Has anyone used 0W30? I found this on sale at Target for $2.80/quart vs. 5W30 @ $3.85/quart. And supposedly it delivers the best fuel economy and its cheaper. It also exceeds API SL and ILSAC GF-3.
As a general rule, the bigger the spread between the upper and lower viscosity numbers...the more additives are in the oil to achieve the lower number. Unless you live in Antarctica, 0W-30 is not necessary. All things being equal, the best oil is straight 30 weight but it's performance when cold is marginal. 10W-30 is probably the best compromise. I don't consider fuel economy when selecting oil.
Originally posted by VettTheRipper As a general rule, the bigger the spread between the upper and lower viscosity numbers...the more additives are in the oil to achieve the lower number. Unless you live in Antarctica, 0W-30 is not necessary. All things being equal, the best oil is straight 30 weight but it's performance when cold is marginal. 10W-30 is probably the best compromise. I don't consider fuel economy when selecting oil.
Very true. But the reason for the better fuel economy is that it takes less power to move the thinner oil around. With thinner oils there is less power lost to oil windage and pumping. Your car will dyno with a few more ponies running 5W-30 than it will running 10W-30.
That said, I'm not going to switch to an even lighter oil. It won't surprise me though if GM does switch to 0W-30 in the future. There will be an oil pressure drop when using a lighter oil, so the manufacturers may need to increase pressure.
I have also noticed 0W-20 oils cropping up for cars like the Honda Insight.
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I only use the Mobil 1 0W-30 for Winter storage.
I use the Mobil 1 5 W-30 for early Spring and late Fall when the morning temps are in high 30's/low 40's.
I use the Mobil 1 10W-30 for Summer street use when morning temps are above 55 degrees
I use the Mobil 1 15W-50 for racing only.
Originally posted by pmontelo Your car will dyno with a few more ponies running 5W-30 than it will running 10W-30.
OK educate me.... I thought that once the oil was up to operating temp, the oil was at it's rated viscosity of 30 regardless of what the lower number is. I can see how fuel mileage may be better on a cold engine with the lighter grades but once hot are they all not the same?
Ripper, multi-vis oils work the other way around. It's actually a 5 weight (5W) base oil in 5W-30, not a 30 weight base oil. It used to confuse me too.
Multi viscosity oils work like this: Polymers are added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.
Originally posted by pmontelo Ripper, multi-vis oils work the other way around. It's actually a 5 weight (5W) base oil in 5W-30, not a 30 weight base oil. It used to confuse me too.
Multi viscosity oils work like this: Polymers are added to a light base (5W, 10W, 20W), which prevent the oil from thinning as much as it warms up. At cold temperatures the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot.
I'm not going to switch to an even lighter oil. It won't surprise me though if GM does switch to 0W-30 in the future. There will be an oil pressure drop when using a lighter oil, so the manufacturers may need to increase pressure.
The oil pressure drop will only be when the oil is cold. As discussed earlier in this thread, at 100 dec C any oil with a Xw-30 viscosity rating will have the same viscosity. Oil pressure is solely a function of the oils viscosity in the same engine at the same RPMs. Therefore, a 0w-30, 5w-30 and 10w-30 oil will all have the same oil pressure when hot because all are equivelant to a 30 weight oil at 100 deg C.
Of course the oil pressure will be alittle lower when cold with 0W-30 as opposed to 10W-30 oil because the cold viscosity ratings are different at the same temperature (0 deg C).
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Originally posted by ZeeOhSix Oil pressure is solely a function of the oils viscosity in the same engine at the same RPMs.
Yes.
Quote:
Originally posted by ZeeOhSix Therefore, a 0w-30, 5w-30 and 10w-30 oil will all have the same oil pressure when hot because all are equivelant to a 30 weight oil at 100 deg C.
I agree with the reasoning you present here. But I assume there are viscosity differences across the *entire* operating temperature range, not just when cold. Normally I get all the way to work (18.2 miles) before my oil temps will even hit 200 deg F. So looking at only 100 deg C or 212 deg F shouldn't be the only data point.
Good discussion. I'll be the first to admit that I am constantly confused by different descriptions of what the second number in a multi-vis oil means. The "More Than You Ever Wanted to Know About Motor Oil" link I refer to above states in plain english that "Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot". It *doesn't* say the 20W-50 and 50W are the same viscosity when hot, but I guess it seems to imply that they are in the same range.
I guess the bottom line is that the oil's viscosity properties will vary not only by grade and temperature, but by formulation (and manufacturer). So it's probably best to throw out theory and look at the actual manufacturers specifications when available.
Surprisingly it looks like the new 0W-30 is actually slightly thicker than 5W-30 @ both 40 deg C and 100 deg C while it's pumpability limit is 4 deg C colder. And that 10W-30 is substantially thicker than 5W-30 at 40 deg C and ever so slightly thicker @ 100 deg C.
So it seems like 5W-30 is the "luke warm to fully warmed oil horepower winner" for Mobil 1.
Your mileage and horepower gain or loss may vary in many, many ways
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oils cropping up for cars like the Honda Insight.
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