Rich on e85 stoich
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Staging Lane
Joined: Mar 2018
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Rich on e85 stoich I switch to e85 and on my hptuners changed the stoich to 9.8 and the wideband is super rich its stays at 10.0 and car isn't even driveble my tune wasn't perfect before so should i maybe just increase stoich. It seems to run fine with 14.7 stoich on e85
if you didn't change your wideband to the e85 scale stoic is 14.7 on any fuel. Iirc you don't change the main afr in the tune either. Are you running flex fuel?
How much fuel was already in the tank? Did you test the e85 to verify the alcohol content?
When I switched to E I tested it at 70 percent and entered stoich for e70 as 10.7. When I fired it up it idled right at 14.7 on the gas scale. I had just done the fuel system as well so the tank was completely empty and the tune was pretty good before the switch.
When I switched to E I tested it at 70 percent and entered stoich for e70 as 10.7. When I fired it up it idled right at 14.7 on the gas scale. I had just done the fuel system as well so the tank was completely empty and the tune was pretty good before the switch.
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Staging Lane
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I've already put more than 50 gallons of e85 and no I didn't check the ethanol% I'm running straight e85 no flex fuel sensor on a 0411 pcm and I have aem wideband and it reads lambda. It seems the perfect stoich is 14.7 should I just keep running it like this
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Use the gas scale. You're concerned with lambda, not actual AFR. Don't overthink it.
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on e85 with your wideband, you are running stoich at 14.7. the reason is the wifebands are scaled to read 14.7 at stoich or lambda of 1.
so pretty much no matter what fuel you are using, your wideband is going to read 14.7 at stoich.
rember, the wideband is not reading fuel. it's only reading left over oxygen. get used to tuning on lambda. its a bit triyk at first, but once you get the hang of it you can tune any fuel.
so pretty much no matter what fuel you are using, your wideband is going to read 14.7 at stoich.
rember, the wideband is not reading fuel. it's only reading left over oxygen. get used to tuning on lambda. its a bit triyk at first, but once you get the hang of it you can tune any fuel.
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are you running closed loop? In my head you should leave the stoic value in the tune 14.7, if you change it it 9.8 then the pcm is gonna try to get it to that with the narrowbands. The pcm doesn't know your using e85. I would leave the tune at 14.7 and tune it to stoic of 1.0 and it should be fine as long as you only ever run e85
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Or to put it another way, O2 sensors have NO IDEA what you are using for fuel. Stoich will ALWAYS be 14.7 to them.... As said, it only reads residual oxygen in the exhaust.
Last edited by G Atsma; Aug 9, 2018 at 08:04 PM.
Changing the stoich in the tune from 14.7 to 9.8 when going from gas to E85 is exactly the correct process.
I’ve converted several turbo cars to E85 from gas.
If the gas tune was good, everything should track nicely.
You first said your wideband said 10.0, then said it reads Lambda then said it goes lean. So a little confusing there.
BTW, Closed loop SD works very well. Turn off LTFT and leave STFT on.
Ron
I’ve converted several turbo cars to E85 from gas.
If the gas tune was good, everything should track nicely.
You first said your wideband said 10.0, then said it reads Lambda then said it goes lean. So a little confusing there.
BTW, Closed loop SD works very well. Turn off LTFT and leave STFT on.
Ron
Changing the stoich in the tune from 14.7 to 9.8 when going from gas to E85 is exactly the correct process.
I’ve converted several turbo cars to E85 from gas.
If the gas tune was good, everything should track nicely.
You first said your wideband said 10.0, then said it reads Lambda then said it goes lean. So a little confusing there.
BTW, Closed loop SD works very well. Turn off LTFT and leave STFT on.
Ron
I’ve converted several turbo cars to E85 from gas.
If the gas tune was good, everything should track nicely.
You first said your wideband said 10.0, then said it reads Lambda then said it goes lean. So a little confusing there.
BTW, Closed loop SD works very well. Turn off LTFT and leave STFT on.
Ron
When it comes to tuning there are always diff ways of achieveing the same thing. Changing stoich for E85 to 10.0 afr is one way, or leave stoich as the factory 14.7 and add 30% to the VE. Either way works.
Thread Starter
Staging Lane
Joined: Mar 2018
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Your e85 is most likely no where near 85% ethanol. The percentage varies enough to be a wild guess in some areas. You could easily be running anywhere from 60 to 90% ethanol at an e85 pump.
I disagree. Changing stoich to the actual stoich of the fuel you are running is absolutely the best way to go. You need to test your fuel and enter the actual stoich for your alcohol percentage and if your tune is good you literally have to change nothing else. Why hack up the VE and possibly create other issues when one number (stoich) is all you need to change?
A lot of people eave stoich 14.6 ad add 30% because they are familiar with the gas scale would be my guess. We just use lambda, easier for us.