Valvoline VR1 Racing Full Synthetic 20W50, 1.3k mi OCI, 8k mi, C7 Corvette Z06

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See previous thread for background. In this one I ran Valvoline VR1 20W-50 (Full Synthetic). I took three UOAs: (1) on 7/12/22 - 100 miles of street driving after oil change, (2) on 7/29/22 - right after first track session, (3) on 8/3/22 - after the track event and about 250 street miles. The oil was not changed in between UOAs, just topped up at the track. I added about 2 qt of top-up oil at the track to keep it between the MIN and MAX markers on the dipstick.

On recommendation of the oil lab analysis engineer and engine builder I've been running Red Line SI-1 fuel cleaner (2-3oz per 10gal of fuel) to make sure fuel injectors are clean enough. This is eliminate the injectors as a likely source of the fuel dilution.

Screenshot 2022-08-14 150726.gif
 
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This engine was already broken in on an engine dyno (see the 5/21/21 sample in the previous thread) before it went into the car. This is picking the oil to use on the track to make sure it gets the lubrication it needs.
 
Possibly, but it's about 10-15% by volume per event, and I sample after every event for now. I try to take samples after the make-up oil has been through several drive cycles on the track, never right after adding it. I don't need to add make up oil on the street. Plus, what I am interested in is the trends not the specific values. So, as long as I maintain the same sampling methodology I think it should be comparable between oil samples.

I would argue that doing an UOA on this engine is much more vital than doing it on a street driven engine with long OCIs. In the latter case, as long as you change the oil often enough and use close enough to the OEM viscosity you'll probably be fine. In my case, if I use the wrong oil I could lose an engine in a single track event. Plus, the wear trends can tell me when it's time to start thinking about a rebuild. I doubt most street engines are rebuilt, but just replaced.
 
That Valvoline oil has a stout anti-wear package.
The wear-metals numbers are scary being quoted in ppm per hundred miles. My normal thing is ppm per thousand miles, and I consider 3 ppm per thousand to be normal wear (Iron). Quoting in ppm per thousand miles, your values would be at 23, which as I said sounds scary. It has been mentioned on BITOG many times that wear numbers spike after an oil change, so paying such close attention to wear numbers on very short intervals could be misleading.
 
VR1 has historically been 98% the same as off the shelf Valvoline with some additional ZDDP added. It seems to working well for you given the use.

That Valvoline oil has a stout anti-wear package.
The wear-metals numbers are scary being quoted in ppm per hundred miles. My normal thing is ppm per thousand miles, and I consider 3 ppm per thousand to be normal wear (Iron). Quoting in ppm per thousand miles, your values would be at 23, which as I said sounds scary. It has been mentioned on BITOG many times that wear numbers spike after an oil change, so paying such close attention to wear numbers on very short intervals could be misleading.

I know the lab engineer he's referring to. He likes to quote in ppm per hundred miles because he has a NASCAR background. You run a 400 mile or 500 mile race. It's easier to state ppm per hundred miles with short, high intensity use like this.
 
VR1 has historically been 98% the same as off the shelf Valvoline with some additional ZDDP added. It seems to working well for you given the use.



I know the lab engineer he's referring to. He likes to quote in ppm per hundred miles because he has a NASCAR background. You run a 400 mile or 500 mile race. It's easier to state ppm per hundred miles with short, high intensity use like this.
I can see that. Do you know what a reasonable value would be for Emperors6 to use as a gauge for engine health?
Or maybe it's a matter of sampling regularly, plotting the data, and watching for increases in trends.
A typical value we used at GM on endurance engines was to change at 120 ppm Iron. When I was running trailers, I would sample occasionally on my long OCI's, and dump the oil when it got to 100 ppm.
His last Iron reading was 28 ppm at 1216 miles, so he could go to maybe 5100 miles on the same duty cycle. Street driving is probably in the ~3ppm/1000 miles range, so the 2.5ppm/100 miles that is on the UOA is mostly due to track days.
As long as viscosity is holding up, I think the limiting factor would be Iron ppm.
I think the TBN would hold out longer than the Iron limit.
 
