Question about AFR on e85 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

RedPandas · 05-12-2019, 11:43 PM

So I just flashed my car on e85/flexfuel with a jdl turbo. My afr sitting idle is ~16.2and my target afr is 16.03. I always thought that I was supposed to stay 14.7, is this an issue? I know that with ethanol, timing could be a little more advanced so that may be why my afr is sitting at 16.03-16.2 idle. Can anyone confirm this? I sent a log over to my tuner already since he wanted a cruising log but I wanted to ask the public as well.

RedPandas · 05-12-2019, 11:44 PM

Also gotta add, when I cruise it's around 15-16

tomm.brz · 05-13-2019, 07:12 AM

are you reading that afr from a wideband or from obd lambda #1?

BigTuna · 05-13-2019, 07:55 AM

I thought e85 stoich was 9.8:1.

RedPandas · 05-13-2019, 11:41 AM

Quote:

Originally Posted by tomm.brz

are you reading that afr from a wideband or from obd lambda #1?

Obd

DarkSunrise · 05-13-2019, 01:29 PM

If it helps, I'm on OTS stage 2 e85 tune. My commanded AFR at idle is 14.94. Actual is around 14.6.

tomm.brz · 05-13-2019, 02:10 PM

i gu3ss that 14.94 is at a cold engine idle. When warm the ecu CAN T target leaner than 14.7

even if e85 stoich is something around 10:1, the lambda sensor will always think in Petrol Afr. so it will target 14.7 even with ethanol

DarkSunrise · 05-13-2019, 03:05 PM

Quote:

Originally Posted by tomm.brz

i gu3ss that 14.94 is at a cold engine idle. When warm the ecu CAN T target leaner than 14.7

Hmm not sure what to tell you. Coolant temps are 195+, oil temps 200+, commanded AFR is 14.94 at idle.

Here's an example from a log:

https://datazap.me/u/darksunrise/e85...3149-3118-3100

tomm.brz · 05-13-2019, 03:34 PM

you have Oft i guess.

well oft is bugged since always. the command afr log value has a strange lean offset, that 14.94 actually is 14.7 as you can see from your actual afr
so many years and Openflash never fixed it. i really personally hate that thing and tuning with tactrix is so much better and so much more values together

RedPandas · 05-13-2019, 04:49 PM

I have ecutek, if you were referring to me lol.

tomm.brz · 05-13-2019, 05:55 PM

No sorry, was replying to DarkSunrise
ecutek always logs perfect and with fast refresh rate

i log more than 60 values at the same time at 40Hz with ecutek, oft less than 12 values and not even 10Hz

steve99 · 05-13-2019, 06:42 PM

The 02 sensor measures free oxygen, not afr. The 02 sensor is scaled to read petrol afr regardless of if car is running e85 or petrol you should see about 14.7 afr target and 14.7 commanded afr at idle once car warm.

Under light load 13 afr heavy richer like low12 or even high 11.

This is the reading you will see if logging using standard 02 regardless of petrol or e85 as the 02 is scaled for petrol afr readings.

The true e85 afr will not be shown

shr133 · 05-22-2019, 11:24 PM

Something is up with your tune, E85 should read the same AF. All my readings stayed the same switching to E85.. You can run + .5 to 1 AF so up to 15.7 but it will down on power. I use this for my economy map. On your power map you will run about the same AF ratio as gas for max power. But you may be running more port injection ect so the AF ratio may change. Your Custom AF ratio map may not be working right....

Breadman · 05-23-2019, 07:44 AM

Quote:

Originally Posted by shr133

Something is up with your tune, E85 should read the same AF. All my readings stayed the same switching to E85.. You can run + .5 to 1 AF so up to 15.7 but it will down on power. I use this for my economy map. On your power map you will run about the same AF ratio as gas for max power. But you may be running more port injection ect so the AF ratio may change. Your Custom AF ratio map may not be working right....

whats the mpg before and after when putting around town?

