10w40 oils with >1200ppm zinc, >100ppm moly?

[zaibatsu]

Any suggestions?

Got a car that ran well on the old synerlec RP, but now that they've changed the formula of the original, and the HPS is a little too high in Zn (1700ppm), I'm not sure what to go for.

Synthetic with low shear is always good, but a strong AW package is important for me in this car. I run M1 0w40 in my other car before someone suggests it, but that is a little thinner than I'd like @ 100C for this one.

The engine ran rough at higher revs on Motul 8100 X-cess 5w40 if that says anything, the (old) RP made it run really smooth. I want to avoid doing an OC that makes it rough again, but I wonder if it's the synerlec (sulfur?) that smoothed it out.

Maybe by looking at ZDDP/Moly I'm looking in the wrong place (for what made the engine smoother at high revs), feel free to enlighten me, but I do like the idea of reasonable Zn/Moly numbers anyway.

 

[supercity]

Shell Helix Hx7, circa 1200-1300 ppm

 

[chubbs1]

Why is RP's 1700ppm "too high" are you worried about a catalytic converter?

It would be helpful to know what vehicle you have. I seriously think you would be fine with M1 0w40. That has the Zn/Mo numbers you are looking for, it meets many spec's and is a great oil.

 

[A_Harman]

Maybe you could try mixing RP HPS with their street oil to cut the zddp concentration from 1790 to ~1300.

 

[Garak]

Originally Posted By: zaibatsu
Got a car that ran well on the old synerlec RP, but now that they've changed the formula of the original, and the HPS is a little too high in Zn (1700ppm), I'm not sure what to go for.

It might be worth watching for or splurging for a VOA of your own on that stuff. That is a rather high zinc level, and the more I think about it, the more skeptical I am. By the way, the 5w-40 RP will still have the Synerlec in it, if I recall correctly, and wasn't removed with the lineup change. The 0w-40 never had it in the first place, so it didn't change, either.

@chubbs1: Too high of a zinc level can be corrosive, causing cam spalling. 1700 ppm is around the upper limit of what I'd be comfortable using.

 

[zaibatsu]

Garak - I'd love to do my own VOA on both, but having bought a pile of oil I don't need I'm in negative budget at the moment and still need to do an OC on this car.

chubbs1 - see Garak's post, ~2000ppm can start causing problems. It's an S15 with SR20DET/VCT, seems some oils make it a little rough at redline, RP quietened it. Tempted to try the M1 but my bad experience with Motul 5w40 left a sour taste in my mouth about using non-recommended weights in this car. I understand xw40 = 40wt at operating temp, but larger gaps do end up being a little thinner @100C.

Originally Posted By: A_Harman
Maybe you could try mixing RP HPS with their street oil to cut the zddp concentration from 1790 to ~1300.


This is exactly what I had in mind, partially because I already bought 4 quarts of the street oil. I was thinking of using a 50/50 mix. It's a bit of a guess without seeing VOAs.

 

[KCJeep]

This is easier than you think. QS Defy in 10w40 runs about 1200 ppm in zinc, has about 100 ppm moly AND another 200 ppm boron. For about 14 bucks a 5 qt jug I'd try that first.

 

[Garak]

The only issue I'd have with mixing their street and their HPS line is that they may use different additive chemistries. I believe the former is sodium, whereas the latter is a calcium type. Nonetheless, that's just my bias against mixing shining through.

I do wonder, though, if that 1700 ppm level, if true, might actually not be as bad as the numbers indicate, given that the detergent level is high. We don't normally see levels of zinc that high except in racing oils, which tend to lack the detergent in the first place. Unfortunately, to answer that question, we need the help of someone like Molakule who isn't simply guessing and theorizing like I am.

 

[zaibatsu]

I think that 1700 number may be a bit of a misnomer, we only have one VOA on HPS to go by (10w30). It'd be great to see some more HPS OAs to confirm.

I emailed RP and got some very prompt and detailed replies. They suggested that in 10w40 for both ZN and P levels, SN = ~800ppm, SL = ~1100ppm, HPS = ~1200ppm.

They initially said mixing is not recommended but after consulting with one of the chemistry guys they then suggested it would be fine and not cause any issues, but it'd be best to stay 3:1 HPS:SN for wear-prone applications (to keep the AW package sufficiently high). Obviously not mixing is preferable in their view (as would be the logical line from any company) but in this case there were no chemical problems according to them.

Seems like the only problems are that I have to buy more oil, and that we don't have definitive numbers for each oil in different weights, so it's hard to predict exactly what additive levels will be present.

 

[Garak]

Well, there we go. We know VOAs can be wrong, as can companies' own data, but at least there is some indication that it's probably less than 1700 ppm. If it's around the 1200 they suggest (which is a rather sensible amount for most non-race applications), I'd use it as it.

 

[CATERHAM]

What's the application here that you think such a high does of ZDDP is required?

 

[zaibatsu]

https://bobistheoilguy.com/forums/posts/3119654/

VCT mechanism in this engine is known for a tendency to develop some wear in cam gears and a resultant rattle at idle. Tends to last longer before developing problems given better lubrication.