If anyone else with a diesel would test this, Id love to know the results. Ive been varying diesel fuels lately trying to find a quality one at a fair price. A sunoco opened not too far from me, and was priced at only 5 cents above the no namers, so I decided to try it in the GL. I went to the Target across the street the next day, and refueled the TDI also. Both of the cars showed a marked improvement. The GL went from an 18-19 average to 22, and the tdi jumped almost 4 mpg as well to 42-43. 2 tanks in the GL since have all netted 21 mpg or better for our mostly local commute, 10 miles a day for me and about 18 for her. Im going to do one more each as a baseline and see if other brands will bring it back down. Anyone know anything about the differences in their fuel?
Noticeable MPG increase with Sunoco diesel
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Probably a good batch of diesel that happens to have a higher cetane number than what your use to using.
At over 800 miles a tank in my Jetta TDI, it will be a while before I can check for you. BTW, you must have a lead foot if 42-43 mpg is all you're getting in that Golf.
Pump calibration off? Your buying more fuel than the pump shows?
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The difference in the TDI is about 0.2 gallons per 100 miles. Not a big deal.
4.5 to 5.6g/100mi is a big deal. Measure over several tanks to see if it just an anomaly. I can't believe a change in fuel would make this difference.
4.5 to 5.6g/100mi is a big deal. Measure over several tanks to see if it just an anomaly. I can't believe a change in fuel would make this difference.
Diesel fuel can be manufactured with varying energy content. Adding biodiesel reduces energy content, but often improves smoothness. Adding kerosene (similar to number 1 diesel in winter) reduces energy content and MPG. Ultra low sulfur diesel contains less energy too.
Energy content is the driving factor behind diesel MPG.
As a general rule, specific gravity (weight) of the fuel is directly proportional to it's energy content per gallon. Summertime diesel can be made with a higher specific gravity as there is less chance of gelling in summer. Put another way: Lighter-thinner-better in cold, but has less energy.
The difference is more than most people realize.
Fuel Oil no.1 1 Gallon 137400 BTU
Fuel Oil no.2 1 Gallon 139600
Fuel Oil no.3 1 Gallon 141800
Fuel Oil no.4 1 Gallon 145100
Fuel Oil no.5 1 Gallon 148800
Fuel Oil no.6 1 Gallon 152400
Diesel Fuel 1 Gallon 139000
Gasoline 1 Gallon 124000
Heating Oil 1 Gallon 139000
Kerosene 1 Gallon 135000
![[Linked Image]](https://www.eia.gov/todayinenergy/images/2015.02.24/main.png "[Linked Image]")
Energy content is the driving factor behind diesel MPG.
As a general rule, specific gravity (weight) of the fuel is directly proportional to it's energy content per gallon. Summertime diesel can be made with a higher specific gravity as there is less chance of gelling in summer. Put another way: Lighter-thinner-better in cold, but has less energy.
The difference is more than most people realize.
Fuel Oil no.1 1 Gallon 137400 BTU
Fuel Oil no.2 1 Gallon 139600
Fuel Oil no.3 1 Gallon 141800
Fuel Oil no.4 1 Gallon 145100
Fuel Oil no.5 1 Gallon 148800
Fuel Oil no.6 1 Gallon 152400
Diesel Fuel 1 Gallon 139000
Gasoline 1 Gallon 124000
Heating Oil 1 Gallon 139000
Kerosene 1 Gallon 135000
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Originally Posted by skyactiv
Probably a good batch of diesel that happens to have a higher cetane number than what your use to using.
So far this has been over 4 total tanks, for me thats a solid 2 months, im guessing this would be more than one tank for them. I refilled a different Sunoco about 10 miles in the other direction yesterday to rule the station out. Im only going about 8k a year in the GL and 6 in the tdi, so a 500 mile tank in the GL is 3 weeks or so.
Originally Posted by atikovi
At over 800 miles a tank in my Jetta TDI, it will be a while before I can check for you. BTW, you must have a lead foot if 42-43 mpg is all you're getting in that Golf.
Nozzles, tune, exhaust high flow cat, larger 18" BBS RC wheels, and commute of 5 miles wacks it down. Most I know with ALH rarely see more than 45, most with tunes and all are in the 38 range. Not complaining at 200k and no consumption. Going to Maine in a month, 750 miles round trip, cant wait to see what happens on a full highway tank.
Originally Posted by Chris142
Pump calibration off? Your buying more fuel than the pump shows?
Trying other stations to rule this out, but I refueled at a Sunoco about 10 miles in the opposite direction and still hand calculated to 21.8, 482 miles to 22.06 gallons, 3.039 a gallon.
Originally Posted by Cujet
Diesel fuel can be manufactured with varying energy content. Adding biodiesel reduces energy content, but often improves smoothness. Adding kerosene (similar to number 1 diesel in winter) reduces energy content and MPG. Ultra low sulfur diesel contains less energy too.
Energy content is the driving factor behind diesel MPG.
As a general rule, specific gravity (weight) of the fuel is directly proportional to it's energy content per gallon. Summertime diesel can be made with a higher specific gravity as there is less chance of gelling in summer. Put another way: Lighter-thinner-better in cold, but has less energy.
The difference is more than most people realize.
Fuel Oil no.1 1 Gallon 137400 BTU
Fuel Oil no.2 1 Gallon 139600
Fuel Oil no.3 1 Gallon 141800
Fuel Oil no.4 1 Gallon 145100
Fuel Oil no.5 1 Gallon 148800
Fuel Oil no.6 1 Gallon 152400
Diesel Fuel 1 Gallon 139000
Gasoline 1 Gallon 124000
Heating Oil 1 Gallon 139000
Kerosene 1 Gallon 135000
Great info thanks. I do know that Sunoco switched to B5 back in 2012 or so, however I do not know if its like that across the board with other refineries. Do you know the BTU of B5, B10, or higher?
