Friday, December 2, 2016

tank #30

Last tank lasted 270 miles before the gas light went on.  No check engine lights thrown.

gallons e85: 4.012 gallons @ $1.559/ gallon
gallons 87 octane gas: 8.896 gallons @ $1.859/ gallon

ethanol content of tank: 34.36%
octane of tank: 92.55

savings per tank compared to premium @ $2.359/ gallon: $7.66

Saturday, November 26, 2016

Tank # 29

No CEL on the last tank, and I went 260 miles before the gas light went on.

Gallons E85: 4.017 @ $1.739/ gallon
Gallons of 87 octane gas: 9.213 @ $2.039/ gallon

ethanol content of tank: 33.76%
octane of tank: 92.42

savings per tank compared to premium at $2.539/ gallon: $7.82

Tuesday, November 22, 2016

Tank # 28

No check engine lights and I got 280 miles on the last tank.  4 gallons of E85 is the sweet spot.  Car is running great.

gallons of E85: 4.006 @ $1.759/ gallon

gallons of 87 octane: 9.829 @ $2.159/ gallon

ethanol content of tank: 33.10%

octane of tank: 92.27

savings per tank compared to premium @ $2.659/ gallon: $8.52

Thursday, November 3, 2016

Tank #27

No CEL's on the last tank.  4 gallons of E85 per tank is the sweet spot.

Gallons E85: 4.026 @ $1.799/ gallon
Gallons of 87 octane gasoline: 9.360 @ $2.099/ gallon

ethanol content of tank: 34.30%
octane of tank: 92.538

savings per tank compared to premium @ $2.599: $7.90

Monday, October 24, 2016

The sweet spot

Putting 4 gallons of E85 in right when the gas light comes on results in about 35% ethanol, and almost 93 octane.  It's about a $7.50 per tank savings, and doesn't really lost much in the way of mileage.  This is the ethanol sweet spot.

If E30 were more widely available at blender pumps, it would be very compelling for cars that require premium fuel.  It would be a nice savings.

Tank #26

I got a CEL a little before halfway through the last tank, and it cleared in about 50 miles or so.  Stayed off for the rest of the tank.

I decreased the amount of ethanol in this tank as a result.  I think 4 gallons of E85 per tank is the sweet spot, the most that can be used without risking a check engine light.  I put a little more than that in this tank.

I got about 269 miles before the low gas light came on, about 11 miles less than the all gasoline tank.  That's a trivial loss in mileage.

gallons e85: 4.182 @ $1.559/ gallon

gallons 87 octane gasoline: 8.469 @ 1.859/ gallon

ethanol content of tank: 36.27%

octane of tank: 92.988

savings per tank compared to premium @ $2.559/ gallon: $7.58

Wednesday, October 19, 2016

Tank #25

So the gas light came on at 280 miles on my all gasoline tank, not really any different that my high ethanol tanks.  Weird.  I did take an on-ramp quite aggressively when it came on, so maybe it would have done more under normal circumstances.

Anyway, the topic at hand:

gallons e85: 4.511 @ $1.649/ gallon
gallons of 87 octane gasoline: 8.161 @ $1.949/ gallon

ethanol content of tank: 36.64%
Octane of tank: 93.095

savings per tank compared to 93 octane @ $2.459/gallon: $7.82

No CEL so far.

Tuesday, October 11, 2016

Just gas!

I was in a hurry today, and one of the E85 pumps at Meijer had a busted gas dispenser, so I just filled up with 100% 87 octane gas.

The last tank was about 32% ethanol, with no CEL's.  I swear, any car in America can run E30, if it were commonly available.

I got about 280 miles on the last tank before the low fuel light came on.  I'll try and see when that happens with this tank, to get a feel for what the hit to mileage is from higher blends of ethanol.

Wednesday, October 5, 2016

Tank #24

Gallons E85: 4.013 @ $1.699/ gallon

Gallons 87 octane gas: 10.496 @ $1.999/ gallon

ethanol content of tank: 32.72%

octane of tank: 92.2

savings per tank compared to premium @ $2.499/ gallon: $8.54

The CEL went off shortly after I refilled.


