swapping m50 into 318 tranny match?

[93bmw325is]

i picked up a 92 325is hit in the rear and a buddy of mine has a 1995 318is. does anyone have a write up on this swap? both cars are stick so thats a bonus right there.is teh front subframe the same? can anyone help me with teh diffrences?

[93bmw325is]

none swapped a I6 motor in a 4 banger e36

[93bmw325is]

?

[Carlo318]

yea buddy, im doing the exact swap this summer, i have a 93 318i and im buying a 95 325ci motor, the motor bolts directly to the 318 tranny, and don't worry theres not a difference alot of people worry and laugh that a 318 tranny will hold up with a m50 motor but in the end, it does, the only thing that will hold up for a while is the 318 differential, but with the 318 ratio and the 325 motor, if you do your swap nice , you will SMOKE any stock e36 and e46 325i, just dont forget to forge your pistons for that day your going to drop in a turbo ;)

[93bmw325is]

any other info obn the engine cradle matching up? also does teh engine harness plug into the connector next to the fuse box?

[cooljess76]

the only thing that will hold up for a while is the 318 differential, but with the 318 ratio and the 325 motor, if you do your swap nice , you will SMOKE any stock e36 and e46 325i, just dont forget to forge your pistons for that day your going to drop in a turbo ;)
The only thing you'll be smoking with an m50 is crack! An extra 40hp isn't going to grenade any differentials so no worries there. The trannys will line up perfectly, you might want to consider a new clutch however. Gear ratio will depend on which model the differential came out of. If you have an "is" and your buddy has an "is" then the gear ratios should be pretty close. BTW, you can't just forge your pistons. Do you even know what forged means? Perhaps you meant polish them. You can replace your internals with forged internals but be prepared to spend a little. I'm assuming that the OP is just doing a swap and more than likely wont be "building" the new motor for performance.
Good luck and congrats on the swap!

[Jeffrie]

^^ agreed 40 extra hp won't be enough to blow up a type 168 diff unless it's already on it's way out.
In NA 318 only had two ratio's, no matter if it's an "i" or "is"
3:45 (5spd) 4:27 (auto). 325 had a 3:15 (5spd) or a 3:91 (auto).

318 & a 325 have the exact same tranny so yah it'll bolt up. Shifter linkage may need to be played with a little to make work.

[93bmw325is]

what else do i need from teh 6cyl car to do teh swap in teh 318?

[runetang[1337]]

^^ agreed 40 extra hp won't be enough to blow up a type 168 diff unless it's already on it's way out.
In NA 318 only had two ratio's, no matter if it's an "i" or "is"
3:45 (5spd) 4:27 (auto). 325 had a 3:15 (5spd) or a 3:91 (auto).


Well, I think what he was implying was that if you had a 318 and were putting a M50 325 motor in it, the final drive gear ratio would be favorable for increased acceleration.

In other words, its a free upgrade if you''re doing the swap anyways, I know most wouldn't want to buy another differential post-swap, especially if the differential in there already makes you faster in acceleration to red line, although rev limiting your top speed in 5th gear to something fierce like 125mph. but you'd accelerate from 0 to 125mph fast as hell. thats all he was saying.

Personally, I think the 4.27 would be a nice upgrade for the 325/8 automatics. i bet it would make the car run the same 1/4 mile time as the manual stock version of the car. But, the manual would have a much higher top speed. However, going from 3.91 to 4.27 isn't HUUUUUUGE so it wouldn't take you down to 125mph redline, more like 140mph redline.

The 318 manual's final drive (which is located in the rear differential if anyone didnt know) is also about 0.30 higher than the 325/8 manual stock. So having a 3.45 or w/e it is would increase acceleration w/an M50 a good deal and will run faster from zero to redline. Top speed would be like 140ish mph..

But a warning to automatic owners who wanna do this: it will wear out your transmission faster because youll b in the "sweet spot" of rpms alot more often.

[93bmw325is]

thank you but im not worried about the gearing i have e36 diffs up the wazzo i have a 3.91 lsd and a 3.15 lsd aswell. but in any event im doing this swap for a freind and i teh stock 318 diff wil stay in teh car. i have for hime teh engine, tranny , harnes, computer, radfiator, air box and complete exhuast front to back. what elso do i need to change for this swap?

[cooljess76]

sounds like you've covered all of the basics. I think you'll need the instrument cluster and perhaps the ignition (because of EWS). You might consider new motor mounts and front springs. Also as mentioned before a new clutch and flex disk(guibo) might be a good idea as well. Not sure if the power streering and brake M/C's are the same or if the A/C components (condensor/compressor) will work. www.realoem.com (http://www.realoem.com) might be helpful. It's hard to tell whats needed for a swap, theres always something that gets overlooked in the planning.

[Jetblack95]

the tranny for the 318 does not have an overdrive. 5th gear is 1:1. and all the other gears are also geared higher. so your acceleration will increase. all i've heard from everyone is that the diff is not as strong. however, you can put a SC on a 318 and the diff handles it fine for some reason. so everything will be fine, you will be faster, but your MPG are going to suffer, and your top end/ highway crusing is going to suffer as well.

[93bmw325is]

dont matter to me about the toipe end or the gas milege its my buddys car im doing the swap as a favor.also im supplying all teh parts hows that for a great deal lol.any info anyone else might have on what else is mneeded would be great. thank you

[Lee101315]

The 168mm diff in the 318 is crap. YOU WILL BREAK IT. I did an M52 swap and broke 3, yes 3 318 diffs in a few months. Just get a 188mm diff and you wont have to worry.

[Jeffrie]

The 168mm diff in the 318 is crap. YOU WILL BREAK IT. I did an M52 swap and broke 3, yes 3 318 diffs in a few months. Just get a 188mm diff and you wont have to worry.

What M52 do you have? 328 2.8l or a 323 2.5l.

I'm SC'd and @ 210HP & 200 TQ and my type 168 is holding up fine for over two years now, and well,.... I drive my car harder then anyone I know.

Agree though, a type 188 diff is very tuff and way more options available for different gear ratio's.

[Lee101315]

2.8 with about 210 whp