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This engine was already broken in on an engine dyno (see the 5/21/21 sample in the previous thread) before it went into the car. This is picking the oil to use on the track to make sure it gets the lubrication it needs.
Broken in and run in are two different things, I think you would see the same trend if you had used the Mobil as well especially in a track car.
 
The UOAs don't show it but there's a lot of street (and some track) driving in between. The engine has about 8k miles on it since being built. For example, between the 7/9/22 and 6/19/21 samples the car racked up 165 engine hours and 6700 miles.

For M1 (sample 7/9/22) vs VR1 (sample 8/3/22) it was a similar OCI with a similar number of street and track hours and the VR1 did much better in wear numbers.
 
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The UOAs don't show it but there's a lot of street (and some track) driving in between. The engine has about 8k miles on it since being built. For example, between the 7/9/22 and 6/19/21 samples the car racked up 165 engine hours and 6700 miles.

For M1 (sample 7/9/22) vs VR1 (sample 8/3/22) it was a similar OCI with a similar number of street and track hours and the VR1 did much better in wear numbers.
You can't really do that sort of comparison though, as break-in is clearly still happening and wear metals are going to naturally trend down the more miles you put on it.
 
All that matters from that report is that between M1 (sample 7/9/22) vs VR1 (sample 8/3/22) which were very close together: (1) wear metals for similar OCI dropped in half, (2) oil viscosity held up better for VR1. (1) might be because break-in is still happening, though after 8k miles I'm not so sure. Regardless the two UOAs were very close together so I would have expected the influence from break-in still happening to be minimal. However, (2) seems unlikely to be caused by the engine breaking-in. However, as I mentioned after over 8k miles I'd expect the engine to have pretty much broken in, so I'm not quite sure why you say break-in is clearly still happening. These weren't easy miles either, a significant amount were driven on the track in high RPM and high engine stress situation.
 
All that matters from that report is that between M1 (sample 7/9/22) vs VR1 (sample 8/3/22) which were very close together: (1) wear metals for similar OCI dropped in half, (2) oil viscosity held up better for VR1. (1) might be because break-in is still happening, though after 8k miles I'm not so sure. Regardless the two UOAs were very close together so I would have expected the influence from break-in still happening to be minimal. However, (2) seems unlikely to be caused by the engine breaking-in. However, as I mentioned after over 8k miles I'd expect the engine to have pretty much broken in, so I'm not quite sure why you say break-in is clearly still happening. These weren't easy miles either, a significant amount were driven on the track in high RPM and high engine stress situation.
Break-in typically takes a lot longer than 8,000 miles, my SRT is still breaking-in, as evidenced by my recent UOA. Our truck is now probably broken-in, as it seems to have settled down to what's pretty normal for that engine.

And that's what used oil analysis is about, finding out what's normal for your equipment, and then tracking for deviations. An engine that is still in the break-in phase will naturally show a trend-down tendency as the miles accrue and eventually, those numbers will settle. Of course the tool is also not supposed to be used to contrast different oils with each other in this manner. It takes hundreds of thousands of miles and hundreds of samples statistically analyzed as @dnewton3 has posted recently. Though I appreciate tear-down analysis isn't a practical proposition, despite being the correct tool for the job.

We should be careful about drawing conclusions about viscosity without looking at the virgin viscosities. The Mobil oil starts out 2.5cSt thinner than the Valvoline at 18cSt vs 20.5cSt. So, all of these results are in the context of that difference.

An example, if I use a viscosity calculator and put in 18cSt as the starting visc for M1 15W-50 and then put in 1.37% of 0.5cSt fuel, the resultant viscosity is 17. Of course a viscosity calculator doesn't work properly on dissimilar fluids, but it should give an idea here. If I bump that to 2.53% fuel, I get 16.2cSt.

