E85 70% ethanol octane rating

[4sfed]

Okay...so I'm looking around at the E85 stations and i see some places with 70% E85. Now...I thought the 85 in E85 meant 85% ethanol. ...looks like it doesn't.

Does anyone know the octane rating of E85 with 70% ethanol?


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[krewat]

E85 is 85% - or so I thought - learn something new every day.

"The ethanol content of E85 is seasonally adjusted to improve vehicle cold-start and warm-up performance. The ethanol content can range from 51% to 83% by volume. Much like gasoline, the volatility of E85 is also adjusted seasonally and geographically by volatility class by increasing the proportion of light hydrocarbons during colder months."

Page 5: http://www.afdc.energy.gov/uploads/publication/ethanol_handbook.pdf

Everywhere else in the world, E85 is 85% - period.

Now I feel bad for all these people using E30 tunes in their Ecoboosts, mixing E85 and gas to get E30. Woops

 

[Lostneye]

Everywhere else in the world, E85 is 85% - period.

Now I feel bad for all these people using E30 tunes in their Ecoboosts, mixing E85 and gas to get E30. Woops

This is exactly what is keeping me from an e30 tune ina daily driver. And yup only in America would something explicitly named e85 never actually be e85 and vary so much.

 

[SHOdded]

The varmints in government at it again.

 

[4sfed]

Excellent! Thanks for the info....

This same station had E15 rated at 88 octane.

SO...Since the ethanol level isn't directly proportional to the octane rating...how do I know the octane level of the 70% E85? (Or ANYONES E85, for that matter). I seriously doubt their 70% E85 is 105 octane...

It seems like THIS will effect the mix calculation more than anything.


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[Lostneye]

Excellent! Thanks for the info....

This same station had E15 rated at 88 octane.

SO...Since the ethanol level isn't directly proportional to the octane rating...how do I know the octane level of the 70% E85? (Or ANYONES E85, for that matter). I seriously doubt their 70% E85 is 105 octane...

It seems like THIS will effect the mix calculation more than anything.


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You don't and the fact that it changes so much is my guess as to why I don't see octane ratings on E pumps. This is why people running e30 tunes are testing the fuel regularly or installing a sensor to know the true E content.

 

[SM105K]

This is exactly what is keeping me from an e30 tune ina daily driver. And yup only in America would something explicitly named e85 never actually be e85 and vary so much.

I only have E51 here in PHX. However I test the fuel every fill up. But I only fill up every 3rd week.

 

[krewat]

I only have E51 here in PHX. However I test the fuel every fill up. But I only fill up every 3rd week.

And how accurate is the content of that E51? Is it 51% all the time?

 

[4sfed]

You don't and the fact that it changes so much is my guess as to why I don't see octane ratings on E pumps. This is why people running e30 tunes are testing the fuel regularly or installing a sensor to know the true E content.

Understood, but my boggle is;

- testing only shows the ethanol level; not the octane rating

- the sensor is after the fact. I mean at that point it's already in the tank.



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[SM105K]

And how accurate is the content of that E51? Is it 51% all the time?

It it is labeled flex fuel (like it is here) it has a minimum of 51% E. Everytime I test it, it is what is being advertised.

It is actually easier in my head. I fill up at a quarter tank. I know that is roughly 15 gallons. So 8 gallons of E51 and 7 gallons of 91 nets me roughly E30.

 

[SM105K]

Understood, but my boggle is;

- testing only shows the ethanol level; not the octane rating

- the sensor is after the fact. I mean at that point it's already in the tank.



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That is why you research what the E was bleneded with.

 

[4sfed]

I only have E51 here in PHX. However I test the fuel every fill up. But I only fill up every 3rd week.

What's the octane rating?


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[4sfed]

That is why you research what the E was bleneded with.

Yup...I went to *** & Go's site to find that info....but couldn't. I suppose a more thorough search from something other than my cell phone might turn up more useful info, but I thought the pumps were supposed to be labeled. And since labeling with ethanol content is NOT indicative of the octane level....it seems somewhat pointless.


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[SM105K]

Here is Phoenix the Octane minimum octane rating is 100. If you mix 113 octane with 87 you get 100 in the E51 blend.

Mix 100 with 91 you get 95 octane.

Running E30 is easy, if you are not lazy and do your homework.

 

[SM105K]

Yup...I went to *** & Go's site to find that info....but couldn't. I suppose a more thorough search from something other than my cell phone might turn up more useful info, but I thought the pumps were supposed to be labeled. And since labeling with ethanol content is NOT indicative of the octane level....it seems somewhat pointless.


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It really isnt pointless. Depending on the what they blend it with even 85 octane with 113 will net you 98 octane. It really doesnt matter.

 

[Lostneye]

Here is Phoenix the Octane minimum octane rating is 100. If you mix 113 octane with 87 you get 100 in the E51 blend.

Mix 100 with 91 you get 95 octane.

Running E30 is easy, if you are not lazy and do your homework.

I am def too lazy to keep up with it all the time with commuting.

 

[76FoMoCo]

this is why I have a 93, 93 with meth, and E30 tune loaded in the live wire Ts in the car. 3 minutes I can change the tune of what ever fuel I want to run. the E30 tune is super smooth.

 

[SM105K]

If you use the same stations then you are golden. I still test it every time because I have the extra 3 mins, the tester stays in my car, and with my plate...I need it to be on **** all of the time. Even when I travel outside of the state, I have a E product app that shows me where E stations are. The 50 more hp and 100 lbs more of tq that comes with my E30 tune over my 91 tune overrides all laziness.

Also, I still have a 91 octane tune stored in my Livewire. If I come to a point where I have no E available and have to get fuel, all I do is flash that tune and put enough fuel in to get to the station that has E product then reflash. I plan my trips accordingly, and have zero issues refilling the car at half a tank to get to my next fuel stop.

 

[SM105K]

this is why I have a 93, 93 with meth, and E30 tune loaded in the live wire Ts in the car. 3 minutes I can change the tune of what ever fuel I want to run. the E30 tune is super smooth.

100% correct. The E30 tunes run cleaner, harder, and are more efficient for power. The only downside is 12 to 20 percent more fuel consumption. On my 91 tune at 83 mph I average right at 400 miles per tank when I drive to CA. On E30 at the same MPH I average 350 miles per tank.

91 octane @ 19 gallons at $3.43 is 65.17 a fill up.
91 @ 9 gallons at $3.43 is $30.87 + E51 @ $2.79 x 10 gallons is 27.90.

$27.90 + 30.87 = $58.77 - $65.17 = $6.40 cheaper. If had the capacity to put another 1.8 gallons of E30 in the car for the price difference I would literally break even and have the same mileage.

 

[4sfed]

Awesome! Thanks for your thoughts everyone!

Love this forum.


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