So on this tank, the CEL went on shortly after refilling, was on for most of the tank, went off about 3/4 into the tank, and turned back on right before I refueled.

Monday, September 26, 2016

10,000 miles on ethanol blends

So it's been 10,000 miles since I started this experiment of mixing E85 with straight 87 octane gasoline (E10, really) to make a higher ethanol content blend.  I've averaged about E30 during this time, going as high as E40.  I have not had one drivability or reliability issue.  Not one.

Again, this car is a 2004 Acura TL with 150k miles on it to start.  It is not a flex fuel vehicle, not specifically designed for high ethanol blends.

There is a lot of misinformation on the 'net about what E85 does to non-flex fuel cars.  Let this blog be evidence that modern cars can easily handle higher ethanol blends (E15, E20, E30), if not straight E85.  By modern cars, I mean everything after, say, 2001.

Considering that the average car is 11 years old, we are rapidly moving to a vehicle fleet that could handle a lot more ethanol in the fuel than is currently available.  If more retailers had E85 and blender pumps, and if the blends were priced fairly, a lot more ethanol could be sold in fuels than is currently the case.

Tank #23

Gallons of E85: 5.023 @ $1.659/ gallon

Gallons of 87 Octane gasoline: 9.172 @ $1.959/ gallon

Ethanol Content of Tank: 38.01%

Octane of tank: 93.43

Savings per tank vs Premium @ $2.459/ gallon: $8.604

CEL on, CEL off

Throughout this tank, the check engine light came on and went off twice.  As I refilled the next tank, the light was off and had been for a number of miles.  I'd say that the CEL was on for half the tank.

~E40 is marginal in this car.  My next tank will be a little lower ethanol to see if we can limit or eliminate the CEL's.

Monday, September 19, 2016

CEL update

The check engine light went off with about 30 miles on the tank... and came back on this morning with about 100 miles on the tank.

D'oh!  I hope it turns off again.

Friday, September 16, 2016

Tank #22

The CEL is still on from the last tank, but with any luck, should turn off soon!

Gallons E85: 5.001 @ $1.499/ gallon

Gallons 87 Octane Gas: 8.708 @ $2.049/ gallon

Ethanol content of tank: 39.51%

Octane of tank: 93.77

Savings per tank vs. premium @ $2.299/ gallon: $8.3548

Monday, September 12, 2016


So my check engine light came on almost immediately with this 43% ethanol tank.  It has stayed lit.

I'm guessing that 40% ethanol is a hard limit for the CEL to light.  On my next tank I'll take it down to around 40% and see what happens.

Regardless of the CEL, the car runs fine.

Wednesday, September 7, 2016

Weird sticker

Saw this on the E85 pump today.  I knew that E85 topped out at 83% ethanol, but I did not know that it could be as little as 51% ethanol.

Tank #21

Gallons of E85: 6.003 @ $1.749 / gallon

Gallons of 87 octane gasoline: 7.660 @ 2.049 / gallon

Ethanol content of tank: 42.99%

Octane of tank: 94.6

Savings per tank compared to premium at $2.549 / gallon: $8.51

Fun with blender pumps

I recently went on vacation with my wife's van.  In Minnesota when gassing up we came across a blender pump, which had E10, E15, E20, E30, and E85 available.

What did I do?  Filled up with E30!

This van has never run higher grades of ethanol before.  It ran flawlessly on E30, and I couldn't even tell if it lost mileage or not (roughly the same mileage before and after).


I got a check engine light on this tank (roughly 37% ethanol).  It lit about 3/4 of the way through the tank, and cleared before I filled up again.

This is the pattern I've seen at higher ethanol levels with this car, the CEL lights late in the tank and then clears itself.

I will be increasing ethanol content on the next tank to see if the CEL lights earlier and stays on.

Monday, August 29, 2016

Tank #20

Since the car did so well with 4.5 gallons of E85 in the tank, I'm pushing on to 5 gallons.

