Flex fuel questions for those with flex fuel kits and Hondata.

[Harlaquin]

So I am thinking of getting the flexfuel kit. First which one did you get and why? Also there are 25% tunes and then flex fuel tunes. Difference? Blending fuel, how do you fill your tank? Do you use the 4 gallon e-85 8 gallon 93? and which tune would use that? Can you just fill up full tank e-85 not blended? Would that be the flex fuel tune? I did some research but seemed to have more questions then answers so I figured I would ask people who actually use the kit. and if you fill up with 93 that is 10% can you just leave the flex full tune on or do you need to go back to the ethanol 10% tune? So many questions.... Thanks in advance.

Also if I were to fill up on pure 93 gas and add a fuel oct booster could I run the 100 oct tune? I rather a noob to all this tuning and fuel stuff.

Also if running pure e-85 do you also add e-85 fuel conditioners? as I have read e-85 is more corrosive adds more deposits and typically comes with no detergents of cleaners like regular gas.

flex fuel vehicles also have some component changes to accommodate the e-85 like fuel pump construction fuel line material and injectors. How will this effect longevity of the R since it was not built with e-85 in mine with its materials?

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[Harlaquin]

No one? I see so many say they have flex fuel set ups.

 

[toddrhodes]

i can't answer all of those questions but I am running Hondata + SiriMoto flex fuel.

Flex fuel just means the system/tuning solution can adapt to varying levels of ethanol in your fuel. Personally, the car feels great from about E20 to E35. Going higher than that is a waste, we simply can't supply enough fuel to use anything over E35-ish. I wouldn't ever fill up the whole tank with E85. It's an equilibrium point for the car that you have to find - as you increase ethanol, Hondata reduces boost. E25-E30 seems to hit the best compromise there where the car is faster, and yet runs lower amounts of boost to obtain that higher performance. Everything is happier at that point - turbo is more efficient, engine runs a little cooler, gas mileage doesn't go straight down, etc...

From my experience, pumps around here have about E10 for 93 octane. So what I do is on a low-ish fuel tank, pump in 1.5G of E85, then fill up the rest with 93. That will get you somewhere between E25 and E30, depending on how much ethanol is in the tanks at that particular station. It varies, and that's why Flex Fuel is great - the tuning solution accounts for the variability.

It's just my opinion but at E30-ish, you're not going to dry out the system or cause problems to a system not designed for E85 from the ground up. Use a high quality 93 octane, plus E85 in small doses, and I'm expecting it to be fine for the long-term.

I hope that helps.

 

[TypeSiR]

^^^ What he said.

A flex fuel kit (FFK)combined with an ethanol tune (OTS or custom) will allow you to run anything between straight gas and E85 (85% ethanol). Basically just fill up and go without worrying about mixing ethanol and gas, if you don’t care about max performance.

An ethanol tune/calibration without an FFK needs careful planning before fill up to ensure a specific gas/ethanol mixture, for maximum performance specific to the tune. And you lose the flexibility to use pump gas without first flashing back to gasoline tune.

 

[Harlaquin]

i can't answer all of those questions but I am running Hondata + SiriMoto flex fuel.

Flex fuel just means the system/tuning solution can adapt to varying levels of ethanol in your fuel. Personally, the car feels great from about E20 to E35. Going higher than that is a waste, we simply can't supply enough fuel to use anything over E35-ish. I wouldn't ever fill up the whole tank with E85. It's an equilibrium point for the car that you have to find - as you increase ethanol, Hondata reduces boost. E25-E30 seems to hit the best compromise there where the car is faster, and yet runs lower amounts of boost to obtain that higher performance. Everything is happier at that point - turbo is more efficient, engine runs a little cooler, gas mileage doesn't go straight down, etc...

From my experience, pumps around here have about E10 for 93 octane. So what I do is on a low-ish fuel tank, pump in 1.5G of E85, then fill up the rest with 93. That will get you somewhere between E25 and E30, depending on how much ethanol is in the tanks at that particular station. It varies, and that's why Flex Fuel is great - the tuning solution accounts for the variability.

It's just my opinion but at E30-ish, you're not going to dry out the system or cause problems to a system not designed for E85 from the ground up. Use a high quality 93 octane, plus E85 in small doses, and I'm expecting it to be fine for the long-term.

I hope that helps.

Thanks. I had seen a video that the guy was putting in 4 gallons of e-85 and then 8 gallons of 91 octane pure . His reasoning was that then the gas would be roughly 30 percent ethanol since the tank on the R is 12.39 gallons. So would that be e-30 then? So with yours most times i have filled up once the gas light comes on its typically about 10.2 or so gallons to fill back up. lets just say 10. So filling up 1 gallon e-85 and then the 10 percent 93 and with the roughly 2 gallons left in tank we would have 2 gallons of ethanol in the tank. So the gas would be roughly 16 percent ethanol at that point. This is where I get confused. So that is e-16? IM so lost when it come to the calculation of gas and octane.

So you could actually put about 1 more gallons of e-85 and one less gallon of 10% 93 (making it about 24 percent considering you are useing 10 percent main fuel)) to bring it closer to the hondata sweet spot of 25 to 28 ethanol?

