If it did happen, that is only one of many significant factors affecting fuel consumption. All of which cause more difference than the oil.
In this case the fuel economy difference is miniscule and deep in the noise of everyday driving.
HPL SAE 40 PCMO
- Thread starter Hohn
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In this case the fuel economy difference is miniscule and deep in the noise of everyday driving.
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Or use mPAO as VM … ?
The Valvoline Restore and Protect data point of 29.0 was January through Aug last year, so it also has a lot of summer fuel in that run.
If the other oils were used in temps below 32°F or lower and this one is used in temps. above or even in the 40s - that makes a big difference regarding the air-fuel mixture at start up and during driving too.
My MPG goes down with 3-4 miles during the winter with same oil and everything else.
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didnt u get exiled from this thread by two other people pages ago?
No, why should I? I wrote two pages ago.
I post on here because I see comparison between different oil viscosities but want to make sure their working conditions were the same. And if they are not - then the comparison is compromised. Isn't in?
Looks like in my area, the refineries do not switch until may 1st and the stations aren’t required to switch over until a June 1st deadline.
So, I’m still very much on winter fuel, or “standard” fuel since the summer blend only runs from June 1 through September 15th.
When I lived in the Midwest it was changed in May.
As tiresome as I find the relentless faultfinding and argumentation of some users I generally ignore, I will mention again that the 15w-40 was run from September last year though Feb this year-- entirely on normal blend fuels. I think that one almost irrefutable takeaway is therefore that the 15w-40 HPL lost essentially zero MPG relative to the Valvoline Valvoline Restore and Protect 5w-30. The HPL has the disadvantage of never any summer fuel and significantly more cold weather operation. And yet the 0.2 mpg difference over a lengthy 4400+ mile interval is essentially statistically indistinguishable from the 5w-30.
How many BITOG users would agree with the assertion that you could use a 15w-40 in place of 5w-30 over a winter and lose essentially no MPG over the 5w-30 that had the benefit of summer fuel? But that's what my data is strongly suggesting. The magnitude of mpg loss from the HPL 15w-40-- if it even exists-- it too small to measure.
Only the Valvoline Restore and Protect 5w-30 has benefited at all from any summer fuel.
Regression to the mean is a thing. Drive something long enough and the differences in fuel, climate, and even duty cycle do not matter.
The point here is that the regression to the mean of ~29mpg *should* have reasonably taken much longer with SAE 40 since the car is using the same fuels in the same duty cycle with the same driver using the same techniques on literally the same exact tires.
I collect and review engineering data for a living. I feel like I know the difference between anecdotes like butt dynos and real actual data. (Hence why I'm building a smarter oil temperature and pressure gauge to get better data). After doing it a couple decades, I have a pretty good feel for how data sets evolve.
Which is why I say that when the first half tank was at 23mpg immediately after the SAE 40 fill, it is quite noteworthy that in only a couple hundred miles the *average* has already risen to the long term average associated with the other oils over their runs. If the true average on SAE 40 was merely equal to the others, the moving average of the SAE 40 would only asymptotically approach the averages of the prior oils.
In order for the SAE 40 to raise it's mpg-for-oci average so quickly to that of the other oils, it simply must have a much higher short run average. Indeed, the first complete tank on SAE 40 ended up at almost 31. I filled up on the way home from work last night, so I have another tank of data in progress.
Granted, it's only one tank but it is indeed representative of my car usage of 35min highway commutes M-W followed by errand running in evenings and weekends.
The data might ultimately support the statement that the monograde raises fuel economy. But all I'm contending at this point is that there's almost certainly no loss-- consistent with the 15w-40 showing that the 40 grade HPL cost me no MPG over the lighter Valvoline Restore and Protect predecessor.
Yeah the oil is so minor here.
It’s not the oil.
Folks, please keep the comments positive and not snide. Thanks.
I suspect many BITOGers will remember Louis Lapointe, who was an advocate of adding acetone to gasoline. This was a hot topic for a lot of us mileage nerds around 25 years ago.
Mr Lapointe had a website, I think called Bright Green, in which he posted a variety of articles he'd written, mostly about improving the efficiency of gasoline engines.
Anyway, I don't want to go too far down the acetone-in-fuel rabbit hole, but was reminded that Mr Lapointe also advocated strongly for thick motor oil, claiming it reduced friction to the point where the vehicle actually used less fuel.
As I recall, he referred to 5W-20 oils as "grinding compound".
In the summer of 2001 I ran Mobil 1 20W-50 in our 1990 Mazda MPV 2.6 5-MT. We did a long family holiday, camping across western Canada, and on one leg recorded the best-ever mileage 35.0 MPG (Imperial) I had seen in the five years we had owned the van. That was a bit of an outlier, but as I recall we did rack up better than 30 MPG (Imperial) overall, which was really good.
I know, one data point, perhaps the prevailing winds were unusually favourable, etc.
However, I felt reasonably sure the thicker oil did not hurt the mileage.
