Are 2-3 MPG Gains Valid from Synthetics?

[TomJones76]

I suggest perusing the following PDF for Cummins Corporation's take on the matter:

http://www.everytime.cummins.com/every/pdf/MPG_Secrets_Whitepaper.pdf

Pages 12 and 13 are particularly pertinent.

 

[Gary Allan]

quote:

---

Originally posted by Bror Jace:
Gary, I agree with you about weight ... but some applications don't seem too weight sensitive. My QR25DE in my Sentra SpecV is one of those.

Last year, I was using a blend of two Schaeffer synthetic blends ... their 10w30 and 15w40. Significantly thicker than the 5w30 I usually use. I went on my trip to Limerock and figured I'd be down from the usual 30-31mpg I get on that trip. But I wasn't. No discernable difference.

--- Bror Jace

---

I totally agree with you. I did two back to back 200 mile trips with 20w-50 and one 230'ish mile trip with 5w-20 two days in a row (back and forth to Lock Haven ..and to Lock Haven and then partially back since we were going off the highway). I got 24.7 with the 20w-50 and 24.3 (IIRC) with the 5w-20. No enough of a difference to not be attributed to "variables". I only had one warm up event for each.

OTOH- if I drive 2-3 miles (my typical short trip) ..then I've got TONS of difference between the two viscosities. That gives me my 3-5 mpg difference.

That's why I have a firm belief that those who will see the most advantage of thinner oils in terms of fuel economy are those who are mostly in the under 20 minute crowd. The shorter their driving event ..the more fuel will be saved. That's what I think the whole lighter evolution is all about. It's not all that much in the steady state fractional hp saving..but in the more measurable difference in visc at colder states. If you plot the difference in visc as they go up in temp they converge somewhere around 150C. Conversely, they spread apart at any temp lower. The lower the wider. Effectively lighter oils give you a "head start" to warmer viscosity. At temp (around 100C), the differnce is probably trumped by your wind resistance or some other power loss (tire pressure ..tire tread composition, who knows what)

So, I'll support the MAX of 1-3% for steady state operations between one oil and another ...synth or dino ..whatever ..that will fall into the calculaton variable for most of us unless we track it for a very long time and monitor our tune and whatnot over that same interval.

OTOH ..if you're just doing short trip stuff ..the diffenence in visc can demand a pretty decent toll ($$$) between weight and between dino and synth.

 

[TooSlick]

I've seen gains of 3%-5% with the Amsoil Series 2000, 0w30 under short trip driving conditions, ie commutes of 15-20 miles - this is in comparison to a conventional 10w30. I've also seen gains of 2%-3% compared to Amsoils' own 10w30 under these same conditions. This testing was done with several Audi/Vw engines....

TS

 

[ConfederateTyrant]

When I first started tracking my mpg I was averaging about 16.5 mpg city driving (which was all I did) using Castrol GTX 10w30. I switched to Castrol High Mileage 10w30 and constantly averaged over 18 mpg (same driving style, conditions, etc.). I spoke with others and they saw about 1 mpg gains with Castrol High Mileage as well.

I then began doing nothing but major highway driving, which I never did before so I can't compare these numbers to a base mpg. I was using Amsoil 5w30 (ASL) and averaged 25.5 mpg twice (December and January). I switched over to Amsoil 80w-90 in the differential and I averaged 26.8 mpg (February) and 26.5 (March) on the same trip. I switched to Amsoil ATF and averaged 28 mpg on the same trip (April).

I always traveled at the same speeds (65-70 mph with rare 75-80 mph burst to pass others), and on the last two trips I got caught up in about 20 minutes of coasting traffic with speeds about 10-15 mph. Wind speeds were always light and never blew me all over the road, and tire pressure was always up to 32 cold psi (I'd check before I left). Also the round trip was 420 miles.

After switching everything to Amsoil I only did one main time of city driving, and I averaged over 3 fill-ups at 20 mpg. Same type of driving I did when I would average 18 mpg with Castrol High Mileage.

 

[Brandon Gatz]

Royal Purple's claims of 3% to 5% gains in fuel economy have proved untrue in my first 1500mi of driving on RP 5w30. not worth $41 for the 6qt's imho....

 

[Blue_Goose]

I'll let you guys know next time I fill up....I have been getting anywhere from 350-390 per tankful since we have switched over to the summer blend gas.

