Are 2-3 MPG Gains Valid from Synthetics?

[Bror Jace]

Yep, I'd say that 2-3 number was percent and NOT miles per gallon.

Using better lubes does make a difference in power and economy (both should increase close to proportionately). But as previously stated, this is very difficult to measure.

You'd need a small fleet of engines running in a lab under controlled conditions to get definitive results. Doable ... but expensive.

--- Bror Jace

 

[Auto-Union]

Audi claimed like 3% gain with SLX II vs 15w40.

 

[wantin150]

quote:

---

Originally posted by toocrazy2yoo:
Hey Wantin!

quote:

---

My experience is that when I switched from Castrol Syntec to Mobil 1 Extended Performance

---

What vis? 5W20?

---

I kept the mfgr's recommended 5W30. I had considered Amsoil's 0W30 but I can't afford it. The EP is expensive enough!

 

[Bill in Utah]

In the following engines;

4.3l V-6

4.8l V-8

3.0l V-6

3.5l V-6

1.7l I4

1.8l I4

2.4l I4

I've run Full Syn, Blends, Dino for atleast 5k miles and kept track of every ounce of fuel and not a single difference of MPG between any oil.

So you can put me in the no difference camp..

Take care, Bill

 

[Mitch Alsup]

quote:

---

I hear on this and other forums about people changing from dino engine and transmission oils to synthetics and reporting 2-3 MPG increases, or even more. Often, this is with the synths. having similar viscosities.

---

They may say that they are using oils (lubricants) of the same 'grade' but to achieve lower pumping losses you need an oil of a different viscosity. Note 10w30 is a 'grade' while 9.6cSt is a viscosity. A 'grade' is about 25% wide at a single temperature, so xxW-30 oil has an operating (t=100dC) viscosity span from 9.6cSt to 12.4cSt.

If you look carefully, you can find thin, medium and thick oils from a single 'grade'. Some people might want to call a 'grade' a weight, and I won't disagree with them, however both terms are used to denote a range of viscosities accross a range of temperatures. At any one given temperature a given oil has a single viscosity. At a differeent temperature, that same oil will have a different viscosity.

quote:

---

The only mileage/power gains I have really felt or measured were when going to a thinner viscosity

---

With the above specifications of viscosity, I agree with you.

 

[Bill in Utah]

quote:

---

Poll: For those of you who see NO difference, how many are dedicated "short trip" type? How many are long commuters?? I'll wager that those who see no difference are longer highway types ..or at least in the over 30 minute crowd.

---

With my Truck it's mostly VERY short trips.

With my Car mostly highway miles.

Take care, Bill

 

[va3ux]

2001 Chrysler(Dodge) Intrepid 2.7 L V6

Zero difference on mine. And I track gas mileage on every tank and have for years. Probably 80/20 highway/short trips

After years on Dino, I switched to synthetic for about 10 months and continued to track gas mileage. During that 10 months I saw absolutely no improvement in gas mileage. In fact, my first stab at synthetic was Mobil 1 and the gas mileage actually got worse. At the time (long before I found BITOG), I didn't understand why that would be. I drained the Mobil 1 after 6 weeks and tried the Canadian Tire branded synthetic 5w30. My gas mileage then returned to normal. It didn't improve beyond normal for this car, but simply returned to normal.

With several months of BITOG now under my belt, I reasonably conclude that the reason for the deterioration in gas mileage with Mobil 1 5w30 was because it was considerably more viscous than any 5w30 conventional I had used before. From this you can further conclude that the portion of gas mileage that is consumed due to the presence of oil circulating in the engine, is due to the viscosity of the oil and the dosage/effectiveness of friction modifers in the oil - but not the really type of the base oil itself.

I could get a further, measureable, repeatable improvement in mileage simply by switching to 5w20 conventional. If I used a 5W-20 Synthetic with the same viscosity as the Dino, then I would see a mileage improvement with that too. Here again, it would be the lower viscosity providing the improvement, not the base oil.

Phil

 

[KJA426]

I've never noticed any difference between the two except the engine seems to run a little smoother on synthetic.