Gallons E85: 5.000 @ $1.839/ gallon

Gallons 87 octane gasoline: 8.373 @ $2.239/ gallon

Ethanol content of tank: 37.87%

Octane of tank: 93.40

Savings per tank vs. premium gasoline @ 2.639/ gallon: $8.19

Discrepancies in E85 pricing due to lack of competition

I was driving on Route 6 in Portage, IN yesterday, and I noticed a lot of stations with E85 (a couple of Family Express', Meijer) within close proximity.  They were charging $1.499 for E85.

At my station, the Meijer in Highland, IN the E85 is priced at $1.889.  It's the only station within miles that sells E85.

That's pretty amazing.  E85 at $1.50 is very compelling when 87 octane (E10) is at $2.29 and 93 octane gas is at $2.69.

I've read that Family Express has started to install blender pumps, and that E85 is the second most popular fuel at their stations.

There is a Family Express in Highland, they just changed brands from Thorton, and they don't yet sell E85.  I hope they upgrade the station soon.

Friday, August 19, 2016

Tank #19

The E85 pump at the Highland Meijer was REALLY SLOW, and I put less E85 in because I was in a hurry.  I wanted to go to 5 gallons, but I only did 4.

Gallons E85: 4.002 @ $1.719/ gallon

Gallons 87 octane: 10.182@ 2.019/ gallon

ethanol content of tank: 32.81%%

octane of tank: 92.2

savings per tank compared to premium @ $2.519/ gallon: $8.2926

Next time I'll put in 5 gallons

CEL lit briefly

So I estimate that this tank is about 35% ethanol.  The CEL lit briefly with three trouble codes, all related to a lean condition.

I was sitting idling for a bit with the AC on, the CEL lit, and after I drove for a bit it went off.  It was the only time on this tank that I got the CEL.

Tuesday, August 9, 2016

Tank #18

Since the last tank was a little higher ethanol content (4 gallons of E85 rather than the 3.5 gallons that I had been doing) and I didn't get any CELs, I chose to up the ethanol content a bit.

Gallons E85: 4.51 @ $1.75/ gallon

Gallons 87 Octane: 8.692 @ $2.05/ gallon

ethanol content of tank: 35.68%

Octane of tank: 92.883

Savings per tank compared to premium @ $2.55/ gallon: $7.954

I predict that I will get a CEL with this tank.  Looking back at my notes, I believe that when the ethanol content gets to be much above 30%, it throws a CEL.

Friday, July 15, 2016

tank #17

gallons E85: 4.004 @ $1.889/ gallon

gallons 87 octane gas: 8.954 @ 2.189/ gallon

ethanol content of tank: 31.77%

Octane of tank: 91.98

savings over premium @ $2.689/ gallon: $7.682

Wednesday, July 6, 2016

Thoughts on E85 pricing

So I have a Meijer right behind my house, and they have E85.  It is very convenient, and I probably would not use E85 if it were not so convenient.

Even so...

My Meijer prices E85 30 cents less than regular gas.  At a Meijer in another town down the road from me, there is a Speedway gas station next door that also sells E85.  There, they sell E85 for a lower, more market oriented price.

For example, when I got E85 for $1.79, they had it for $1.61 a gallon.  Speedway had it for $1.63 a gallon.

I have heard that, for stations that carry it and price it right, E85 is the second best selling fuel after regular gas.  Sells better than 89 or 93 octane.  I guess I just don't understand why Meijer doesn't use a market price wherever they sell E85 and sell more of it.  I guess that doesn't make the most money for them.

tank #16

The E85 pumps at Meijer are in bad shape, one was out of service on the E85 side, the other out of service on the gas side.  Even that pump was pumping really slow, so I only got 3 gallons of E85 instead of 4, and had to go to a second pump to get the gas!

Gallons E85: 3.004 @ $1.749/ gallon

Gallons of 87 octane gas: 9.695 @ 2.049/ gallon

ethanol content of tank: 20.56% to 23.94%

octane of tank: 89.2 to 90.2

savings over premium @ 2.749/ gallon: $9.98

Wednesday, June 15, 2016

Two tanks of nuthin!

