[TDIwyse]

Originally Posted by Andy198712

whats the reasoning behind this?...

The European standards have some differences from the US standards, and it appears the European engineers don't like our standards :-)

https://www.dieselnet.com/tech/fuel_biodiesel_std.php

I've been using B5-20 in my 335d for many years now and have not been able to tease out any statistically significant mpg differences from the ~370 fill-ups tracked in my spreadsheet.

Before the 335d I also used to make my own home processed biodiesel... had a mini refinery in my shed where I'd make 30 gallon batches that I used in my tractor, TDI, Jeep Liberty, my Jeep Wrangler Cummins conversion... My 14 year old common rail Cummins also had most of it's first 7 years running 50-70% primarily home made biodiesel blends... but that hobby got old so I shut down the refinery.