# Exxon-Mobil Synergy Diesel (image fixed)



## alacey (Mar 14, 2018)

Filled up on Exxon-Mobil Synergy diesel and this happened.









Nothing else changed. I drove the same 41 mile commute to work like I normally do at the same speeds. I normally get around 43 mpg, but will get 40-42 mpg if I do more city driving than usual on the weekends. My highest fuel mileage before this was 45.7 mpg, but that was a road trip with 80% highway.


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## jck66 (Nov 28, 2017)

Cool, hope those results are repeatable. :thumbup:


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## Doug Huffman (Apr 25, 2015)

More interesting and valuable would be the variance among his numbers and their standard deviation.


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## alacey (Mar 14, 2018)

jck66 said:


> Cool, hope those results are repeatable. :thumbup:


That is what I am hoping. I filled up with the same fuel from the same station. I am 8th of a tank in and the computer is showing 49-50 mpg. My computer is generally about 2-3 mpg higher than my actual so when my actual is 43.x mpg, my computer shows 46.x mpg. When I got the 46.6 mpg, my computer showed 49.0 mpg.


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## alacey (Mar 14, 2018)

Well, it was repeatable. I even did a little more city driving than usual this tank.

Computer stated 49.0 mpg like last time.


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## Flyingman (Sep 13, 2009)

Alacey, assume you are in SA, Tx?

I have used Fuelly religiously for many years on all my diesel vehicles. I started noticing a few interesting trends. During summer months my MPG would improve and the drop in winter months on the 335D.

I know for sure that running the AC will impact your MPG as well.

Traffic patterns changed from summer to winter as in summer the kids are out of school and there is less trafiic. That seemed to override the fact that in summer I use AC and in Winter, well in South Florida, sometimes I don't need the A/C and can open windows.

Also, every once in a while they change the traffic pattern with new construction. They just opened up a new express lane and I expected my MPG would improve, but in fact it dropped. Why would that be? Well, it seems I drive considerably faster now in the express lanes, say 80-90mph vs the usual 55-70mph.

So, while I don't want to doubt the fuel may be the cause, be sure there are no other variables like traffic, mph, and weather/temps that may be a factor.

Look at my data on Fuelly. I have the old 335D (sold) and now the 2016 328d, plus a GL 350.


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## Flyingman (Sep 13, 2009)

Looks like I removed the 335d so that data is no longer. Too bad, good reference.

Actually looking at my 328d, I've only had it one winter so far but the MPG did improve during the cooler months which I believe I attributed to the lower use of A/C. Because traffic is slower in the winter than the summer because of the schools being on vacation.

The difference is maybe less than 1-2mpg overall.

My commute is just about always the same route.


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## alacey (Mar 14, 2018)

This car is mainly used as a commuter car for work. It travels down the same roads 41 miles to work and the same back. Not much has changed with very little traffic. I just put it on cruise control between 70-75 mph for most of the trip and 60 mph when I get on the backroads. I very seldom use it on the weekend since I prefer to drive my truck.

As I stated I usually get 42-43 mph on this commute and the only time I got above 44 mpg was from a few business trips from San Antonio to Houston and back. So getting above 44 mpg on my work commute is abnormal.

It is still fairly warm during the day so I was stilling using my A/C in those two tanks. We just recently got out first 20F cold front a few days ago so I did not use the A/C at the end of the last tank.


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## jfxogara (Oct 26, 2012)

alacey said:


> Well, it was repeatable. I even did a little more city driving than usual this tank.
> 
> Computer stated 49.0 mpg like last time.
> 
> View attachment 827753


That is outstanding -- well done.


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## FaRKle! (Jun 18, 2016)

I just went through a tank of diesel from a Synergy branded station and saw no change in fuel economy.

Where the fuel is refined probably has a lot to do with it. In TX, your Exxon fuel probably came from an Exxon refinery. In NorCal, there aren't any Exxon refineries around and my friend who works at Chevron HQ said that the Exxon stations up here typically buy their diesel from Shell (Shell, Chevron, Valero, Tesoro, and Conocophillips have refineries in the Bay Area).


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## dzlbimmer (Jul 16, 2017)

FaRKle! said:


> I just went through a tank of diesel from a Synergy branded station and saw no change in fuel economy.
> 
> Where the fuel is refined probably has a lot to do with it. In TX, your Exxon fuel probably came from an Exxon refinery. In NorCal, there aren't any Exxon refineries around and my friend who works at Chevron HQ said that the Exxon stations up here typically buy their diesel from Shell (Shell, Chevron, Valero, Tesoro, and Conocophillips have refineries in the Bay Area).


RWD 328d will start with the highest fuel economy, and the OP's highway driven car is partially or fully deleted... so any scaling for normal folk has an asterisk.
Also my understanding, in California, diesel is regulated more so than in most other states. So what is mandated in CA might not be that much different than Synergy available elsewhere.


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## alacey (Mar 14, 2018)

I believe Farkle's car is deleted as well. 

On another note, after two tanks of the Synergy fuel I had to fill up at a Valero last week on the way to Houston. I filled up on Monday to find out that i got 42.7 mpg(45.6 mpg per computer) from the Valero fuel which is about normal for that brand. 

I used Synergy when I filled up Monday and with a little over half a tank left my computer is sitting at 49.6 mpg which is what it showed when I got 46 mpg on the previous tanks of Synergy. So two back to back tanks of Synergy returned 46+ mpg and the following tank of Valero returned almost 43 mpg with the current fill up with Synergy going right back up to 46 mpg. Not sure what it is, but I will take it.


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## FaRKle! (Jun 18, 2016)

alacey said:


> I believe Farkle's car is deleted as well.


I'm not deleted. Emissions system is fully intact.


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