[g80_nick]

Hey guys was curious as too what the ethanol percentage in 100 octane fuel is? Should i just put 10% like i would for 91 in my calculator? Or do you think it has a higher or lower ethanol percentage?

Thank you!

[jb-slow]

Likely 0

[rtl32]

Dude you have 11 of the posts on the front page of this section alone and most of them are answered with a simple google search on "how to calculate ethanol content", using one of the many e85 apps, or literally google searching for a MSDS of the fuel you are looking into using. Some of them look like troll threads too. Please use google.

Like he said probably none. But you shouldn't be using any E level tune if you don't have a tester to find out for yourself.

[g80_nick]

Originally Posted by jb-slow

Likely 0

okay i'm trying to fill up my e30 map but i have a half tank of 100 octane in my car still, and there's only 91 at the pump next to e85. Does the current octane in my car matter or should i just calculate like normal as if i didn't have 100 octane in my car? I had like 3 percent of e30 in my car before i just filled up with 100 so i'm assuming my ethanol in my tank at the moment is around 10% or so since i just filled up with 100 and still had e30 in my car. My IATs are running high both on my E30 map and my 100+ octane race map on BM3. Should i just use the normal calculator like i'm normally filling up with 91 and not worry about the octane level in my tank?

[g80_nick]

Originally Posted by rtl32

Dude you have 11 of the posts on the front page of this section alone and most of them are answered with a simple google search on "how to calculate ethanol content", using one of the many e85 apps, or literally google searching for a MSDS of the fuel you are looking into using. Some of them look like troll threads too. Please use google.

Like he said probably none. But you shouldn't be using any E level tune if you don't have a tester to find out for yourself.

i was literally asking to get opinions from you guys to make sure. What's the point in flaming? I looked it up on google and barely found any answers and when i did, they were different numbers. I'm literally trying to learn as I go and isn't the point of a forum to ask questions to learn? What's the point in being an asshole? Get off my thread

[Rich.Wolfson]

Originally Posted by white_f22

Hey guys was curious as too what the ethanol percentage in 100 octane fuel is? Should i just put 10% like i would for 91 in my calculator? Or do you think it has a higher or lower ethanol percentage?

Thank you!

Hard to say but I would guess probably around 8%.

The Sunoco 93 Optima race fuel pumps at Summit Point was E0 for many years. I know as we tested it regularly.

This year they changed to VP race fuels which is E10 but tests around 8% ethanol. Every brand is different and needs to be tested no matter what octane you need.

You can get a simple test kit here. I like having a graduated cylinder and large syringe to go with it. And some QuickCheck alcohol dye makes the test easier to read.

E0 is not easy to come by these days away from a marina. And modern cars are ok with E10 but not my old carbureted RX-7 where the ethanol eats seals for lunch.

///Rich

[rtl32]

Originally Posted by white_f22

i was literally asking to get opinions from you guys to make sure. What's the point in flaming? I looked it up on google and barely found any answers and when i did, they were different numbers. I'm literally trying to learn as I go and isn't the point of a forum to ask questions to learn? What's the point in being an asshole? Get off my thread

Didn't mean to come off so short, my bad. Like everyone else has been saying you've really got to test ethanol to know it, even published % aren't very accurate sometimes and every gas is different. the 100~ octane race gases are all super refined products and are usually produced in much smaller batches than E or pump gas is made in, and can differ wildly between who makes them. Some will use Ethanol to support the octane while others will keep it out of their gas to preserve the energy density.

Ethanol is very cold/clean burning, stable, and aggressive to seals but is very "thin" and lacks energy density compared with straight refined "thick" petroleum that most race gases are. This means it is a great fuel but its caveat is you need the correct volume of it to do it's job properly (to compensate for the lost energy if you are comparing 1 unit of E to 1 unit of another fuel). This correct volume is more, sometimes a lot more like 35-40% more fuel volume in comparison to do the same amount of work.

Ethanol content varies wildly, one pump I go to is over 85%, one is always 62%, and another is always 67%. My buddy has 3 year old E90 in his garage that was only E76 when we tested it.

The varied content alongside the need for proper fuel scaling (properly measuring each fuel injection pulse to account for energy density) is why no matter the application or tune, if there is ethanol you should be testing how much is there.

