Originally Posted by SkulltulaHouse
I've been meaning to start a topic with very similar questions so hope it is OK to add this here rather than a new topic.
With the move to SP I've been looking for a 'higher' ZDDP oil, but not too much because my cars do have catalytic converters. 1984 VW GLI 1.8L gas and 1985 Audi 4000 2.2L gas. Both call for 20w50 in my climate. I also want full conventional (no syn blends). I've read some of the recent zinc posts here in addition to various reading. Here are some of my questions. My desire for higher ZDDP is for anti oxidation as well as anti-wear, as the cars rotate between daily driver and sitting for months at a time. In terms of the catalytic converter, I know any ZDDP may be an issue, but I am OK with a level that was in the original oils made for these cars before they started really lowering it (i.e. these cars have run SF through SJ, etc for years so a ZDDP level similar to those is fine with me)
Here are my questions
• What are folks thoughts on Kendall GT-1 Competition Motor Oil with LiquiTek, 20w50, for use in a daily driver, in terms of detergents or other considerations? I note Kendall states the oil is for "gasoline-fueled passenger cars" but I did not want to automatically assume that term is synonymous with "street" driving.
https://kendallmotoroil.com/product/gt-1-competition-motor-oil-with-liquitek/
This LiquiTek oil appears to be rather new, replacing GT-1 Competition Motor Oil with Liquid Titanium, so please share any experience with the Liquid Titanium version. Other than the Titanium additive, most of the specs look the same.
The Liquid Titanium info is still available, but does not like you can get to it using the 'front' of the Kendall website or their product search: (
https://kendallmotoroil.com/product/gt-1-competition-motor-oil-with-liquid-titanium/)
Kendall GT-1 Competition Motor Oil with LiquiTek has 0.120 (wt %) Zinc; 0.109 (wt %) Phosphorus. Is 0.120 (wt %) Zinc the same as 1200 ppm? I especially ask since I understand ppm could be based on volume or mass, and don't know how that aligns to % wt
Kendall GT-1 Competition Motor Oil with LiquiTek is Rated API Service SP, SN PLUS, which surprises me given the 0.120 (wt %) Zinc, unless I misunderstand what the wt % means. I thought certain API certifications had max zinc levels, or is that only for other viscosity grades. Given it meets SP/SN Plus, it seems it would be acceptable for daily driving
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I have also looked at Valvoline VR1 Racing Oil, conventional, 20w50. My concerns with VR1 is zinc may be too high for a car with a catalytic converter. This VR1 has 1400 ppm zinc and 1300 ppm Phosphorus. I've read in some places (been trying to re-find it) that 1200 ppm is the maximum recommended level for zinc before you run into cat problems. However, elsewhere, I think recently on here, a higher number was referenced by a poster (1800ppm?). I also note VR1, unlike Kendall (unless I missed it), specifically says not recommended for use in cars with cat. converters, although I wonder if that is more legal CYA than 1400 being a significantly higher risk than what Kendall (1200?) has. For a car with a cat. converter, what do people think the maximum level of zinc that is appropriate is?
https://sharena21.springcm.com/Publ...bd3/a61538b4-0cbd-e711-9c12-ac162d889bd1
I am also interested in any other oils, 20w50, full conventional, with ZDDP around 1200-1800ppm that may be out there I haven't found or verified yet
I have seen Motul's Classic Performance 20w50, which says it has higher zinc, but haven't found a specific number yet
https://www.motul.com/us/en-US/prod...w50-22064e03-a302-4747-bf86-9881333c9389
https://d23zpyj32c5wn3.cloudfront.n...SIC_PERFORMANCE_20W50_TDS.pdf?1523381292
Just some final thoughts in general. As stated, looking for full conventional, so that rules out Brad Penn/Penngrade and a lot of the boutique oils. Also would prefer a 'regular' oil, not high mileage (that rules out a Lucas oil that otherwise was a possibility). Racing-type oil (Lucas, etc) may be OK for the OP, but have too much zinc for my application. I need a 20w50, so 15w40's (like Classic Car Motor Oil) are a not an option. I also do not want a diesel/HDEO engine oil.
Thanks for any thoughts
Don't look at Zinc content. Look at Phosphorous content. That is the value that API standards regulate to control ZDDP content. Phosphorous is the element that damages catalytic converters.
So you can use Valvoline VR1, which has 1200 ppm P.
To convert from weight % to ppm, move the decimal point four places to the right. Think of percentage as "parts per hundred", in the same way that ppm is "parts per million". You have to multiply hundreds by 10,000 to get millions. So the ppm is weight or mass related, not volume.
If an oil has an API rating on it, it's OK to run in a street car. So don't get hung up on the Competition title they put on it.
40 and 50 weight oils can have more ZDDP than 30 and lower weight oils can have. The lower viscosity grades are currently limited to 800 ppm P. So a 50-weight can have 1200 ppm P, and still have an SN Plus or SP API rating.
Your cars are 35 and 36 years old. Are you sure the catalytic converters still work? The cars are pre-OBD, so there is no check engine light that will come on to tell that the cat has reduced efficiency.
I think that Valvoline VR1 would fit your needs. It's basically their Premium Conventional motor oil with extra ZDDP. It's available at just about every parts store that I go into.
But the Kendall is fine oil.