89 M20B25 in to 85 325e

[MR 325]

Ok, so I have decided to swap the M20B25 from my 89 325i in to my 85 325e. Why not get an extra 47 hp for free? Anyway, I know there is some wiring to be done which James and I have already discussed. That's no problem. I have some other questions though...

I bought a clutch for for my 89 325i since I will be using an E30 tranny with my S50 swap in that car. This clutch will work with the 325e trans aswell, right? [And the 325e trans will work on the 325i motor, right?]

Also, I am planning to switch the 85 to a late model cooling system [even though James told me not to] so I am wondering if there are any issues fitting the late model radiator in to that car and what else needs to be done, etc.

Next question, I put a brand new cap and rotor on my 325e when I bought it and am just double checking that these will also work on the 325i motor.

And the final question... How much would I be restricting my B25 by using the Eta manifolds and exhaust that are already on the car? The exhaust has been all redone and I really love the way the car sounds. I don't want the sound to change and I don't want to have an exhaust made.

Thanks guys.

[James Crivellone]

Ok, so I have decided to swap the M20B25 from my 89 325i in to my 85 325e. Why not get an extra 47 hp for free? Anyway, I know there is some wiring to be done which James and I have already discussed. That's no problem. I have some other questions though...

I bought a clutch for for my 89 325i since I will be using an E30 tranny with my S50 swap in that car. This clutch will work with the 325e trans aswell, right? [And the 325e trans will work on the 325i motor, right?]

Also, I am planning to switch the 85 to a late model cooling system [even though James told me not to] so I am wondering if there are any issues fitting the late model radiator in to that car and what else needs to be done, etc.

Next question, I put a brand new cap and rotor on my 325e when I bought it and am just double checking that these will also work on the 325i motor.

And the final question... How much would I be restricting my B25 by using the Eta manifolds and exhaust that are already on the car? The exhaust has been all redone and I really love the way the car sounds. I don't want the sound to change and I don't want to have an exhaust made.

Thanks guys.

Oh nobody listens to me.

if you MUST use the late-model cooling system (which I consider subpar to the early model) you need to fab lower radiator brackets, plus coolant overflow tank brackets, obtain all the pluming, and cut off the old coolant oveflow tank brackets from the passenger strut tower...again pointless.

Clutch should be fine depending on flywheel, but if you use an I flywheel (obviously) it should work fine....E30 E tranny will work fine however I would use a 533i throwout bearing for quicker clutch engagement.

E cap/rotor will work fine.

Use the I manifolds if you can, ETA runners are just a tad thinner.. Overall exhaust, well the E is fairly restrictive, so it may increase ur torque a little bit, but don't expect it to scream as much at the high end.


my

[MR 325]

Clutch should be fine depending on flywheel, but if you use an I flywheel (obviously) it should work fine....E30 E tranny will work fine however I would use a 533i throwout bearing for quicker clutch engagement.

So the B25 flywheel is a must then, right? I have one out of an 87 325i, will that work? Why would the Eta flywheel not work with my setup? Do you happen to have the part number for that throwout bearing? If not, the year of the car I should order it from would be cool. Also, should I bother lightening my flywheel since it will all be apart or just resurface it and call it a day.

Thanks for the help James.

[James Crivellone]

So the B25 flywheel is a must then, right? I have one out of an 87 325i, will that work? Why would the Eta flywheel not work with my setup? Do you happen to have the part number for that throwout bearing? If not, the year of the car I should order it from would be cool. Also, should I bother lightening my flywheel since it will all be apart or just resurface it and call it a day.

Thanks for the help James.

It has to do with the alignment pins on the flywheel, if it fits the E flywheel. then you are fine, if not you need an I flywheel.

Throwout Bearing 21 51 1 204 525

Lighten an I flywheel, don't bother with an ETA dual mass

[MR 325]

It has to do with the alignment pins on the flywheel, if it fits the E flywheel. then you are fine, if not you need an I flywheel.

Throwout Bearing 21 51 1 204 525

Lighten an I flywheel, don't bother with an ETA dual mass

Ok, so I'll just have to see how it works out. There's a place that will do a resurface, balance, and lighten for $95 which doesn't seem to bad to me. They do top notch work too.

I am planning on starting work on the 89 teardown tomorrow. What can I get for a nice auto tranny? :)

[James Crivellone]

Ok, so I'll just have to see how it works out. There's a place that will do a resurface, balance, and lighten for $95 which doesn't seem to bad to me. They do top notch work too.

I am planning on starting work on the 89 teardown tomorrow. What can I get for a nice auto tranny? :)

auto tranny? I put mine in the alley behind my garage, 2 days later it was gone.. thank god, I was about to drop it off an overpass or something.

[MR 325]

Will I have any issues using an automatic radiator on a 5 speed car? Never actually looked at the difference between the two.

[James Crivellone]

Will I have any issues using an automatic radiator on a 5 speed car? Never actually looked at the difference between the two.

No issues..the auto radiator is the only part left from my car when I bought it..still works great even with the auto tranny coolant line ports left unplugged.

[JGood]

Can you please post the wiring details? I am doing an identical swap (but with a k27 motor, it's still motronic 1.3 though).

Thanks!

[EtaSport]

for the above poster.

If you have a square c101 connector, then you'll have to modify it to the round c101 from a late model i car (motronic 1.3). I've done this on a 84 318i. Just get yourself a 'car' side c101 from an 86 or 87 eta, or even i car. Then you will need to splice the wires for each pin (note, some of the pins for your eta will not go to some of the pins in the I c101). Basically chop off your square plug and put the round one in its place so that you can plug it right into the plug from the 1.3 harness.

You'll need to find the c104 which is located in the glovebox area near the ecu. It's a 3 pin plug that has your tach wiring, fuel rate, and fuel cutoff for your obc (if you have one). Next you'll need to get yourself an etm and match the wires from each c101 plug depending on the year of your car. They are NOT all color matched, but pretty close. Once you do this a few times, you will damn near memorize everything, I know I have. There is also a lot of info on this in the engine forum.

I wasnt aware that the late model radiator needed a lower bracket. m42 radiator dropped right in on my 87, used a the top bracket and its nice and solid. I was going to switch to an 89+ rad because I feel the 4 cyl. rad isnt enough for the m50, but it hasnt really been hot enough to tell.

[JGood]

Excellent. Maybe I'll try to do an excel spreadsheet for each model car, and then anyone can use it to match up the engine wiring to the car wiring of their choice. Or did somebody already beat me to this?

Thanks for the info.

[EtaSport]

I was going to do the same for m50 swaps. We do have a lot of the cars covered in one thread and I have a notebook with 88,89 e30s and 93,94 e36s, probably some more in there too. Im sure others would appreciate a quick reference, but I've kinda strayed away from it because it takes a lot of time, and people should really learn to do it themselves. There is a reason the treehouse adaptor costs 400 bucks for an m50 swap.

[MR 325]

Strated tearing down the 89 today... fun fun.

Will pull the motor and trans [together] tomorrow I think.

[MR 325]

Got the motor and trans out of the car last night. Auto's suck btw.

[Funkmasta]

Auto's suck btw.

emphasis.
Try tearing apart an E34 540 Auto. No wonder people jump off bridges.