Thin oils *do* produce better MPG

[ToyotaNSaturn]

I was originally going to title this "Best MPG with Pennzoil 5w-20 dino", but that's not the whole story.

Parsing through the last two years of fuel records, a clear trend emerges: thinner oils produce consistently higher MPG numbers.

Looking at stints of at least 5 "best of" tankfuls in a row with regular commute driving (75% hwy/25% city), little to no A/C usage and minimal cold weather starting (which will take it's toll on any oil) tells the tale. Also, all fuel was 87 grade gas, save for the one line mentioned below:

39.60, Average of May 2007 fillups w/Pennzoil 5w-20 dino
38.83, Avg of best of M1 0w-20 SL
38.42, Avg of best of M1 5w30 SL
38.32, Avg of best of Castrol 10w-40 HM 93 octane BP fuel
35.25, Avg of best of Castrol 10w-40 HM 87 octane


Interesting to note that the spreadsheet shows all 40+MPG tankfuls (regular commute, not on vacation strapped to 60mph speeds) have happened with 20wt oils.

I'm sold on 20wt oils! Last tankful was 43.45mpg.

 

[Mr Nice]

What type of car do you have ??

Auto, 5 speed, 2 door, 4 door, etc....?

 

[ToyotaNSaturn]

Sorry 'bout that...96 Saturn DOHC. 5speed sedan. K&N air filter added about a year ago. No other mod's.

 

[Laminar Lou]

Although not earth shattering, it's good to see some empirical evidence. It's interesting that the 5W20 Pennzoil Dino did better than the M1 0W20. Are you still on the Pennzoil with that 43.35mpg latest reading?

Also, what are the dates of your test? Do you have winter RFG?

Are you going to try the new Amsoil 0W20?

Thanks for sharing your data!

 

[ToyotaNSaturn]

For more comparison's sake:
33.75 Avg of best of M1 15w-50 SL
35.14 Avg of best of Havoline 10w30 HM SL

M1 15w-50 w/AC most of the time
Havoline HM during winter months

Dates for data in first post from spring-fall, no winter/cold start data in there to mess with the data interpretation.

Amsoil 0w-20 looks VERY interesting, I just have so much other oil on hand right now.

 

[Ramblin Fever]

Well, at these gas prices, I'm curious to see how many others attempt to use 0w-20 or 5w-20 oils, even in cars NOT spec'd for it.

I'm *almost* tempted to try that in our '04 Tacoma 3.4L - but maybe only initially through a cold winter run, first.

 

[ToyotaNSaturn]

Forgot to say that this car sees LC & FP at recommended intervals save for the most recent Pennzoil 5w-20 dino numbers as FP was used at half the recommended dosage (running low on FP now).

 

[Merkava_4]

What gets me is that people are starting to call 10w30 a thick oil.

 

[JTK]

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Well, at these gas prices, I'm curious to see how many others attempt to use 0w-20 or 5w-20 oils, even in cars NOT spec'd for it.

I'm *almost* tempted to try that in our '04 Tacoma 3.4L - but maybe only initially through a cold winter run, first.

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Ramblin, remember when I ran 5w-20 in my 2002 Isuzu 3.2L? She ran super smooth and quiet on it. No UOA data to back it up though. This was a heavy and inefficient PT 4x4 truck so MPG increase was not the easiest to track. IIRC, I did hit ~21mpg per tank mostly hywy on 5w-20. I may run a 5w-20 in my atlas/vortec 4.2L once my stash of Kendall GT-1 5w30 runs out. Thing is, it's tough to pass up the Kendall 30wt's when I can grab them for under $1/qt. Most of the 5w-20's in my area approach $3/qt if you can even find the stuff.

Joel

 

[Ramblin Fever]

Yes, JTK, I do remember, and I remembered that you liked it too. I only wish I had the guts to run that thin of an oil in my Rodeo - tried it 1 time, Motorcraft, in fact, just in the yard and it tapped horribly. Didn't have the guts to take it on the road.

But, I have to keep reminding myself, that that was before the timing belt replacement, as it was on it's way out around that same time.

Thing is, I've got SOOOO much 5/10w-30 sitting around that still needs used up - but I can't help in being curious just how many more mpg I can get out of a slightly thinner oil in the Tacoma.

