E85...any reason Not to use it?

[Kraig]

Is that from the top of the tank or the bottom?

I take a half gallon each from the top and bottom before starting my truck in the morning just to be safe.

 

[derfman00]

... If E30 isn't available you can make your own. Soon as the light comes on pump in 5 gallons of E85 and 17 of gasoline for those of you with the short trucks. This will give yield an alcohol content of around 20-22% and the octane rating will be 91 if you use 87. If you pump in 93, it will jump to 95.

If you have a 31 gallon tank and wait for the light, pump in 6 gallons of E85 and 20 of gasoline. If you're starting out with a higher alcohol content you can get the R+M octane rating up to 96 with these mixes.

For those trying this for the first time, you can't just fill up once and expect the full benefits, you've got to give the motor AND transmission time to adjust and it usually tanks at least 2 tanks and usually 4 or 5...

If available, why would anyone use straight 91 or E85?

I have E85 nearby, so I'm doing this starting on my next fill-up! I'll log my results. We go through about a tank per week, so I'll update after tank # 4.



****update****
E85 costs $.10 more than regular unleaded in San Antonio... That now makes this a little less attractive.

 

[Fless]

E85 costs $.10 more than regular unleaded in San Antonio... That now makes this a little less attractive.

That's messed up. The government subsidizes the production of ethanol, so as taxpayers we're already paying to have it produced. Typically there is a pretty good spread of the price at the pump because of that, with E85 being much less costly. If you can speak to the station manager you might ask him/her why the prices are not right.

 

[gooffeyguy]

Currently around here E85 is $2.28 and regular (87) is $2.60 and premium (92 or 93) is $3.13

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Fless]

Talk about messed up... went to top off with E85 last night and it's only 2 cents cheaper than E10 regular. I don't run it a lot, and won't if the price stays so similar to regular. I'll just buy premium when towing or for "joy".

 

[intheburbs]

Talk about messed up... went to top off with E85 last night and it's only 2 cents cheaper than E10 regular. I don't run it a lot, and won't if the price stays so similar to regular. I'll just buy premium when towing or for "joy".

The part in bold, you're just wasting money. Unless you have a tune, you'll see no performance difference between 87 and 91 octane.

 

[fastscirocco]

Not really. It allows the engine to make more horsepower and torque and if the cost is low enough, can be less expensive to run. It certainly burns cleaner too. I've seen no ill effects with the truck sitting in the driveway for 1-2 weeks with a 1/4 tank of E85 on board. Until recently, that was often the norm.

Now for the kicker, I've just completed my 12th tank of E30. E30 costs less than 87 octane and delivers more mpgs than 93 octane gasoline in my truck. If E30 isn't available you can make your own. Soon as the light comes on pump in 5 gallons of E85 and 17 of gasoline for those of you with the short trucks. This will give yield an alcohol content of around 20-22% and the octane rating will be 91 if you use 87. If you pump in 93, it will jump to 95.

If you have a 31 gallon tank and wait for the light, pump in 6 gallons of E85 and 20 of gasoline. If you're starting out with a higher alcohol content you can get the R+M octane rating up to 96 with these mixes.

I don't think we have E30, It sounds like mixing E85 with Premium will yield lower cost than premium and better mileage than E85.
What kind of mileage have you been achieving using E30? Does it mix well in the gas tank?


Thanks for the info!

 

[swathdiver]

I don't think we have E30, It sounds like mixing E85 with Premium will yield lower cost than premium and better mileage than E85.
What kind of mileage have you been achieving using E30? Does it mix well in the gas tank?

On 93 Octane Gasoline, the last 14 tanks averaged 14.65 MPG or twenty-four cents a mile.

On E30, the last 20 tanks averaged 15.18 MPG or sixteen cents a mile.

While we're talking ethanol, the last 25 tanks of E85 averaged 12.01 MPG when not towing or twenty cents a mile.

Ohh, does it mix well? I guess so, have not experienced any adverse effects.

 

[fastscirocco]

@swathdiver - while searching for a source for E30 fuel I stumbled across this post echoing what you said about E30, thought you might find it interesting.

https://www.greenhybrid.com/forums/f78/how-blend-your-own-fuel-why-you-should-16411/

 

[swathdiver]

****update****
E85 costs $.10 more than regular unleaded in San Antonio... That now makes this a little less attractive.

Gas Buddy is showing lowest 87 @ $2.00 per gallon with average about $2.20 across the area.

