AFM swap, 318i -> 325i

[Xhawk]

Hey everybody,

So I'm planing to swap my M40B18 AFM to bigger M20B25 AFM. I just wanted to know has anybody done this and can I expect any results out of this. Increase in throttle response or even in horse power?

If the swap works I am thinking of replacing injectors with M30B30 injectors. Any problems in that area?

[hoshy]

I don't think you can just swap parts like this around mate. the ecu is calibrated to give the correct air/fuel mixture based on standard components.

I'm happy to be put right here if I'm talking balls.

[smithy318i]

I read somewhere that the plug on the AFM is different. And wouldn't work anyway!

[Xhawk]

Yes, but if I change the electronics inside from the 318i to the 325i? There are many who have done this in their turbo projects. Changed from 325 afm to 535 afm just by changing the insides. My swap would be just no turbo change.

http://www.davelength.net/car/bigsix.html

[Jon_Bmw]

I think you'd have to somehow retro-fit the curcuit board from your 318 into the 325 afm. This is possible between an m20 afm and a m30 unit but i think its very unlikely that it would be possible between m40 and m20.

I do hope you are joking about the injectors, that would overfuel it so so much. Put it this way 2 mins at idle, and i think you would be looking at cleaning the spark plugs, or perhaps having to use a tea towel to dry them.

I'm using m30b35 injectors in an m20 that has a turbo on, it idles rich and that is with tightening up the afm spring a fair bit, once i'm going they supply the right fuel, well just about enough. You are thinking of using 3.0l ones i know but your car was only a 1.8 to start with wheras i was already on a 2.5 and the need for them was the turbo, unlike yours which unless i'm mistaken is still N/A.

My 2pence worth

Jon

EDIT:welcome to the zone by the way

[Xhawk]

Thanks Jon about the info and welcoming to the forum. Now I'm 2 pence smarter if one can say so. Could there be any other way to let more air to the engine than forcing it? How about smaller injectors? Witch would be better. Or am I just beggin' for engine swap

I think you'd have to somehow retro-fit the curcuit board from your 318 into the 325 afm. This is possible between an m20 afm and a m30 unit but i think its very unlikely that it would be possible between m40 and m20.

I do hope you are joking about the injectors, that would overfuel it so so much. Put it this way 2 mins at idle, and i think you would be looking at cleaning the spark plugs, or perhaps having to use a tea towel to dry them.

I'm using m30b35 injectors in an m20 that has a turbo on, it idles rich and that is with tightening up the afm spring a fair bit, once i'm going they supply the right fuel, well just about enough. You are thinking of using 3.0l ones i know but your car was only a 1.8 to start with wheras i was already on a 2.5 and the need for them was the turbo, unlike yours which unless i'm mistaken is still N/A.

My 2pence worth

Jon

EDIT:welcome to the zone by the way

[Jon_Bmw]

Thanks Jon about the info and welcoming to the forum. Now I'm 2 pence smarter if one can say so. Could there be any other way to let more air to the engine than forcing it? How about smaller injectors? Witch would be better. Or am I just beggin' for engine swap

I think you'd have to somehow retro-fit the curcuit board from your 318 into the 325 afm. This is possible between an m20 afm and a m30 unit but i think its very unlikely that it would be possible between m40 and m20.

I do hope you are joking about the injectors, that would overfuel it so so much. Put it this way 2 mins at idle, and i think you would be looking at cleaning the spark plugs, or perhaps having to use a tea towel to dry them.

I'm using m30b35 injectors in an m20 that has a turbo on, it idles rich and that is with tightening up the afm spring a fair bit, once i'm going they supply the right fuel, well just about enough. You are thinking of using 3.0l ones i know but your car was only a 1.8 to start with wheras i was already on a 2.5 and the need for them was the turbo, unlike yours which unless i'm mistaken is still N/A.

My 2pence worth

Jon

EDIT:welcome to the zone by the way

Quite simply no there isn't an easy way to get more air into the engine without forcing it to be honest. Turbocharging whilst its not unthinkabley hard, its not easy either! Loads of things to be thinking about when you start doing it.

Leave the injectors well alone, you don't want smaller ones either, that will lead to fuel stavation, detonation of you engine and well then you will need a new engine.

A good starting point would be sell up the 318, get a 318is(16v m42 engine) and get a zone chip of the zones very own Ant. If your m40 is in good nick you might want to put a 2.5 in, but you'll need ecu, wireing harness, rear subframe and diff-rear disc etc. 2.5 front brake setup, just buy a shitter 325 for Ԛ£300 have a laugh with it. Get to know how to work on them then look for something smarter.