Need Details On 318is to M3 Engine swap.

[Shawn W]

Ok so here is the deal. I recently got a 1992 318is. I orignally bought the car to resale and make some money on. However i really like the little car and would like to keep it and sell one of my other cars.

It truly doesn't have that much power though. It's adequate but i want more. I know it would be a lot less hasle to just buy an M3 but money wise it would not be smart for me. The car i have now is nice and clean. Even has the original paint. Has a 5 speed and sunroof. all the options i want. I paid $4000 for it.

I know even high mile M3's go for about $17k+. If i did have a M3 i would probably upgrade stuff like shocks, and struts, exhaust, and that sorta thing anyway.

The only parts i really would want to keep on the M3 is the seats, body kit, and of course the motor.

With all that said. How much work is it really? Everyone acts like its just a bolt in procedure which i find hard to believe. What about wirring? I know you have to change the entire engine wirring harness, but does it go through the firewall in the same place? What about connecting the engine wirring harness to the chasis wirring harness? does it just plug right in? Or is there splicing involved? What about the mounts for the motor, tranny and rear? Are they the same?

What i really need to know is the gritty details of it. I have the general info but need to know stuff like that.

I have a parts list that i picked up from searching that i can start with. Let me know what else i need?

3.0 M3 engine
M3 Tranny, Clutch, Flywheel, Shifter, driveshaft
Complete M3 Engine wirring harness
M3 ECU
M3 Radiator, Fan, Fan shroud, Radiator mounts
M3 Motor mounts
M3 tranny mounts
M3 A/C Compressor, P/S pump, P/S lines
M3 Front engine brackets
M3 Fuel pump

Some of this stuff i am just guessing i will need and am not sure.

I also plan on eventually doing the rear end. How hard is it to install? Any cutting and welding to do on that?

My main thing is i don't want to have to cut and splice wires and i don't want to have to cut and weld anything? However i dought highly that i won't have to do some.

Let me know what you guys think.

Thanks
Shawn

[TINIK]

here is minimum things you need to convert your 318 to M3 power:
1 3.0/3.2 M3 engine
2 Clutch, Flywheel
3 Complete M3/325 OBDI Engine wirring harness
4 M3 ECU
5 M3 Motor mounts
6 M3 A/C Compressor A/C lines and brackets, P/S pump, P/S lines
7 M3 Front engine brackets
8 325/or M3 front suspension.

there is not much involved in electrical portion, but if you want your RPMs work right then you need 6 cyl cluster also.

here is those things you can retain, but upgrade later on:
1 Radiator
2 5speed tranny, drive shaft and diff.
3 master and slave clutch cyl
4 318 Fuel pump
5 rear suspension

[Shawn W]

ok cool. The biggest thing i fear is the wirring? Does the M3 engine wirring harness connect into the chassis wirring harness through one of those big scew together type connectors? Are there any wires at all that will have to be cut and spliced? I wanna stay with a OBDI M3 engine.

I notice that i will have to drill out the spot welds that hold the brackets for the coils, P/S pump and what looks to be the evap canister.

Are there any brackets such as these that will have to be welded back on?

any other cutting and welding neccesary?

If i do this i am going to make a step by step install procedure for all you guys. This info is damn hard to find.

Thanks
Shawn

[TINIK]

Originally posted by Shawn W
ok cool. The biggest thing i fear is the wirring? Does the M3 engine wirring harness connect into the chassis wirring harness through one of those big scew together type connectors? Are there any wires at all that will have to be cut and spliced? I wanna stay with a OBDI M3 engine.

I notice that i will have to drill out the spot welds that hold the brackets for the coils, P/S pump and what looks to be the evap canister.

Are there any brackets such as these that will have to be welded back on?

any other cutting and welding neccesary?

If i do this i am going to make a step by step install procedure for all you guys. This info is damn hard to find.

Thanks
Shawn

you can keep coil brakets, but you will need to remove Power Steering bracket.

Electrical, most likely you will not have to modify a lot for your car, only problem you'll have to deal is with EWS (and once again, it all depends what kind of ECU/DME you'll get for your engine)

[Shawn W]

What exactly is the EWS and DME? Sorry for the newbie question but i guess i need to get a better understanding of it.

The way i understand it is i need to get the DME from the same car that i get the M3 engine. Correct?

I have no clue on the EWS though.

I just want this to look and operate just as if it came from the factory with this motor installed. I have been poking around under my hood looking at pics of 6 cyl cars and seeing whats in different places. I really like the way BMW put things together on here. Makes it looks like they are fairly interchangable.

Thanks
Shawn