Hey all,

What should I expect to pay to have a good shop put in an S54?

Would those 'in the know' recommend swapping my 5 speed manual for 6 speed at the same time, what what would that cost?

Thanks in advance,

Do you have goals for the project? Is this something you're looking to get power out of or just doing it for the sake of doing it?

My goal is to use THIS car for auto-x, and other stuff moving forward.

I want to evaluate what the best engine to start with would be as a base for future upgrades before I invest more in this car.

So it's either new engine - or cams/headers/FI in current one.

If I go the new engine route it will give me a much longer path with my current car before I'm ready for a new one (power-wise).

Why not do an S52? Seems like it would be a much simpler conversion with many many more common parts. Everything should bolt in exactly the same as an M52TU, the only challenges would be converting to the earlier engine control setup. It may even be possible to use a Shark injector to reprogram the ecu for running an S52, omitting the double-VANOS, drive by wire and variable intake stuff. Once an S52 is in the car, the possibilities for huge power would be limitless.

I don't know if anyone's tried it but it seems like a great way to go if you're really dead set on not buying an M3 and starting out the right way. :) The numbers I've heard tossed about for an S54 conversion on a sedan have been in the range of $15k.

I have always wondered why people with early E46's - 323/328 did not do S52 swap! This is a lot easier then trying to figure out the S54. The S52 will bolt right in to your car as it is very similar to the M52 you currently have. There are so many more options for power on the S52 at a resonable price. Good Luck!

Yeah its very feasible mechanically but electrically, a nightmare unless you scrap your entire CAN system and use S52 electronics. Check out Rogue's 323 Touring S54 swap, cool as shit but very expensive.

I have always wondered why people with early E46's - 323/328 did not do S52 swap! This is a lot easier then trying to figure out the S54. The S52 will bolt right in to your car as it is very similar to the M52 you currently have. There are so many more options for power on the S52 at a resonable price. Good Luck!

Not really. All the M52s that came in e46's are M52TU's which are dual VANOS, and use a different engine management than the S52. He would be better off sticking to an engine that came in the E46 originally, unless you want to start splicing wiring harnesses together

Not really. All the M52s that came in e46's are M52TU's which are dual VANOS, and use a different engine management than the S52. He would be better off sticking to an engine that came in the E46 originally, unless you want to start splicing wiring harnesses together

So I'm confused - Which engine is it that you are suggesting I base my engine swap on the S52 or S54? After reading these replies I think I'm leaning to the S52 - it sounds like a smaller investment in resources for about the same gain.

Why not do an S52? Seems like it would be a much simpler conversion with many many more common parts. Everything should bolt in exactly the same as an M52TU, the only challenges would be converting to the earlier engine control setup. It may even be possible to use a Shark injector to reprogram the ecu for running an S52, omitting the double-VANOS, drive by wire and variable intake stuff. Once an S52 is in the car, the possibilities for huge power would be limitless.

I don't know if anyone's tried it but it seems like a great way to go if you're really dead set on not buying an M3 and starting out the right way. :) The numbers I've heard tossed about for an S54 conversion on a sedan have been in the range of $15k.

And I would buy an M3, but it looks like only the 1998 had a 4 door option (excluding the new one, which I might end up getting), and none of them I have seen are as good looking on the inside (10 years old and rode hard!). ;)

So I'm confused - Which engine is it that you are suggesting I base my engine swap on the S52 or S54? After reading these replies I think I'm leaning to the S52 - it sounds like a smaller investment in resources for about the same gain.

Read what I posted. The S52 has single VANOS and a different DME class than your car. I don't know how many have swapped an S52 into E46s, but logically it would take some wire splicing and maybe a custom/modified wiring harness. Then you have to deal with all the other E46 BS that the E36 didn't have. If I were you I'd swap in an S54 if you really want to do a motor swap - there are a lot of differences that you don't seem to be aware of between the S52 and the M52TU. I know people have done the S52 swap into Z3s, but I believe they were the same model years.

So I'm confused - Which engine is it that you are suggesting I base my engine swap on the S52 or S54? After reading these replies I think I'm leaning to the S52 - it sounds like a smaller investment in resources for about the same gain.

The S52 doesn't literally exist. The "S52" is a S50b32, which means it's an S50 stroked to 3.2 litres (opposed to 3.0). This is a european motor. The S50b32 puts out 321hp at the crank.

Unfortunately in the USA the m3 never got the S50 in either form. from 1995 to 1999 (the BMW e36 M3..) they got either an M50tu or M52tu depending on year. This engine is closer to the regular (shares more common parts) than the "motorsport" motors of bmw.

