What's the HTHS on that oil?
New Ravenol Ultra Fuel Economy 0W-8
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AEhaas long 1000 word posts which push his narrative on how thin oil protects better leaves out 1 important fact: Lower HTHS oil gives exponentially higher engine wear, once the 20 weight sheers down way below HTHS 2.6 which happens during a normal oil change interval.
The other argument AEhaas gave is that thinner oil flow better at first startup.
But a 5W-20 and 5W-30 oil have identical viscosities at cold startup, so no advantage to the 5W-20.
But if 2018 Toyota Camry's using 0W-16 and 10k oil change intervals reach 200,000 miles with little to no engine wear, I will admit I'm wrong.
Lets see how Toyota's 0W-16 gamble plays out.
The other argument AEhaas gave is that thinner oil flow better at first startup.
But a 5W-20 and 5W-30 oil have identical viscosities at cold startup, so no advantage to the 5W-20.
But if 2018 Toyota Camry's using 0W-16 and 10k oil change intervals reach 200,000 miles with little to no engine wear, I will admit I'm wrong.
Lets see how Toyota's 0W-16 gamble plays out.
Yep, that's all been discussed and shown a hundred times on this site, but seems most people for some reason don't believe the data.
Lots of stuff wrong in those fantasy write-ups, and probably responsible for misleading a lot of people on oil and tribology.
Especially since HTHS has been proven to have much more impact (positive or negative) on wear than KV100.
Picking an oil based solely on KV100 is like picking a cake icing based on the color, not the taste.
The only problem with HTHS is that many oil companies keep it secret.
For example, the Pennzoil Platinum High Mileage 5W-30 oil that I like to use only lists a KV 11.4 @100C, but it doesn't list a HTHS spec.
So I estimate HTHS for it to be 3.1 or 3.2, but wish there was a mathematical formula for converting KV @ 100C to predicting HTHS @ 150C.
I've also used Castrol 5W-30 A3/B4 European formula, which is HTHS=3.5 (3.5 is ideal for lowest engine wear), but unfortunately there is no high mileage version of that Castrol 5W-30 A3/B4 European formula oil which treats engine seals to minimize oil leaks. I was looking for an oil additive which could turn a regular oil into a high mileage oil, but could't find such an additive. All I saw was the super aggressive additives like BAR Leaks, etc which could do more harm than good.
Its 1.15% that puts them that much closer to their cafe requirements without having to do anything else. They will go 0w-4 from the factory if they can get it to last through the warranty period.
Valvoline does sell Maxlife 5W-30 in A3/B4 flavor in Europe.
A 1.15% increase in fuel economy and a 1000% increase in engine wear.
That 0W-8 likely has the same 4 cSt PAO base oil as the 0W-16 (and 0W-20) just without the VII. Throw in some POE and AN and you can have a pretty stout oil when it comes down to the actual dynamic viscosity under load.
OEM SBF timing chains weren't exactly known for their longevity. You could run the stoutest 20W-50 oil and the chain would still be stretched and cam 4 degrees out of time at 100k miles. Excessive timing chain wear in those engines is just a fact of life. If anything, the quality of the oil likely has a bigger impact than the viscosity.
If the idea of a 0W-16, 0W-12, or 0W-8 oil is unsettling, then pour in whatever 5W-30 is on sale and drive on. Nobody has a gun to anyone's head and forcing them to use it.
If the thickies want to see how well low viscosity oils can hold up to extreme conditions, look at NASCAR. They run small crank journals with tight bearing clearances and a 0W-5 oil for qualifying and 0W-16 oil on race day. At sustained 7500-8500 rpm around Daytona, the sump temp is 280-290°F with oil temps of 350-360°F at bearing exit. They run 2 races on one engine. At teardown, the bearings, timing chain, cam lobes and lifters, valve tips, pushrods, rings, etc... usually look as new as when it was assembled.
A cup engine has a BMEP of ~230 psi, and the 0W-16 they use is less stout that common API 0W-16 in terms of dynamic viscosity and film thickness as they favor power from reduced hydrodynamic friction over longevity. Despite this, the wear rates are very low. A 4 cylinder with a BMEP <180 psi, far less rpm, 100°F lower oil temp, and much less WOT time will be just fine.
OEM SBF timing chains weren't exactly known for their longevity. You could run the stoutest 20W-50 oil and the chain would still be stretched and cam 4 degrees out of time at 100k miles. Excessive timing chain wear in those engines is just a fact of life. If anything, the quality of the oil likely has a bigger impact than the viscosity.
If the idea of a 0W-16, 0W-12, or 0W-8 oil is unsettling, then pour in whatever 5W-30 is on sale and drive on. Nobody has a gun to anyone's head and forcing them to use it.
