M50 conversion/swap to S50 or S52

[SoulsInSync]

A few general questions...

I have a 1995 325is E36 and I'm thinking about swapping the engine for a S50 or S52 (or boring the block and converting to an S52 if I want to spend the extra money). Would an S52 be the best way to go? Could I potentially get more power from my M50 if I rebuild the engine? Whichever path I go down, I want to have a turbocharger setup in the long run. I know approximately what each of these options would cost, I'm just looking for opinions.

Thanks!

[XnWarden]

I think my S52 swap ended up costing about $4k. That price includes rebuilding the top end of the motor while I had it out, a new clutch in it, a tune and an exhaust that I fabricated.

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[pbonsalb]

Building a motor can be expensive and not needed unless you want over 500 rwhp. But an S52 is about 20 years old so it may need going through. Bearings might be fine. Maybe hone and rings and seals. Head could probably use a rebuild. For turbo use, open up the ring gaps and use a compression lowering gasket like the cutting and spacer that CES sells, along with ARP bolts.

[gdavid]

What is your goals and intended use for the car? Also your budget, resources and capabilities? How much power are you looking for, how many miles are you planning to put on it and what are your expectations for reliability?

I would expect very different answers if this is a spirited daily driver, track toy or drag strip monster.

[ChuckDizzle]

A few general questions...

I have a 1995 325is E36 and I'm thinking about swapping the engine for a S50 or S52 (or boring the block and converting to an S52 if I want to spend the extra money). Would an S52 be the best way to go? Could I potentially get more power from my M50 if I rebuild the engine? Whichever path I go down, I want to have a turbocharger setup in the long run. I know approximately what each of these options would cost, I'm just looking for opinions.

Thanks!

Between an s50 and s52, you might as well get the s52. There are a lot more of them available as well compared to the s50, which was offered only for 1995 and from there on it was s52's.

The big turbo guys will debate between the m52 or s52 being better for high boost.

[GG///M3]

I have an s50 with updated s52 retainers/keepers makes 245whp/240wtq. I’d let it go for 1,700 or so.

[ChuckDizzle]

I have an s50 with updated s52 retainers/keepers makes 245whp/240wtq. I’d let it go for 1,700 or so.

Stock motor? If so, that's awesome.

[GG///M3]

Yes sir

[ChuckDizzle]

Yes sir

If I can get my e30 sold soon and open up some space in the garage, I might be interested in your s50. But otherwise, that's an amazing dyno result for a stock s50.

[bluptgm3]

S50 is going to be an easier swap as it is also OBDI.
S52 will require conversion to OBDI for the simplest swap, though you could go OBDII and have some coding done to eliminate some basic ‘stuff’ like SAP and post catalytic converter O2 sensors and EWS from the OBDII ECU.


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[pbonsalb]

S52 with M50 intake has more torque and horsepower than S50. I have never had too much power.

[Richkid79]

I think my S52 swap ended up costing about $4k. That price includes rebuilding the top end of the motor while I had it out, a new clutch in it, a tune and an exhaust that I fabricated.

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This is true. You never specified what your intention for use, ie Drift, Street, Drag, or Track..
Any which way, you're going to have to make sure you're up to the task with fuel (cams) and transmission upgrades (brakes too).

Cheapest way for big power is to go turbo.there are many members on this forum who use turbo their M50/M52 with great results

S50 engine is great, but harder to find in decent shape and it's obd1 which is the easiest swap to do.

S52 is even better but you have to swap over some components to make it obd1 and have a chip burned (I think TMS carries these)

S52 converted to OBD2. You need engine harness, extra sensors,MAF, and DME with the EWS, and air pump coded out of it. You also need OBD2 exhaust with additional O2 sensor bungs welded in.

M52 converted to OBD1 and TURBO!
This is what I ended up with when it came time for me to build a 325ic (the black one in my signature).
The car was originally an obd1 M50 Auto. I bought an M52 WITH 5sp ZF trans for $1,200 and swapped it. Kept it obd1.

From what I'm told, the M52 engine is the best stock engine to turbo because it has thicker cylinder walls and therefore can handle more boost. It's also way cheaper than a S50/52 and probably wasn't beat on as hard. The $ saved on getting a M52 over an S50 could cover costs on many other important turbo parts. With a new head gasket, head studs, and fuel & engine management, you could make good reliable hp. Just make sure you reinforce your rear subframe to handle the extra twist on the chassis

...or you do like my old e39 and drop a big turbo 1jz into it.

Good luck
Richie

[pbonsalb]

Turbo M52 is the bang for the buck. M52 can be found for $500. Drop CR with a cut ring gasket and spacer. 500 rwhp has been done many times. But turbo S52 is even more fun. The added displacement spools the turbo faster.

[66 6]

I have a great donor S52 in Maryland. 210K in all cylinders except #3 is 60. still in a running car. It's a gasket or head issue $900. I also sell heads for $100
PM me if interested.