Possibly a numpty question, but what's the deal with bio diesel...

...would I be able to run a VAG 1.9TDI PD engine on it without any mods and without damaging it?

...can you chop and change between normal and bio diesel and have a mix in the fuel tank?

Possibly.
It burns different to normal diesel and is a bit more viscous. A lot of modern engines don't
like it without other mods such a heating systems and tweeks to the management
system.

Both my 200Tdi Defender and 300Tdi Discovery run happily on it straight from
the pump but my Toyota Hiace van, a boggo motor with no turbo hates it.
Tried it on a 50/50 mix and it was gutless (more than usual ), lumpy and a pig
to start from cold. Vehicles with Bosch pumps are generally more able to cope with the
viscosity issue.
The 200Tdi will even run on pure veg !

Even if it does run fine you generally find the fuel filter needs changing soon after
as bio strips the cack out of the system. Usually a one off thing though.

Suck it and see really. I'd try 50/50, see how it goes then full. Even then I'd still
run normal every 4th tank or so.


[Edited on 19/5/10 by NigeEss]

I've used it (B100 100% bio) in the standard (non PD) VAG engines without any mods, issues or damage for tens of thousands of miles in a 1995 Audi 80 1.9TDI and a 1996 Audi A4 1.9 TDI. No performance or economy issues, even in below zero weather.

On cold mornings it can take a little longer to start when cranking (like a few more seconds) and you get some white smoke when it first starts. Other than that, you can just detect a slight whiff of chips at the exhaust. I believe some dino diesel in the mix resolves this but it was never enough of an issue for me to bother trying.

I now have a 2004 Audi A4 1.9 TDI PD engine and have tried the same stuff in it. The car does work but it takes a lot longer to start and the car dropped 10 to 15mpg which made it a false economy for me. I only tried one tank before going back to dino diesel. I didn't try a mix which may have improved this.

This is all on 100% biodiesel made by converting waste vegetable oil by two local suppliers who sell it. I.e. not the same as running new straight vegetable oil or filtered waste vegetable oil, neither of which I have tried.

Oh, and yes - you can chop and change/mix as much or as little as you like. I believe all pump diesel is now as much as 5% bio anyway.

[Edited on 19/5/10 by ironside]

From what i've read, newer cars with common rail diesel injection do not really like biodiesel and it tends to damage the fuel pump seals.

However older less complex diesels are supposed to be perfectly fine with the green juice.

What you could do however is run your car directly on chip fat oil if you what to mod your car. You need to put in a small fuel tank to have some dino diesel in, and then you need a heater matrix to heat up the chip fat oil as its too viscous otherwise. You can't start or stop your car on chip fat oil meaning you need to have a fuel switching system in place which you flick when your car is warmed up, and then you turn off a few miles before you get to the place you are going to stop.

You can also make your own biodiesel at home, it just requires a bit of setting up equipment and finding suppliers for the chip fat oil and chemicals, you can make the fuel for under 30p a litre tho.

i run a bmw 2004 e60 on biodiesel.

just need to mess with the filter more often.

and they suggest warming the fuel in the tank.

i just use in summer and runs ok.

older the car the better.

mine also runs on veg oil. used and filtered very well. but does run a little sluggish.

dave

not really relevant to your question but i run my tractor for boat launching on recycled cooking oil from my local restraunt. lasr month they had a curry on the menu and you could smell lamb madrass every time it ran. yummy

The injectors and pumps on pd's dont like biodiesel. If you get a new one and run it on bio straight from the off then you may be ok. My mates done quite a few pumps etc when theyv been run on that.

The sticker inside the fuel flap on my 2005 1.9 PD engined Golf says not to use biodiesel. It doesn't say why not.
I guess the reason is that the pumps, injectors and ECU will be optimised for regular fossil fuel.

I run my Shogun on 100% bio, it is quieter and smoother and haven't noticed a dip in mpg (thank god!) Just means I get more fuel in the tank for the same money.

As said bio cleans the internals of the tank of that brown scaly stuff so a filter change is needed soon after changing and its best to have a new one in the boot as well.