If you are looking to mix Ethanol with 100 octane or other high octane race gases keep in mind that proper E85 is only like 95-96 octane in itself. You will be lowering the overall octane, along with making the gas energy thinner. If you aren't using a Stage 1 or 2 pump gas map and adding ethanol through the liveadjust feature OR changing the 2+ E30 map to another ethanol content, then it is best to ask the tuner or BM3 if it is safe to do so. It's hard to know exactly how the race gas and ethanol features mix because almost anybody looking to get that deep into fuels is getting custom tuned for their application. Those are not conventional mixes and with these new tunes and flexfuel features, I would hate to see you adjust the race gas map to 30% ethanol, put 30% in, and then blow something up because the tune actually made itself more demanding and asked for more octane than you have.

[g80_nick]

Originally Posted by rtl32

Didn't mean to come off so short, my bad. Like everyone else has been saying you've really got to test ethanol to know it, even published % aren't very accurate sometimes and every gas is different. the 100~ octane race gases are all super refined products and are usually produced in much smaller batches than E or pump gas is made in, and can differ wildly between who makes them. Some will use Ethanol to support the octane while others will keep it out of their gas to preserve the energy density.

Ethanol is very cold/clean burning, stable, and aggressive to seals but is very "thin" and lacks energy density compared with straight refined "thick" petroleum that most race gases are. This means it is a great fuel but its caveat is you need the correct volume of it to do it's job properly (to compensate for the lost energy if you are comparing 1 unit of E to 1 unit of another fuel). This correct volume is more, sometimes a lot more like 35-40% more fuel volume in comparison to do the same amount of work.

Ethanol content varies wildly, one pump I go to is over 85%, one is always 62%, and another is always 67%. My buddy has 3 year old E90 in his garage that was only E76 when we tested it.

The varied content alongside the need for proper fuel scaling (properly measuring each fuel injection pulse to account for energy density) is why no matter the application or tune, if there is ethanol you should be testing how much is there.

If you are looking to mix Ethanol with 100 octane or other high octane race gases keep in mind that proper E85 is only like 95-96 octane in itself. You will be lowering the overall octane, along with making the gas energy thinner. If you aren't using a Stage 1 or 2 pump gas map and adding ethanol through the liveadjust feature OR changing the 2+ E30 map to another ethanol content, then it is best to ask the tuner or BM3 if it is safe to do so. It's hard to know exactly how the race gas and ethanol features mix because almost anybody looking to get that deep into fuels is getting custom tuned for their application. Those are not conventional mixes and with these new tunes and flexfuel features, I would hate to see you adjust the race gas map to 30% ethanol, put 30% in, and then blow something up because the tune actually made itself more demanding and asked for more octane than you have.

Okay yeah cus i talked to BM3 and they said octane doesn't matter it's just the ethanol % in it. I'm probably gonna put ethanol % in the race gas as 10% or so just to be safe. I filled up with race gas yesterday and i'm thinking my current ethanol in tank is prob around 15% or so since i still had a little bit of e30 in it but i don't wanna go over e30 in my tank since my car is still stock. I unfortunately lost my ethanol test kit so i still have to order a new one but i tested it at the gas station 2 weeks ago (e85) and it was testing at 95+ and i'm also in a FB group and it's still testing at that the past few days and they get it from the same supplier each time so im gonna put 95 as the percentage in e85. Wish me luck i'd rather be on the safer side if you know what i mean. Hopefully running the e30 tune is ok for my car if my ethanol % in my tank isn't at e30. It's all good brother sorry i'm just trying to learn as i go and to make sure i don't hurt my car along the way. Thank you for helping though i really appreciate it!

[rtl32]

Originally Posted by white_f22

Okay yeah cus i talked to BM3 and they said octane doesn't matter it's just the ethanol % in it. I'm probably gonna put ethanol % in the race gas as 10% or so just to be safe. I filled up with race gas yesterday and i'm thinking my current ethanol in tank is prob around 15% or so since i still had a little bit of e30 in it but i don't wanna go over e30 in my tank since my car is still stock. I unfortunately lost my ethanol test kit so i still have to order a new one but i tested it at the gas station 2 weeks ago (e85) and it was testing at 95+ and i'm also in a FB group and it's still testing at that the past few days and they get it from the same supplier each time so im gonna put 95 as the percentage in e85. Wish me luck i'd rather be on the safer side if you know what i mean. Hopefully running the e30 tune is ok for my car if my ethanol % in my tank isn't at e30. It's all good brother sorry i'm just trying to learn as i go and to make sure i don't hurt my car along the way. Thank you for helping though i really appreciate it!

Running an ethanol tune like e30 when you don’t have at least almost E30 (and the other mods) WILL damage your car

Please don’t do that