E15 gasoline

[NightShade]

Alcohol burns with almost no flame because it carries an extra O2 molecule so even though it may have less energy per gallon than pure gasoline it will generally help the fuel burn more completely. Way too many people claim major drops in economy which is technically not possible. Even just looking at pure mathematical BTU and not actual test data which will run a little higher because of the alcohol acting as an oxidizer the change in BTU isn't as much as the fuel economy drops claimed which some people say is as high as the percentage of ethanol in the fuel. I actually have a spreadsheet I messed around with that shows the percentage change and expected changes in MPG based on only the mathematical BTU difference. Most people who see changes larger than that are being heavy footed throwing their results off even if doing so unconsciously.

 

[TulsaMike]

Alcohol burns with almost no flame because it carries an extra O2 molecule so even though it may have less energy per gallon than pure gasoline it will generally help the fuel burn more completely. Way too many people claim major drops in economy which is technically not possible. Even just looking at pure mathematical BTU and not actual test data which will run a little higher because of the alcohol acting as an oxidizer the change in BTU isn't as much as the fuel economy drops claimed which some people say is as high as the percentage of ethanol in the fuel. I actually have a spreadsheet I messed around with that shows the percentage change and expected changes in MPG based on only the mathematical BTU difference. Most people who see changes larger than that are being heavy footed throwing their results off even if doing so unconsciously.

View attachment 158802​

There is a 35% loss in fuel economy going from straight gasoline to e85, and e100 is about 40%. The change from straight gasoline to the e10 at the pump will be minimal, but the only reason that’s done is to produce the fuel at a cheaper cost since ethanol is subsidized, where as oil is not. Most newer vehicles have computers that can adjust for about 25% more or less fuel when running ethanol blends, so the e10 has a minimal impact, but much beyond that some will start getting check engine lights and lean codes. From a fuel system standpoint, it requires 40% more flow for a vehicle to run e85+ over straight gasoline, which is why most vehicles aren’t flex fuel.

 

[mr ed]

How do you know what your really getting? In Tulsa the Tankers all pull up to the same tank farm in west Tulsa.
They just push some buttons and the additives get mixed in. Who know what was still in the tanker?

 

[PBramble]

How do you know what your really getting? In Tulsa the Tankers all pull up to the same tank farm in west Tulsa.
They just push some buttons and the additives get mixed in. Who know what was still in the tanker?

Exactly. I've seen the stickers that read this fuel may contain up to 10 percent Ethanol. So you don't know the actual percentage. It varies by region.

 

[El Pablo]

How do you know what your really getting? In Tulsa the Tankers all pull up to the same tank farm in west Tulsa.
They just push some buttons and the additives get mixed in. Who know what was still in the tanker?

Get a sensor.
I can run this one on my brz Delicious Tuning Flex Fuel Bluetooth MK1 Kit - FRS/BRZ/86
then I can adjust tune on the fly since e85 is 100-105 octane equivalent. I’m always tempted when e85 costs 2/3rd or less than 91 octane.

 

[Shadowrider]

Get a sensor.
I can run this one on my brz Delicious Tuning Flex Fuel Bluetooth MK1 Kit - FRS/BRZ/86
then I can adjust tune on the fly since e85 is 100-105 octane equivalent. I’m always tempted when e85 costs 2/3rd or less than 91 octane.

Most people don't understand octane. Propane has an octane rating up around 110. NG is about 130. Either will get you less horsepower and a little less mileage than gasoline. The difference isn't huge, but it's there.

On another note, I really wish the BRZ was AWD like the rest of the line. I'd totally have one!

 

[El Pablo]

Most people don't understand octane. Propane has an octane rating up around 110. NG is about 130. Either will get you less horsepower and a little less mileage than gasoline.

On another note, I really wish the BRZ was AWD like the rest of the line. I'd totally have one!

I should get more hp due to more aggressive tuning since it would be harder to get premature detonations, not a lot but 5-10% more hp, but 1/3 less mpg. I can really crank up the tune and it runs a bit cooler. Which is why I’m only interested when e85 is 2/3 the price of 91. Well, I’m interested all the time, stil haven’t pulled the trigger. I just hate e85s hygroscopic properties and I let that car sit a bit, which doesn’t work well with e85.

id take 300 hp over awd in a brz

 

[SiGArmed]

You can test the ethanol concentration with one of these:

Tester.


My Tundra is flex fuel, while I do get less MPG it def runs like a scalded ass ape on it lol. I feel like I break even on cost vs mpg running it and out here most places don't have E85 so I don't worry about it.

 

[TulsaMike]

How do you know what your really getting? In Tulsa the Tankers all pull up to the same tank farm in west Tulsa.
They just push some buttons and the additives get mixed in. Who know what was still in the tanker?

So there is a $10 tester kit you can buy, however if your truck is flex fuel it automatically adjusts, and if it’s out of a pump, it’s “supposed” to be e10 or e15 depending on summer or winter blend. The pump will usually say the max ethanol content, but ad you said, who knows what’s in the ground or the tank. That being said, I have an ethanol gauge I watch like a hawk because many of my race cars were not flex fuel and tuned for a specific alcohol content. Kum and go has been very consistently e70 for their ethanol blend, and e10-e11 for their gasoline. I’d imagine QT and Costco are similar due to the amount of traffic they have and how rare fuel sits in their tanks.

 

[TulsaMike]

Most people don't understand octane. Propane has an octane rating up around 110. NG is about 130. Either will get you less horsepower and a little less mileage than gasoline. The difference isn't huge, but it's there.

On another note, I really wish the BRZ was AWD like the rest of the line. I'd totally have one!

This is absolutely true IF your car isn’t tuned for the higher octane. A car meant to run on 87 won’t make any more power (actually makes less) with 91 or 93. A car properly adjusted for higher octane can make significant gains. I’ve done a lot of e85 tunes on vehicles and even naturally aspirated, the ethanol makes a noticeable part throttle different with the better resistance to knock. Unfortunately the cheaper cost of ethanol when factored against the lower mileage usually evens out unless gas is on a high week.