Then, other times, as you mentioned heavy 4x4 inefficiency, I wonder if light weight cars/vans/small suv's see more advancements in a thinner oil then mid-sized trucks/suvs, etc.

This Tacoma weighs almost as much as the Rodeo, if not equal - which has nothing to do with choice of oil viscosity, but mpg has everything to do with differences in a car with 15" street tires >3,000< and one on 32" A/T tires, 1,000lb of tools, etc.

And, aside from that, is the warranty factor.

But, I'm still curious!

 

[ARB1977]

Quote:

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Yes, JTK, I do remember, and I remembered that you liked it too. I only wish I had the guts to run that thin of an oil in my Rodeo - tried it 1 time, Motorcraft, in fact, just in the yard and it tapped horribly. Didn't have the guts to take it on the road.

But, I have to keep reminding myself, that that was before the timing belt replacement, as it was on it's way out around that same time.

Thing is, I've got SOOOO much 5/10w-30 sitting around that still needs used up - but I can't help in being curious just how many more mpg I can get out of a slightly thinner oil in the Tacoma.

Then, other times, as you mentioned heavy 4x4 inefficiency, I wonder if light weight cars/vans/small suv's see more advancements in a thinner oil then mid-sized trucks/suvs, etc.

This Tacoma weighs almost as much as the Rodeo, if not equal - which has nothing to do with choice of oil viscosity, but mpg has everything to do with differences in a car with 15" street tires >3,000< and one on 32" A/T tires, 1,000lb of tools, etc.

And, aside from that, is the warranty factor.

But, I'm still curious!

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HHHHMMMM....me too. Maybe start with a 50/50 mix then get a UOA and go from there.

 

[OriginHacker21]

I'm running Amsoil 0w20 in my 2.2l GM Ecotec. I'm seeing 1-2MPG difference. Unfortunately, on the recent trips to work I've had unusual wind storms, traffic, and other external factors to mess up mpg data. However, on the few unhindered days that I've recorded: 1-2MPG difference.

Engine definitely likes to rev higher with less resistance but I noticed that at idle the engine shakes a lot more than it does with GC 0w30.

 

[Curious Kid]

Several years ago my now brother-in-law had said he would get over 40mpg while traveling the interstate. He might have been using M1 at the time or perhaps not, but no thinner than a 5w30...likely a 10w30 in the summer months as I believe that was the time he did some travel for his work.

I can't and I won't disput the data presented - having less viscous drag and back pressure leading to efficiency gains makes sense, as long as the lubrication regimen doesn't take a shift heavily into the mixed film/boundry layer behaviors.

A lot of variables at play, but interesting none-the-less.

Thanks for sharing.

 

[The Critic]

I'm getting 36-38 mpg on a 96 Saturn SL2 Auto w/102k miles running Maxlife 5W30. This is mainly 60 mph highway driving, easy throttle, but lots of idling/stop-n-go during rush hour Sacramento. No A/C. Of course, this is all driving that my father does.

 

[GROUCHO MARX]

Max-Life syn?

 

[The Critic]

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Max-Life syn?

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Maxlife dino. And it exposed a new oil leak too.

 

[Lexura]

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What gets me is that people are starting to call 10w30 a thick oil.

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It IS a thicker oil. I remember 10w30 was the recommendated oil weight for many cars, but that was when there was no cell phone, no internet, no HD TV.

 

[06VtecV6]

PP is a tad too thick for me...thinking abou going M1 for a tad thinner goo.

 

[MONKEYMAN]

I am using 1 quart per 1,000 miles in my 99 SL2 with 10w30. With 20 weight oil I would probably have to fill-up with oil and check the gas.

 

[ToyotaNSaturn]

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PP is a tad too thick for me...thinking abou going M1 for a tad thinner goo.

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You'll be in for a surprise if you think M1 is thinner than PP.

Comparing the hot temp viscosity (the most important piece of data for summer driving IMO), 100C cSt metric, from the vendor's Product Data Sheets, PP is thinner in 5w30 and 5w30 viscosities. M1 is only a smidgen thinner in the 10w30 flavor.