Why I Switched to 0W8

As the lighter fractions flash off? Potentially. But the base oils used are insanely light (hence the Noack) so you'd probably just end up with disappearing lube and the potential for significant deposits.
Right, I'd be more worried about what the volatiles are doing elsewhere in the engine than I am about the oil thickening up.
 
As the lighter fractions flash off? Potentially. But the base oils used are insanely light (hence the Noack) so you'd probably just end up with disappearing lube and the potential for significant deposits.
mid 2010s tgmo 0w20 managed to get through with a finished VI in the 200s. it might still be that way?

the honda oil probably would benefit from a gtl or non-hc base
 
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tgmo 0w20 managed to get through with a finished VI in the 200s
Yup, probably a lot of 4cSt Yubase Plus (Noack 13.5%) which has a VI of 136 and a good slug of polymer. The Honda 0w-8 clearly is using something even lighter, like YU-3, which is significantly more volatile.

That's how you get finished VI's that high, very light bases and lots of VII. If you use a heavier PAO base, you don't need much VII, so then the VI of the finished oil won't be anywhere near as high, but the Noack will be lower.

See Formula C, which is straight YU-4 Plus w 7% VII. It has the highest VI, Noack at 12.3%. Add a splash of YU-3 and some more VII and you can get above 200 while kissing the Noack limit:
Screen Shot 2021-09-09 at 11.44.29 AM.jpg
 
Assuming the sump oil temperature on the Pro-Stock cars is at 80C (176F) when they launch down the track, which is probably being generous, then 0W-8 at 80C is the same viscosity as shown below. When looking at viscosity, this is why 0W-8 is used and works for 1/4 mile racing. I'm betting the sump temperature is actually lower than 80C when they launch, probably closer to 50-60C (122-140F) ... call it 55C (131F). Y-axis is viscosity in cSt.

Equal Viscosity Temperatures
0W-8 @ 80C (176F)
0W-16 @ 90C (194F)
0W-20 @ 98C (208F)
5W-30 @ 109C (228F)

1631208732924.jpg



Equal Viscosity Temperatures
0W-8 @ 55C (131F)
0W-16 @ 63C (145F)
0W-20 @ 70C (158F)
5W-30 @ 79C (174F)

1631209784756.jpg
 
Assuming the sump oil temperature on the Pro-Stock cars is at 80C (176F) when they launch down the track, which is probably being generous, then 0W-8 at 80C is the same viscosity as shown below. When looking at viscosity, this is why 0W-8 is used and works for 1/4 mile racing. I'm betting the sump temperature is actually lower than 80C when they launch, probably closer to 50-60C (122-140F) ... call it 55C (131F). Y-axis is viscosity in cSt.

Equal Viscosity Temperatures
0W-8 @ 80C (176F)
0W-16 @ 90C (194F)
0W-20 @ 98C (208F)
5W-30 @ 109C (228F)

View attachment 70444


Equal Viscosity Temperatures
0W-8 @ 55C (131F)
0W-16 @ 63C (145F)
0W-20 @ 70C (158F)
5W-30 @ 79C (174F)

View attachment 70449
How would that 0W8 do in the Daytona 500?
 
Depends on how cool they can keep it with crazy oil coolers. It's all about the viscosity, since viscosity is the main factor that keeps moving parts separated.
My bet is the cooling needed would be more trouble than it's worth.
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My bet is the cooling needed would be more trouble than it's worth.
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Maybe, but whatever oil viscosity they use the oil temperature still needs to be controlled. All race cars (except 1/4 mile cars that instead need oil heaters) are going to need an oil cooler approprate for their race conditions. If the oil can't do it's job, you're going to lose the race for sure.
 
Maybe, but whatever oil viscosity they use the oil temperature still needs to be controlled. All race cars (except 1/4 mile cars that instead need oil heaters) are going to need an oil cooler approprate for their race conditions. If the oil can't do it's job, you're going to lose the race for sure.
True. My point was it would probably take more cooling with the 0W8 than it would with a 0w20 or 5W20 oil to maintain the additional safety margin the 20 grade would have over the 8 grade oil if things got a little iffy. I didn't make that clear.
 
True. My point was it would probably take more cooling with the 0W8 than it would with a 0w20 or 5W20 oil to maintain the additional safety margin the 20 grade would have over the 8 grade oil if things got a little iffy. I didn't make that clear.
Yes, even though 0W-8 would heat up less due to shearing, it would take more cooler to pull enough heat out to get the viscosity down to keep the motor happy. It starts by determining what viscosity is ideal for the race engine (design and tolerances are a factor), then determine what it takes to keep the oil temperature in a safe range to allow the chosen viscosity to work properly. Of course, NASCAR engines are also somewhat "sacrificial" and just need to make it through the race while maintaining adequate power. Who knows what kind of special additives there might also be in race oils so they can mitigate friction and wear better (and keep it from blowing up) if excessive metal-to-metal contact does occur.
 
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I know, they're built for a totally different purpose though, all they have to do is get through the race. Some last a few races, but their lives are not measured in hundreds of thousands of miles.


Very true demarpaint...

One thing of note though... Nascar has not really allowed the teams to push those motors to the max. Gear rules have a while lot to do with that.

Used to be teams could pull any gear they wanted too.... Thus why there were so many motor failures in the 70s, 80s and into the 90s and even in the early 2000s.

Now they have not been really pushing those motors super hard like they did. That's sucks in my opinion. Let them push the envelope and see what can work and what will not work.

Interesting listening to old Nascar races from the 90s and the debate over conventional vs synthetic was a big one. And what viscosity was best to run too. I think some teams at that time were starting to play with 10w30 in their race cars.
 
Even if that number was correct for both oils there is no guarantee the oil would be pumpable nor the engine crank at that temperature. Pour point doesn't correlate properly to that.
True, but the point is it's still a 0W rating and should be pumpable in the most extreme temperatures found on planet earth. Redline CCS viscosity is 5700cP @-35°C, which is better than necessary to qualify as a 0W. If they had a -5W it'd probably qualify.
 
True, but the point is it's still a 0W rating and should be pumpable in the most extreme temperatures found on planet earth. Redline CCS viscosity is 5700cP @-35°C, which is better than necessary to qualify as a 0W. If they had a -5W it'd probably qualify.

If we use the "doubling rule" it wouldn't, it'd be ~11,400cP at -40C ;)
 
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