How to run E85 on stock 86 BRZ FRS with OFT tune

[CJRhoades]

Flashed the latest v3.02 Stg2 E85 tune for MY17 last week and have driven about 100 miles now. Car feels pretty good and I haven't had any issue with cold starts. LTFT hovers around -3% when driving but sits at -12.5% at idle. Is this a problem? I couldn't find any stations in my area that carry actual E85. Most of the pumps say Min 51% but I found a place that said Min 70% and filled up with that. Maybe just residual 93 in the tank?

Edit: Finished first tank and refueled. Idle LTFT down to -3% now. Drove about 240 miles today with an average speed of 53mph and got 23.5mpg. Not bad.

[Toyarzee]

So if the California blends are shown as 51-83% on all stations in my area, and I'm seeing some knock between 3-4k rpms and negative ltft between -2 to -6% range and sometimes more, is it best to abort the e85 plan and stick to 91, or is it really that easy to edit the ignition advance to compensate for low ethanol content and make the tune safe to run without second guessing every day? Im afraid of messing this up (stock car except for cbe) and the car sounds horrible under load right at 4k rpms

[Submarinesonce]

Originally Posted by Toyarzee

So if the California blends are shown as 51-83% on all stations in my area, and I'm seeing some knock between 3-4k rpms and negative ltft between -2 to -6% range and sometimes more, is it best to abort the e85 plan and stick to 91, or is it really that easy to edit the ignition advance to compensate for low ethanol content and make the tune safe to run without second guessing every day? Im afraid of messing this up (stock car except for cbe) and the car sounds horrible under load right at 4k rpms

sounds like you need a flex fuel kit

[guybo]

Yeah, everything I've read looking into E85 says that anything below E60 is dangerous and will run very lean. How's your AFR?

[Toyarzee]

Originally Posted by Submarinesonce

sounds like you need a flex fuel kit

yeah... ok... in Northern California especially, it sounds...

Originally Posted by guybo

Yeah, everything I've read looking into E85 says that anything below E60 is dangerous and will run very lean. How's your AFR?

AFR seemed fine i thought... but I need to take it out for another drive to get better readings

https://datazap.me/u/toyarzee/first-...=0&data=2-8-10

[steve99]

Originally Posted by Toyarzee

yeah... ok... in Northern California especially, it sounds...



AFR seemed fine i thought... but I need to take it out for another drive to get better readings

https://datazap.me/u/toyarzee/first-...=0&data=2-8-10

ltft look ok suspect ethanol content is fine, if ethanol content was way low the ltft would be quite negative at low rpm like -10% or more.


not seeing any knock correction or FLKC in that log and IAM is 1


looks like it might be a little rich under full load though.


the horrible noise around 4000 rpm is likely the el header cam timing.


If you don't like it load the UEL header E85 tune you wont get the raspy noise at 4000

[Lantanafrs2]

Since adding the ofh and uel tune my idle is nice and steady even with a.c. on. With stock manifold and el e85 tune it was bouncing around a bit. Car is smooth and strong with header and e85.

[Toyarzee]

Few more questions on tuning for e85 and afr. I understand that e85 lambda or afr reads differently than 91, and the safe tuning range is more broad with e85. However, what I'm not understanding is if the reported afr on the oft and its data logs are an innacurate reading since the sensor is tuned for gasoline afr. If I'm seeing the typical 14.7 at idle and cruise, and between high 10s and low 11s sometimes when wot, what afr is it really running at? If it's already too rich and the reading is actually richer than the oft is reporting, then I'm waaay too rich accross the board.

I was hesitant to necro some old threads on fuel filter degradation and lamda readings such as this: http://www.ft86club.com/forums/showthread.php?t=46582

[Lincoln Logs]

Originally Posted by Toyarzee

Few more questions on tuning for e85 and afr. I understand that e85 lambda or afr reads differently than 91, and the safe tuning range is more broad with e85. However, what I'm not understanding is if the reported afr on the oft and its data logs are an innacurate reading since the sensor is tuned for gasoline afr. If I'm seeing the typical 14.7 at idle and cruise, and between high 10s and low 11s sometimes when wot, what afr is it really running at? If it's already too rich and the reading is actually richer than the oft is reporting, then I'm waaay too rich accross the board.

I was hesitant to necro some old threads on fuel filter degradation and lamda readings such as this: http://www.ft86club.com/forums/showthread.php?t=46582

The AFR you see on your OFT is just a translation of lambda reported by the o2 sensor. So yes, while the actual AFR is richer it really doesn't matter just tune and use the same "AFR" targets as gasoline. Could you do the work to translate the gasoline AFR to ethanol AFR, sure, but it doesn't help you tune.