Not questioning anything you are saying Im just talking may way through to understand this. or am I way off here and dont understand at all?

 

[Harlaquin]

^^^ What he said.

A flex fuel kit (FFK)combined with an ethanol tune (OTS or custom) will allow you to run anything between straight gas and E85 (85% ethanol). Basically just fill up and go without worrying about mixing ethanol and gas, if you don’t care about max performance.

An ethanol tune/calibration without an FFK needs careful planning before fill up to ensure a specific gas/ethanol mixture, for maximum performance specific to the tune. And you lose the flexibility to use pump gas without first flashing back to gasoline tune.

So if I plan my fuel precisely and use the 25% tune I dont need the FFK? The Kit allows me to just use what ever is what it does?

 

[toddrhodes]

To be honest, I don't fully understand the math here and I think you're overthinking it a little. It's one of those things where once you are ready for it - just like anything - start small and work up. I have a post lying around the forums somewhere that talks about my first fillup with an ethanol blend. Low fuel tank light was on, and I put in specific amounts of each and reported back the gauge readings. I remember the first fillup I hit E40 and based on rough map, did not think it would be that high. I've since adjusted it and kinda don't worry about trying to figure out the perfect ratio since that's flex fuel's job to sort out.

I haven't run flex in a little while as I'm finishing up an e-tune on 93 octane. That's what's so nice about it - if you don't have ethanol handy, you don't have to run it and the car works as it normally would. But when you do have a station nearby, you get to have a little more fun for that tank of fuel.

 

[toddrhodes]

So if I plan my fuel precisely and use the 25% tune I dont need the FFK? The Kit allows me to just use what ever is what it does?

That's technically correct but practically, considering FF is now available and supported, a big gamble. You unfortunately can't know what ethanol level is in the tanks at the station. Without that variable, you're still just taking a guess on the percentages.

 

[Harlaquin]

That's technically correct but practically, considering FF is now available and supported, a big gamble. You unfortunately can't know what ethanol level is in the tanks at the station. Without that variable, you're still just taking a guess on the percentages.

Got ya. here we do have guaranteed pure 93 gas stations and the regular ethanol ones. We even have one station has 93 pure and e-85 same station so makes it easy

But basically it can be done if nit picked about gas percentages with out a flex fuel but the kit makes it fool proof and worry free in case you don't carry a 1 or move a decimal ?

And you are correct I over think but it works for me I seldom run into regrets because I pick everything apart before I buy something. I just like to know the ifs and whys of how something works instead of just blindly trusting it. Not saying you are , just explaining my thought process .

 

[boosted180sx]

So I am thinking of getting the flexfuel kit. First which one did you get and why? Also there are 25% tunes and then flex fuel tunes. Difference? Blending fuel, how do you fill your tank? Do you use the 4 gallon e-85 8 gallon 93? and which tune would use that? Can you just fill up full tank e-85 not blended? Would that be the flex fuel tune? I did some research but seemed to have more questions then answers so I figured I would ask people who actually use the kit. and if you fill up with 93 that is 10% can you just leave the flex full tune on or do you need to go back to the ethanol 10% tune? So many questions.... Thanks in advance.

Also if I were to fill up on pure 93 gas and add a fuel oct booster could I run the 100 oct tune? I rather a noob to all this tuning and fuel stuff.

Also if running pure e-85 do you also add e-85 fuel conditioners? as I have read e-85 is more corrosive adds more deposits and typically comes with no detergents of cleaners like regular gas.

flex fuel vehicles also have some component changes to accommodate the e-85 like fuel pump construction fuel line material and injectors. How will this effect longevity of the R since it was not built with e-85 in mine with its materials?

1. 25% Tune and a flex fuel tune are totally different.

25% tune = tune strictly for E25 plus or minus few E%. Makes it hard because E85 labaled at the pump is not necessary 85%. Can be as low as E51 and can still legally be called E85.
flex fuel = the ability to run w/e ethanol % you would like and have the tune automatically adjust boost/ign timing/afr hence the world "flex"

2. Blending fuel depends on what % you are trying to run. Here in california, pump gas has E10 so I initially filled up with like 2.5 gallons of E85 and rest on E10 91 octane to get ~27%.

3. You can run E85 without blending technically with the flex fuel. Although i highly suggest against it due to the limitation of our fuel system. Your aircharge will be much lower and you probably would end up having less power than straight pump gas. The pro of a flex fuel imo is not necessary the ability to run straight E85 but the ability to run pump gas without reflashing in a pinch that you don't have access to ethanol.

4. Once you have enabled flex fuel, there is no need to change the tune at all. The flex part of it will automatically adjust depending on the E% that the fuel fuel sensor sees.

5. Technically you can yes. However, I am not a big fan of octane boosters. They contain MMT which has been shown to leave orange deposits on plugs and stuff. You can read it up on google if you are curious.

6. You shouldn't have to worry about fuel conditioner stuff. Ideally you want to be in the 20-30% range in my opinion and fuel components nowadays are build to handle that.

