# Tested the alcohol % in my fuel today

#### LotI

I bought an inexpensive graduated cylinder set on Amazon for various reasons so I decided to test the alcohol content of my fuel today. The last two tanks were run with E0 91 octane from Kwik Trip. Today I filled up with 11.2 gal(13.5 tank size)of E15 88 octane that I normally use. VW gives their blessing on up to E15 and that's my normal fill because it gets the same mileage as E10 and E0 in my testing over the last year. It's consistently \$0.05/ gallon less than E10. That's about 2 tanks for free a year for me. Using the instructions from Delphi
I took 2 mL of water and added it to 10mL of fuel drawn from the tank of my GTI and shook it up. Subtracting the initial amount of water it read around 9% ethanol content. I plan on testing again after using this tank.

#### Audios

So youre actually getting E10 at the E15 price?

#### A_Harman

Very cool. 11.2 gal*x + 2.3 gal*0 = 13.5 gal*.09 ===> x = 1.215/11.2 = 10.8% ethanol in the "E15" that you bought, assuming the 2.3 gallons left in your tank was E0. Do you feel good paying for E15 and getting E10?

#### kschachn

Originally Posted by LotI
Today I filled up with 11.2 gal (13.5 tank size) of E15 88 octane that I normally use. VW gives their blessing on up to E15 and that's my normal fill because it gets the same mileage as E10 and E0 in my testing over the last year. It's consistently \$0.05/ gallon less than E10. That's about 2 tanks for free a year for me.
If their ratio is off then one would expect a slightly lower octane rating as well. Slightly higher energy density however.

#### SevenBizzos

Very cool! Have you actually measured the real volume of your fuel tank to arrive at the 13.5? And depending on how "full" you filled it could affect total volume. Run this tank empty, try the same E15 and report back. I'm curious.

#### Kestas

Staff member
A couple times this summer I got E0 from the regular pumps at Costco. One of those times was when gas was \$1.69 a gallon.

#### LotI

Originally Posted by SevenBizzos
Very cool! Have you actually measured the real volume of your fuel tank to arrive at the 13.5? And depending on how "full" you filled it could affect total volume. Run this tank empty, try the same E15 and report back. I'm curious.
The most I've put in is 12.423g which was about -15 miles of range and it's about as far as my range anxiety would take me! I normally fill up at the same station and use the same pump too. I always fill the same way at the KT pumps with one click, turn the pump off and then get the "bonus" in the hose. The pumps they use have a manual start/stop lever that has to be flipped, and they have individual pumps/hoses for each grade so it guarantees the advertised fuel delivery with no dilution. That's why I prefer them, in addition to being Top-Tier. My plan is to update after the next fill up of E15, and the next...stay tuned. I'm wondering if they would mind if I brought my graduated cylinders to the pumps...hmmm!

#### Audios

Just get a gallon or so in a container.

#### Danno

Can you give us more details on your mileage testing? My research would say E10 should give you about a 3% lower mpg number than E0 due to less available BTUs in the fuel, all things being equal.

#### TXCarGeek

Buy a gallon of each in clean containers and test them...would love to know if E0 is actually E0. Same with E10 and E15.

#### GoldDot40

Originally Posted by TXCarGeek
Buy a gallon of each in clean containers and test them...would love to know if E0 is actually E0. Same with E10 and E15.
I can tell you for 100% certainty, whenever we load pure gas...aka E0...aka rec fuel....aka ethanol free gas, there is ZERO ethanol loaded. When we preset to load E10, the first ~10% of the total load is pure ethanol. The loading briefly stops, then restarts and transitions to CBOB (Convention Blendstock for Oxygenated Blending). The only way for a store to have E0 that didn't spec E0 is for the delivery driver accidentally dropping the wrong product or he didn't completely drain the compartment from his prior delivery that had the oxygenated blend in it.

#### LotI

Originally Posted by Danno
Can you give us more details on your mileage testing? My research would say E10 should give you about a 3% lower mpg number than E0 due to less available BTUs in the fuel, all things being equal.
Fuelly for GTI 3% difference in mpg is equivalent to one WOT application over a tank!. The nut behind the wheel has a bigger effect. I don't think anyone has the patience to drive 450 miles(approximate range of my GTI) without goosing it a bit. Stop thinking mpg and look at g/100 miles or L/100k...it gives a better picture of fuel used.

#### LotI

Originally Posted by TXCarGeek
Buy a gallon of each in clean containers and test them...would love to know if E0 is actually E0. Same with E10 and E15.
I have some 91 octane E0 that I use for OPE but as GoldDot40 said, there's little chance of alcohol. Next fill up I will also test the E0...for the sake of testing. Science!

#### RedlineOilUser

I had to use a gas station that had top tier 91 E 0 but share the nozzle with the E10ers. So at most I may get a couple ounces of ethanol? I guess thats not too bad as it keeps it clean? Help.

#### GoldDot40

Originally Posted by Marco620
I had to use a gas station that had top tier 91 E 0 but share the nozzle with the E10ers. So at most I may get a couple ounces of ethanol? I guess thats not too bad as it keeps it clean? Help.
That is certainly possible, but you're talking about 3 ounces of ethanol if you get whatever is left in the hose from the previous use with E10. Assuming there's about .25 gallon that may or may not be retained in the hose from the previous sale.

#### TXCarGeek

Good thread...Going to continue to follow.

#### Danno

Originally Posted by LotI
Originally Posted by Danno
Can you give us more details on your mileage testing? My research would say E10 should give you about a 3% lower mpg number than E0 due to less available BTUs in the fuel, all things being equal.
Fuelly for GTI 3% difference in mpg is equivalent to one WOT application over a tank!. The nut behind the wheel has a bigger effect. I don't think anyone has the patience to drive 450 miles(approximate range of my GTI) without goosing it a bit. Stop thinking mpg and look at g/100 miles or L/100k...it gives a better picture of fuel used.
When you look at the whole USA fleet of cars/trucks(gas) at about 250 million and the 2.0 trillion miles driven annually (gas), 3% adds up to a really big number. Start to think about the big numbers.

#### LotI

Test from today's fill up of 10.846g of E15. I had a slight amount of spillage during agitation so I'm going to call this 11%. Consumption came in at 2.99g/100mi which is a little low because I may have reached fuel cutoff once, or twice...maybe thrice . I think I read somewhere that GTI's are limited to 124mph, but how would I know!

#### Ded Mazai

I guess the reading in this type of measurement is lower than the actual ethanol content by about 1/3. I did the same and I got about 7% for all E10 I tested. I really doubt that all manufacturers are so kind that they put less ethanol than they legally can. So if you got 10% the real ethanol content is probably 15%.

#### dave1251

Originally Posted by Ded Mazai
I guess the reading in this type of measurement is lower than the actual ethanol content by about 1/3. I did the same and I got about 7% for all E10 I tested. I really doubt that all manufacturers are so kind that they put less ethanol than they legally can. So if you got 10% the real ethanol content is probably 15%.
Don't you have business to attend to Comrade? You can believe what you want but you should present evidence to contradict the findings Comrade.

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