Seatmann wrote No he wont and he doesn't need it anyway DAD
"Air Pollution from Motor Vehicles: Standards and Technologies for controlling emissions", Asif Faiz, Christopher S. Weaver, Michael P. Walsh, 1996, The World Bank, ISBN 0-8213-3444-1
P 96
"Some of the requirements for a catalytic converter to be used in two-stroke engines include high hydrocarbon conversion efficiency, resistance to thermal damage, resistance to poisoning by sulphur and phosphorus compounds in the lubricating oil and low light-off temperature"
The catalyst in our TDI engines has none of these properties.
Two stroke oil is a lubricating oil and not a fuel oil: it contains additives not found in fuel. It does NOT burn cleaner than diesel. Most of the two-stroke oil you can buy today is meant for engines that do not have a catalyst: chain saws, strimmers, hedge-trimmers and the like.
Oxidation Catalyst Performance Considerations: Catalyst Temperature, Space Velocity, and Fouling
Presented at the 2011 Gas Machinery Conference Nashville, Tennessee
Daniel B. Olsen, Engines & Energy Conversion Laboratory, Colorado State University
Gregg Arney, Southern California Gas (SoCal)
Arthur Reining, Stationary Emissions Control, Johnson Matthey
Introduction
"Catalyst poisoning is attributed to sulfur, phosphorous, zinc, and calcium compounds. Sulfur
normally originates from the fuel and is significant in low grade diesel and some gaseous fuels, such
as digester gas. Phosphorous, zinc, and calcium compounds come from lubricating oil. Catalyst
poisoning from sulfur should not be problematic for engines operating on natural gas and diesel fuels
that comply with current sulfur standards. However, compounds from lubricating oil can cause
significant degradation in catalyst efficiency, even in 4-stroke engines with no cylinder lubricating
port2,3. For integral two stroke compressor engines with cylinder lubricating ports catalyst poisoning
from oil derived compounds is expected to be more severe."
That's just a couple of quotes from the first page of a google search. There is a huge amount of additional data out there, all of which says that two-stroke oil in fuel will damage a conventional catalyst.
Catalysts can be applied to two-stroke engines, but they are radically different from those on our TDI's.
Now, it is true that at present the oxidation catalyst on diesel cars is not tested at MOT, the only test applied is a smoke test. I still feel that owners should be aware of what they are doing when adding things to their fuel.