So, from personal experience, I am not skeptical about your good results with 15W-40 oil.
But on the other hand, I'm sure that if thicker oil did give consistently better results, the auto manufacturers would specify it.
Count me confused. Looking forward to seeing further data from you!
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Man, you dug deep for that one!
As I recall, he advocated Torco 20w-50 and tested his theories in a Dodge Neon with the 2.0.
In my case, the improvement with SAE 40 is mere curiousity until I get more miles on it. But I’m 500 miles plus into a representative duty cycle and the OCI average is still (slowly) climbing with everything the same as before, at least as near as I can make it.
I’d love it if somehow the better MPG showed up as lower dilution too, although I see no mechanism how the SAE 40 could possibly reduce dilution relative to the 15w-40. I’ve always felt that in these TGDI cars, the oil itself is powerless to influence dilution rate; it can only manage the consequences of that dilution.
I have a lot of brain sludge. These things stick with me.
I have a vague memory of the Torco oil; he was also big on Schaeffer, wasn't he?
He also advocated pre-heating the fuel pre-combustion (that is, heating the fuel before it entered the engine) so it would vaporize better. His method was to splice an aluminum cylinder into the fuel line and clamp the cylinder to a rad hose. The theory was that heat from the coolant would be transferred to the fuel.
The rationale was that hotter inputs meant less differential between the inputs (the air-fuel mixture) and the outputs (the exhaust).
Less heat differential meant higher thermal efficiency. (This seemed dubious to me, but the old heat stoves of carburetor days did feed pre-warmed air off the exhaust manifold into the carburetor, so maybe there was something to it.)
Mr Lapointe was also highly opposed to the use of ethanol as a fuel additive. Rather than citing the lower BTUs per unit volume, he focused on the different stoichiometry, with pure gasoline burning at 14.7:1, and ethanol being closer to 13:1, with the mixture being wrong for the O2 sensor.
The acetone was supposed to counteract the ethanol to some extent.
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Some years ago I attempted to do some controlled testing to see whether acetone helped.
I did about five runs through a 10 km odometer test section, added a bit of acetone, and did another five runs.
I tried to keep the speed constant (no cruise control), and of course reset the ScanGauge at the beginning of each run.
The acetone runs showed an average decrease in fuel consumption of 7%.
I am not highly confident in these results, though, or I would still be adding it.
Doing some searching, I found info that says that fuel dilution of a multi-viscosity oil can affect the VIIs and therefore result in less viscosity at operating temperature and under shear compared to an oil with no VIIs. Basically that fuel dilution reduces the effectiveness of the VIIs at operating temperature. Since the straight 40 grade doesn't have VIIs, then it should do better from fuel dilution than a multi-grade 15W-40.
Right. I expect it fully to be more robust to dilution.
But it can’t *reduce* dilution.
I agree with the comparison b/w 5W-30 in the summer and 15W-40 in the winter. The lack of any difference in the MGP is remarkable. I'm not familiar with water vs summer gasoline. I never knew there is a difference b/w the two. Just read today that winter gasoline is more volatile to make starting in low temp. easier, which means evaporates quicker than summer gasoline. So I wasn't talking about different fuels.
I was trying to say that 15W-40 was run through the winter when the fuel consumption goes higher, not because the oil viscosity but just because the car ECU run more fuel at start up and during driving for longer periods of time (because the engine needs longer time to warm up compared to summer time) to compensate for the higher amount of oxygen in the air in the cold winter air. For that reason peoples MPG always gets worse in the winter even if they use the same oil viscosity all-year-round. Matter of fact the cars' HP increase in the winter because the air/gasoline volume entering the cylinders is larger than in the summer. The air volume is the same but contains higher oxygen which the ECU tries to balance with more gasoline, so the total air/fuel mixture volume is higher.
The thing I was trying to say is that SAE 40 has the same MPG at 40s and 50s degrees Fahrenheit as 15W-40 had at 20 and 15 degrees during the winter where fuel consumption is much higher not because the oil viscosity but because the ECU needs more gasoline to balance the higher oxygen level in the cold air and at the same time run those richer mixtures for longer periods of time (explained above). I understand that is not recommended and is not healthy for the engine to run SAE 40 below 32°F. So, more accurate comparison between the two 40 grade oils would be to run 15W-40 again (right after SAE 40) in late summer or early fall when the temps would be similar to those now in the spring.
Thanks for the link, I'll definitely read it. That looks like an interesting device.
"Winter blend" gasoline typically adds 10% ethyl alcohol which gives the fuel less energy (around 3-4% less) when it combusts in the cylinder. So it takes more fuel flow (meaning a bit more throttle opening) to get the same level of energy on the pistons for engine power output. Some areas use winter blend all year long because it supposedly reduces emissions.
Only if you're driving around at wide open throttle. With less than WOT, it would take a hair less throttle to make the same output power if the air was denser, and the amount of fuel injected would be less too with less throttle because the ECU is always trying to hit the ideal stoichiometric A/F ratio.
