What is in your oil will be in your exhaust, and some metal compounds can play nasty with the fairly chemically fragile catalytic converter materials.

 

Yep, and unfortunately ZDDP is a bad guy for those applications...

 

The quote isn't me,, its actually plagiarized from the guy who ran the Audi Diesel Lemans Program.
The reason that car was so quiet was his theory was sound is lost energy,, if you can make a moving thing quieter the energy goes to the tires.
I mean it was a 200 mile an hour Diesel car and sounded like it was on the freeway when it went by..
There is a really interesting bunch of stuff in the Documentary on their race program.
You gotta pay attention to the casual comments stuff in the background here and there.

 

Sometimes those casual comments can speak VOLUMES....
....but the right ears need to hear and comprehend them....

 

I wouldn't recommend 80W-140 gear oil unless you have a lot of gear clearance. Gear oil between the gear teeth gets rather hot from the pressure and friction. The higher the viscosity, the greater that hydrodynamic friction. A 140 grade will run quite a bit hotter than a 110 or 90 grade which can lead to gear fatigue.

Lucas's fuel supplements are decent. I use their ethanol stabilizer for extending E85 storage life. Other than that, they tend to put out bottom shelf products with top shelf prices. They also tend to suffer from QC issues.

The phosphorus and sulfur from ZDDP (and other additives) can damage catalytic converters in large quantities. While that's true, it's a bit of a dramatized issue as far as the general population is concerned. Even with 1500 ppm ZDDP, you'd have to be consuming a lot of oil (>1 quart in 1,000 miles) to make any substantial impact on the catalytic converter. Now the cats will only last 400k miles instead of a potential 500k miles. It doesn't matter much when 95% of cars end up in the scrapyard with <200k miles on them.

I can understand and respect that theory. I'm going to take some time this afternoon to pull out some old books and discuss this with some colleagues as it's got me thinking more about it. I want to test this again.

Engine noise can be from a number of different things that could or could not affect power. Things like the notorious LS piston slap are harmless and unremarkable, for example. In my previous testing, I've had oil formulas make some engines quieter in terms of things like piston slap and lifter ticks (not due to lifter damage) with no change in power, longevity, or performance either way. I think it may be more of a placebo thing where a quiet running engine is just more appealing, and I totally get that. Thanks for bringing this up because it's got me curious about it again. Do you have a link to the white paper you got that from?