140A -> 250A alternator upgrade

fekillix

New Member
Hello folks.

I have my HPFP out for refurbishment and I've noticed how good access I now have to the alternator, it is usually sandwiched between the HPFP and the AC compressor.

alternator upgrade.jpg
The 250A alternator appears to me to have the same size pulley, same connector and power terminal (albeit placed differently on the back).

The 250A appears to have a bit more junk in the trunk, but the mounting points to the engine case look to be the same.

I've seen a lot of talk about it here but has anyone done the upgrade? My alternator has 220K km and is 14 years old, so I thought spending €200 on a younger 250A unit isn't a bad idea as it could potentially power one heck of a DC/DC charger for a secondary battery in the future, and then I know it won't fail in a few years time being a cumbersome job to replace. I have a CAAC engine T5.1.

Best regards
 
After more research, I've discovered the connector is different. The 250A unit uses LIN communication while my 140A does not.

alternator plug.png
So although the 250A unit appears to bolt in (I found a spec sheet with the dimensions), I suppose I'd get dash messages.

The 180A unit from the T6.1 part 03H 903 026 uses the same connector as the 250A and LIN.

So my conclusion is that the 250A upgrade is only possible on the T6.1 unless someone makes a LIN->DFM adapter.
 
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Go with the 140a and spend the difference on as much solar as you can cram on your roof?

Good research on the plugs.
 
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