 

[bruce381]

3-5 MPG sorry not possible with just a oil chnage must be some mesurement error.

2-3% Max based on oronite engine stand testing runing a "road" program on the dyno.

I get 2-3 MPG variation on every fuel fill up.

3-5 MPG no way.

bruce

 

[Gary Allan]

3-5 MPG no way.

Sure ..just use an oil that is above a 70 weight at that temp and never let it warm. Then use an oil that's a high 30 weight in the same operation.

QED the difference between 15-17 and 18-20. No problem at all bruce ..and that wasn't even using a synthetic.

If a 5w-20 or 0w-20 synthetic had been used on the low end ...the spread may have been more.

Now the difference between 20w-50 and 5w-20 on a "one warming event" trip of over 200 miles

...fractional with the minor edge to the heavier oil (that can surely be some minute error factor there). 24.x vs. 24.x. ..or ..no difference at all.

 

[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

 

[Steve S]

All things equal as possible , minimal if any.

 

[carock]

Because the EPA wanted manufacturers to switch to 5-20W for increased fuel economy, I will assume that oil can make a difference. Myself, and many others have been involved in fuel economy tests, and if a synthetic oil actually gave an improvement in fuel economy, the manufacturers would use it. Fuel economy is taken very seriously. The fact that some manufacurers now use synthetics means that synthetics do not hurt fuel economy. If Audi is claiming an improvement in economy using synthetics, then that would have to settle any doubts I have. I have no way to verify that above post about Audi's claim.

 

[Gary Allan]

I can get 3-5 mpg difference between dinos. Easily and distinctly measurable.

You just use 15w40 or 20w-50 for a short trip deal ..then switch to 5w-20 for the same service. Viola~! Instant high % of fuel economy. A synthetic would do even better.

In any fleet ...highway ...etc. ..fractional mpg gains at best, imo.

Poll: For those of you who see NO difference, how many are dedicated "short trip" type? How many are long commuters?? I'll wager that those who see no difference are longer highway types ..or at least in the over 30 minute crowd.

 

[mechtech]

I see a very high degree of consistency from everyone.
Thanks.
I will direct arguments about this [from other forums] directly to this post, for their perusal.

 

[Alcibiades]

After more than 50k miles of very close observation and measurement, I have concluded that Redline 5W-20 has consistently given a 2-3 mpg improvement over both GTX and Syntec 5W-20 in an '03 Honda.

I dumped the factory fill at 5k and ran GTX for the next 10k at 3-4k OCIs (pre-BITOG). Then, Syntec for the next 10k at 5k OCIs. With both of these, I consistently saw 22-23 mpg in the city and 28-29 on summer trips: just a hair shy of the EPA estimates for the vehicle.

For the last 20k+ miles I've run the Redline and seen 24-25 (occassionally 26) in the city and 30-32 on the longer trips, exceeding the EPA estimate.

Over all this time I've not changed my driving habits, have taken the same roads, in the same climate conditions, using the same gas (Amoco/BP 93) 95% of the time, and always ~65 mph on the freeway. Anybody know of any other variables that could have caused the improvement? I had the dealer flush and refill the transmission fluid a few weeks ago, and so far that has not affected the mpg.

 

[Alcibiades]

On the other hand, Redline 10w30 might be causing a slight drop in mpg compared to GTX 10w30 in my other car, but the jury is still out, as I'll have to run several more tanks of gas to average it properly.

 

[Slick 55]

I've never noticed a difference in any of my vehicles but I always used the same weight.

 

[ScottB]

My mileage has certainly improved since I put in synthetic at 6k miles. I'm using what some have said is a "middle of the road" synthetic - Kendall, but my Scion tC is getting more miles per tank now.
Makes sense - but I think you have to truly be anal about measuring long-term to know for sure.

Scott

 

[bruce381]

Gary Said
"Sure ..just use an oil that is above a 70 weight at that temp and never let it warm. Then use an oil that's a high 30 weight in the same operation."

Ok got me there.

bruce