I went on a trip with the car last weekend, I had two partial tanks of gas (~10 gallons each).  Just 87 octane, not premium, no E85.  I think I detected some pre-detonation on acceleration onto the highway, hard to tell.

No CEL's on the last tank with ethanol, but I only got down to about 3/4 of a tank.  My next tank will be 4 gallons of E85 and the rest 87 octane gas, just to prove one way or the other that I get a CEL or not over about 25% ethanol, which is what I found during the winter.

I'm now running about 13% ethanol in my tank, car running great.  No issues at this time.  Almost 159k miles on the odometer.

Saturday, June 4, 2016

Tank #15

Since we are in the summer months, you'd think that the ethanol content of E85 would be higher.  But I have not seen evidence of that, no CEL's.

I've decided to increase my ethanol content a bit, going with 4 gallons of E85 instead of 3.5.  In the winter, this gave me an occasional CEL, towards the end of the tank and which would clear itself.  We'll see.

Gallons E85: 4.000 @ $1.949/ gal

Gallons 87 octane: 8.821 @ 2.249 / gal

Ethanol content of tank: 27.2%

Octane of tank: 90.7

Savings per tank vs. premium at $2.749/ gal: $7.6105

Friday, June 3, 2016

Tank 14

Pricing of E85 has improved.  It is now 30 cents less than regular gas.

Gallons E85: 3.507 @ $1.979/gal

Gallons 87 Octane: 10.5 @ 2.279

Ethanol content of tank: 22.64%

Octane of tank: 89.74

Savings per tank over premium at 2.779: $8.06

Getting 30 cents off really increased the savings per tank.

Monday, May 23, 2016

tank 13: all gas!

I was out an about when I ran out of gas, and had to go all 87 octane straight gas.

Since then I've driven about 200 miles with no noticeable performance difference.  I'm not noticing less power or pinging.

Acura recommends 91 octane fuel for this vehicle, but being a modern vehicle with electronic ignition and a knock sensor, it can run fine on 87 octane.  You don't notice the power drop under normal driving.

Tuesday, May 17, 2016

tank #12

Running great with no check engine lights

gallons e85: 3.506@ $1.829/gal

gallons regular: 10.35 @ 2.029/ gallon

ethanol content of tank 25.25%

octane of tank: 90.3

savings over premium @ $2.29 / gal: $3.474

Tuesday, May 3, 2016

Tank #11

Still running great with no check engine lights.

Gallons E85: 3.535 @ $2.029/ gallon

Gallons regular: 10.417 @ $2.229/ gallon

Premium: $2.629/ gallon

Ethanol content of tank: 25.38%

Octane of tank: 90.34

Savings per tank over premium: $6.28

tank #10

Still running great with no check engine lights.

Gallons E85: 3.527 @ 1.56/ gallon

Gallons regular: 10.013 @ 1.76 / gallon

Premium: 2.16/ gallon

Ethanol content of tank: 25.08%

Octane of tank: 90.5

Saturday, April 2, 2016

Tank #9

Gallons E85: 3.513 @ $1.629

Gallons 87 Octane: 9.923 @ $1.779

Ethanol content of tank: 23.01%

Octane: 90.84

Savings per tank: 6.883

Car is running good, no CEL's.

I suspect that the ethanol content of E85 has gone up, Meijer is selling it for 20 cents less than regular instead of 10 cents less.  But I did my calc on 70% ethanol in E85.

Friday, March 18, 2016

Tank #8

I was running late today, but the low fuel light was on so I had to get gas.

Pulled up to Meijer and someone had just pulled into one of the E85 capable pumps, and the other one was out of service.  D'oh!

I took the opportunity to fill up with 93 octane to see how the car runs on that.

First impression?  No difference.  The same sound the engine makes under load with E25 it made with 93 octane.  Maybe it's not a pre-ignition sound like I think, could just be something else.

No CEL's

3.5 gallons of E85 in the tank is the sweet spot, got through this tank with no CEL's whatsoever.  Right around E25.

