I was thinking about switching to 0-20 Full Synthetic on my next oil chg ,anyone have feedback ?

 

If you have a new car you already using 0w20. I personally dont see a big difference. 2 percent tops.

 

I'd be shocked if the extra cost of the 0w-20 equals the gas savings.

 

I haven't noticed a significant improvement in my fuel economy maybe .5 to 1 mpg but I got a case of idemitsu Honda 0w20 shipped to my house for like $60 so for around $5 a quart it's worth it for a quality synthetic. An oil change that I do myself is around $23 compared to the $50 or $60 it is at the dealership.

 

WallyWorld here has all Mobil 1 viscosities at the same price.

Just for fun tho if your Fit got 30 mpg with 5-30W and 30.6 mpg (2%) with 0-20W and you drive 5000 miles between oil changes the savings is 3.3 gallons, or $11.88 for $3.60 gas. Mobil 1 just increased from $24 to $27 fr the 5 quart container.
So when the politicians beam at the 8% increase in sales you'll know the increase was only for increased prices, not because more was sold.

 

You really shouldn't see any improvement since the 0w and the 5w in their respective oils represents cold viscosity. Once you are at operating temperatures both oils are pretty identical with a viscosity of 20w. The friction should be the same, most of the time after you start your engines.

 

well, depends on if you actually follow the maintenance minder and go the estimated 12k miles before changing the oil.
If you were changing at 3k or 5k intervals, then there's bigger money to be saved by changing your oil change intervals.

Have you checked the latest prices on motor oil? The extra
cost of 0w-20 is minuscule now; whereas gas has gone up. If savings are 1%, over 12,000miles, that means 120extra miles, which is 4gallons of gas.


Einstein you are right with your facts but wrong on your conclusion.
The improvement that mobil1 states only comes from the startup period. How many time do you drive per session? How many minutes of that is in cold period where the oil could save some fuel. How much fuel is saved during the cold period? Of all those calculations, Mobil1 still makes the modest claims of up to 2%, not a huge amount. That's best case, so realistically expect half of that or less (1% or less).
Cars are relatively efficient now, there is no simple change that yields big multi-digit improvement.

Do you alternatively think you could've changed your driving habits to save 1% another way? One less set of errands for example could completely make more of a difference.

 

The difference between 20 and 30 weight viscosity is noticeable and the effort to push the thicker 30 weight oil thru the holes and slots in an engineis noticeable. Its not friction but the power it takes for the oil pump to force the oil thru those tiny holes and slits that create the change in mpg. After confering with some old cohorts the 2% estimate between 20 and 30 weight is not bad.Once warmed up the 20 or 30 weight oil is the oil being used.

 

Given that the fit only came with 5w-20 and 0w-20, I'm not sure the 20 to 30 comparison matters.

I did switch my wife's 04 accord to 0w-20 from 5w-20, but she doesn't keep good enough records to notice an improvement of a few percent. That said, I didn't do it for fuel economy, but because her work parking is directly adjacent to the interstate and several interchanges, so she's driving a cold engine with several heavy accelerations.

 

I switched to synthetic at my first oil change (approx 7,000mi) during the first 7,000mi i seemed to average around 38-39mpg.. I now have about 26,000mi, and I average 40-42mpg.. but I have no idea if my better mileage is due to the oil or the engine being broken in nicely.. regardless I now change my Synthetic oil every 10,000mi.

 

Not likely to give anything extra. 5W-20 synthetic had a negligible impact over dino oil. 0w unlikely to do anything.

 

Again, what is negligible? 2%? 1%? .5%? With the long change interval, relatively low increase in oil price, and high gas price, then even this fraction of a % increase is NOT negligible but significant.

When talking about fuel economy you add up all these fractions from this any any other improvements/maintenance and suddenly you're a couple percent and you've got something you can see.

But at the same time you're correct and on the point that there is not enough precision to be able to measure this in your regular car. So it's not easily observable, but it's not negligible.

 

you kinda misread the post, it's the 0w versus 5w number that is in question. both are 20weight oils.

