Diesels and veggie oil
 

Just curious, does anyone know if the MGR BMW derived diesels will run on vegetable oil without any mods?

Edit: Ignore, just realised they're common rail so it's a no.

For the curious, please could you explain why it being a common rail design makes a difference?

I don't know the specifics, just that common rail diesels don't play well with veggie oil. Older direct injection ones fare better I believe.

My friend ran his R75 on a mixture of diesel and veggie oil. Didn’t have any problems in 30k miles. He only used new oil not used oil. 😉
Modern engines are a different kettle of fish but the older ones are fine. The old story was if unsure add a few litres to a full tank and if it works fine gradually build up your confidence and add more over time.

I looked into this many years ago. It puts too much strain on the high pressure fuel pump.

I think the issue is viscosity so some people used to fit a pre-heater

My old B4 Passat had the 1Z engine and loved fresh veggie oil. It had an 80l tank so I would buy 3 x 20l jugs of fresh oil from Costco for 55p/litre and fill it up, then top up with about 10l of diesel (which was about £1.30/litre at the time).
Ran smoother and quieter. 55+mpg. Smelt great. Only issue was in sub-zero temps when it would take a few extra seconds to start.
Only sold it because I accidentally bought an E36 320i Touring.

I remember when it was that cheap but also when it went up over a pound a litre (wonder if that was related to people using it as fuel lol) so the difference in price with diesel wasn't all that. Now seems like an interesting proposition ...

Be interesting to hear of anyone using veg oil in a 75 and what sort of combination, ie: 50/50 veg/diesel ??

Used to run my old Rover 600 diesel on used veggie oil , hardest part was filtering all the old bits of chips out of it !