1987 325e, help with I head swap

[VirginiaE30]

I have read the 1.3 swap sticky, this one, and am still unsure what I will need to do. My questions are:

Since it's an 87, most forums and sites say it's Motronic 1.1, How do I confirm? And if it is 1.1, will I need to swap it to Motronic 1.3 if I am JUST swapping the b25 head?

^^ If that is even possible, that's another one of my questions. I've read a bunch of places that if I use the i head and eta pistons, I will have perfect turbo compression, which is the plan.

If I do swap just the head, will I also need to swap the intake manafold and such?


Basically I want to know if I can just put the I head on and go, or if I will need to swap the harness/glove-box computer/everything from the head up in the engine bay.

I will also be putting in a new dash sometime around doing this operation, I will need to get an "i" cluster as well, right?

[MrWolf]

Yes you need an i intake manifold. The intake ports on the 885 head are significantly larger, plus the i manifold provides more volume and better flow. And yes you need the 1.3 Motronic ECU and harness. The goal of the e to i swap is to get some performance out of the 2.7 liter block. Part of that is upgrading the ECU, injectors, harness to get a higher rev limit and better top end HP. Simply put why would you do this swap and try to use the same ECU, manifolds, injectors, etc? Let's just talk injectors for a moment. 325i injectors were rated at 17# I think, but it would be a decent upgrade to 19 or 22lb even before turbo, once you turbo you are probably looking at 44# green tops or higher. All of these run high impedance, which is going to require 1.3 Motronic, as the 1.1 used low impedance signal to the injectors - i.e. the eta and i ECUs and injectors don't mix.

Lots of this is documented throughout r3v, e30tech, e30zone.net - Based on the questions you listed here I'd suggest doing a bunch more research before getting started. I just finished my e2i conversion. It was work but fun and I'm happy with the results.

[jeffnhiscars]

The difference in injectors is the impedance so they have to match the ecu (1.1 or 1.3) in order to fire. I believe they are all 14#

[superj]

Yes, 14