If the thickies want to see how well low viscosity oils can hold up to extreme conditions, look at NASCAR. They run small crank journals with tight bearing clearances and a 0W-5 oil for qualifying and 0W-16 oil on race day. At sustained 7500-8500 rpm around Daytona, the sump temp is 280-290°F with oil temps of 350-360°F at bearing exit. They run 2 races on one engine. At teardown, the bearings, timing chain, cam lobes and lifters, valve tips, pushrods, rings, etc... usually look as new as when it was assembled.
A cup engine has a BMEP of ~230 psi, and the 0W-16 they use is less stout that common API 0W-16 in terms of dynamic viscosity and film thickness as they favor power from reduced hydrodynamic friction over longevity. Despite this, the wear rates are very low. A 4 cylinder with a BMEP <180 psi, far less rpm, 100°F lower oil temp, and much less WOT time will be just fine.
In a 14 MPG truck that adds up to, hmmm, carry the 1, and uh, 14.15.
So, small enough that it’s measurement error. I get more effect on MPG from things like air temperature, traffic conditions, and tire inflation.
Perhaps it’s significant across large fleets, or the entire motor vehicle operation of a nation, but for the individual user?
Statistical noise.
1.929
The engines that 0W-8 would apply to would be small displacement 4 cylinder engines, usually hybrids, that are getting 50 mpg or even better. It's a 0.5 mpg difference then. Still not substantial and well within a margin of error, but it's one of those things than can be accumulative if you're really chasing every bit of fuel economy. Brake drag, tire rolling resistance, bearing grease, etc... all can add up to something measurable and part of routine maintenance.
Very interesting. Sustained 7500-8500 RPM with oil temperatures at 350°F-360°F on a 0W-16 is frightening. If you've ever poured 0W-16 oil into a funnel, it pours just like thin water. The metal on metal contact must be continuous and severe, with severe engine damage. I know you mentioned the wear rates are very low. Would be interesting if there was a youtube video showing the teardown after the 2 races on 0W-16.
If I owned that race car, I would use a 20W-50 synthetic (Perhaps Redline brand), and change the oil in between the 2 races, so that no teardown would be needed at all. Then maybe after 500 races, would consider a tear down just to see how perfect the engine still is.
Keep in mind the 1.15% improved economy over a 16 grade. Let's call it 1.5% over a 20 grade.
So if you spend $400 a month on fuel, you're saving about $72 a year, which I don't think I would call a rounding error. That's more than a full tank for most vehicles, just from using different oil.
So if you spend $400 a month on fuel, you're saving about $72 a year, which I don't think I would call a rounding error. That's more than a full tank for most vehicles, just from using different oil.
If they used Red Line 20W-50, the engine likely wouldn't survive the race. The hydrodynamic friction with the 0W-16 already contributes a 75°F temp rise across the bearing. The temp rise through the bearing (in those engines) is ~10°F for every 0.6 cP increase in HTHS. Their oil is ~2.3 cP and Red Line HP 20W-50 is 6.1 cP. The bearings would likely give way to fatigue from the friction and heat, that's if you can still get sufficient oil flow. They run way too tight of bearing clearance to run a 50 grade oil.
$72/year is $6/mo. Assuming it has the exact same protection properties as the 0W-20 and doesn't cause any extra maintenance issues, then yes, it's "worth it." But the second it has worse protection properties or causes extra maintenance issues, then no, it's not worth it.
But when you need a $10,000 new engine after it wears out after 100,000 miles on 0W-8, those $72 a year savings won't cover it.
Also, all the top off oil you would need to add due to the increased engine wear/oil consumption could use up the $72 a year.
But seriously, I honestly would feel very uneasy if I ever had to use a 20 weight or 16 weight or 8 weight oil.
Using any viscosity less than a thick 30 weight is like buying a beautiful $3,000 wood dining room table to seat 8 people, and then never use place mats, so it gets badly scratched up after the first few months. Whenever I've got 8 people in my minivan with the Air Conditioning on and we're going up some steep mountain hill with RPM's rising above 3k, I feel like I've done everything I can to protect my engine and should have 0 wear at the end of that trip. But if I had 0W-16 instead, I'd be worried that we just damaged the engine during that high engine temperature / high RPM trip.
A perfect scientific experiment is easy to monitor for the "thick versus thin" debate.
Toyota switched nearly all their new cars to 0W-16 with 10k oil change intervals.
I plan to monitor the toyota nation forum over the next decade to see what happens
after those cars get high mileage. I predict massive class action lawsuits against Toyota from owners saying
their cars should at least be able to make it to 100k miles.
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