My '90 325is LS3 Swap Build Thread

[CLM21]

I think stock is a return style? Not quite sure... but the stock hardlines run from the fuel tank on the pass side across underneath the body to the drivers side, and then run up along that frame rail. Then turn up into the engine bay right by where the brake proportioning valve is. And then assuming its a return style, the return follows the exact same route because I remember there being 2 fuel lines along the drivers side frame rail.

I'm planning on doing pretty much the same thing, just with all new lines. And Im using earl's pro-lite 350, not using hard lines.

[ultimateracing335i]

I just looked at the sikky oil pan instructions. It says to trim the baffle. Did you do that?

[CLM21]

Yeah I saw that too, and no I didn't do it. I wasn't quite sure why they said to do it? They didn't put any reasoning in there.

[ultimateracing335i]

You will find it tight for the remote filter on the drivers side. I ran it to the passengers side.

[CLM21]

Ok, haven't really even thought about the process of mounting that yet. How close are you with your build? Seems like youre getting close to firing up...

[ultimateracing335i]

I'm just wiring in bmw sensors. I can start it any day now.

[CLM21]

Cool, how bad is the wiring? That's the only part that I'm not looking forward too.

[ultimateracing335i]

Do you have a gm performance harness? It seems straight forward. I'm building a street car, so I'm trying to get all the guages and ac to work. The gm performance harness has a fan output as well as a fuel pump output, so all you need is ignition and you can start it. I built a bracket for the drive by wire pedal, made an intake with a maf bung, modified the bmw temp sensor to fit the caped ls port in the head and made a bung for the bmw oil pressure sensor that screws into the existing valley pan.

[CLM21]

Yeah I was either gonna get one from GM performance or another company who makes standalone harnesses for swaps. I'm not worried about wiring the engine harness, that's easy enough. I wanna make all the stock gauges work as well, although I'm not gonna have ac. I'm just worried about that mostly as well as the ignition wiring. And yeah the temp sensor and oil sensor were my biggest questions. I may copy what you did. Speedo is easy enough because that's just in the diff... Haven't really looked into the tach at all yet.

[ultimateracing335i]

I'll have it all figured out by Tuesday.

[Q8y_drifter]

I haven't figured it all out yet, but for now I was able to source an engine harness and a 411 ECU from an 04 Chevy Caprice LS1/4L60E. Ran me about $200 for both.
The fuel level sender, fuel pump, speedo and all other accessories should all be wired to the BMW fuse box. So no need to worry about that.
I also had a 16" Spal fan mounted and connected to the AUX fan pin in the fuse box which runs full speed all the time (might redo that and stick a fan controller later on).
Running an Autometer tach at the moment with my current RB engine (My car is a 316i, I never had a tach to begin with) and will be buying aftermarket gauges for coolant, oil temp, pressure and AFR.
A friend of mine will be helping me out with the rest of the wiring.

[1991 e30 bmw 318is]

everything you need to wire it up is here.... http://lt1swap.com/

[CLM21]

Does anyone have part numbers for the e30 coolant temp and oil pressure sensors?

^ I'm not worried about the engine harness side, that's easy enough. I'm worried about the bmw side. That shits confusing. Looking under my dash right now boggles my mind.

[ultimateracing335i]

Oil pressure switch m12x1,5 12617568480
oil pressure switch m12x1,5 12617620512
engine coolant temp sensor 12621710512

[ultimateracing335i]

You have to modify the coolant temp sensor to fit the ls head. It has to be turned into m12 1.5 thread. The oil pressure switch is to small to fit where the gm one goes. I bought a drain plug that fits the gm hole and drilled and tapped it to fit the bmw sensor.