Thanks all for the learning experience. So would this account for a 1 mpg difference in fuel economy?
Does grade REALLY effect fuel economy???
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Because of getting a bunch of oil essentially free, I am running STRAIGHT 40 WT. in my truck right now. I have not noticed any difference in anything, mpg's included.
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In my experience,none whatsoever. I've run 10W30-25W50,synth and dino and can't tell any difference in fuel economy.
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Originally Posted By: needsducktape
If you really want to to save gas drive less, accelerate softly and don't speed. Keep an eye on tire pressure and wheel alignment.
Changing weights of oil in order to save gas is like being overweight and expecting Diet Coke to solve your problem.
Originally Posted By: needsducktape
If you really want to to save gas drive less, accelerate softly and don't speed. Keep an eye on tire pressure and wheel alignment.
Changing weights of oil in order to save gas is like being overweight and expecting Diet Coke to solve your problem.
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Originally Posted By: MajorCavalry
Thanks all for the learning experience. So would this account for a 1 mpg difference in fuel economy?
Going from an HTHS of 2.6 to 3.6? Yeah, I would say it certainly could.
Thanks all for the learning experience. So would this account for a 1 mpg difference in fuel economy?
Going from an HTHS of 2.6 to 3.6? Yeah, I would say it certainly could.
Well, just because you can't tell a difference doesn't mean one doesn't exist. There will be a reduction in internal engine resistance the lighter you go. The Starburst label represents testing that shows a particular motor oil to be resource conserving.
The counter is also true however, people who claim to be able to detect a 1% difference are nuts IMHO. With all the variables in real-world driving there's no way you are going to detect 1% and prove it was the oil that did it.
Originally Posted By: aquariuscsm
In my experience,none whatsoever. I've run 10W30-25W50,synth and dino and can't tell any difference in fuel economy.
The counter is also true however, people who claim to be able to detect a 1% difference are nuts IMHO. With all the variables in real-world driving there's no way you are going to detect 1% and prove it was the oil that did it.
Originally Posted By: aquariuscsm
In my experience,none whatsoever. I've run 10W30-25W50,synth and dino and can't tell any difference in fuel economy.
I haven't noticed a bit of change using both 5w20 and 5w30. I just use 5w30 in both of my vehicles so I don't have to buy two different weights. It doesn't get cold enough here in the High Desert to worry about in the winter.
Originally Posted By: A_Harman
You've put your finger on the fallacy of fuel-efficient oils. Yes, thinner oils save fuel, but conscientious people such as yourself can't prove it with the low precision of the instruments they have available. To get the API Fuel Conserving stamp, a 5w20 has to demonstrate that it saves 1.2% over a 10w40 reference oil after an aging period of 100 hours. Likewise, a 5w30 has to show a 0.9% improvement over the same 10w40, and a 10w30 has to show 0.6% improvement.
So if you're comparing a 5w20 to a 10w30, you should only expect to see a fuel economy improvement of 0.6%, all other factors being equal. If your car gets 30 mpg on 10w30, then you would expect to see 30.18 mpg with 5w20 if you could control your daily driving routine consistently enough, and measure fuel consumption with laboratory grade instruments. The REAL WORLD being what it is thwarts such attempts at precision outside of a laboratory. Maybe you sit in traffic jams for 30 minutes more on one tank of fuel than the previous, or the weather is warmer, making you run the AC more.
Excellent post...
I can advise that going from an SAE 30 to a 25W-70 created heavy cranking, retarded performance, and heavily impacted the economy of my old J-Car. It was instantly and immediately noticeable.
And it was done purposely to prove to my peers that a 30 was fine in summer, and posted on BITOG at the time that a 25W-70, even in winter didn't cause immediate destruction.
You've put your finger on the fallacy of fuel-efficient oils. Yes, thinner oils save fuel, but conscientious people such as yourself can't prove it with the low precision of the instruments they have available. To get the API Fuel Conserving stamp, a 5w20 has to demonstrate that it saves 1.2% over a 10w40 reference oil after an aging period of 100 hours. Likewise, a 5w30 has to show a 0.9% improvement over the same 10w40, and a 10w30 has to show 0.6% improvement.