Monday, March 14, 2016

Tank #7

E85: 3.5 gallons @ $1.599/ gallon

87 Octane: 8.74 gallons @ $1.889/ gallon

Ethanol %: 25.56%

Octane: 90.371

So far so good, I ran 175 miles on this tank with no CEL's, but it was mostly highway miles.  I tend to get the CEL driving aggressively around town.

No CEL's!

I finished out this tank of E20 with no CEL's whatsoever.  E20 is stable in this vehicle.  Unfortunately, that is only about 89 octane according to my calculations.

Friday, March 11, 2016

Tank #6

Well, I f-ed up.  I meant to put in 3.5 gallons of E85, and instead I put in $3.50 of E85!  D'Oh!  At least I'm not getting any CEL's, although I think it sounds worse under acceleration (i.e. pre-detonation)

Gallons E85: 2.204 @ $1.589/ gallon

Gallons 87 Octane: 11.536 @ 1.689/ gallon

Ethanol %: 20.06%
Octane: 89.4

Savings per tank over premium @ $2.089/ gallon: $5.72

The car is running well, other than the occasional CEL, no issues.

I'm going on a trip this weekend and will run some premium (93 octane) to see how that compared to my E85 mix.


This tank was BAD.  I got the CEL early and often.  It eventually cleared right before I had to fill up again.

Bottom line is that 4 gallons of E85 in a tank is pushing it.  ~E25 is not stable in this car.

I'll try 3.5 gallons of E85 in my next tank

Tuesday, March 1, 2016

Tank #5

Gallons E85: 4.020
Price E85: $1.509

Gallons 87: 8.371
price 87: $1.609

tank ethanol %: 27.59
tank octane: 91.13

Savings per tank compared with premium @ 2.009: $5.35

Despite getting a CEL briefly, the car ran well.  I also added some Seafoam to the tank about halfway through to further clean the fuel system.

Got a CEL, cleared itself

Once again at about 3/4 of a tank, I got a CEL.  This time is was P0171 and P0174, both lean conditions related to too much E85, I believe.

After a few miles, the CEL cleared.  I'm not sure what is actually going on except that E25 is borderline for this vehicle.

Wednesday, February 24, 2016

Tank #4

Gallons E85: 4.020
Price E85: $1.409

Gallons 87: 8.866
price 87: $1.509

tank ethanol %: 26.6
tank octane: 90.89

Savings per tank compared with premium @ 1.909: $5.56


Car is driving great.  Drivability on E25 is excellent.

CEL cleared itself

The check engine light turned off itself about 50 miles after it came on, same tank of fuel.  It must have been an anomaly.

Just to be sure, when the tank was empty, I put in 5 gallons of 87 and ran that to empty.

My observation on running on straight 87 octane gasoline (10% ethanol) is that the engine runs about the same, but I did notice some knocking under hard acceleration.  It is not something you notice on ~90 octane ~E25.  The car accelerates very smoothly and quietly on E25.

I have the scanguage II, I'm looking at ignition timing, and I did not notice any change in timing from E25 to E10 and back.  The ECU should be changing timing in order to deal with the lower octane rating of E10, but it is not noticeable at the frequency that the scangauge monitors ignition timing.

Wednesday, February 17, 2016

CEL comes on, P2195, O2 lean


Halfway through tank #3, I got the Check Engine Light.  My Scanguage II says it's P2195, which is for one of the O2 sensors, lean condition.

I tried to clear it, but my scanguage wouldn't clear it.

I'll run through the rest of this tank and fill up with 87 octane to see if it clears.  If it does, it would seem that this car is much more sensitive to E85 than my Saab was (which wouldn't get the code until 40% ethanol).

Or... this is just a car with 153k miles and the O2 sensor went.

I'll keep you posted.