Same app shows E85 @ $1.87 for the lowest, some at $1.98 and most around $2.09.

I bet if you mixed 87 and E85 to get around 20% alcohol content you'd get better mileage and performance and save a little to boot.

 

[swathdiver]

@swathdiver - while searching for a source for E30 fuel I stumbled across this post echoing what you said about E30, thought you might find it interesting.

https://www.greenhybrid.com/forums/f78/how-blend-your-own-fuel-why-you-should-16411/

Good post, thanks! Now you can download apps that tell you how many of each to pump to arrive at a certain alcohol percentage.

My truck has a BlackBear tune but still runs stock E85 tables. I would love to see the performance and mileage increase of this engine with an "ethanol tune".

If these Gen IV motors made just 5 to 6 more horsepower per cylinder, then AFMs duty cycle would increase to at least 50% and mileage would go way up like the Gen V Direct Injection LT motors.

 

[gooffeyguy]

Good post, thanks! Now you can download apps that tell you how many of each to pump to arrive at a certain alcohol percentage.

My truck has a BlackBear tune but still runs stock E85 tables. I would love to see the performance and mileage increase of this engine with an "ethanol tune".

If these Gen IV motors made just 5 to 6 more horsepower per cylinder, then AFMs duty cycle would increase to at least 50% and mileage would go way up like the Gen V Direct Injection LT motors.

It'd be nice for an app to also calculate the octane rating of the blended fuels

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Fless]

My truck has a BlackBear tune but still runs stock E85 tables. I would love to see the performance and mileage increase of this engine with an "ethanol tune".

@swathdiver, wouldn't a stock table be E10? I'm confused. What would be the difference between an E85 table and an ethanol tune?

 

[BG1988]

Less stuttering(knock) from the AFM when using 91 octane and above...
that is the whole point of using 91/93 octane or better (or e85)

 

[HiHoeSilver]

@swathdiver, wouldn't a stock table be E10? I'm confused. What would be the difference between an E85 table and an ethanol tune?

The flex truck has two tables. One for gas and one for ethanol. When he runs ethanol, the truck goes to the stock ethanol table and the tune is only commanding the TCM. A tune specifically for ethanol would alter that table the way his current tune altered the gasoline table.

 

[swathdiver]

It'd be nice for an app to also calculate the octane rating of the blended fuels

I think there is one that costs a few bucks. I've been working on one in an excel spreadsheet.

 

[gooffeyguy]

I think there is one that costs a few bucks. I've been working on one in an excel spreadsheet.

Well just playing around with a couple different calculators I've figured a 50/50 mix of 87 octane and E85 will give an octane of 96. A 50/50 mix of 93 octane and E85 will give 99 octane.

A 50/50 mix of non-ethanol fuel and E85 will give you a mix of E30 - E40 depending on the alcohol content of the E85 (usually 60 - 80%, at least around here, never seen anything over 75% with E85).

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[Fless]

The flex truck has two tables. One for gas and one for ethanol. When he runs ethanol, the truck goes to the stock ethanol table and the tune is only commanding the TCM. A tune specifically for ethanol would alter that table the way his current tune altered the gasoline table.

Ahhh! I get it now. Obviously mine does the same thing.

 

[derfman00]

Gas Buddy is showing lowest 87 @ $2.00 per gallon with average about $2.20 across the area.

Same app shows E85 @ $1.87 for the lowest, some at $1.98 and most around $2.09.

I bet if you mixed 87 and E85 to get around 20% alcohol content you'd get better mileage and performance and save a little to boot.

That is the plan! I'm about 30 miles away from that 1.87 but live real close to the $2.09. The price dropped from when I made my post.

 

[fastscirocco]

If you have a 31 gallon tank and wait for the light, pump in 6 gallons of E85 and 20 of gasoline. If you're starting out with a higher alcohol content you can get the R+M octane rating up to 96 with these mixes.

I live in Michigan, come winter E85 can drop as low as 61% ethanol. I've read about using E85 test kits (glass vial) is there an easier way to confirm the ethanol percentage?
Is there a website that lists when the E85 has the ethanol percentage lowered?