I also remembered I used one tank of Valero after the inital Sunoco run in the TDI, and lost 2 mpg. Im about halfway through another Sunoco refill and again showing 40+, 303 miles to half tank (7 gal) but well see when its time.
Probably a good batch of diesel that happens to have a higher cetane number than what your use to using.
So far this has been over 4 total tanks, for me thats a solid 2 months, im guessing this would be more than one tank for them. I refilled a different Sunoco about 10 miles in the other direction yesterday to rule the station out. Im only going about 8k a year in the GL and 6 in the tdi, so a 500 mile tank in the GL is 3 weeks or so.
Originally Posted by atikovi
At over 800 miles a tank in my Jetta TDI, it will be a while before I can check for you. BTW, you must have a lead foot if 42-43 mpg is all you're getting in that Golf.
Nozzles, tune, exhaust high flow cat, larger 18" BBS RC wheels, and commute of 5 miles wacks it down. Most I know with ALH rarely see more than 45, most with tunes and all are in the 38 range. Not complaining at 200k and no consumption. Going to Maine in a month, 750 miles round trip, cant wait to see what happens on a full highway tank.
Originally Posted by Chris142
Pump calibration off? Your buying more fuel than the pump shows?
Trying other stations to rule this out, but I refueled at a Sunoco about 10 miles in the opposite direction and still hand calculated to 21.8, 482 miles to 22.06 gallons, 3.039 a gallon.
Originally Posted by Cujet
Diesel fuel can be manufactured with varying energy content. Adding biodiesel reduces energy content, but often improves smoothness. Adding kerosene (similar to number 1 diesel in winter) reduces energy content and MPG. Ultra low sulfur diesel contains less energy too.
Energy content is the driving factor behind diesel MPG.
As a general rule, specific gravity (weight) of the fuel is directly proportional to it's energy content per gallon. Summertime diesel can be made with a higher specific gravity as there is less chance of gelling in summer. Put another way: Lighter-thinner-better in cold, but has less energy.
The difference is more than most people realize.
Fuel Oil no.1 1 Gallon 137400 BTU
Fuel Oil no.2 1 Gallon 139600
Fuel Oil no.3 1 Gallon 141800
Fuel Oil no.4 1 Gallon 145100
Fuel Oil no.5 1 Gallon 148800
Fuel Oil no.6 1 Gallon 152400
Diesel Fuel 1 Gallon 139000
Gasoline 1 Gallon 124000
Heating Oil 1 Gallon 139000
Kerosene 1 Gallon 135000
Great info thanks. I do know that Sunoco switched to B5 back in 2012 or so, however I do not know if its like that across the board with other refineries. Do you know the BTU of B5, B10, or higher?
I also remembered I used one tank of Valero after the inital Sunoco run in the TDI, and lost 2 mpg. Im about halfway through another Sunoco refill and again showing 40+, 303 miles to half tank (7 gal) but well see when its time.
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I do know that Exxon/Mobil stations use to sell whatever local diesel they could get. Not Exxon/Mobil branded. Recently Exxon/Mobil now requires dealers to sell only Exxon/Mobil branded diesel that is now part of their SYNERGY brand of cleaner burning fuels. Maybe Sunoco has done a similar thing.
I am hoping the Exxon/Mobil diesel will not have the gelling issues I had last winter.
I am hoping the Exxon/Mobil diesel will not have the gelling issues I had last winter.
Just another note, some diesel fuel such as B20, can have a BTU content as low as 127,500.
I fill at two stations repeatedly for my diesels, a Loaf and Jug and an Exxon. The Exxon always returns a mile or two better MPG than the loaf and jug. We are only talking 12-24 miles per tank on my Golf's so not usually worth the fight into and out of the Exxon. I fill up the neck and use hand calculations so it isn't the Lie-O-Meter. May have to do with the after treatment used by the differing stations or the Loaf and jug allows the distributor to dump other than number two diesel into its tanks....leftover #1 or whatever.
Hopefully it solved your soot production issue. A stock or moderately tuned 1.9 TDI should not smoke with good fuel and a fuel/air/turbo system that is working properly.
An effective diesel fuel additive can change marginal fuel into top-tier. It can also improve premium diesel as well for $0.10/gal
An effective diesel fuel additive can change marginal fuel into top-tier. It can also improve premium diesel as well for $0.10/gal
Ive added a 2.5" high flow exhaust since my last analysis on the tdi, im hoping that brings the numbers down a bit. I was thinking that the exhuast was accounting for the bump in wear metals and thickening from soot, but mpg dropped again when i used Valero.
Could just be a higher cetane which has reduced the ash loading of your DPF and by extension the subsequent # of DPF regen cycles. OR perhaps you're driving more highway?
I miss the days of adding bulk cetane (2EHN) booster/ additive pack at fill-ups. The stuff made my 335d purr.
I miss the days of adding bulk cetane (2EHN) booster/ additive pack at fill-ups. The stuff made my 335d purr.
Higher cetane would be nice, there is nothing on the pump about number except Diesel. Ill take a picture next time. The GL is tuned, so the number of regens are probably reduced to aid in effciency, but Ive had this tune for a while now and only have seen the jump recently. Im going to email Sunoco, but Im sure ill get a vague response about how theirs is the best and why.
I don't know the GTL (gas to liquid) diesel's BTU/Gal. But some companies are now including a small percentage of GTL diesel. I suspect GTL diesel can be made to any specification.
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