Tuesday, February 9, 2016

Tank #3

I just about ran out of gas yesterday nowhere near Meiher, had to put in $5 of 87 octane from another station, and drove about 50 miles before filling up today, which makes the calculations difficult.  Not sure exactly how much was left in the tank, nor what it's ethanol% really was.  Just going to assume that it all was there this morning, and calculate accordingly (adding 3.73413 gallons of 87 octane to my calcs)

Gallons E85: 4.014
Price E85: $1.189

Gallons 87: 11.88218
price 87: $1.289

tank ethanol %: 24.11
tank octane: 90.288

Savings: $7.15

The car is running great, no issues so far.

I got my Scangauge hooked up, looking at ignition timing, to get a feel for what it runs with an ethanol mix.  At some point I'll have to run straight 97 octane gas, and maybe premium, for comparison.

Tuesday, January 26, 2016

Tank #2

4.029 gallons E85 @ $1.37/ gallon

9.522 gallons 87 octane @ 1.47/ gallon

Premium priced at $1.91

Octane of tank: 80.5
Ethanol content of tank: 25%

Savings over full tank of premium: $6.38
% savings over full tank of premium: 25%

Not a bad savings!

The last tank ran fine, no driveability or reliability issues at this time.

Wednesday, January 6, 2016

Ethanol blends greater than E10

You probably know that most gasoline sold has 10% ethanol (i.e. E10).  You might not know that there is a federal mandate for gasoline blenders to use a certain amount (gallons) of ethanol per year, and that only blending 10% ethanol into gasoline does not use enough total gallons of ethanol to meet that mandate.  This is called "the blend wall".

Because of this, ethanol producers are very motivated to increase the amount of ethanol in gasoline, and have pushed through a law making E15 available.

Here is an article about the effect of E15 on your car:>

What is E15 and why should I care?
E15 is shorthand for gasoline blended with 15 percent ethanol. The reason it's a big deal is that ethanol is fairly corrosive to rubber and certain metals, so it can cause damage to vital components. Ethanol also attracts and bonds with water from the air, and that water can separate out inside the tank due to phase separation. If your vehicle sits for long periods between use, the moisture settles to the bottom of the tank and can potentially clog in-tank pumps and filters. Damage is also possible in fuel lines, injectors, seals, gaskets, and valve seats as well as carburetors on older engines.
Most Popular
Is it really okay for my car?
This is a tricky question and the subject of a lot of hand-wringing right now. The gas you use now is often 10 percent ethanol, but some industry groups believe the higher concentration of E15 will cause problems. All cars 2007 and newer should be compatible with E15 because automakers have changed the formulation of the affected components. The EPA has certified vehicles in the U.S. fleet made in 2001 or newer, and all Flex Fuel–capable vehicles (able to use up to an 85 percent ethanol, 15 percent gasoline mix) as E15 compatible. One study conducted at Kettering University found no remarkable degradation in fuel systems all the way back to 1995 model years. But the main issue is whether or not your vehicle will be covered under warranty for any damage caused by E15 usage, and in many cases the answer is no. GM and Ford have certified their own vehicles starting with the 2012 and 2013 model years, respectively, so some brand-new cars will have no trouble at all.
My car is older than 2001. What should I do?
Don't fill your fuel tank with E15, simple as that. Even though the new fuel is coming to market, the gasoline or E10 you fill your tank with now will still be available. There is a twist, though. At gas stations that use blender pumps (a single spout that dispenses all octanes) you'll have to purchase at least 4 gallons of E10 to insure any E15 in the hose is diluted to safe levels in your fuel tank. Fuel pumps will be required to have a 4-inch-square label warning motorists not to use the fuel for uncertified engines. With that in mind, the best advice if you have an older car is to stick to stations that have not switched over.
Will this damage my lawnmower, boat, jet ski, snowmobile, or four-wheeler?
It sure will if you don't pay attention. Generally, small engines are not designed to deal with the more corrosive E15 blend. And, as we mentioned in 2010, ethanol forms a brown goo when left in a fuel tank too long, which can clog fuel-system components. Two-stroke engines run hotter with an ethanol blend, which accelerates the potential damage. And ethanol can wreak havoc on fiberglass fuel tanks in older boats. Groups like the National Marine Manufacturers Association and Outdoor Power Equipment Institute have issued strong warnings to consumers to pay attention to their fuels or risk severe engine damage. Use a fuel stabilizer if the engine will sit for more than a few weeks without use; this will reduce the ethanol–water separation and potential gumming issues. Be careful to avoid using E15 in uncertified engines like these, at least until the subject is studied more thoroughly, and the engineering catches up to the fuel.
The bottom line is that higher blends of ethanol (e15, E20, E25) are probably no big deal for a modern, fuel injected car, certainly one made since 2001.

