Help me plan my swap (M20)

[dahows]

Hey R3v,

I need your input and advice. I have an 84 323i that needs a new powerplant. Long term, I want to build a stroker for this car but that is down the road. For now, I want to start with an upgrade to Motronic 1.3 and a M20B25.

I'm running L-Jetronic currently so I know I need to update C101, harness etc. In fact I have:

C101
Engine bay harness
173 ecu

I know I need an late model i cluster as well.

Where I need some advice:

Radiator - my current radiator is pretty small compared to the B25 rads. I assume I'll need more cooling capability with the B25. Should I source a radiator from an 87?

Oil cooler - I don't have one currently on my car, I assume this is a must and are different between early (87) and late M20B25.

Fuel pump - Not sure if I need to change this or not. I've read that it is optional. What determines if the fuel pump needs to be changed?

Flywheel - I've read that the 323i flywheel is a desirable change (or was it the e21 323i?) since it is lighter. Would this simply be a straight swap to the B25? Would the starter from the B23 be used with it?

Transmission - any issues mating up an early G260 transmission with a B25? I've read that Eta transmissions work...I need to pull the numbers off my transmission

Thanks for any advice,
David

[EatsHondas]

Radiator - Yes, get a B25 rad. Auto or manual, doesn't matter.

Oil cooler - BMW's aren't known for stellar cooling systems, I would definitely source a cooler.

Fuel pump - Not sure here, but for piece of mind, I would get a new B25 pump or suitable aftermarket unit. It's getting to be the time where the factory ones shit out.

Flywheel - Not sure about that specific flywheel, but whichever one you end up using, you will need the accompanying starter.

Transmission - The G260 came stock behind all the B25's. They're smooth and strong, but they leak like bastards. Make sure you reseal the input, output, and selector shafts, as well as the 2-bolt plate on top.

[dahows]

Thanks Eats, I appreciate the advice.

Seems like the G260 name is pretty generic and there are some significant differences between eta and early i transmissions vs. late i transmissions. Since I have an early euro car with a 260, I need to figure out if it can still be used with a b25.

Cheers

[EatsHondas]

Thanks Eats, I appreciate the advice.

Seems like the G260 name is pretty generic and there are some significant differences between eta and early i transmissions vs. late i transmissions. Since I have an early euro car with a 260, I need to figure out if it can still be used with a b25.

Cheers

Sure thing man.

This looks like Getrag 260 interchange gold, czech it out if you haven't already: http://www.r3vlimited.com/board/showthread.php?t=109919

[SmokeE30]

You can use all your 323 stuff trans, clutch setup, flywhee and starter. If you start swapping components around then you hve to pay attention but all your stock stuff should bolt right up to a m20b25. Also you must pay attention to which cooling setup you use as the early and late b25s used different setups so you must match the water pump, expansion tank, and radiator and hoses with each other. Most prefer the later style cooling setup but either one will work fine if in good shape.

[dahows]

thanks guys, this helps.

[Bimmer_man]

just a suggestion if your going to stroke a M20. I was curious on better cooling options and one that was suggested to me was a e36 Mishimoto radiator. Read into it and see how well it works with your stroker plans down the road. i suggest it so you dont have to replace the radiator again and wast time and money.

[karmatose]

My two cents on the radiator would be to get a Godspeed Project aluminum radiator. I have one in my car and it's going on it's second year now with zero issues. It's identical to the Mishimoto rad and can be had on Ebay for less than an OEM replacement with free shipping if you look around.

Best part about it, NO PLASTIC TANKS!!!

[dahows]

Good advice guys. Any issues mounting the mishi or the godspeed in an early model? Would these then require the late model coolant set up?

[digger]

A aftermarket Behr radiator is fine. mine worked flawlessly in a 115F day in traffic

[dahows]

A new Behr is nearly as much as the Mishimoto which has a lifetime warranty. Seems like the Mishimoto is a no brainer.