318ti / Mcoupe swap

[manofgun]

I just bought a 318ti and want to put a s50 or s52 engine in it. I was told by the person i bought it off of that I could buy a salvaged mcoupe (2000 and lower) and swap everything on it since it is the same chassis. Would this be advisable or is there a better way to go about the conversion.

[BMW_Hatchback]

most of us are going to tell you to get the motor from the E36 M3. Either OBD1 S50 or OBDII S52. I'm sure getting the motor from the mcoupe wouldn't be much more difficult, but you're more likely to find more M motors from M3s cheaper as well.

[96cali]

buying the entire Mcoupe/Mroady in salvage gets you a lot but not everything you need. There are a few S52 motor differences according to J!m that are easily addressed before installation, but difficult after. The headers and exhaust is completely different too. Suspension I think is usable too. The rear end is really coveted. if you came across a good deal on a wrecked Mcouperoady it may work, especially if you can part the rest.

[manofgun]

thanks this really helps.
does the s50 have more power and performance than the s52? if so how easy are they to get a hold of?
if i do find a good deal on a mcoupe will the springs be just as good as upgrading to bilstiens?

[Philly]

if your interested in doing a swap (of any motor) ... I suggest getting Jims manual and it will let you know what your in for.

He gives great info on the Mroady swap... and its definitly more intensive than a regular S50/S52 swap.

As for your above questions... the S50 is a 3.0L .. the S52 is the 3.2L - I don't know the figures off the top of my head, but I believe the 3.2 is a tad more powerful.

The killer is you'll probably have to spend $2500-3000+ for a real good M motor and some of the parts that go with it, as they are not cheap. Your best bet would be to find a wrecker and pull everything yourself, and maybe make some money back with the extra parts.

Alternatively, you could swap a 2.8L like I did, do many other "fun" upgrades, and still be on par with a stock M.

[manofgun]

Jim's manual?

How do you get a hold of one?

[96cali]

Go to the engine swap forum on this site and look for his sticky, then pay him $$$.

[manofgun]

hey guys wanted to send my appreciation out for all the help and direction. i got the manual and have decided to swap the entire front and rear end of the mcoupe/roady. then ill get a salvaged M3 (OBDII) and use whatever i can before i part it out.

[96cali]

did you buy that setup from zionsville on ebay? $1500 was a great price.

[BimmerBum]

Originally Posted by 96cali

did you buy that setup from zionsville on ebay? $1500 was a great price.

I thought 1500 was steep... I got rear trailing arms with brakes and axles for 300 and I know a fellow ti'er who got a Z3 2.8 coupe diff (same as M coupe less the cover) for 250 shipped. I opted for the 3:46 ratio so I got an LSD from an E28. There is a Z3 torsen alternative but it only came in the 3.0 automatics and I have only seen one on the bay.

If it sold I'm happy! That just means I could make out like a bandit on my stuff if I chose to sell it!

[J!m]

I have to assume the M Roadster is also a Torsen (I thought it was; now sure) as when I did my diff oil change, it had no clutch dust in it- totally clear (I should have left it in!). After two years in there.

Two years on a clutch LSD and the oil is BLACK.

The diff case is the same, but what about the rest of the rear sub frame assembly? The 3.0 set up is a good alternative; however I think (have not compared part numbers to confirm) the M Roadster/Coupe parts are beefier than the Z3 2.8/3.0 counterparts.

In any event, the 2.8/3.0 parts are up to the task with a stock S50B32.

[BimmerBum]

Originally Posted by J!m

I have to assume the M Roadster is also a Torsen (I thought it was; now sure) as when I did my diff oil change, it had no clutch dust in it- totally clear (I should have left it in!). After two years in there.

Two years on a clutch LSD and the oil is BLACK.

The diff case is the same, but what about the rest of the rear sub frame assembly? The 3.0 set up is a good alternative; however I think (have not compared part numbers to confirm) the M Roadster/Coupe parts are beefier than the Z3 2.8/3.0 counterparts.

In any event, the 2.8/3.0 parts are up to the task with a stock S50B32.

All Z3 6 cyls have torsen diffs.

The difference between the M coupe rear sub frame cross member and the Z3 2.8/3.0 unit is the muffler hangers.

As for the trailing arms... when comparing Z3 2.8/3.0 to M Coupe the ONLY clear difference is the brakes. My 2.8 coupe has arms with all the same reinforcements the M Coupe arms have. I have a hunch that if you were to strip a standard Z3 arms down all the way you may be able to rebuild them with M Coupe stuff... I have not tried this however.

[manofgun]

sadly enough i did not get the one zmotorsports was selling. but i live a little over an hour from them and i'm going to go up there and see what they've got laying around.

[J!m]

Originally Posted by BimmerBum

All Z3 6 cyls have torsen diffs.

Are you sure? I think/thought the early 2.5 and 2.8 sill had clutch packs, and it wasn't until the M Roadster came along (1998 I think) that the Torsen was used there, and then subsequently carried over as the 'standard' LSD offering.

I guess it doesn't matter at the end of the day. I'm sure my diff (1999) is a Torsen.

[manofgun]

what is the difference between torsen and clutch?