For a modern diesel engine to use vegetable oil effectively as a fuel, a converter system is required. Not using a converter system is simply a means to expensive mechanical repairs and I wouldn't advise it. Certainly when it came to my diesel car, I wanted to keep it, and so I chose to use a converter system.
I am not a mechanic so my explanation of a conversion system is basic at best, but my understanding is this:
Starting a cold engine on cold vegetable oil is risky in a modern engine and can cause damage, as is starting a cold engine with hot vegetable oil. But hot vegetable oil in a hot engine makes for happy combustion. Consequently a quality converter system uses standard diesel for cold starting – a two tank system. I've made a YouTube Video on the subject that you may find helpful.
As I said, this is NOT a technical explanation. For more details as a professional fitter. You may have seen them on the "Angry Frog" episode of Chop Shop - where Bernie and Leepu converted a car to run partly on veg oil (50/50 mix of veg oil and diesel).
The two tank system is exactly what it sounds like - a system that require two fuel tanks.
Usually the existing fuel tank is utilised to hold the vegetable oil. A second, smaller tank is fitted elsewhere in the vehicle (normally inside the boot) which holds the diesel for starting and stopping.
Inside the driving cabin, usually on the dashboard, a control switch is placed, allowing the driver to operate the system. Under the bonnet all the fuel management, preheating bits do the wonderous mechanical magic of which I have no insight whatsover. Sorry. I just know it works...
Given my obvious technical inneptness, obviously the question needs to be asked, who should fit your converter system... DIY or professional fitting?
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