So if you're comparing a 5w20 to a 10w30, you should only expect to see a fuel economy improvement of 0.6%, all other factors being equal. If your car gets 30 mpg on 10w30, then you would expect to see 30.18 mpg with 5w20 if you could control your daily driving routine consistently enough, and measure fuel consumption with laboratory grade instruments. The REAL WORLD being what it is thwarts such attempts at precision outside of a laboratory. Maybe you sit in traffic jams for 30 minutes more on one tank of fuel than the previous, or the weather is warmer, making you run the AC more.
Excellent post...
I can advise that going from an SAE 30 to a 25W-70 created heavy cranking, retarded performance, and heavily impacted the economy of my old J-Car. It was instantly and immediately noticeable.
And it was done purposely to prove to my peers that a 30 was fine in summer, and posted on BITOG at the time that a 25W-70, even in winter didn't cause immediate destruction.
Originally Posted By: aquariuscsm
In my experience,none whatsoever. I've run 10W30-25W50,synth and dino and can't tell any difference in fuel economy.
I've experimented in my Lexus V8 and could definitely tell a difference when I ran Mobil 0W-40 vs 0w30 and 0W-20. The car was more lethargic with the 40 weight and a lot less peppy and I lost about 1-2 MPG. I will admit that in regards to the 30 vs the 20 weight I couldn't measure an MPG difference.
In my experience,none whatsoever. I've run 10W30-25W50,synth and dino and can't tell any difference in fuel economy.
I've experimented in my Lexus V8 and could definitely tell a difference when I ran Mobil 0W-40 vs 0w30 and 0W-20. The car was more lethargic with the 40 weight and a lot less peppy and I lost about 1-2 MPG. I will admit that in regards to the 30 vs the 20 weight I couldn't measure an MPG difference.
To demonstrate the vagaries of "real world", here's the early life of my turbodiesel Nissan...
FF was a Nissan 10w30.
Changed Early to Delo CXJ, dino, 15+cst, for two short oil changes.
Mobil 1 0W-40 once past 10,000km.
Castrol EDGE 0W-40, as it was 10% thinner @100C than Mobil 1 (worse average milage, go figure).
Castrol Magnatec SP 5W-40.
Nearly ever fill is at the same station (a few different ones on holidays, but the local Caltex 90+% of the time).
Note up to 15% variance from the OCI average.
FF was a Nissan 10w30.
Changed Early to Delo CXJ, dino, 15+cst, for two short oil changes.
Mobil 1 0W-40 once past 10,000km.
Castrol EDGE 0W-40, as it was 10% thinner @100C than Mobil 1 (worse average milage, go figure).
Castrol Magnatec SP 5W-40.
Nearly ever fill is at the same station (a few different ones on holidays, but the local Caltex 90+% of the time).
Note up to 15% variance from the OCI average.
I think you're right in that you won't see any changes in fuel consumption you'd feel in your pocket between a grade or two lighter or heavier.
I've run much heavier than recommended grades in some of our cars over the years, like Mobil 1 15W-50, Pennzoil Conventional 10w40 and Tection Extra 15w40 in 5w30 applications, and saw no systematic loss in fuel economy.
I am anal retentive enough that I have a log for each car in which I track every fill-up as well as everything else done to the car over its life by date and miles recorded.
I actually got better mileage on the first tank with Mobil 1 15W-50 in the '99 Accord than I had with the last tank using Mobil 1 Advanced Fuel Economy 0w30.
What I'm trying to say is that while lighter oils may offer real benefits in fuel economy, the diference is small enough, among many other variables, that you'll likely never measure it in your use of your cars.
It's a bit of a unicorn.
I've run much heavier than recommended grades in some of our cars over the years, like Mobil 1 15W-50, Pennzoil Conventional 10w40 and Tection Extra 15w40 in 5w30 applications, and saw no systematic loss in fuel economy.