M50tu = S50 "US" 240hp
M52tu = S52 "US" 240hp
This is how they are commonly referred to. IIRC

If you swap in an "S52" from a US car, you're going to have 240hp at the crank at best. If you swap in a S54 from a US car, you're going to put down 321 at the crank, and a S54 euro put down 343hp at the crank from the factory.


There's an understandable difference in the power between a US "S50"(240hp from factory) and a US S54 (321hp from factory) or
even better yet, a euro S54 (343hp from factory) at least this is what I gathered. Oh, and the S54's potential isn't close to tapped yet. It's got a great flowing head for FI.

http://www.bimmerforums.com/engine_faq/ Check it out.

With THAT said.. The cheapest way to get alot of power out of that car imo is to stroke the thing using an M3 crank, use M3 rods (they are forged) and get new pistons with a low compression ratio and then go with forced induction. You can also just stroke it and keep the CR normal, throw in M3 cams and get near-m3 power levels for a fraction of the price of the motor. Use the search function and find out more.. there is alot of info on it.

The S52 doesn't literally exist. The "S52" is a S50b32, which means it's an S50 stroked to 3.2 litres (opposed to 3.0). This is a european motor. The S50b32 puts out 321hp at the crank.

Unfortunately in the USA the m3 never got the S50 in either form. from 1995 to 1999 (the BMW e36 M3..) they got either an M50tu or M52tu depending on year. This engine is closer to the regular (shares more common parts) than the "motorsport" motors of bmw.

M50tu = S50 "US" 240hp
M52tu = S52 "US" 240hp
This is how they are commonly referred to.

If you swap in an "S52" from a US car, you're going to have 240hp at the crank at best. If you swap in a S54 from a US car, you're going to put down 321 at the crank, and a S54 euro put down 343hp at the crank from the factory.


There's an understandable difference in the power between a US "S50"(240hp from factory) and a US S54 (321hp from factory) or
even better yet, a euro S54 (343hp from factory) at least this is what I gathered. Oh, and the S54's potential isn't close to tapped yet. It's got a great flowing head for FI.

http://www.bimmerforums.com/engine_faq/ Check it out.

With THAT said.. The cheapest way to get alot of power out of that car imo is to stroke the thing using an M3 crank, use M3 rods (they are forged) and get new pistons with a low compression ratio and then go with forced induction. You can also just stroke it and keep the CR normal, throw in M3 cams and get near-m3 power levels for a fraction of the price of the motor. Use the search function and find out more.. there is alot of info on it.

That is not true. The S52 absolutely exists - check the engine designation on ANY 96-99 US spec M3. It is an S52B32US.

You're incorrect also in your previous designations. Let me set it straight - there is a lot of misinformation in your post.

M50B25 - M50 non vanos, 2.5L, 92 325
M50B25TU - M50 Single VANOS, 2.5L, 93-95 325
M52B25 - M52 Single VANOS, 98-99 323
M52B28 - M52 Single VANOS, 96-99 E36 328's
M52B25TU or B28TU, M52 Dual VANOS, 99-2000 E46s, 2.5 and 2.8L

I'm amazed nobody here has helped this guy out by mentioning that his M52tu is an aluminum block vs anything else (except the M54) which would be an iron block. I know the latter can be built up with much more horsepower, but that's really not a factor at this guy's level.

With that said, I'd keep the M52 and rebuild the hell out of it. You can get some amazing horsepower out of it, pretty much the same if you decided to drop in an S52 and rebuild it, but you'd still have your aluminum block which is nice and light.

I know when my S52 dies, my dream engine would be an M54 just for the aluminum factor up front.

Proper operation of the single VANOS is the only major issue I can think of with an S52 in an M52TU equipped chassis. Otherwise, an S52 is nothing but a heavier version of the same motor with bigger cams and more displacement, and that's as simple as map tuning. The DME shouldn't care if the DBW and dual intake manifold are working. The map tuning is nothing one couldn't do with a megasquirt. It's too bad there's no user-servicable DME reflash software for the OBDII cars. The technology exists but nobody has tried to sell it yet. The Shark Injector is nothing but a complicated ECU reflash. Making the tables and thresholds in the software on a Shark Injector user-servicable would probably be almost as easy as selling the software they used to develop the shark with a big "NOT RESPONSIBLE FOR ENGINE DAMAGE" sticker on it.

But I'll never do it because swaps are a waste of time when M3's are relatively inexpensive and plentiful. :) I wish whoever comes across this thread and is inspired to do it a bunch of luck.