I thought a how to might be useful to dispel some myths and summarise much research over the last months.
Background.....
Tax - it is now legal to use veg oil as a fuel - you used to have to register as a fuel producer and pay tax according to your declared litreage....however this has now changed and you only have to do this if you use more than 2500 litres per year....which is quite a lot.. and who's counting ;)
There a a number of veg oil related options available to you related to veg oil....these are as follows:
Biodiesel - this is diesel refined from Vegetable oil rather than mineral oil - no conversion is necessary for this just pump it in and away you go. Its time consuming to make and only about 10p per liter cheaper to buy...one for the environmentalists really.
Blend - depending on your diesel pump (eg Bosch/ Lucas/ Cav - some dont like it) you can run a blend - this involves tipping veg oil into your tank, chucking in a bit of additive and mixing with diesel - you vary the amounts through the year as it can impair your starting ability - no conversion is necessary but you still end up spending about 70p per litre on fuel.
100% veg oil - this is the option I have chosen and can use either new clean straight veg oil (SVO) or waste veg oil (chip fat) also known as WVO. Depending on the vehicle and its pump you will find that most diesel pumps will last a short while on 100% veg oil. HOwever two problems occur: Starting in cold weather is near impossible due to viscosity of the oil so you'll need a blend, and for the same reason your diesel pump will not like it...consequently your engine will not run. There is always someone in the pub who will tell you how they just pour it in off the shelf....but if you want reliability and longevity this is not the way. The answer is to run a 'two tank system'. The disadvantage of this approach is you have to spend time and money converting your vehicle - but then you can run on 100% veg oil - which if you get it free (WVO) soon pays for itself.
What is a two tank system?: essentially you use your existing tank for veg oil, and add another small tank for diesel for starting. To overcome the cold starting and viscosity problems the kit does two things: 1) you start on diesel and switch over to veg 2) you preheat the oil to make it less viscous.
which kit should I use?
There are a lot of kits out there - SmartVeg, Dieselveg, etc etc and all are a variation on a theme. Obviously its up to you to offset which each kit offers you - but for me it was quality parts, good reviews, good tech help and having an auto switch over that sold me on the DieselVeg ATG kit.
The kit is as below:
the main components = switchover valves, tanks, pipes and clips, wiring loom, dash mounted switching unit, tank, and heat exchanger, instructions.
Heat Exchanger
Dash Mount Switching Unit
Switchover Valves
This kit cost me £550 - if you want to save a bit on this you can for example provide your own tank etc. As I say there a a lot of much cheaper kits on the market so do your research - smartveg and dieselveg ATG are generally considered to be the top end. If you have more time then you can put together your own kit - its fairly simple and will prob cost you £150-200 - but for me the priority was to get on the road for free ASAP and with minimal teething problems.
WVO - waste veg oil
I will be using waste veg oil - sourced from take aways etc for free. There is a lot of info on the net and if filtering/ settling isn't for you then you can buy this pre-filtered at approx 45p a litre. initially I used 20L of clean oil for £13 from cash and carry to get the system running. A week down the line and I'm now running on WVO which I have been given from local pubs.
It seems there are lots of options for filtering kits but I sourced mine from http://www.oilybits.com" onclick="window.open(this.href);return false; for £145 - it includes a pump, inline filters, pertol station type nozle, pipes etc (again cheaper options available if you have time to figure something out)- i am filtering to 1 micron via a 10 micron filter. Firstly I have left the oil to settle for a minimum of 2 weeks by which time the good stuff rises to the top. I then remove the good stuff from the top by puncturing holes in the clear barrels just above the line of the fatty rubbish oil this then flows into a large container which is then tapped into old jeans legs (yes the ones you wear) with knots tied in the end. This get rid of the worst of the cr&p from the WVO then when I pump the WVO into the car it is further filtered through the inline 10 and then 1 micron filters.
The most common question I get asked is what happens when you run out of veg oil in eg france. Well there are a few options 1) if you have space carry some spare filtered barrels with you. 2) Go to any supermarket and pour in veg oil - still cheaper than diesel 3) last resort - override the system and run on diesel.
This is the fat from the chippy - its good stuff - after two weeks it has not seperated out or gone creamy suggesting low animal fat content. I reckon of the 80L of my first batch - 60L is usable. The other parts are the inline filters, nozzle and pump.
Fitting
The diesel veg kit is 'suitable for a competent home mechanic and can be fitted in two days'. It took me 1 evening on my own and 2 further evenings with help of a friend.
First I read the instructions several times during tea breaks at work where the kit got delivered, to get my head around what needed to be done.
First job was to identify diesel pump feed and return. I then identified the heater matrix feed and return by running the engine (heater on) and seeing which pipe got hot first. It's important that the heat exchanger fuel and water flow in opposite directions. I then mounted the heat exchanger in a convenient place where it could easily receive all pipes on the bulkhead
Note I mounted this on some rubber bobbins I had kicking around
I cut the fuel supply line from the original tank, put the inline filter in and connected to the H-exchanger.
Then i cut into the heater pipes and inserted the t-pieces. It's important that the Heat exchanger is fitted across the circuit (i.e you cut into both pipes) you can just make out the blue t-pieces on the bulkhead. The gold thing is the inline temp sender which actuates the switchover relay once 60 degrees is reached
Next you need to find a suitable location for the supply/return valves...this switches between Veg oil and diesel. I mounted these on the right side of the engine where there is a nice big gap and a bracket to mount them on. It is also near the fuel supplies and the heat exchanger this means minimal heat is lost when the veg oil is pumped into the engine.
Bracket attached minus the valves
With Valves and Pipes connected
Although there are a lot of pipes it is fairly straight forward to workout which pipe goes where and how to plumb it into the orig set up. One strange thing is the return on the passat goes through the diesel filter ! this is not required on this set up so I have just looped the return on the filter, I will probably use a different filter that has a basic 1 in 1 out set up when I change filters in 6k.
The auxiliary diesel tank can be mounted anywhere and can be any size - too small and you'll be filling up forever - too big - you loose space - Mine 22L and I fitted it in the left storage place in the boot.
First I removed all these plastic shelves
Then Cut out the bottom section (didn't want to but need must)
Fit Some Straps
Slot in Tank
Conveniently VW left an extra space to run the pipe down to the engine which made things simple and neat.
Next I found a suitable location to mount the control module
Then removed the cover from beneath the steering wheel and threaded the loom from the controller up through the ECU (thanks for this tip from some guys on this forum).
Under Steering Wheel
Ecu Box under bonnet (top left) opened up
Once loom is passed in through the ECU box (under ECU) then ran along the top of the bulk head and through a convenient hole in the bulkhead where I mounted the relays and rest of the loom which links it all together.
OK so it's all in and running I have noticed no difference in performance the switch over between diesel and chip fat is seamless, MPG is the same, engine sounds a bit smoother and slightly quieter on chip fat.
One question I get asked a lot is does it SMELL !!! answer... when inside driving not at all... when you get out the car having turned off the engine there is a slight wiff and a stronger wiff when you stand behind/downwind of the exhaust... personally I find the smell quite nice it's kinda like when you drive past the chippy
it's not good if you're hungry though !Well this has turned into a mighty post hope you found it interesting if you are thinking of doing it I highly recommend using the dieselveg kit and the support on the phone is excellent... I think if I was doing it again I would easily achieve this in a couple of nights most time is spent pondering where to mount stuff (I've done that all for you now).
does this mean my car is officially CHIPPED ? 8)