I am anal retentive enough that I have a log for each car in which I track every fill-up as well as everything else done to the car over its life by date and miles recorded.
I actually got better mileage on the first tank with Mobil 1 15W-50 in the '99 Accord than I had with the last tank using Mobil 1 Advanced Fuel Economy 0w30.
What I'm trying to say is that while lighter oils may offer real benefits in fuel economy, the diference is small enough, among many other variables, that you'll likely never measure it in your use of your cars.
It's a bit of a unicorn.
Yeah I though changing from 5w-20 to 5w30 might make a very small hit but the display [Avg MPG] doesn't show it, and to/from work I get on a highway about an hour and set cruse control. I also been checking tire psi weekly. Seem I get a change from one fill up to next (up & down), but the Avg MPH is consistent during the tank of fuel, and other change on same fuel is windy days.
So I changed to the 5w30 for the triple digit summer temps, and planned on switching to 5w-20 for the cooler seasons. Now I don't know - although manufacturer states to use 5w-20 for best fuel economy.
No AC in the morning, and using AC on way home.
So I changed to the 5w30 for the triple digit summer temps, and planned on switching to 5w-20 for the cooler seasons. Now I don't know - although manufacturer states to use 5w-20 for best fuel economy.
No AC in the morning, and using AC on way home.
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My Ion gets exactly the same mileage on the 5-40 Euro as it did on 5-30. My Beetle is consistently better on 5-40 T6 and Mag1 All-Fleet than it ever was on 10-30.
Originally Posted By: Shannow
To demonstrate the vagaries of "real world", here's the early life of my turbodiesel Nissan...
Yes Shannow, that graph quite nicely shows how the "random" variations from one tank to the next can easily outweigh any differences due to the oil choice. Your graph is mainly xw40's, so it's a bit hard to extrapolate to other weights, but there's a about a 3% average variation in the oils you have there.
I find it interesting that the one 15W40 gave you the best fuel economy. Mind you, the VOA of delo posted here recently showed it had massive amounts of Moly and Boron (and Zinc), so perhaps that's the reason.
BTW. What was that last oil you used? The one that's unlabeled, starting from about "85" on your graph. I want to give that one a try
To demonstrate the vagaries of "real world", here's the early life of my turbodiesel Nissan...
Yes Shannow, that graph quite nicely shows how the "random" variations from one tank to the next can easily outweigh any differences due to the oil choice. Your graph is mainly xw40's, so it's a bit hard to extrapolate to other weights, but there's a about a 3% average variation in the oils you have there.
I find it interesting that the one 15W40 gave you the best fuel economy. Mind you, the VOA of delo posted here recently showed it had massive amounts of Moly and Boron (and Zinc), so perhaps that's the reason.
BTW. What was that last oil you used? The one that's unlabeled, starting from about "85" on your graph. I want to give that one a try
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Put a 5w50 in your 5w20 cars and let us know.
Originally Posted By: uart
Originally Posted By: Shannow
To demonstrate the vagaries of "real world", here's the early life of my turbodiesel Nissan...
Yes Shannow, that graph quite nicely shows how the "random" variations from one tank to the next can easily outweigh any differences due to the oil choice. Your graph is mainly xw40's, so it's a bit hard to extrapolate to other weights, but there's a about a 3% average variation in the oils you have there.
I find it interesting that the one 15W40 gave you the best fuel economy. Mind you, the VOA of delo posted here recently showed it had massive amounts of Moly and Boron (and Zinc), so perhaps that's the reason.
BTW. What was that last oil you used? The one that's unlabeled, starting from about "85" on your graph. I want to give that one a try
uart, sorry, the chart is in km/l...my engineering sense is more how far will a tank get me than how many litres do I need to get there.
Delo CXJ was CF, Jaso DH-1, high ash, and IIRC 15.something cst.
