Veg Oil MPG.

[falling-out-with-my-car]

I have noticed that on a run my 1.9td Xantia estate does about 80mpg with a 50/50 mix of veggie oil and diesel.

I have installed a stadayne fuel heater to heat up the fuel lines in colder weather and only use a mix of 15litres of oil/30 litres diesel in weather with temperatures lower tha 10 degree C, so far so good five years and no probs yet, I have noticed that deisel is not going the distance anymore a full tank of diesel goes about 300 miles or so which is rubbish, I got some inside information the other day a friend works for Shell refinerys apparently they have been adding more and more so called detergents to the tankers before adding fuels for delivery, in the case of diesels its ethernol, I can't remember what it was for petrols but they are apparentrly thinninning down the fuel somewhat and shell does this less than say tescos or sainsburys, running neat diesel I have really notice the difference between these garages, have you? anyone having similar mileage differences on veggie oil compared to standard diesel?

regards Nigel.

[deian]

80mpg???

[nick]

Not possible surely ??

[citroenesque]

Buy a new calculator!

[Kowalski]

If you think oil is expensive (e.g. diesel) you should look into the costs of the additives that get added to oil. Generally the additives are much more expensive than the oil they're added to so there won't be a whole lot of thinning going on.

[Gammy leg]

Nigel,
I would guess that a Xantia tank holds about 12 gallons so your current mpg of 25 is very low. Others on this forum I believe are getting in the region of 45mpg without too much trouble running on straight derv. I doubt that fuel quality is the cause, particularly if you are filling up at different garages.

I'm tempted to suggest options to look at, however there are others on this forum who are far more experienced with XUD fueling and economy issues so I'll leave it to them.

I would say 80mpg is a tad optimistic - A typo a assume.


Gammy

[XantiaMan]

80mpg lol!

Adding SVO in high amounts will always reduce the mpg i'm afraid, quite drastically in fact, but not enough to make its use unviable.

I find my car performs best when on no more than 50% mix, after that mpg really drops, and performance is not as good.

A thicker fuel will not atomise as well as a thinner one, and this is one of the advantages of diesel, aswell as a higher cetane value.

Xantia tank takes more than 65 litres (over 14 gallons), i put 66 litres in last week and it didnt conk out, i suspect its 65 litres with 5 litres as reserve.

A full tank of diesel only lasting 300 miles is almost impossible. From a full tank i've got 500 miles, but not running it into reserve, as my fuel gauge cannot be trusted. In those miles, its been driven hard with high speed cruising and spirited acceleration. 600 miles should be acheivable for most, i just cant help myself sometimes!

[nick]

I would say 80mpg is a tad optimistic - A typo a assume.

Or it's 80 mpg purely in terms of the derv used, ignoring the quantity of veg oil added to it perhaps?!

[falling-out-with-my-car]

The mix must have been just right because I have never acheived such high values on a regular basis, I think the atmospheric conditions contribute to the running economny of your vechicle I tried very hard to use a tank full of 60% oil to 40% diesel and only do 50mph the tank holds 55 litres which is 12.2 gallons at 4.5litres to a gallon, that week was very hot weather. I did 942 miles on a tankfull of veg diesel mix that equates to around 78.5 Miles per gallon, excuse my flippance in suggesting it was 80mph but it was close enough until I found the place where I had it recorded on paper.

Thats the honest truth. and for much of that week I was ferrying around a man weighing 32 stone.

I was wondering if people are using a teaspoon of castor oil per tank full to break down the veggie oil? if not you wil be wasting a lot of oil as it burns differently if you do not add the castor oil it does not brek down quite so easily and eventually gumms up you injectors. (you mix it with a bottle of oil before it goes in the tank).

Regards Nigel.

[nick]

Doesn't the tank on a Xantia hold 65 litres not 55?

For 942 miles that would equate to 65.9 MPG, assuming all the fuel was used up.

[falling-out-with-my-car]

Kowalski, these are huge oil corporations and remember they are buying in bulk and they don't pay public prices it's trade prices for them so yes they do thin down the diesel quite a lot, I think you forget diesel is hardly ever seen we trust that we are putting a pure product in our tank when we stick the nossel in the hole sure we can smell it but we don't have a clue whats in it and we somehow stick an 18,000 pound car on their forcourt and blindly fill up from a nozzle not knowing what we are putting into the car. it is the easiest way to scam people they can pretty much do what they like to the mix and we will never question it because it makes our cars go.

I wonder if you did a survey how many people would actually know the colour of road diesel? in fact they could change the colour over night and if not told people probably wouldn't know until a mechanic stripped out the fuel system and discovered something different about the fuel

Veg oil is not expensive if you know where to buy it, unfortunately I'm not about to broard cast online where other wise it will increase threefold in price currently 65p a litre, shop around people it will be worth it. you could like me also arrange a constant supply and negeotiate with the shop Manager to hold the price as long as you keep ordering a fixed amount, most shop managers want to make a profit if your buying 3 litres it will be nearly£3 a bottle but if your buying 45 litres the price can come down. whant a tip target a corner shop if you catch my drift, they don't sell much and they like to sell a lot, negeoaite what have you got to loose?

Regards Nigel.

[falling-out-with-my-car]

80mpg lol!

Adding SVO in high amounts will always reduce the mpg i'm afraid, quite drastically in fact, but not enough to make its use unviable.

I find my car performs best when on no more than 50% mix, after that mpg really drops, and performance is not as good.

A thicker fuel will not atomise as well as a thinner one, and this is one of the advantages of diesel, aswell as a higher cetane value.

Thats because it needs a teaspoonful of castor oil per tankfull to break it down, simply using veg oil/diesel mix eventually causes cologged injectors and lots of smoke from the exaust pipe esspecially on start up.

However I do agree that to much veggie oil and the economny goes down significantly, I have found in the summers hottest conditions 25 degree C plus the mix can be as high as 25% diesel to 75% oil and the economny is pretty good, but as you say it all depends on your driving style and wether or not you are a heavy footed driver. did I mention the fact that I have fitted a stanadyne fuel heater which preheats my fuel line both sides of the filter for easy starting in colder temperatures perhaps this is my edge? the heater can be left on all of the time its thermostatic so it kicks in and out automatically.

Regards Nigel.

[falling-out-with-my-car]

Thats odd very odd I ran out of diesel once living in a rural area its a long way to the garage, I filled up and tshe took 58 litres thats fillingm up the filler pipe as well so i assumed the tank was 55litres 12.2 gallons.

maybe its a MK2 trait I will however check tha manual and get back to you on that one.

regards Nigel.

[falling-out-with-my-car]

Nigel,
I would guess that a Xantia tank holds about 12 gallons so your current mpg of 25 is very low. Others on this forum I believe are getting in the region of 45mpg without too much trouble running on straight derv. I doubt that fuel quality is the cause, particularly if you are filling up at different garages.

I'm tempted to suggest options to look at, however there are others on this forum who are far more experienced with XUD fueling and economy issues so I'll leave it to them.

I would say 80mpg is a tad optimistic - A typo a assume.


Gammy

sorry youve lost m,e ther who mentioned 25MPG?

[lolingram]

Castor oil is also veggie and should NOT be added under risk of gumming things up. I have run racing engines since the '50s when Castrol 'R' was the only viable oil for boundary lubrication (Manx Nortons for exapmple). Now we have pure synth oils which are as good from the lube aspect, without the need to strip and un-gum the rings every 500 racing miles.

Thats because it needs a teaspoonful of castor oil per tankfull to break it down, simply using veg oil/diesel mix eventually causes cologged injectors and lots of smoke from the exaust pipe esspecially on start up.