M50 vs S50

[HalexH]

I am looking around for a engine to buy for a swap into a e30. I was wondering which would be better of the two for a turbocharged application. Also if the e30 is Auto. Is that a problem if I plan on changing the transmission. Does it add to the confusion. I have about 8k saved up and ready to go. Which do you guys think will be better.

[DrMcDave]

i think for 8k you can easily do an s50 and the tranny swap. The manual swap should be under 1k. how much hp do you want to make. boosted s50's make huge hp on very little boost. Or you could buy and m50 for cheap and spend some money on rebuilding the bottom end. You have a ton of options. s50 would be best i'd say but that only leaves about 4k for turbo if you can do work on your own.

[nando]

N/A S50 would be my choice

[HalexH]

i think for 8k you can easily do an s50 and the tranny swap. The manual swap should be under 1k. how much hp do you want to make. boosted s50's make huge hp on very little boost. Or you could buy and m50 for cheap and spend some money on rebuilding the bottom end. You have a ton of options. s50 would be best i'd say but that only leaves about 4k for turbo if you can do work on your own.

I was thinking of completley rebuilding the bottom end. So that it can handle boost of up to 15-20 pounds. I was just wondering for the m50 vs s50 question what is the diffrance in blocks and how can I make the m50 head flow as freely as the s50 also what is a good shop to talk to about doing the work on the bottom end. And the tranny Q's I was more worried about the mounting points.

[DrMcDave]

you might want to take this question to bimmerforums because most of us are m20 oriented and not as familiar w/ the s50. I know that the blocks m50 and s50 are the same, but if you buy the s50 block you'll have the s50 crank which provides the extra .5 displacement. an m50 head w/ s50 cam flows pretty well. You don't need a ton of head flow w/ forced induction but does help sometimes it all depends what you are going for. What are your goals for this engine? like i said go ask on bimmerforums where most of the guys are boosted e36's w/ m50, m52's, s50's and so on.

[Mot]

built m52 + boost, easy 500whp. Proven on bimmerforums several times over. Hell some one was running 480whp on a stock m52 with headgasket.

[german g]

for 8k you could do ALOT and have a VERY fast e30..

[HST]

The M50 and S50 blocks are different. The S50 has a 86mm bore the M50 is 84mm bore.The M50 block is stronger than the S50 block due to the M50 having thicker sidewalls due to the smaller bore. You can take a M50, swap in an S50 crank and have a 2.9l. Or you can swap in a M52 crank fo a 2.8l. Then put in S50 cams. If you use the S50 crank you will be close to 11.0:1 CR so turbo is kinda risky IMO without lowering compression. M52 pistons are 5mm shorter and should lower compression enough for some turbo action, but I don't know about 20PSI.

[RobertK]

An S52 is basically a M52B32

For $8000 I would get a real S52 from the beautiful land of Europe.

Otherwise a N/A 2.9L M50 stroker w/ S50 cams can outperform a stock S50 or S52 and cost $2000 less to buy and build.

[FredK]

Just to be a dick, there is no "real" S52. ;) The M3 Evo came with an S50B32. There is no Euro S52B32.

That said, the engine is still pricey, and you are not going to be able to pull off a euro motor swap for 8K. Otherwise, I would have done it. I believe this guy wants a suspension upgrade as well, so the real budget is probably a decent amount smaller than 8K.

[asubimmer]

just a thought, have you done anything w/ your brakes and susp?

[mops]

aswell, alot of choices for that kind of money...
you have to decide whether you want a mad drag weapon or maybe a more street friendly setup.

you have to be realistic about your goals... I think (I got no experience, maby somebody knows better) that more than 400-500 WHP in e30 is just useless, because traction will be a major problem... and you cant run drag slicks on the street.

But If I had the money you have, i would research the following setup:
m52b28 bottom end with s52b32 head (it has been done before, that produces about 250 crankhp easy). if you feel enthusiasitc replace crank with m3 one (few mm more stroke). custom pistons for about 8.5:1 compression ratio... decent turbo on the setup, such as holset HX40 good EMS (like autronic... that should bring you to about 500 crank hp... should be nicely driveable around town. rest of the money i would spend on suspension updrades. 17" wheels with good rubber, replace all bushes with polyurethane ones, bilstein sport shocks all round with H&R springs.... thats about it ultimate e30...

as i sai, ou can go crazy ang build 700whp engine but that will lack bottom end pull and be hard to drive on the street and once in powerband it will just spin rear wheels freely.....

[Jordan325iC]

One guy on bimmerforums pushed his 2.8L m52 to 27psi and 704rwhp on a stock bottom end before it blew. Those engines can handle boost pretty well.

[RobertK]

Just to be a dick, there is no "real" S52. ;) The M3 Evo came with an S50B32. There is no Euro S52B32.

That said, the engine is still pricey, and you are not going to be able to pull off a euro motor swap for 8K. Otherwise, I would have done it. I believe this guy wants a suspension upgrade as well, so the real budget is probably a decent amount smaller than 8K.

I stand corrected. Euro S50 FTW none the less.

300-400rwhp is a nice setup for a street setup on an E30. Anything else = traction troubles. Though a good turbo setup makes a bit of difference in the fact that you can adjust it to bring most of the HP on in the top end so you can get off the line without losing traction.

[skatebline]

N/A S50 would be my choice

why would you rather have the n/a s50 than boosted?