JHZR2
Staff member
IIRC, the reason for the lowered additive levels, were really for the purpose of EXTENDING the warranty on emissions systems including the expensive cat converters. It is well known in heterogeneous catalysis that inorganics can eaand sulfur can easily poison oxidizing and reducing catalysts. This is often at VERY low contents.
If manufacturers have to extend their warranties from 100k to 150k, and the average car isnt well kept past, say, 60k, how can they ensure this? Especially considering that the average 80 or 100k car is worth pennies on the dollar compared to what they were new.
Cars do use oil... considering that there is a microscopic layer of oil protecting surfaces, there isnt a lot to get in to a cylinder to burn and get out to the cat, however, analyses that I have read from the theory of operatinon indicate that a tiny bit of oil is used. If someone has real data stating otherwise, please let me know...
But, assuming that, say, one milliliter out of of five liters of oil gets burned up in three thousand miles, youll never see any use, but it wtill happens... and a milliliter is about a gram of oil (less because the densities are less than water, but good enough for back of the envelope), then at 1000 ppm of phosphorous and zinc, youre putting about 1mg of each through the cat each 3000 miles. Under optimal conditions. Start burning the slightest bit more, and youre putting more and more in. It doesnt take much to poison PM catalysts. I do fuel reformation in my day job, and know this for a fact.
Depending upon how well you maintain your car, and how nicely you treat it in driving, your oil burnign might be quite low, and your cat last nearly forever... or your cat may die early without your engine consuming any oil (like mine). Low ZDDP is in the game of warranty extention, and warranties are all a game of numbers. obviously the know something about the onset of oil usde, and what it takes to kill a modern cat with a known PM loading.
JMH
If manufacturers have to extend their warranties from 100k to 150k, and the average car isnt well kept past, say, 60k, how can they ensure this? Especially considering that the average 80 or 100k car is worth pennies on the dollar compared to what they were new.
Cars do use oil... considering that there is a microscopic layer of oil protecting surfaces, there isnt a lot to get in to a cylinder to burn and get out to the cat, however, analyses that I have read from the theory of operatinon indicate that a tiny bit of oil is used. If someone has real data stating otherwise, please let me know...
But, assuming that, say, one milliliter out of of five liters of oil gets burned up in three thousand miles, youll never see any use, but it wtill happens... and a milliliter is about a gram of oil (less because the densities are less than water, but good enough for back of the envelope), then at 1000 ppm of phosphorous and zinc, youre putting about 1mg of each through the cat each 3000 miles. Under optimal conditions. Start burning the slightest bit more, and youre putting more and more in. It doesnt take much to poison PM catalysts. I do fuel reformation in my day job, and know this for a fact.
Depending upon how well you maintain your car, and how nicely you treat it in driving, your oil burnign might be quite low, and your cat last nearly forever... or your cat may die early without your engine consuming any oil (like mine). Low ZDDP is in the game of warranty extention, and warranties are all a game of numbers. obviously the know something about the onset of oil usde, and what it takes to kill a modern cat with a known PM loading.
JMH
