When I lived in CA, my wife's van used to get 17 mpg in town. This was using Royal Purple synthetic.

I decided that I was tired of paying 7 bucks a quart, so I switched to Havoline dino oil.

At the same time of my move to dino oil, I moved to IA and decided that the new average mileage of 15 mpg was due to the ethanol in the gas.

Well, I tried Royal Purple again. I topped off the tank, and in one week, the van is back to 17 mpg in town.

This kills me. I tried everything (including running straight 87) to get the mileage back up.

I still don't like paying 7 bucks a quart. I only used 2 quarts mixed with 3 of my Havoline. SO, is it the oil? The weather was cooler this week.

 

Lots of variable here, so it's hard to say.

Generally, ethanol in gasoline doesn't help it's btu content. Ethanol isn't as energy dense per unit volume, so adding it to gasoine cuts gasolnes btu energy output per unit of volume.

Ethanol is more difficult to ignite & burns slower, so it has a higher octane rating, but our engines compression, valve & ignition timing isn't set up to take advantage of slower burning, higher octane fuel, so the exhaust valve is opening while the higher octane fuel is still burning & that heat is wasted, right out the exhaust!!!!!

Some advantanges of adding ethanol to the fuel blend is that the refiner can begin with lower octane fuel (which is less expensive for him to make) then depend on the Ethanol to boost the blends octane rating up to the required value & if the blender is in a part of the country where Ethanol is produced, he can save some more money by replacing the more expensive gasolne, with the less expensive Ethanol.

Seeing as how Ethanol is an oxygenate & helps with emissions, it's use is also encouraged by the EPA, so the fuel mfgr has all kinds of financial incentives to use it.

Now for us, it can remove moisture from the gas tank, by putting it into solution, to be burned in the combustion chamber, where the water will cool the flame, lowering temps & that'll lower oxides of nitrogen, & the steam will also help clean up combustion camber deposits, BUT maybe at a slight drop in mpg!!!!! There just aint no free lunch!!!! lol

So I don't know why your mpg MAY have gone up.
Maybe the ethanol cleaned up some combustion chamber deposits, about the time you mixed in the synthetic & it was all a coincidence!!!!

My expierence with synthetics on my 99 4.0L Ranger & 94 Taurus 3.8L, is that I get 1.8-2.2 better highway mpg, but no change in city/urban mpg.

 

Lets say the Royal Purple is getting you 2 more miles per gallon it's still more expensive the the gas your burning. Use the cheaper oil.

vanman250

 

2 more miles per gallon is at 2.75 (todays price) saves me .01 per mile. Over 5000 miles, that would be a total savings of 50 bucks. I spent $14.00 on the two quarts that I mixed with Havoline, so I would say I am saving $36.00, if it stays this high.

 

I find it very hard to believe that a different oil (presumably the same weight) could increase mpg by well over 10%.

 

I believe your 2 mpg increase is saving you more than $ 0.01 per mile, I believe it's a little more than $0.02 a mile, or a little over $0.036 cents per gallon, or about 13%, so it wouldn't take long to pay for a full RP oil change at that rate!!!!!

As I posted above, I've gotten 1,8-2.2 better mpg, using synthetic, BUT they were ALL highway mpg, using my dino mfgrs synthetic.

My theory was it was mainly due to less parasitic pumping loss. That is, the synthetic flows at high rates, with less resistance.

But the mpg gain was real.

I had changed the oil & fllter the night before a all road trip. tanked up at the same Chevron station, right next to the interstate, before & after the trip, using the same pump, facing the truck the same way & refilled at the same pump speed, so I was pretty danged confident the mpg numbers were real & as accurate as I could make them.

I was less than 10 miles from the house & commeted to the wife, that I felt we were going to get better mpg, because it seemed to me the engine felt a little different & the rpm it was turning at the 45 mph speed limit on that portion of road, was about 50 less than normal for that speed.

We've made this trip several times before & had always had to tank up before the return trip & this time, I had well over 1/2 tank remaining, AT our destination.

On the same trip many times before, I always had less than 1/2 tank remaining, at that destination.

The road portion was all at 45-70 mph & the flat country portion was with cruise control, just as I had always done. All the trips were done at the posted speed limits of 45-70 mph.

I've just never seen any mpg increase in city/urban driving, using synthetic. Oh btw all the oils were the same brand, Havoline & the gas the same brand, Chevron!!!!

So maybe CA55F100 is doing all highway driving, or maybe there is some complimentary synergy going on, between the RP & Havoline!!!!!! lol

Who cares, if the mpg is real, he's savng a little over thirty six cents a gallon & now days, who wouldn't stop at a station selling gas for thiry six cents less per gallon!!!!!

Maybe cranking the numbers will encourage all of us to do that tune up we've been putting off, or maybe mash the gas a little less, or keep closer track of our consumption & see if we can increase our mpg by 13% too!!!!!

 

there is a site that actually shows that royal purple is the only oil that will actually reduce friction so much it will net you a slight HP gain. i foud this like because i myself was going to switch to royal purple but am running Mobil 1 fully synthetic instead(cost vs effectiveness).

here is the link for the site.

http://www.lubricantsandmore.com/index.html

 

There was also a site that showed actual dyno numbers using Royal Purple oil. Conventional oil was drained then replaced by Royal Purple and a new oil filter, horsepower at rear wheels jumped immediatly by 9%.

Then they changed transmission fluid and rear differential fluid with corresponding Royal Purple lubricants. Flushed radiator, installed 25% Zerex G-05 coolant, 75% distilled water + Royal Purple's "Purple Ice" coolant transfer agent.

Fully warmed up, dyno results hovered at around 12% net gain to rear wheels based on dyno numbers from their baseline readings.

Royal Purple is used in many different forms or racing. Their product line is top-tier, and I feel the investment is well worth it, plus the extended OCI'sthe icing on the cake.

RED LINE, Mobil 1, Torco Synthetic Oils, I also back 100%. I use RED LINE's power steering fluid in all of my vehicles.

Ed

 

Ed, that was the site i was trying to find but could not locate it in the time i had(im at work). but yes, i agree with you 100%.