 

[ebatr24]

To the OP, you are over complicating this a bit. E85 refers to 85 percent ethanol content in the gas. The reason you get a flex fuel kit is because it adds a sensor that reads the ethanol content and communicates it to the ECU, you should not run a Flex Fuel tune if you do not have a kit btw, you can run a tune for 25% ethanol content without a sensor but you are really chancing your cars reliability to the ethanol content of your mixture being correct. Spend the money and do it right, get a flex fuel kit and then the car will automatically adjust timing. You guys with E85 at the pump are quite lucky, I am out here in the Northwest and we have very few stations so I tend to store gas and add it myself before filling up. I run Thunderbolt E98 though so I need less of it to get the right mixture which is about E35-37.

Edit: Also there is handy E85 calculator apps that can help you when you go to fill up to know how much of each gas you need to run. I find the ones on the iPhone are kinda garbage if you have an iPhone though, had better luck with the ones on Android.

 

[boosted180sx]

Thanks. I had seen a video that the guy was putting in 4 gallons of e-85 and then 8 gallons of 91 octane pure . His reasoning was that then the gas would be roughly 30 percent ethanol since the tank on the R is 12.39 gallons. So would that be e-30 then? So with yours most times i have filled up once the gas light comes on its typically about 10.2 or so gallons to fill back up. lets just say 10. So filling up 1 gallon e-85 and then the 10 percent 93 and with the roughly 2 gallons left in tank we would have 2 gallons of ethanol in the tank. So the gas would be roughly 16 percent ethanol at that point. This is where I get confused. So that is e-16? IM so lost when it come to the calculation of gas and octane.

So you could actually put about 1 more gallons of e-85 and one less gallon of 10% 93 (making it about 24 percent considering you are useing 10 percent main fuel)) to bring it closer to the hondata sweet spot of 25 to 28 ethanol?

Not questioning anything you are saying Im just talking may way through to understand this. or am I way off here and dont understand at all?

calculating that way is not the best way to do it. The ethanol content at the gas stations can vary from E51-E85 and can still be legally called E85.
4 gallons of E51 vs 4 gallons of E85 would give you a totally different final Ethanol % value. From my experience, gas stations in my area all usually contain 75% but in colder climates, they tend to have a lower ethanol content to aid in start up in cold weather.

there are lots of calculators online if you know the ethanol content at the pump.
http://www.georgebelton.com/E85Calculator.php
https://www.hondata.com/flex-fuel-calculator
and lots more.

 

[Harlaquin]

1. 25% Tune and a flex fuel tune are totally different.

6. You shouldn't have to worry about fuel conditioner stuff. Ideally you want to be in the 20-30% range in my opinion and fuel components nowadays are build to handle that.

Thanks. Can you explain how different so I can understand? so a 25 tune I could do on own with just gas mixture and tune no kit required?

Reason I asked about fuel conditioners is on a dedicated ethanol site i read that the conditioners and cleaners in gas are not solvable in ethanol. Ethanol tends to suspend them and they just get caught in the fuel filter. They suggested adding ethanol cleaners if you ran it a lot. But I ask here as well because no one site is ever 100 correct. I like different view points.

 

[Harlaquin]

To the OP, you are over complicating this a bit. E85 refers to 85 percent ethanol content in the gas. The reason you get a flex fuel kit is because it adds a sensor that reads the ethanol content and communicates it to the ECU, you should not run a Flex Fuel tune if you do not have a kit btw, you can run a tune for 25% ethanol content without a sensor but you are really chancing your cars reliability to the ethanol content of your mixture being correct. Spend the money and do it right, get a flex fuel kit and then the car will automatically adjust timing. You guys with E85 at the pump are quite lucky, I am out here in the Northwest and we have very few stations so I tend to store gas and add it myself before filling up. I run Thunderbolt E98 though so I need less of it to get the right mixture which is about E35-37.

Edit: Also there is handy E85 calculator apps that can help you when you go to fill up to know how much of each gas you need to run. I find the ones on the iPhone are kinda garbage if you have an iPhone though, had better luck with the ones on Android.

Thanks I see my mistake I was figuring e-85 as pure ethanol so would have messed up the percentages. My plan is to get the kit, im just talking all angles to get as much info and knowledge as possible from those who have run it and have the kit.

Also what is the other 15 % in the e-85? just gas? what oct? or something else?

 

[Harlaquin]

calculating that way is not the best way to do it. The ethanol content at the gas stations can vary from E51-E85 and can still be legally called E85.
4 gallons of E51 vs 4 gallons of E85 would give you a totally different final Ethanol % value. From my experience, gas stations in my area all usually contain 75% but in colder climates, they tend to have a lower ethanol content to aid in start up in cold weather.

there are lots of calculators online if you know the ethanol content at the pump.
http://www.georgebelton.com/E85Calculator.php
https://www.hondata.com/flex-fuel-calculator
and lots more.

Ah so we are at the mercy of legally allowed to say.... even though its not what you are actually paying for. Typical BS marketing. Like saying you can get UP TO a 15% discount but no one ever gets it because it CAN be UP TO but never is. But that s what they advertise.

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