Tuesday, January 5, 2016

Tank #1

17.1 gallon tank

2 gallons E85 @ $1.73/ gallon

11 gallons 87 octane @ $1.83/ gallon

I'm assuming the last tank was 87 octane, I don't know because I didn't ask the guy I bought the car from.

% ethanol: 17%

Octane: 88.5

Compared to buying mid grade at $2.07/ gallon, I saved $3.38 cents on the fillup, a 12% savings

Of course, it's not a pure savings because I'll lose a mpg or two on the tank.  Ethanol doesn't contain as much energy as gasoline.

Why does premium gas cost so much in Chicago?

The answer:>

The premium paid for higher-octane gas in Chicago is a byproduct of several factors, but analysts attribute it mostly to a fracking problem. Shale production has created a glut of crude oil in the U.S. But that source offers a lower-octane base for refining gasoline. Most Midwestern refineries use shale crude, according to Green.
Now, I've never heard this explanation before, but it does make some sense to me.  Fracked crude is very "light", perhaps there are not as many of the hydrocarbon species needed for high octane gasoline?

So, if this is the problem, what is the answer?

Mixing in E85, which itself has large amounts of ethanol in it, as much as 83%.  Ethanol has an octane of 120!

That is the focus of this blog going forward, how does mixing ethanol into gasoline at the pump impact the performance and reliability of a 2004 Acura TL with 153k miles on it?

The Experiment is restarted! E85 as octane booster!

Man, I can't believe this blog is still around.  I haven't posted in 6 years!

So the Saab is long gone.  Since then I've driven a flexfuel Buick Regal, using E85 when it was economical to do so, or when I felt that a tank or two of E85 would clean out the fuel system.

Just recently, I got a 2004 Acura TL with 153k miles on it.  The TL requires premium fuel, and as you may have noticed, premium fuel is very expensive these days.

When I was a young man, premium was always 10 cents more than mid grade, which was always 10 cents more than regular.

No longer.  It seems that stations are using a more cost based market price for their fuels.  Today premium was 40 cents more than regular.  I have noticed that the premium for premium varies.

I read that US refineries are using a lot of oil recovered from fracking, which evidently doesn't have an much higher octane hydrocarbons as non-fracked oil does.  Thus, it costs more to make higher octane fuels, and they're priced accordingly.

Well, what's the best octane booster around?  E85, of course!

Now, it's not easy to determine what the octane of E85 really is.  Meijer's sign says that it's 105 octane.  I have read that E85 is between 96 and 97 octane, but I also don't think that is correct.  I also have read that straight ethanol is 120 octane.

Looking through my notes, I see that when calculating octane, I assumed 100 octane for winter blend E85 (E70, really).  So my calculations will reflect that, until we switch to summer blend.  I think I assumed that summer blend is 105 octane and derated based on ethanol content as a percentage.

So... I put 2 gallons of E85 in with 11 gallons of 87 octane gasoline.  I'm running roughly E17 and have roughly 89 octane.

I want to ease into the higher ethanol contents so as not to clean the fuel system too aggressively.  I intend to limit the ethanol content from going TOO high, there is no advantage to going much over 91 octane on this engine, and with so many miles there is the risk of killing a fuel pump or some fuel system component.  I'm going to be very interested to see how well things last and if I kill something quickly or not.  We know from this blog that long term use of higher grades of ethanol doesn't hurt a modern vehicle, but that was on a relatively new vehicle, this is one that may have end of life components even without higher grades of ethanol.  We will see what happens.

I intend the next tank to be 3 gallons of E85, which will take me to roughly E23, and maybe 90 octane.  I won't go much over that.