How simple is an ETA swap?

#1

I am going to likely buy an ETA powered 325es…

How simple is the physical swap of these motors?

#2

Depends on the year and the harness connector. If everything fits and both motors are straight shift, you only need to swap the motors and ECUs, and the cluster if you are using one. That is the best case scenario…after that, things get more complicated. Chuck

#3

So, the car I want is an 86, I am looking at an 87 M20B25 IS motor from a BMW Club connection here, it’s OK, needs your basic maintenance and a baffle, but otherwise just a high mileage POS like every other motor out there.

Still a straight up swap? I can get the ECU and Wiring harness with it…

Gauge clusters apparently fall out of trees in SoCal

#4

What you are looking for is a round connector driver’s side firewall. That car should have one. That means an “i” motor and harness will connect without problems. Note, make sure both motors are straight shift if you want to keep your anti lock unit working. The automatic cars had a different pin out in the round connector for the anti lock. Plug in motor and ECU and you should be good to go. Good luck, Chuck

#5

OK, Chuck, you rock, a pretty blue E30 is about to be mine.

See you out there one day.

#6

cwbaader wrote:

Chuck,

You now have me worried…I’m builiding my spec e30 from a 89 auto donor. I’ve converted to a five speed and am installing a different engine… Am I in trouble with the ABS and if so how do I correct?

Awaiting the cage builder to finish the the home stretch…I hope
Thanks

#7

You should be okay with your ABS, but the rear end in the automatic is a 4:10.

#8

Gasman wrote:

Oh yeah,That one I already caught!

Luckily I found a local guy who’s willing swap his 3.73 lsd for my 4.10

#9

Yeah the diff… that’s gotta be high on the list, mine is a 2.9 :o

#10

If the car is stick and the motor auto, there is one wire different in the engine side of the round connector…you can just jumper under the dust cover. Actually, I traced it down on an 89 and had the ABS working fine. You realize, however, you will be faster without ABS??? CB

#11

I just got my eta swap running and on track.

Chassis is an '86 eta, the engine is from an '87 325i.

I kept the eta 5 speed tranny and swapped in the appropriate LSD diff.

You gotta get the engine harness, AFM and DME (ECU) with the engine your going to swap in. Of course, the update engine should include the intake manifold, ICV and Throttle Body as well. If you’re lucky, you’ll get an oil cooler with the donor motor too.

I had to open up the hole in the fire wall to get the '87 harness through. Everything else was pretty much straight forward.

A digital camera is your best friend. Take lots o’ pics before you start tearing things apart.

#12

cwbaader wrote:

Ha! I was going to start trouble shooting my ABS this weekend. My donor motor is from an automatic car. :blush: I was unaware of any differences in the motor between the 2 powertrains.

But to stir things up a bit, if the ABS has it’s own CPU and harness, how does the engine pin out have anything to do with it?