E39 with S52...??: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Feb. 10, 2011 7:57 a.m. Teh E36 M3 HalfDork

I'm looking for a replacement E36 M3 (sedan, hopefully this time) and found this:

S52 swapped E39

I thought E39's were: 1. Heavy 2. More powerful than S52 if you got the 540

I'm questioning why you would do this swap? Fuel efficiency? The V8 (non-m5) models make 282hp while the S52 only makes 240.

Seems like a bunch of work for not much reward, but I'm interested in your thoughts.
Feb. 10, 2011 8:07 a.m. miatame Reader
Well a couple reasons probably.
1. The I6 E39 uses a steering rack rather than a steering box (used in the V8 cars for packaging reasons I think).
2. The V8 (4.0L) can be expensive to maintain.
3. The V8 in the M5 is uber expensive so you wouldn't go that route, you'd just get an M5.
I like the idea but you're right, it isn't going to be a rocket ship, but it will be a fun car.
Feb. 10, 2011 8:07 a.m. nderwater HalfDork

The 2.5/2.8/3.0/3.2 engines share a common architecture and many components, with the S52 overbored for extra displacement. The 3.2 is an easy swap (only need new block/heads/ecu, everything else is retained) and posts notably better numbers than the 2.8 which originally appeared in this car. If the original engine blew, it's not a bad upgrade.
Feb. 10, 2011 8:12 a.m. DILYSI Dave SuperDork

Why - Easy upgrade for a 525, 530, etc.

But yeah - it will be slower than the E36 M3 or the E39 540.
Feb. 10, 2011 8:13 a.m. Giant Purple Snorklewacker SuperDork

E39s are heavier than the E36 by a bit but if it was a 525i to start with then the wiring harness/exhaust/trans and all the bits would work without changes. A true bolt in. Swapping the V8 in is more work for little gain. You need a whole donor 540. There are more tuning options at better cost than the V8 too. An S52 with cams, maf, injectors, headers and software will make 280-300 at the crank.
Feb. 10, 2011 8:45 a.m. ansonivan HalfDork

I wouldn't touch that particular car with a ten foot pole but I do like the idea of swapping an s50b32 into an e39. I've considered doing just the s50 cams and an obd1 intake for a nice little bump in power.
Feb. 10, 2011 8:57 a.m. DILYSI Dave SuperDork

If I was going to bother with a swapped E39, it would be an LSx.
Feb. 10, 2011 2:31 p.m. Teh E36 M3 HalfDork

DILYSI Dave wrote:

If I was going to bother with a swapped E39, it would be an LSx.

That's what confused me about the whole thing. I can't imagine the s52 being that much cheaper than an LSx. But I've never priced either. I suppose it may be the "plug n play" nature of sticking with the BMW. For my PITA, time, and $$, I'm putting an LS in there.
Feb. 10, 2011 2:36 p.m. mad_machine SuperDork

yes.. it is the plug and play option that makes it easier and better.. maybe an S54 instead?
Feb. 10, 2011 6:19 p.m. 02Pilot Reader

I have impure thoughts about swapping an S54 into my 525i. A spiritual successor to the E34 M5 (I'm quite devoted to the BMW I6). I imagine it's rather more complicated than the M52->S52 swap, however.