crimp on connectors for something as important as your engine loom for reliability.

If you use an M20 loom and unwrap it, there are only a couple of injector wires to lengthen and the alternator exciter wire. Everything else can just be re-routed and rewrapped.

Wiring is fun :)



I basically have the setup that BearMW has suggested above, but with a 3.73 diff. It's a blast to drive.

[bsturman92]

Shit that looks like a mess haha.. But I know I can extend a few injector wires no problem... And yes I would for sure use a m20 harness,,, but I read that my car being a 318is it's gun able a lot more of a pain involving fuse box and exe... Can someone explain this to me? I wanna do it SOO bad

[lukeADE335i]

lol... nah - it's not as bad as it looks. It's just an unwrapped M20 loom, it's not cut at all.

Once I had all connectors hooked up on the M30, I just re-wrapped it.

If you have a 318is, you don't need to swap the fuse box - just get hold of a Motronic 1.3 loom from an M20 and lengthen a few wires (assuming you are using an M30B35 from an e32 or e34).

The engine harness will plug straight into the C101 connector (which is the big round one near the firewall).

The M30B35 engine will be easier into your car than an earlier M30.

[///Maddog9000]

I <3 my 335i BUT I cant wait till this lump blows so I can put in a LS1... now thats some really cheap, simple power!

[Doughnut]

I <3 my 335i BUT I cant wait till this lump blows so I can put in a LS1... now thats some really cheap, simple power!

You'll be waiting awhile, mofo's take a lot of abuse...

[Zacm829]

So where is this secret junkyard. I'm itching to start wrenching on another m30.

[yert315]

Why is everyone saying to run the m20 wire harness? What's wrong with the b35 harness?

The m30 harness plugs right in to the e30 c101, looks cleaner, and doesn't require any lengthening of wires. Seems like a no-brainer to me if he wants to keep it as simple as possible.

[chance]

Why is everyone saying to run the m20 wire harness? What's wrong with the b35 harness?

The m30 harness plugs right in to the e30 c101, looks cleaner, and doesn't require any lengthening of wires. Seems like a no-brainer to me if he wants to keep it as simple as possible.

mine wasnt a plug an play. Yes the plugs are the same, but a few of the pins are different.

[Zacm829]

mine wasnt a plug an play. Yes the plugs are the same, but a few of the pins are different.

I had the same issue on my 90 325i with b34 swap. I just used the late model harness with extensions.

[yert315]

That's odd. Mine went straight in with no dicking around other than the unloader relay jumper wire. I still think its the better option when it comes to fit and finish.

[bsturman92]

That's the first time I have heard of a stock b35 harness that's plugs right in every connector.. Always heard go withnm20

[chance]

That's odd. Mine went straight in with no dicking around other than the unloader relay jumper wire. I still think its the better option when it comes to fit and finish.

Thats pretty awesome. What exact car did the engine fome from and what is your car?

Mine was very close, but still needed 3 or 4 wires jumped. I could have repinned my connector but didnt want to go through that hassle

[n3nyongmini]

You can do it. I started with a low-mile m30b35 that had a cut harness, so I cut my m20 harness and matched them up. Only one spare wire from the m30 harness: the ground for the temp gauge sender; the m30 uses two wires, grounding back at the ECU, where the m20 uses just one, grounding through the sender.

[porschelou]

We did a full b34 swap in 3 weeks ( only working a few hrs each night + weekends).. Had two friends helping. We also rebuilt the entire motor during that time. I had ordered all of the parts ahead of time - engine mounts / oil pan / oil pump. I had the correct year e30 so I used part of it's drive shaft mated to the e28 shaft and had to cut 2 3/4" out of it.

Been racing it for 2 years ( drag and road racing).. We did put the motor in position 3 so we modified the firewall (I have a access plate on the inside that allows access to the top of the trans/rear of the motor.