05-13-2019, 07:55 AM	#4
BigTuna Senior Member Join Date: Jun 2015 Drives: 2013 WRB BRZ Location: Ohio Posts: 672 Thanks: 258 Thanked 477 Times in 275 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	I thought e85 stoich was 9.8:1. __________________ 2013 WRB "Build" Thread

05-13-2019, 01:29 PM	#6
DarkSunrise Senior Member Join Date: Apr 2012 Drives: 22 BRZ (Previously 13 FR-S) Location: USA Posts: 5,794 Thanks: 2,164 Thanked 4,242 Times in 2,220 Posts Mentioned: 48 Post(s) Tagged: 2 Thread(s)	If it helps, I'm on OTS stage 2 e85 tune. My commanded AFR at idle is 14.94. Actual is around 14.6. __________________ "Never run out of real estate, traction, and ideas at the same time." 2022 BRZ Build 2013 FR-S Build

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05-12-2019, 11:43 PM	#1
RedPandas Member Join Date: May 2019 Drives: 2018 BRZ Location: West Covina Posts: 26 Thanks: 7 Thanked 2 Times in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Question about AFR on e85 So I just flashed my car on e85/flexfuel with a jdl turbo. My afr sitting idle is ~16.2and my target afr is 16.03. I always thought that I was supposed to stay 14.7, is this an issue? I know that with ethanol, timing could be a little more advanced so that may be why my afr is sitting at 16.03-16.2 idle. Can anyone confirm this? I sent a log over to my tuner already since he wanted a cruising log but I wanted to ask the public as well.

05-12-2019, 11:44 PM	#2
RedPandas Member Join Date: May 2019 Drives: 2018 BRZ Location: West Covina Posts: 26 Thanks: 7 Thanked 2 Times in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Also gotta add, when I cruise it's around 15-16

05-13-2019, 07:12 AM	#3
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	are you reading that afr from a wideband or from obd lambda #1?

05-13-2019, 02:10 PM	#7
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	i gu3ss that 14.94 is at a cold engine idle. When warm the ecu CAN T target leaner than 14.7 even if e85 stoich is something around 10:1, the lambda sensor will always think in Petrol Afr. so it will target 14.7 even with ethanol

05-13-2019, 03:34 PM	#9
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	you have Oft i guess. well oft is bugged since always. the command afr log value has a strange lean offset, that 14.94 actually is 14.7 as you can see from your actual afr so many years and Openflash never fixed it. i really personally hate that thing and tuning with tactrix is so much better and so much more values together

05-13-2019, 04:49 PM	#10
RedPandas Member Join Date: May 2019 Drives: 2018 BRZ Location: West Covina Posts: 26 Thanks: 7 Thanked 2 Times in 1 Post Mentioned: 0 Post(s) Tagged: 0 Thread(s)	I have ecutek, if you were referring to me lol.

05-13-2019, 05:55 PM	#11
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,196 Thanks: 500 Thanked 1,067 Times in 775 Posts Mentioned: 65 Post(s) Tagged: 0 Thread(s)	No sorry, was replying to DarkSunrise ecutek always logs perfect and with fast refresh rate i log more than 60 values at the same time at 40Hz with ecutek, oft less than 12 values and not even 10Hz

05-13-2019, 06:42 PM	#12
steve99 Banned Join Date: Dec 2013 Drives: FT86 Location: Australia Posts: 7,998 Thanks: 1,035 Thanked 4,987 Times in 2,981 Posts Mentioned: 598 Post(s) Tagged: 2 Thread(s)	The 02 sensor measures free oxygen, not afr. The 02 sensor is scaled to read petrol afr regardless of if car is running e85 or petrol you should see about 14.7 afr target and 14.7 commanded afr at idle once car warm. Under light load 13 afr heavy richer like low12 or even high 11. This is the reading you will see if logging using standard 02 regardless of petrol or e85 as the 02 is scaled for petrol afr readings. The true e85 afr will not be shown

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