Citroen XM Forum

Just done a 262 mile trip from Surrey to North Wales on 25 litres of vegetable oil in my 2.5 VSX TD.

This morning the tank was already exactly half full (according to the fuel gauge) before I added 25 litres of veg. I decided to drive with the cruise control on at 70mph, motorways all the way, M25, M40, M42, M6, M56, A55, had to slow to 50mph & 40mph at some roadworks with average speed cameras.

The fuel gauge at the end of my trip is at exactly halfway again so I presume I've used 25 litres. Trip computer shows average mpg to be 49.4mpg, average speed 52mph. Took a bloody long time but at least no chance of being done for speeding!

I work out 262 miles on 25 litres (5 & a half gallons) comes to 47.6 miles per gallon, trip computer wasn't far out.

I reckon its pretty impressive for a 2.5 litre engine pulling a heavy car (I also had 100 litres of spare veg oil in the boot!)

Car drove very well, the suspension feels nice but I think the front spheres are probably a little hard as it bounces a bit over bumps (not on the motorway though) the rear suspension performs as it should.

All in all very happy with the car, I was worried that it would be much thirsier than my ZX Volcane TD on fuel but doesn't appear to be.

Wish I could find a way of locking the car though! (still looking for a set of locks, keys & transponder)

MOT tomorrow!

Hi endorfin,sounds great.Was it new ,straight veg oil,or processed waste veg oil?Or,was it part diesel mix?Do you have fuel heater?I presume no fuel system mods.I'm looking to experiment,but need to assess critically for use with Lucas EPIC pump.Lots of negative advice,but no anecdotal evidence.Thanks for any info.
robertm

Processed waste veg oil. I process my own in the back garden when I can get it, very easy to do, rough filter the oil thru a sieve & let settle for a few weeks (gravity does the filtering for you, all the crap & water goes to the bottom) pour out the good stuff thru a half micro sock filter & use in the tank. When I'm short of wvo I buy it off a local processor for 40p a litre. Bargain compared to £1.20 a litre!

I've just started using waste veg on this XM so easing it in as the veg acts as a cleaner so can flush out all the crap & block the fuel filter, I used 30% diesel this time. Gonna service it tomorrow after the mot test & change the filter then start using 100% veg. In colder weather I'll add 5% petrol to thin the veg oil out. I think this has a fuel heater on the fuel filter housing but I intend to add a heated fuel filter and/or a flat plate heat exchanger before the colder weather comes.

With regards to Lucas pumps I'm afraid I have a few negative things to say about them. My ZX TD Volcane originally had a Lucas pump & I only managed 450 miles on 50/50 veg & diesel before it packed in.

If you want to get away with using veg on a Lucas pump its either use a twin tank OR run the engine until its hot with just diesel in it then add veg oil...do your journey & use up all the veg then before you put the car to bed put some diesel in it. Repeat the above on your next journey. I know people who've got away with this method for many thousand miles.

For advice on veg oil motoring the best place is the forum on www.vegetableoildiesel.co.uk go there & click on discussion board & join. Its where I learned everything I know, some very knowledgable chaps on there.

Good luck,
Nige

Which part of North wales did you visit??

Paul

Denbigh & Towyn.

Still here, car being put thru mot tomorrow.

Hi endorfin,many thanks for detailed info.I have been researching websites,but no hard evidence for veg oil use on Lucas systems.
robertm

endorfin wrote:
With regards to Lucas pumps I'm afraid I have a few negative things to say about them. My ZX TD Volcane originally had a Lucas pump & I only managed 450 miles on 50/50 veg & diesel before it packed in.

We all know how weak lucas pumps are for Veggie.... fine for 100% DERV... my 1991 H reg has a lucas pump, while it performs remarkedly well, the day it throws its toys out, its comming off...

Paul

That's good MPG but around town I got around 32/33mpg.

Steve.

Hi Endorfin.

Impressive figures for the 2.5, especially using cruise. My impression is that using cruise actually increases fuel consumption; certainly on mine if the cruise is looking to restore speed, it accelerates far more viciously than I would, manually. All the 2.5s I've had have been broadly similar and returned between about 39.5 - 42 mpg, overall average, with a very noticeable drop to around 30mpg if towing something substantial.

I may be a lone voice here, but I would urge caution in the use of anything other than straight commercial Diesel. I used commercial bio for a couple of years and never spent so much time changing clogged filters and chasing seeping pipes. Ultimately, the pump itself died -- the only one I've ever had give out on a Diesel Cit. It may be coincidence, of course, but I suspect not.

Mike.

The trip computer works from the length of time the ecu opens the injectors for and adds each opening up to give a total of fuel used against the mileage done which is again recorded electronically. So provided your injectors are in good condition the trip will be more accurate than trying to work out how much fuel you have used by the fuel guage.