[Toyarzee]

Originally Posted by Lincoln Logs

The AFR you see on your OFT is just a translation of lambda reported by the o2 sensor. So yes, while the actual AFR is richer it really doesn't matter just tune and use the same "AFR" targets as gasoline. Could you do the work to translate the gasoline AFR to ethanol AFR, sure, but it doesn't help you tune.

Ok... pardon my ignorance, but if the actual afr is different, then why wouldn't my target afr be different from gasoline as well? Or is the difference in afr reading the same difference in target afr anyway? Trying to understand when the tune would be outside the safe boundaries for e85 afr, and why

[Lincoln Logs]

Originally Posted by Toyarzee

Ok... pardon my ignorance, but if the actual afr is different, then why wouldn't my target afr be different from gasoline as well? Or is the difference in afr reading the same difference in target afr anyway? Trying to understand when the tune would be outside the safe boundaries for e85 afr, and why

Let me rephrase, the reason it doesn't really matter is because AFR is just a translation we use to make it easier to understand the lambda value from the o2 sensor. The ECU never sees an AFR value it just sees lambda, which doesn't care about fuel type.

Another example: if the o2 sensor reports a lambda of 1.0 it doesn't care weather it is pump gas or E85...it just sees a lambda of 1.0 and will tune accordingly.

What you are actually talking about is altering the car's AFR reference to stoich which is a completely different thing. This is something you could do on a standalone ECU but it will just make your brain hurt trying to translate gasoline AFRs to E85 AFRs. The bottom line is just leave the AFR targets as they are and just tune your AFR as if it was gas. On a high strung race car you might want to run them a touch leaner but for anyone else, don't worry about it since the sweet spot on E85 is so much bigger.

[Toyarzee]

Damn, ok I'm cluing in finally, THANK YOU.... I thought the lamda would be different too since a different fuel density and energy.

I watched a video last night with some guys tuning and comparing 114 octane race fuel and e85 race fuel rated at 112 octane, and they were swapping carbs on a Chevy big block at 13:1 while on a dyno. Each time they tried adding more timing and fuel, they were discussing how the fuel was burning slower and it wasnt working, referencing how lamda readings were different and it was making my brain hurt. They also went through the long list of e85 cons making me paranoid, including fuel line and pump filter degradation, buildup and blockages, aluminum components breakdown, and storage issues, along with AFR conversions and issues running too rich creating knock.

I trust that the hundreds of oft users running e85 ots tunes would be up in arms if the tune wasn't compatible, but between hearing new noises, new butt dyno and the torque dip still prevailing on oem header, I don't wanna screw up the motor out of lack in understanding.

[Lincoln Logs]

Originally Posted by Toyarzee

Damn, ok I'm cluing in finally, THANK YOU.... I thought the lamda would be different too since a different fuel density and energy.

I watched a video last night with some guys tuning and comparing 114 octane race fuel and e85 race fuel rated at 112 octane, and they were swapping carbs on a Chevy big block at 13:1 while on a dyno. Each time they tried adding more timing and fuel, they were discussing how the fuel was burning slower and it wasnt working, referencing how lamda readings were different and it was making my brain hurt.

They also went through the long list of e85 cons making me paranoid, including fuel line and pump filter degradation, buildup and blockages, aluminum components breakdown, and storage issues, along with AFR conversions and issues running too rich creating knock.

I trust that the hundreds of oft users running e85 ots tunes would be up in arms if the tune wasn't compatible, but between hearing new noises, new butt dyno and the torque dip still prevailing on oem header, I don't wanna screw up the motor out of lack in understanding.

I know the video you are referencing, there was a lot to like but I feel their representation of it was a bit shortsighted. I've been running E85 in my cars for and tuning cars with it for years and many of the myths you hear about are simple not true.

The tales about build up and corrosion really only apply to much older cars. If the car was built in the late 80s or newer most items are already ethanol compatible. In the event you still have 20 year rubber fuel lines on a car with E85, shame on you...replace that with any rubber line from your local auto parts store and it will be E85 compatible.

If it's an older car you should replace the fuel filter as the E85 will loosen up dirt...so if you picked up the shell for your race car from a junk yard don't be surprised if it's full of crap. That is usually the cause for a car running E85 suddenly having problems.

[Kodename47]

Simple maths:
Lambda 1 = 9.76 AFR E85 / 14.7 Gasoline

((OFT AFR)/14.7)*9.76 = E85 AFR

That's why most tuners work with Lambda as it's not fuel specific.