93oct E30 Fuel

[Spektyr]

There's a gas station around these parts called "Jumpstart" that does an exceptionally poor job of labelling their fuel properly. They have 93 octane (which isn't common in the Midwest) and as far as I can tell it says nowhere on the pump that it's E30 (it is) - simply that it has "Kansas ethanol".

Lucky for me there's a Casey's about the same distance in another direction that has real 93oct with 10% ethanol - for a substantially higher price.

I've done some Internet Sleuthing and earned my Internet PhD (worth the paper it isn't printed on) but I wanted to bounce the topic off folks here.

My truck is FlexFuel so it'll run on damn near anything flammable and I've ordered an ethanol test cylinder so I can check to verify that they're selling unmarked E30 at their pumps.

From what I've read the primary concerns for running E30 in a car rated for only E10 or E15 are:

• Reduced Fuel Economy
• Potential HPFP clogging
• Hotter Engine Temps

The first and last are less of a concern for daily driving, and the middle one seems connected mostly to cars that are infrequently driven.

I saw one dyno graph that showed E30 on a stock 91 octane ECU tune (different vehicle) had some modest hp/torque gains, and then tuning for E30 gave even higher gains.

So I'm wondering exactly what harm running E30 in the GR86 could cause, since I'm now considering the possibility of getting an E30 tune in the future. It'd be nice to be able to do some side-by-side testing on MPG between standard 93 octane and E30 octane - both on a proper ECU tune - to see if there's actual money to be saved. (E30 is a lot cheaper at Jumpstart, but if you use enough more per mile it isn't actually a bargain.)

Obviously if it's going to clog stuff up or otherwise risk the warranty, that changes the math considerably.

[Lantanafrs2]

I thought e30 is higher than 93 octane

[gnarjunkie]

Originally Posted by Lantanafrs2

I thought e30 is higher than 93 octane

It's probably pretty similar, considering e50 is 100 octane and e85 is 105.

I can't really think of a reason it wouldn't work mechanically... all the fuel components would be the same as if you got an e30 tune. You might need bigger injectors or fuel pump but it wouldn't hurt you to not have them... you just wouldn't really see power gains without.

Ethanol also has a cooling effect, so e30 shouldn't cause higher engine temps.

I still wouldn't run a fuel other than what was my car was tuned for though. In theory, it seems logical enough. But I wouldn't want to test it for the sake of slightly cheaper gas.

[tomm.brz]

Originally Posted by Lantanafrs2

I thought e30 is higher than 93 octane

Not necessarily, they make a blend usually, so if it s only 93 but e30 means the petrol base is lower cheaper quality

You could drive it, trims can handle that if you drive slow for a while to let it learn, but ideally you would see a log during a pull to see where the afr sits, but difficult at the mom in a gr86

[OkieSnuffBox]

Originally Posted by Spektyr

There's a gas station around these parts called "Jumpstart" that does an exceptionally poor job of labelling their fuel properly. They have 93 octane (which isn't common in the Midwest) and as far as I can tell it says nowhere on the pump that it's E30 (it is) - simply that it has "Kansas ethanol".

Lucky for me there's a Casey's about the same distance in another direction that has real 93oct with 10% ethanol - for a substantially higher price.

I've done some Internet Sleuthing and earned my Internet PhD (worth the paper it isn't printed on) but I wanted to bounce the topic off folks here.

My truck is FlexFuel so it'll run on damn near anything flammable and I've ordered an ethanol test cylinder so I can check to verify that they're selling unmarked E30 at their pumps.

From what I've read the primary concerns for running E30 in a car rated for only E10 or E15 are:

• Reduced Fuel Economy
• Potential HPFP clogging
• Hotter Engine Temps

The first and last are less of a concern for daily driving, and the middle one seems connected mostly to cars that are infrequently driven.

I saw one dyno graph that showed E30 on a stock 91 octane ECU tune (different vehicle) had some modest hp/torque gains, and then tuning for E30 gave even higher gains.

So I'm wondering exactly what harm running E30 in the GR86 could cause, since I'm now considering the possibility of getting an E30 tune in the future. It'd be nice to be able to do some side-by-side testing on MPG between standard 93 octane and E30 octane - both on a proper ECU tune - to see if there's actual money to be saved. (E30 is a lot cheaper at Jumpstart, but if you use enough more per mile it isn't actually a bargain.)

Obviously if it's going to clog stuff up or otherwise risk the warranty, that changes the math considerably.

Well, your truck is Flex Fuel. Which means it's capable of running everything from E0 to E85. So I wouldn't worry about it.

[Spektyr]

Originally Posted by OkieSnuffBox

Well, your truck is Flex Fuel. Which means it's capable of running everything from E0 to E85. So I wouldn't worry about it.

I mentioned that because it means I have a vehicle I can fill up on "mystery gas" and then have some to test to find out what it really is. Otherwise you're squirting just a bit into some kind of container, drawing an even smaller bit of it into a pipette to load the testing cylinder, and then potentially finding that you have no use for any of the fuel and no easy way to dispose of it safely (if you didn't have a flex fuel vehicle available.)

