Flex Fuel kit, tunes - switching between fuels

[Nigruto]

Hey guys,

I'm new to the 86/BRZ scene, recently sold my 96' NA Supra for my 2013 Manual 86.

I'm currently running a stock exhaust and headers w stock ecu map.
So far ive settled on these mods for the next few months:
- XForce catless headers
- Xforce catback
- K&N hi flow filter
- stage 2+ (E85) via ecuflash tactrix

My question is: is it worth buying a Flex Fuel kit for my 86? Is there any other benefit besides knowing ethanol percentages. If i do, will my ecu be able to recognise when I'm running 98 octane or E85 (can i switch fuel without having to re-tune)?

Worst case if im low on fuel and theres no other options for E85 i just re-tune my ecu to 98 octane when im at the servo (just carry my laptop around along w tactrix).

Need some advice just not sure what to run atm, i have E85 pumps rly close to me so daily driving w E85 is not a problem at all.

Thanks

[Grady]

Originally Posted by Nigruto

recently sold my 96' NA Supra

Not that you should have not gotten the 86 but I understand some people not wanting 2 vehicles.

As far a flex fuel sensor it makes it easy. You just put in what fuel you have available and you are good. I am on E85 90+% of the time. It is that one time you get somewhere and it is not available. With the sensor it no worries.

[Drifter X]

If you plan on constantly switching between the or just like being able to switch between the two, the a flex fuel kit is needed. With the kit, and your e85 tune, your ecu will be able to handle the changes in type of fuel.


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[Irace86.2.0]

Originally Posted by Nigruto

Hey guys,

I'm new to the 86/BRZ scene, recently sold my 96' NA Supra for my 2013 Manual 86.

I'm currently running a stock exhaust and headers w stock ecu map.
So far ive settled on these mods for the next few months:
- XForce catless headers
- Xforce catback
- K&N hi flow filter
- stage 2+ (E85) via ecuflash tactrix

My question is: is it worth buying a Flex Fuel kit for my 86? Is there any other benefit besides knowing ethanol percentages. If i do, will my ecu be able to recognise when I'm running 98 octane or E85 (can i switch fuel without having to re-tune)?

Worst case if im low on fuel and theres no other options for E85 i just re-tune my ecu to 98 octane when im at the servo (just carry my laptop around along w tactrix).

Need some advice just not sure what to run atm, i have E85 pumps rly close to me so daily driving w E85 is not a problem at all.

Thanks

E85 here is never E85. It is E55-85, so for me, running a flex-fuel setup is a must. The flex-fuel system works with a flex-fuel tune to modify fuel trims based on ethanol percentage. In winter, the blend at the pumps is closer to E65 to reduce the difficulties associated with a cold start. In summer, the blend is closer to E85, but the highest I have ever gotten mine is E78-82, and that is running ethanol exclusively for many fill ups.

If you run only a dual tune then you should deplete your tank as much as possible before switching fuels and remapping the computer. If you have a toggle that switches maps without a reflash (I have different maps using the cruise control stalk) then that makes life easier, but the accuracy is never as good as it could be with a flex-fuel setup. For instance, if you were on an E85 tune with too much pump gas in the mix then you would be running rich, and if you were on a pump gas tune with too much E85 in the tank then you would run too lean. It could be bad. The ECU could compensate for those conditions by adjusting fuel maps and ignition timing, but if this was good and possible then no one would need flex-fuel systems, which is not the case.