Low viscosity motor oil = better gas milage?

[JEDI]

If low viscosity motor oils does give better gas milage, then how much better would Mobil1 give over non-synthetics?

edit:
and how long inbetween oil changes for Synthetics if you drive 90% highway? (Mazda3 manual says 7.5k miles (i think) for mostly highway driving for regular 5w-20.)

 

[overst33r]

0-2-4mpg depending on vehicle...

Synthetics are generally more slippery than conventional oils, so theoretically as I understand it, one would get the best gas mileage with the lowest viscosity synthetic the engine is good for.

 

[fstime]

Ehh, you might gain .5 to 1 mpg.

 

[LTC8K6]

0W20 and 5W20 are both 20 weight at operating temperature, iirc. Your only gain would be from the switch to synthetic, not from a "thinner" oil.

 

[chucky2]

Originally posted by: JEDI
If low viscosity motor oils does give better gas milage, then how much better would Mobil1 give over non-synthetics?

edit:
and how long inbetween oil changes for Synthetics if you drive 90% highway? (Mazda3 manual says 7.5k miles (i think) for mostly highway driving for regular 5w-20.)

The only way to know that for your ride, driving style, and conditions, is to run the Mobil-1 for say 7.5k and then do a Used Oil Analysis on it. It costs $31.52 in total for the UOA going through Blackstone Labs...$20 for the base UOA, and extra $10 which you'll need to get TBN, and then the $1.52 in postage. The test kit is free.

Blackstone Laboratories - Free Test Kit

Btw, run a Motorcraft or other good filter on that thing....don't use a Fram or Fram knockoff.

Chuck

 

[jagec]

Originally posted by: JEDI
If low viscosity motor oils does give better gas milage, then how much better would Mobil1 give over non-synthetics?

edit:
and how long inbetween oil changes for Synthetics if you drive 90% highway? (Mazda3 manual says 7.5k miles (i think) for mostly highway driving for regular 5w-20.)

For mostly highway, if there aren't significant temperature fluctuations and you don't drive some ridiculous distance like 3k a year, you could probably go 10k without worries. Change the filter every time of course. If you get your oil analyzed, you could probably extend that to 15k or more.

 

[lurk3r]

The answer varies alot based on which car, driving habits etc. In my 95 dodge avenger 2.0 5 speed switching to synthetic took the car to unreal milage (40mpg cruising from 70-80 for 500 miles in a car thats rated well under that), the 2.5L avenger I got after that car got a bit of gain, 1-2mpg. My brand new Altima it made nearly no difference on. Theories varry, but the general idea seem to be that you want the engine to wear in before switching to synthetic, up to about 20k miles, and synthetic will not be very helpful in very high milage engines either, since its generally thinner and will just be consumed.

 

[exdeath]

I use 6.5 quarts of Mobil 1 5W20. Some people like thicker oils, esp. in hot Arizona where I live, but 5W20 is what the SVT engineers recommend due to the tight hand toleranced clearances in that engine.

I seriously doubt you will see any difference going to 0W20. From 20W50 or SAE30 maybe, but not from 5W20. You'll see much more tangible improvements by simply speeding 5 mph less and learning how to coast and engine brake and hardly having to use your regular brakes. Learning to control your speed at all times with only your right foot and using your brakes at 25 mph or under for the final stop works wonders on mileage. As for sudden stops in front of you, if you cant maintain distance by down shifting or a light quick tap to the brake when someone in front of you slows down or stops abruptly you are following to close to begin with.

Synthetic can go anywhere from 5k miles to 15k miles. Still recommend to change the filter regularly however even if you go through 3 filters between synth oil changes. The oil may not break down as fast, but it's still constantly picking up new junk and blow by and circulating it.

Personally I don't pay attention to mileage anymore. I keep an eye on my oil constantly and change it as soon as it starts to get anything other than clear, which is about 3-5k miles, when the clear bright yellow starts to turn into a darker golden orange-red color. May be a bit of extremism on my part, but most enthusiasts tend to pamper their special car.

 

[JEDI]

Originally posted by: exdeath
I use 6.5 quarts of Mobil 1 5W20. Some people like thicker oils, esp. in hot Arizona where I live, but 5W20 is what the SVT engineers recommend due to the tight hand toleranced clearances in that engine.

I seriously doubt you will see any difference going to 0W20. From 20W50 or SAE30 maybe, but not from 5W20.

meant from non-syn 5w20 to syn 0w20

 

[Hyperlite]

Originally posted by: chucky2

Originally posted by: JEDI
If low viscosity motor oils does give better gas milage, then how much better would Mobil1 give over non-synthetics?

edit:
and how long inbetween oil changes for Synthetics if you drive 90% highway? (Mazda3 manual says 7.5k miles (i think) for mostly highway driving for regular 5w-20.)

The only way to know that for your ride, driving style, and conditions, is to run the Mobil-1 for say 7.5k and then do a Used Oil Analysis on it. It costs $31.52 in total for the UOA going through Blackstone Labs...$20 for the base UOA, and extra $10 which you'll need to get TBN, and then the $1.52 in postage. The test kit is free.

Blackstone Laboratories - Free Test Kit

Btw, run a Motorcraft or other good filter on that thing....don't use a Fram or Fram knockoff.

Chuck

whats wrong with fram filters?

 

[overst33r]

Originally posted by: Hyperlite

Originally posted by: chucky2

Originally posted by: JEDI
If low viscosity motor oils does give better gas milage, then how much better would Mobil1 give over non-synthetics?

edit:
and how long inbetween oil changes for Synthetics if you drive 90% highway? (Mazda3 manual says 7.5k miles (i think) for mostly highway driving for regular 5w-20.)

The only way to know that for your ride, driving style, and conditions, is to run the Mobil-1 for say 7.5k and then do a Used Oil Analysis on it. It costs $31.52 in total for the UOA going through Blackstone Labs...$20 for the base UOA, and extra $10 which you'll need to get TBN, and then the $1.52 in postage. The test kit is free.

Blackstone Laboratories - Free Test Kit

Btw, run a Motorcraft or other good filter on that thing....don't use a Fram or Fram knockoff.

Chuck

whats wrong with fram filters?

Nothing wrong with their high end filters, though there are better ones for less money.

 

[Pacfanweb]

Originally posted by: exdeath
Personally I don't pay attention to mileage anymore. I keep an eye on my oil constantly and change it as soon as it starts to get anything other than clear, which is about 3-5k miles, when the clear bright yellow starts to turn into a darker golden orange-red color. May be a bit of extremism on my part, but most enthusiasts tend to pamper their special car.

More than a bit, I'd say. 😉

 

[chucky2]

Originally posted by: Hyperlite

whats wrong with fram filters?

For me, it's not that they use cardboard endcaps where the competition spends more money and uses metal. Cardboard is strong, and as long as it seals well and doesn't rip, I'm OK with it.

Where the "orange can of death" as it's commonly referred to really sux IMHO is the bypass valve and the ADBV designs, along with it's shoddy construction.

It makes absolutely no sense to buy an orange Fram filter when a NAPA Gold/Wix/Carquest Premium blue is available for what, $2 more? For $2 more over the life of that oil change, is it really worth it to use a cr@p Fram over a better filter?

Makes no sense at all to me why people still use the orange Fram's, other than out of complete ignorance of their construction...it can't be because the other worthy substitutes arent' available..there's stores all over that sell NAPA/Wix Gold/Carquest Premium, Purolator, h3ll, even SuperTech from Walmart.

Chuck