[timstar]

Howdy all,
Apologies if this has been covered, I have tried searching but am having trouble finding a straight answer.

I have an Australian version 2005 325i with N52B25 (MSV70). I've been looking into doing an N52B30 swap for a little while and have come across a low KM engine for a good price, but it's from a 2012 125i which I believe uses a MSV80.
Am I correct in my understanding that the N52B30 from the 125i won't work with my MSV70 and I would need to get the DME and CAS from the 125i?
Or would the N52B30 work with my MSV70 but require the MSV70 to be reprogrammed.. which I understand is alot easier to do than an MSV80?

[Carlish_sr]

Hey man also in the same boat right now, did you have any luck with this swap or have any info on how easy it is?

[cheerio]

Generally, the easiest solution here would be to keep your existing DME, connect it up to the new engine, and flash the N52B30 tune to it, with powerclass edit so it's accepted by the DME.

In this case, things are complicated by the fact that you're replacing an MSV70 N52 with an MSV80 N52K. There are some minor mechanical improvements on the N52K, but I believe they're close enough that a different tune is not required. Electrically, there are a couple of minor differences between them - the MAF sensor and throttle body are different on the N52K. I believe these are identical between N52B25 and N52B30, which gives you a couple of options:

1. Transfer your original MAF sensor and throttle body over to the N52B30. Use the wiring harness and DME from your MSV70 car. Flash Bimmerlabs 330i tune to your MSV70 and enjoy. This is probably the easiest option, but the downside is you'll be using MSV70 with N52K, which isn't "as intended" by BMW, and IIRC the highest tune available on the MSV70 is only 190kW.

2. Transplant the CAS and DME from the MSV80 car into yours. Use the MSV80 wiring harness. Flash Bimmerlabs 330i tune to the 125i DME. Now you'll be running the MSV80 with the N52K, as intended. No weird wiring harness splicing required. This may give you access to the 200kW tune available on MSV80 cars. Downside is you'll need a key from the 125i, and the VIN in the CAS/DME won't match your chassis. You'll likely have to code the donor car's VIN to all the other modules in your car to make everything match and work properly.

Each option has pros and cons. Up to you as to which you choose.

[hassmaschine]

MSV70 will work with a newer N52. the main differences are in the wiring but the differences are minor and can be fixed pretty easy.

[Maxmax73]

Originally Posted by hassmaschine

MSV70 will work with a newer N52. the main differences are in the wiring but the differences are minor and can be fixed pretty easy.

the pinout on DME connectors is not the same between msv70 and msv80, I'm not sure if average users should try re-pinning it.

[hassmaschine]

Originally Posted by Maxmax73

the pinout on DME connectors is not the same between msv70 and msv80, I'm not sure if average users should try re-pinning it.

yeah, I know. 99% of it is the same though.

average users aren't doing engine swaps either..

[ptpending]

if you want msv80 with newer N52B30 you need to get msv80 engine harness and MAF and throttle body from donor car.
Because while N52B25 has 2.5 displacement, the N52B30 has 3.0 displacement and to match 125i power output it is downtuned by DISA removal or some other trick.
So you will need to find someone local who bind MSV80 with your CAS or you have to sent to someone on this forum to virginize MSV80 and later, again have someone to code it to your car locally

[Maxmax73]

Originally Posted by hassmaschine

yeah, I know. 99% of it is the same though.

average users aren't doing engine swaps either..

I'm actually considering downgrading to msv70 at this point.

[Maxmax73]

Originally Posted by ptpending

if you want msv80 with newer N52B30 you need to get msv80 engine harness and MAF and throttle body from donor car.
Because while N52B25 has 2.5 displacement, the N52B30 has 3.0 displacement and to match 125i power output it is downtuned by DISA removal or some other trick.
So you will need to find someone local who bind MSV80 with your CAS or you have to sent to someone on this forum to virginize MSV80 and later, again have someone to code it to your car locally

msv70 and msv80 engine harnesses have exactly the same pinout on DME connector, 2 disa connectors are present on all engine harnesses also, it's just they are not used on 1sim manifold n52s.