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Kit

M50B20tu

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Hello.

 

My 520i Touring lacks a little power at times (unsurprisingly), I understand from reading other posts that there is not much you can do to improve the power and torque of these 2L motors.

 

Any ideas on stuff worth doing outside of the basic service type things? 

 

If it did go pop one day what are my best options to upgrade it without it being a total nightmare? 

 

Thanks

 

Kit

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Easiest thing is probably to swap in a b25 lump unless you fancy building a stoker 2.8

Otherwise just make sure it's running as well as it can.

Tuning an NA engine really doesn't yield much these days or certainly not without a big outlay.


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On 31/08/2019 at 00:37, boiliebasher said:

I personally would just swap in a decent m50b25 engine. Never done it myself but from what I've read, it should be plug and play :)

 

 

 Fit the M50b25  as Marc rightly put  :) There are plenty still around, So finding an healthy one should be easy.  

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Thanks.

 

Can anyone confirm it’s literally a plug a play job? Any issues with the ecu? Guessing adding 0.5L won’t confuse it! 

 

Kit

Edited by Kit

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I used to own a 520i tourer and as lovely as it was, it was utterly gutless...

My next plan of action was drop in an M50B25 as like I said it should be a straight forward swap. But...... I sold it and bought a 540i instead :D

 

There's really not a great deal you can do to a m50b2O engine to significantly up the power other than forced induction.

Then your talking custom setup etc and your best bang for buck without a doubt is to find a good used m50b25 to drop in.

You "might" have to change or chip ECU, but again easily done. 

 

Do a bit of research, but iirc, it might just run with original m50b20 ECU. 

 

Good luck in whatever you decide to do, all best,

Marc.

 

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If you’re handy with spanners you could go with a m50b25 with 3.0 internals with an upgraded ecu tb and maf other wise just go with the b25 

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2 hours ago, alex525 said:

If you’re handy with spanners you could go with a m50b25 with 3.0 internals with an upgraded ecu tb and maf other wise just go with the b25 

 

My friend has done this with his E36 325 and with a pair of schrick cams, an M3 6 branch manifold and a decent exhaust it makes a solid 240hp. Well worth it if you can get the bits cheaply.

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Thanks for all the advice.

 

I have a late B20TU unit currently, should I aim to source a B25TU over an earlier B25? Or is it all about condition when it boils down to it?

 

Lastly, what would you expect a decent garage to charge for the job, unlike many of you I don’t have the experience or tools to do this at home.

 

Cheers,

 

Kit

Edited by Kit

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Doesn’t the b20 have a Siemens Ecu? Probably better to put the sump and oil pick up on a m52b28 with Siemens Ecu flashed to delete ews?

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It might be possible to try to source the replacement engine including the ECU. 

 

I am am sure someone on this forum will be able to explain how to program your keys into the replacement ECU.

 

I do like the idea of steven3828 about the M52B28. 

 

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