A few days ago I changed out my oil from Chevron 5W30 dino and put in 5W30 Castrol Syntec BLEND. Right now I have traveled 300 miles on this tank of gas and I'm right about inbetween the 1/2 full to 1/4 full markings on my gauge. Based on where my gauge normally is at when I have gone 300 miles I should get almost 450 miles before I need to fill again. That would be a record for this car(Matrix)

I drive 100 miles per day round trip 98% highway. All gas in my area save 1 station states that their gas in now blended with ethanol...I've pretty much tried to stick to the same regiment to save gas...keep rpm's under 3k, 70 or less on highway..no fast starts from stop lights/no racing up to red lights and hitting brakes...car is rated 28/34(automatic) so if I can break 35 I'll be pretty happy

I'm not really doing to much different than my last batch of "Gas'n'Go" which doesn't state it has ethanol...still eeked out 33 mpg which I shouldn't sneeze at....if I can break 35 mpg I'll be pretty happy

Any of this attributed to the oil change? Who knows...maybe not and just a coincidence but either way I'm happy.


Goose

 

[Blue_Goose]

Well 414, not 450 but got 36.10 mpg on this last tank..with Castrol Syntec Blend in the sump...coincidence

Whatever the reason I'm happy getting over 2 more mpg than EPA rated

Goose

 

[Auto-Union]

I went from a top mpg of 31 to 34 in a flash after changing to Redline MTF. I have a post going in Trans Forum, but only nay-sayers responding. 10% gain is a 10% gain, no matter what they say.

 

[Curious Kid]

Gary beat me to the impact of short trips, where it seems that dino's tend to be thicker than synthetics which have a naturally higher VI...Cold temps and short trips = MPG penalty.

Getting things up to temp and having a larger proportion of time/fuel consumption during such conditions would deminish any mileage differences to a degree that I think individual trip variences would have a greater impact (tire pressure variences, traffic flow, vehicle loading, utilizing AC, accelerating up hills and to the next red light, etc.).

 

[Ramblin Fever]

No difference seen here either.

 

[meep424]

Only small differences, and greatly depended on vehicle.

'02 accord I4 auto. zero difference, zilch. both engine and trans. BUT, the synth motor oil doesn't "tire" as quickly as dino "tap tap tap"/free-rev smoothness. synth atf is a bit quieter, too. but no discernable mpg difference. 8,500 OCI, at 300 miles/wk.

97 subaru 2.2L MT. all diffs, transmission + engine, a solid 1.5 mpg average increase. Solid 1.5. 450 miles/per week, so I had a lot of data to go by. engine only contriubted 1/3 of that. transmission and rear eng gained the other 2/3. 10,000 OCI.

01 Chrysler T&C 3.3L. engine oil only, mileage fluctuated alot. Achieved as high as 24.5 mpg regularly at 65mph *max* speeds after switching to M1, but also as low as 17 in the same commute. Speed was such a huge factor in mileage that I have to discount any changes. However, the 10,000 OCI on synth was happy, until my commute became shorter. M1 couldn't make it past 6,500 comfortably when I came off the 450 miles/week drive.

'97 pathfinder 3.0L AT 4x4. full synth in engine, maybe too small to notice. full synth in rear diff, Solid .5 mpg increase. full synth in transmission and xfer case, easy 1 mpg increase. Changed to manual lock/unlock front hubs, easy 1 mpg increase. Insulating the stock intake gave another .5 mpg. Went from 18 to 21+ mpg, max speed 65, 10,000 OCI. Note- pathfinder V6 w/ 4 qt sump was hard on oil. The subaru held out to 12.5k when I'd get nervous, 'finder would make a racket under the hood at 11k.

your mileage may vary.

Meep!

 

[mechtech]

Auto Union - You also stated that the engine and drivetrain weren't broken in, and your original mileage was in winter conditions!
C'mon now!

 

[Steelers]

Synthetic front to rear in an F150--no difference. Synthetic in RSX--no difference.

 

[XS650]

quote:

---

Originally posted by Steelers:
Synthetic front to rear in an F150--no difference. Synthetic in RSX--no difference.

---

That's because you aren't a true believer.

I've never seen a differance either, although I've never done a compelte fron to rear change, usually just an engine or transmission.

 

[XS650]

quote:

---

Originally posted by XS650:

quote:

---

Originally posted by Steelers:
Synthetic front to rear in an F150--no difference. Synthetic in RSX--no difference.

---

That's because you aren't a true believer.

I've never seen a differance either, although I've never done a complete front to rear change, usually just an engine or transmission.

I'm about to change transmission and diff on one car from dino to synth, but now that I'm retired I never drive two tanks of gas the same way so wouldn't be able to tell if there was adifference if there was one.

---

 

[another Todd]

Put me in the no difference camp. Although I do run synthetics in everything I own. Even the lawn mower!!! Synthetics allow me to change the oil, lets just say, not very often, and it never comes out looking burnt like petroleum oils.