Edit...found it (now obsolete)
PERFORMANCE CHARACTERISTICS
SAE 15W/40
JASO DH-1
API CF
Japanese CD and CD "Plus" industry guidelines
Double length Mitsubishi 4D34T4 wear test
KEY PROPERTIES
Density at 15°C, kg/L 0.895
Base No., D2896, mgKOH/g 15.0
Base No., D4739, mgKOH/g 13.9
Sulfated Ash, %m 2.0
Viscosity, cSt at 40°C 113
Viscosity, cSt at 100°C 15.1
Viscosity Index 139
Zinc, %m 0.17
Originally Posted By: Shannow
To demonstrate the vagaries of "real world", here's the early life of my turbodiesel Nissan...
Yes Shannow, that graph quite nicely shows how the "random" variations from one tank to the next can easily outweigh any differences due to the oil choice. Your graph is mainly xw40's, so it's a bit hard to extrapolate to other weights, but there's a about a 3% average variation in the oils you have there.
I find it interesting that the one 15W40 gave you the best fuel economy. Mind you, the VOA of delo posted here recently showed it had massive amounts of Moly and Boron (and Zinc), so perhaps that's the reason.
BTW. What was that last oil you used? The one that's unlabeled, starting from about "85" on your graph. I want to give that one a try
uart, sorry, the chart is in km/l...my engineering sense is more how far will a tank get me than how many litres do I need to get there.
Delo CXJ was CF, Jaso DH-1, high ash, and IIRC 15.something cst.
Edit...found it (now obsolete)
PERFORMANCE CHARACTERISTICS
SAE 15W/40
JASO DH-1
API CF
Japanese CD and CD "Plus" industry guidelines
Double length Mitsubishi 4D34T4 wear test
KEY PROPERTIES
Density at 15°C, kg/L 0.895
Base No., D2896, mgKOH/g 15.0
Base No., D4739, mgKOH/g 13.9
Sulfated Ash, %m 2.0
Viscosity, cSt at 40°C 113
Viscosity, cSt at 100°C 15.1
Viscosity Index 139
Zinc, %m 0.17
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Originally Posted By: Shannow
uart, sorry, the chart is in km/l...my engineering sense is more how far will a tank get me than how many litres do I need to get there.
Ok, that puts a different light on it. Makes a lot more sense now.
Actually I prefer km/L too, but I've kind of been worn down over the years with everyone else here (especially manufactures) using L/100 km. I'm old enough to remember using MPG when I was a kid, so going from MPG to km/L was fairly natural compared to reciprocal units of L/100km.
There are some cases where L/100km has advantages though. Say for example you made a two way trip and averaged 10L/100km in one direction and 5L/100km in the other (just to make the numbers easy). The overall average would be 7.5L/100km, the simple arithmetic mean. With km/L (or MPG) on the other hand a simple average doesn't work and you need to use a reciprocal (harmonic) mean.
uart, sorry, the chart is in km/l...my engineering sense is more how far will a tank get me than how many litres do I need to get there.
Ok, that puts a different light on it. Makes a lot more sense now.
Actually I prefer km/L too, but I've kind of been worn down over the years with everyone else here (especially manufactures) using L/100 km. I'm old enough to remember using MPG when I was a kid, so going from MPG to km/L was fairly natural compared to reciprocal units of L/100km.
There are some cases where L/100km has advantages though. Say for example you made a two way trip and averaged 10L/100km in one direction and 5L/100km in the other (just to make the numbers easy). The overall average would be 7.5L/100km, the simple arithmetic mean. With km/L (or MPG) on the other hand a simple average doesn't work and you need to use a reciprocal (harmonic) mean.
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Yep, good points...driving a Prius to the central coast from here is 4.5l/100 there, and just under 6 on the way back, which makes comparison pretty easy on the fly.
And watching a Subaru Forrester 4 cylinder auto get 11.6L/100km on 0W-20 makes seeing the same number on my L67 with "light 40" blend (152 calculated VI, 13.3 calculated KV100, and 3.6HTHS min) warms the cockles of my heart.
And watching a Subaru Forrester 4 cylinder auto get 11.6L/100km on 0W-20 makes seeing the same number on my L67 with "light 40" blend (152 calculated VI, 13.3 calculated KV100, and 3.6HTHS min) warms the cockles of my heart.
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