You wouldn’t be able to feel, hear or see a difference between 5w30 and 5w20 in most cases.
Switching back to 5W20 (SuperTech) for mpg!
- Thread starter Navi
- Start date
No perceivable MPG difference between 0w-20, 5w-20, 5w-30, 10w-40 and 5w-40 oil in all my vehicles. My engines do run smoother and quieter (I know, subjective) on the 40 grades and that's what I'm staying with. Too many other things influence MPG than oil grade.
Also, I expected a hit in MPG when changing out gear oil from 75w-90 to 75w-140. Again, no noticeable difference.
I think using synthetic fluids contributed to my results.
Also, I expected a hit in MPG when changing out gear oil from 75w-90 to 75w-140. Again, no noticeable difference.
I think using synthetic fluids contributed to my results.
A change that makes a small improvement may not be noticeable amid the noise of uncontrolled testing, but that doesn't prove it doesn't exist.
The question is whether the small improvement is worth the potential additional wear, if that will bite you in the arse before you want to get rid of the vehicle.
I can rev it faster quicker, more performance, more win. Yeah, there is always a tradeoff even if it's just that you drive it more aggressively.
Maybe just buy the most appropriate viscosity for your engine and climate? I know, it's boring to do the right thing. Certain forums have many topics about being a masochist instead of just following time tested, proven... wait, do I smell nachos?
I can rev it faster quicker, more performance, more win. Yeah, there is always a tradeoff even if it's just that you drive it more aggressively.
Maybe just buy the most appropriate viscosity for your engine and climate? I know, it's boring to do the right thing. Certain forums have many topics about being a masochist instead of just following time tested, proven... wait, do I smell nachos?
Unless he is doing longer idles in the cooler mornings. Which has zero to do with oil lol.
wemay
Site Donor 2023
Both are true between xW-20 and xW-30:
Lower hths absolutely gain you mpg.
Higher hths absolutely show less wear.
How significant are these differences in the real world? Way to many variables to conclusively respond either way.
But the OP knows what he feels and has experienced.
Lower hths absolutely gain you mpg.
Higher hths absolutely show less wear.
How significant are these differences in the real world? Way to many variables to conclusively respond either way.
But the OP knows what he feels and has experienced.
Let's say you own an older less efficient vehicle and you want to improve its fuel economy. OK?
This engine requires Oh IDK, lets say 5W30/10W30...
*And you change to a 5W20 or 0W20
*Check for sticking/binding anything, such as brakes
*Then you install a set(4) LRR tires on the vehicle
*Use the lowest octane fuel allowable...Or the highest octane, IDK!
*Drive more efficiently
*Clean out all of the heavy junk you've been carrying around and remove stuff that you don't use/need
*Properly running engine w/filters, new fluids for the tranny/diff etc.
Then, and only then may you see some fuel economy benefits. But, you better have a baseline/data to work with.
This engine requires Oh IDK, lets say 5W30/10W30...
*And you change to a 5W20 or 0W20
*Check for sticking/binding anything, such as brakes
*Then you install a set(4) LRR tires on the vehicle
*Use the lowest octane fuel allowable...Or the highest octane, IDK!
*Drive more efficiently
*Clean out all of the heavy junk you've been carrying around and remove stuff that you don't use/need
*Properly running engine w/filters, new fluids for the tranny/diff etc.
Then, and only then may you see some fuel economy benefits. But, you better have a baseline/data to work with.
No it doesn't but this is an entirely backwards way of looking at this situation. The onus is on proving oil did have an effect and if you can't do that then the only responsible conclusion you can come to is you just don't know what effect oil grade has on MPG in this application. If you can't clearly separate the perceived effect from random variation you can't conclude there was an effect.
lol, I’m still guilty of this to this day
In that case, as is usual for uncontrolled seat-of-the-pants testing, you should pay attention to results of controlled tests performed by competent groups.
...and we already discussed that in this thread. Expect a maximum of a 1% difference between grades and that means light trucks in the US. Although, your mileage will vary, and for my vehicles it would be a maximum of difference of 0.14, 0.2, and 0.35mpg for each step up or step down in grade.
6 PSI in tire pressure buys me about 2 MPG I have never seen any increase in the use of thinner oil!
I would agree with this. In the past i have used 20wt to 40wt with no measurable difference in fuel mileage. Its probably there, but so small its lost in the normal variability of fuel mileage from tank to tank. Number of stops , idle time , throttle angle, road incline, temperature, wind resistance etc. , all these variabilities are more than the fuel savings of the thinner oil. Its not measurable in most situations.
Yup, just too small of a difference although that doesn't stop people from claiming it's a significant difference.
Agree, tire pressure makes a difference. With colder temps now everyone should check their pressures.
As a general reminder to those who may not know, the recommended pressures are when the tire is cold.
Yes the last time I checked mine was about two weeks ago when temps were running in the mid to high 40's since then we are running low to middle thirties I'll be my tire pressure has dropped.
My understanding is that every 10° change in temperature changes the tire pressure by 1 lb.
Jackson_Slugger
$50 Site Donor 2022
I have the same Mazda-tweaked Duratec that was originally used in the previous gen Mazda6 and CX-9. The initial manual for the 2009 M6 said you could use pretty much what you wanted "if 5W-20 isn't available". But I see no reason (unless you have oil stockpiled) to run anything but 0/5W-20. Mine takes 6.5 qts. and has a pretty hefty cooling system and takes lots of other fluids as well. I suspect these engines well regulated temp wise with an oil cooler so no need for anything heavier than 5W-30. That said the original Mazda6 manual said you CAN use 10W-30/40 or 5W-40 in what I presume are mainly non-NA markets. No mention of 5W-30 oddly though, although I probably will use a 5W-30 in it this summer just to get rid of M1 from 2019. I definitely will use 0/5W-20 in Fall and Winter..
My LTFA just went from 23.3mpg to 26.7 (all majority around town driving) installing a low vm 10W30 synthetic over well used 5W50 synthetic QS. Same brand. The D.I. 4 cyl SUV chugs better at low rpm and pulls right up hills where it wouldn't before without automatically downshifting. Better cylinder sealing with less blowby? Summer gas? Both?
I have the 3.7 Duratec in my 2012 crew cab F150, it gets a workout pushing around that truck. 11 mpg towing, 16-18 normal driving, 19-21 mpg 55 mph and under. I run 5w30/10W30 and will soon try 10W40 in it. No 20 grades for me. Has been rock solid reliable, and likes to rev.