So, deviation from calculated:
1. 1.37% fuel: 4.3% visc loss (17cSt vs 16.3cSt actual)
2. 2.53% fuel: 4.5% visc loss (16.2cSt vs 15.5cSt actual)

Now, let's do it for VR1. I put in 20.5cSt as the starting visc, then put in 2.36% of 0.5cSt fuel, the resultant viscosity is 18.48. I bump that to 1.84% and its 18.9cSt. Bump it to 2.43% and it's 18.42.

deviation from calculated:
1. 2.36% fuel: 10.0% visc loss (18.48cSt vs 16.8cSt actual)
2. 1.84% fuel: 11.8% visc loss (18.9cSt vs 16.9cSt actual)
3. 2.43% fuel: 12.3% visc loss (18.42 vs 16.4cSt actual)

I have a thread on this imperfect method of determining visc loss from fuel dilution here:

But the takeaway here is that even if the visc loss for fuel isn't perfect, the deviation, applied universally here, still gives us a useful result.

If we add one more set of calculations here:
M1 at 2.53% fuel is a deviation from virgin (18.0cSt vs 15.5cSt) of 16%
VR at 2.43% fuel is a deviation from virgin (20.5cSt vs 16.4cSt) of 25%

So, overall, the Valvoline oil has actually experienced higher viscosity loss than the Mobil. The problem is that the virgin viscosity isn't being taken into consideration when looking at the results.
 
The virgin viscosity you mention is the spec given, however to do a proper comparison I would need to send in VOA from my unused oil to get what the measured viscosity is. Even if the VR1 sheared more than the M1 as a percentage, all I care in this case is that it held a higher viscosity. I'm not looking to find the oil that shears the least. I'm looking to find the one that holds the highest viscosity in my use case, which might not be the same as the one that shears the least. VR1

As for the fuel dilution, I will change my sampling procedure to only sample when the oil temp can get above 212F or so. Right now my oil is around 185F on the street and won't climb any higher. I'm suspecting is that it's not boiling off the volatile fuel components right before I sample. If I can sample at a higher temp I'm hoping the fuel dilution will drop in all my samples. The only oil sample taken at a high oil temp (i.e. 240F) was 7/29/22.

As for finding what's normal for my equipment, the engine will probably get rebuilt before the numbers settle down. As long as the numbers keep going down, I don't mind playing around with different oils. The next non-UOA parameter I'm looking to address next is the hot oil min pressure at idle I see when coming off the track. I'll try different oils to see which one holds the most (probably the thickest one), while not increasing wear numbers. I understand that my use case for oil analysis might be different than others. However, I still think I can get actionable data.
 
The virgin viscosity you mention is the spec given, however to do a proper comparison I would need to send in VOA from my unused oil to get what the measured viscosity is. Even if the VR1 sheared more than the M1 as a percentage, all I care in this case is that it held a higher viscosity. I'm not looking to find the oil that shears the least. I'm looking to find the one that holds the highest viscosity in my use case, which might not be the same as the one that shears the least. VR1
Yeah, if all you are looking for is to keep the oil above 16cSt or something then starting with a heavier oil is going to make that more likely. The Mobil product starts considerably thinner, so it's not surprising that it ended up with the lower viscosity of the two, despite actually experiencing less shear.
As for the fuel dilution, I will change my sampling procedure to only sample when the oil temp can get above 212F or so. Right now my oil is around 185F on the street and won't climb any higher. I'm suspecting is that it's not boiling off the volatile fuel components right before I sample. If I can sample at a higher temp I'm hoping the fuel dilution will drop in all my samples. The only oil sample taken at a high oil temp (i.e. 240F) was 7/29/22.
Sounds like a good move.
As for finding what's normal for my equipment, the engine will probably get rebuilt before the numbers settle down. As long as the numbers keep going down, I don't mind playing around with different oils. The next non-UOA parameter I'm looking to address next is the hot oil min pressure at idle I see when coming off the track. I'll try different oils to see which one holds the most (probably the thickest one), while not increasing wear numbers. I understand that my use case for oil analysis might be different than others. However, I still think I can get actionable data.
Absolutely, you can get some useful information here about how things are looking and if something is starting to go sideways for sure.
 
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