[OkieSnuffBox]

Originally Posted by Spektyr

I mentioned that because it means I have a vehicle I can fill up on "mystery gas" and then have some to test to find out what it really is. Otherwise you're squirting just a bit into some kind of container, drawing an even smaller bit of it into a pipette to load the testing cylinder, and then potentially finding that you have no use for any of the fuel and no easy way to dispose of it safely (if you didn't have a flex fuel vehicle available.)

Buuuuuuuuut, you do have a Flex Fuel vehicle, so I'm not sure why you're hung up on it.

Hell if you're that worried about it just don't use it.

[Spektyr]

I can't fill up the truck with gas to solve an empty tank in the GR86.

All of the vehicles require gas in each of their tanks to run, and I'm posting this here not on a Chevy S-10 forum. The truck will happily burn 87oct of any blend of alcohol so it's role in this conversation is - exclusively - as a repository for gasoline I want to test as a potential fuel for the GR86.

It also can conveniently carry a fuel can - get a gallon of gas, test at my leisure, dump the remainder in the truck's tank.

I'm specifically bringing up 93oct E30 as a topic of discussion as a potential fuel for the GR86.

[NoHaveMSG]

I would not advise running fuel the car is not tuned for

Edit: Picture looked fine on my phone and not like a potato. Manual says not to run more then E15.

[Spektyr]

Yeah, I knew that. I've also read the government studies that claim that E30 can be safely run in any car with a modern ECU that's tuned for E10 or E15, with the potential concerns I listed in the original post.

Since it's possible now to tune these cars and it's simply a matter of time before someone develops an E30 tune, I posted to the forum to see what people thought about that since A: there's likely some power gains to be had and B: there's some talk about higher ethanol fuels being bad for HPFPs.

[NoHaveMSG]

Originally Posted by Spektyr

Yeah, I knew that. I've also read the government studies that claim that E30 can be safely run in any car with a modern ECU that's tuned for E10 or E15, with the potential concerns I listed in the original post.

Since it's possible now to tune these cars and it's simply a matter of time before someone develops an E30 tune, I posted to the forum to see what people thought about that since A: there's likely some power gains to be had and B: there's some talk about higher ethanol fuels being bad for HPFPs.

Not all cars are the same so I don't think I would be going off a government study.

HPFP issues?? Peeps been running flex fuel on the first gen for almost a decade. I think we would be hearing about failures on them by now.

[alphasaur]

ethanol has a different stoich value than regular fuel, it has to run richer to reach stoich (9.7:1), meaning you burn a higher amount of ethanol vs gasoline (14.7:1)

If your car is not tuned for it you risk running lean

ethanol has an effective octane of ~160 in direct injection engines which is why even a blend like e30 can have a huge positive effect when tuned in a direct injection engine.

HPFP issue likely come from the Mazdaspeed community as higher than 50% ethanol on that platform can lead to "black death" of the HPFP, it's really just oil and fuel mixing and gumming up the HPFP. This platform does not have that issue. I guess the HPFP might also have to work harder since more fuel volume is needed?

[Spektyr]

Originally Posted by alphasaur

ethanol has a different stoich value than regular fuel, it has to run richer to reach stoich (9.7:1), meaning you burn a higher amount of ethanol vs gasoline (14.7:1)

If your car is not tuned for it you risk running lean

ethanol has an effective octane of ~160 in direct injection engines which is why even a blend like e30 can have a huge positive effect when tuned in a direct injection engine.

HPFP issue likely come from the Mazdaspeed community as higher than 50% ethanol on that platform can lead to "black death" of the HPFP, it's really just oil and fuel mixing and gumming up the HPFP. This platform does not that that issue. I guess the HPFP might also have to work harder since more fuel volume is needed?

Nice explanation. I knew that higher E## gas got fewer MPG, but not the explanation behind it. According to the government study on E30 I read, a modern ECU can adjust the fuel mixture to run E30 even if the car is rated for E10 or E15. I'm not saying that's a good idea, or that it even applies to our specific cars - I'm just saying that's what a study (that may or may not have any bias) said.

So it sounds like if you had an E30 tune on a twin it would be a solid option. Probably not as much power as an E85 tune, but also probably better MPG.

[alphasaur]

Originally Posted by Spektyr

Nice explanation. I knew that higher E## gas got fewer MPG, but not the explanation behind it. According to the government study on E30 I read, a modern ECU can adjust the fuel mixture to run E30 even if the car is rated for E10 or E15. I'm not saying that's a good idea, or that it even applies to our specific cars - I'm just saying that's what a study (that may or may not have any bias) said.

So it sounds like if you had an E30 tune on a twin it would be a solid option. Probably not as much power as an E85 tune, but also probably better MPG.

On the mazdaspeed platform you can hit mbt with ~e30, so there's not much more power to be made with higher concentrations of eth at least on that platform.

The study you're referring to is likely just the car recognizing it's running lean and adjusting fuel trims in order to maintain near the AFR it wants to hit.

I would imagine it's similar on this platform where a higher concentration of ethanol offers diminishing returns, and you can mitigate much of the negative effects of ethanol with a blend.