Emission System Degredation

[El_Schaf]

Hi all -

Does anyone know what the typical acceleration of catalytic converter degredation is with high tbn high anti-wear additive (ZDDP) oils vs. something like amsoil/edge/M1 EP?. For instance, would say 1.5 quarts of consumption in 13,000 miles cause a noticeably reduced life for a catalytic converter (given that the consumption occurs in normal driving conditions)?

 

[bepperb]

It's impossible to tell.

If you lurk this forum enough, you will find that the general beliefs are that:

1. Using SL or other high zddp doesn't do anything to cats or o2 sensors and we're all smarter than the API.
2. o2 sensors only have a life of 80,000 miles and it's not uncommon for cats to fail.

Which to me are two contradictory things.

 

[lexus114]

Remember Catalytic converters don`t die,their murdered!!

(a quote from Shade tree Mechanic)

 

[FrankN4]

You do not have to burn oil for it to get to the cat. It also gets there by volatilization. How much hurt it does, I am not sure. I have a 1999 Cavalier that has used an oil that has 1200 ZDDP since the very day it came from the dealer. At 175,000 miles, getting new tires, I was told I needed a new cat and a new muffler. They tested it with whatever it is they test with and it passed with flying colors. I still have the same cat and muffler and the car now has 213,000 miles.

 

[lexus114]

Just curious is that on the regular 2.2 non Ecotec,or the 2.4 over head cam motor??

 

[getnpsi]

80k miles on a vehicle depending on all other maintenance could be just stretching its legs or huffing and puffing up a single flight of stairs methaphorically.

Relacing o2's on other friends' cars in the past made the vehicles "change their tunes." When ive replaced them on my personal vehicles, the idle when hot is the same, the mpg's are the same etc. I feel like I could have bought more oil.

Interesting to speculate if a car built in 1989 or 1999 would enjoy longer life of all components if it was ran exclusively on current 2009 oil and fuel. It was tolerable to burn 10x times as much oil as your numbers not long ago. It got a car clear of its warranty.

 

[FrankN4]

Originally Posted By: lexus114
Just curious is that on the regular 2.2 non Ecotec,or the 2.4 over head cam motor??


I have the old 2.2, pushrod, Bubba engine.

 

[Vilan]

My Metro was burning about a quart per 1000 miles for a couple years. Eventually it got to about a quart per 300 (!) miles... added a quart every week. Failed smog testing from all the hydrocarbons I was putting out. Rebuilt the engine, passed smog easily, with the same cat as before. So it seems to me cats can survive a *lot* of oil going through them.

 

[es350]

Originally Posted By: El_Schaf
Hi all -

Does anyone know what the typical acceleration of catalytic converter degredation is with high tbn high anti-wear additive (ZDDP) oils vs. something like amsoil/edge/M1 EP?. For instance, would say 1.5 quarts of consumption in 13,000 miles cause a noticeably reduced life for a catalytic converter (given that the consumption occurs in normal driving conditions)?


No..I have had to many cars with oil issues and the cat is never an issue..EGR, O2 etc are.

 

[Gary Allan]

Until someone produces bona fide evidence to the contrary, I retain my belief that it's a time weighted average of the amount of zddp going through the motor. If asked if a % of zddp volatilizes out of each sump, the answer will probably be, YES.

If that's true (any dispute?), then the concentration of zddp is not as important as the mass of zddp over a given mileage.

That would mean (again- I'm just giving you MY logic train - feel free to derail it) that someone stuck in the 3k/3m prison with SM could be doing MORE poisoning over someone who is doing longer OCI's with SJ/SL.

The next step is to reason that there were PLENTY of 3k/3m types using SJ/SL ..so they would be poisoning their cats EVEN MORE ..yet mass cat failures aren't occurring on OBDII cars due to cat minimum efficiency standards being reached.

My conclusion? That OBDII (CAN?) catalyst efficiency standards are going to be tightened in FUTURE (SM forward MY) vehicles.

That is, whatever collective damage being done to catalysts, over the WHOLE rolling fleet, will, on average, be reduced.

It has to be policy driven.

Maybe future cats may have to be smaller due to demand for platinum and reclamation isn't producing enough to keep up with demand. To reach even higher mileage integrity numbers (100k vs. 80k ..or whatever) the OEM's need policy change to make that possible.


In short: 3k/3m with SM ...less damage than 3k/3m with SL. YMMV due to your personal habits.