fxz

Is it right for modern 9a1 modified "catless" as well? ( zddp is
dangerous for catalyzers but protect engine surface)
If not worth on modern which protection additive?

From Steve

"The majority of the damaged (cams) ones I saw here were due to people using the wrong oils (insufficient ZDDP in the oil), compared to spray bar obstructions.*

IMHO, its not a factory defect, based on my observations since 2003 when this really started in earnest. From 1969 to 2002 or so, we never saw any cams that suffered such damage unless the spray bars were blocked with dirt of some kind and that was rare. Once the EPA mandated reductions in ZDDP, this problem became more frequent."

https://rennlist.com/forums/964-foru...am-horror.html

Serge944

The only reason manufacturers don't support the use of engine oil with high ZDDP content is because they have to warranty emissions equipment well past the standard warranty. So, it's a business decision to prolong the life of catalytic converters, for example, at the cost of engine wear (which will occur past the warranty period).

bergx7

Don't add off the shelf additive packs to properly blended oils. Buy the right oil for your car. If running a classic, buy one formulated for that. If running a modern car, buy what is approved.

Get oil analysis if you are really worried about wear... I run Mobil 1 5w50 in a 4.0 liter converted engine that I drive the **** out of (with proper warm up) and my oil analysis is pristine.

Serge944

More than that, don't add anything to you engine oil. Period.

It's an ongoing debate about ZDDP and some reduction-supporters are claiming that modern engine designs don't require as much ZDDP as older ones, and a common item that is brought up is the shape of valve lifters. Some older cars had flat lifters, whereas many modern lifters are not, e.g., radiused (see 996 GT3 engine image below). However, no one is arguing that a higher ZDDP content has any disadvantage from an engine wear perspective.

Finally, you will find extremely high ZDDP content in any "racing oil" on the market. Do your research and come to your own conclusion.

fxz

Thanks Serge

this argument suits well in front of the fireplace on these winter days awaiting Geneva (bored of R speculations so at least something concrete about the reality)

Keith Verges - Dallas

I want to say the diesel oil formulations remain high in ZDDP. At least last time I researched this, they did. I personally use Rotella T6 and the Mobil Delvac 1 and now there is a Mobil diesel formulation as well and I think replaces the Delvac. All are synthetic and have serve me well in my race cars. Also, since they are certified for use in gasoline engines, who cares if they screw up catalytic converters, if they help with the engine longevity.

Mech33

You care when your GT3 cat gets clogged.

Serge944

The difference in quantity of zinc and phosphorus (the relevant elements in ZDDP) for say Mobil 1 vs Mobil 1 Turbo Diesel vs Mobile 1 racing is 2100, 2380, and 3600 ppm, respectively. If your cat is going to fail, it's possible with either oil - it might just happen a little sooner with oil that's better for your engine. If you're lucky, your cats will fail under the 8 years/80k miles federal emissions warranty. In reality, most GT3s will never see that kind of mileage. Most GT3 owners will replace the car within a few years anyways, so this may be a moot topic.

Spec citation: https://mobiloil.com/~/media/amer/us...pecs-guide.pdf