 

0w20 is great if you only drive short distances at relatively low speeds in stop and go traffic.. Starting and driving 10 miles or more before shutting the engine down you would be better off using oil with higher viscosity... I think a higher viscosity oil is the only way to go during the summer months if you are trying to keep up with traffic.

 

We're not talking about the difference between 20w and 30w oil. We're talking about the change from the recommended 5w-20w to the 0w-20w. After five minutes of warm up they are identical in nature and viscosity. There will be no difference in friction after warm up which is 99% of driving. There will be a slight difference between 20w and 30w, but Honda Fits have never had a recommendation of a 30w oil.

 

I think you may have overestimated by saying 99%. That means saying your car warms up in 1min and you drive 99minutes. Or for your 5min of warmup, you're driving 495minutes. I'd estimate more like 95% maybe more realistic.

There is a point though that 0w-20 versus 5w-20 "technically" should be the same, but realistically 0w-20 will be on the lower edge of the 20 range, especially as it begins to wear in.


Again, single digit percentages and fractions of percents count when talking about mpg.

 

[QUOTE=raytseng;1065045 I'd estimate more like 95% maybe more realistic.

[/QUOTE]
So what you are saying is that a car stays completely cold for 5 % from start-up and then instantly gets to operating temperature after that time? It doesn't work that way. As for top rating of 20w, that is a lab specification from actual testing... there will be no appreciable difference. Certainly not even a .1%.

 

An now we have an oil thread...
For the 5% I'd agree with you it isn't a step function but a slope, but I'd clarify that the 5% of the time is the startup period where there is a temperature difference. Then you'll need to apply a different formula of how much difference the oil applies during that period where there is the temperature difference.

So while you got that things aren't step functions in real-world nature, this applies to the oils as well. 20 oils don't just step up to to 30 oils, there's a whole range of viscosities.
As far as your comment that they are .1% of each other, this depends on what scale you're measuring against. If you're measuring viscosity against like tar, then all motor oils, are pretty close in viscosity to each other.

If you're measuring 20 versus 30 for example, then the oils are ranged and come up to each other, they are not distinct points within a range.

The spec is saej300, here is one site that puts it into a table:
http://www.tribology-abc.com/abc/viscosity.htm
Notice that for high temperatures
20 goes from 5.6 to 9.3
30 goes from 9.3 to 12.5

So taking this chart, a "thick" 20 oil could be closer to a "thin" 30oil than to it's thin "20" oil brother.

I'll still agree with you that out of the bottle maybe both 5w and 0w oils should be pretty close but there are definitely potential for variance, and I'd suspect out of the bottle the 0w will be *slightly* lower than it's 5w brother (not sure).

I'd like to clarify my other point too that even if you had the exact same viscosity out of the bottle fresh, as the additives wear out and the oil gets really used, you end up something in between the multigrade. I claim that when this wearout happens the 0w will shift lower then the 5w, as more additive modifiers to achieve the bigger multigrade jump. Usually this happens when you exceed the suggested change interval, but can happen sooner.

I suggest take this discussion over to bitog if you disagree or want to adjudicate with "expert" oil people more.

But circling back to the original question, if you're talking about MPG affects, then the percentage there will be as mobil1 states somewhere between 0-2%. I'd guess 1% is more realistic.
Whether you consider this difference "negligible" or "non appreciable" are subjective adjectives that you have to decide for yourself.

 

I noticed an improvement...it wasn't drastic but it was an improvement

 

In theory, you should be getting improved gas mileage by UP TO 2%, it'll be undetectable at best in normal driving conditions. Maybe if we did a controlled test with the car driving in the exact same conditions. It will not improve your gas mileage by anything detectable as someone stated going from the 30's mpg to reaching 40mpg, just physically impossible.

Do it cause you want to use a good oil. I started using Mobil1 0w-20 from my first oil change because I always use synthetics in my car. I'm a ChemE by training and I know it's a waste of money and that dino oil will do just fine but I like doing it, getting the best for my car. Or getting the best within reason, I don't mind paying for the 5Q jug at Walmart for the 0W-20 but I wouldn't buy Amsoil at double the price..haha.. Let's face it, you just change the oil when the MM tells you with anything, the engine will outlast the rest of the car, unless you're unlucky.