E85 Flex Fuel - 2019 AT4

[killramos]

Diesel is a great fuel too. Maybe you should mix a bit of that in your tank lol.

 

This forum has an odd obsession with putting fuels in these Trucks that they aren’t designed to take. 

[TXGREEK]

Diesel is a great fuel too. Maybe you should mix a bit of that in your tank lol.  

This forum has an odd obsession with putting fuels in these Trucks that they aren’t designed to take. 

 

 

It’s already mixed in the fuel and my only reasoning for adding some extra in my tank is for its cleaning abilities “ONLY!”

 

 

Sent from Above

 

 

[TJay74]

On 10/24/2019 at 5:36 PM, Black02Silverado said:

The 2019's for the 5.3 and 6.2 are not FF.  Makes me mad that they didn't offer it.  I still run a 50/50 mix of E85 and Premium in mine.  Same goes for my 2002 Silverado.  It isn't flex fuel but I do the same, 50/50 mix.  Love the way they run with it since it boost the octane up nicely.  Not to mention I like the exhaust smell.

 

While adding some E85 up to maybe E20 is ok as the ECM is programmed up to E10 with no issues, running E50 can and will cause some problems up to and including the A/F ratio to be off. AS the E85 percentage climbs the stoichiometric value changes from gas to E85 and actually richens up. If the FF portion of your tune is not enabled (from the factory they are not unless the truck was one that had it as an option, which the 18+ trucks dont have) then the ECM will not change the A/F ration to compensate for the E85.

You will be running lean in your case.

[TJay74]

On 10/27/2019 at 9:26 AM, killramos said:

Diesel is a great fuel too. Maybe you should mix a bit of that in your tank lol.

 

This forum has an odd obsession with putting fuels in these Trucks that they aren’t designed to take. 

The fuel system in the trucks is more than capable of handling E85, even the ECM has all of the parameters in place for E85 but as said there are 2 important parts of the tune turned off that enables those features along with the sensor not being plumbed in.

Anything GM made with in the last 5-7 years can handle and run E85 just fine once the sensor is added and the calibration is changed. Zero issues at all. While E85 is Hygroscopic it isnt like it attracts every ounce of moisture instantly. It is an issue that happens over time, more so if the fuel is left just sitting. AS long as you run the fuel out and replace it and even run a full tank of regular ole gasoline thru the system there are zero issues. 

With the gas tank being 26 gallons in the trucks, you can run up to 5 gallons of E85 with zero issues which is 20%. If you run 4 gallons it puts you at 15%, the extra octane will help with detonation that the DI engines are really prone to during the warmer months of the year.

[TXGREEK]

The fuel system in the trucks is more than capable of handling E85, even the ECM has all of the parameters in place for E85 but as said there are 2 important parts of the tune turned off that enables those features along with the sensor not being plumbed in.

Anything GM made with in the last 5-7 years can handle and run E85 just fine once the sensor is added and the calibration is changed. Zero issues at all. While E85 is Hygroscopic it isnt like it attracts every ounce of moisture instantly. It is an issue that happens over time, more so if the fuel is left just sitting. AS long as you run the fuel out and replace it and even run a full tank of regular ole gasoline thru the system there are zero issues. 

With the gas tank being 26 gallons in the trucks, you can run up to 5 gallons of E85 with zero issues which is 20%. If you run 4 gallons it puts you at 15%, the extra octane will help with detonation that the DI engines are really prone to during the warmer months of the year.

I’ve been adding 6 gallons of E85 then filling the rest up with super, ZERO problems


Sent from Above

[Black02Silverado]

1 hour ago, TJay74 said:

 

While adding some E85 up to maybe E20 is ok as the ECM is programmed up to E10 with no issues, running E50 can and will cause some problems up to and including the A/F ratio to be off. AS the E85 percentage climbs the stoichiometric value changes from gas to E85 and actually richens up. If the FF portion of your tune is not enabled (from the factory they are not unless the truck was one that had it as an option, which the 18+ trucks dont have) then the ECM will not change the A/F ration to compensate for the E85.

You will be running lean in your case.

I pretty much don't go past a 50/50 mix.  Been doing it for over 3 years  now.  I guess what damage that might occur has already been done.  It is just a matter of time before it shows up I guess.  At least my UOA's are showing no issues at all and are just as good if not better than before running straight premium.  What I need to do is run a scope down the spark plug holes and see what the piston tops look like.

[Doolin-Dalton]

On 10/26/2019 at 9:12 PM, CamGTP said:

There is no sensor and if the truck is not E85 equipped, even the virtual sensor is set to disable. That is done even on the K2XX trucks.

 

GM has also been setting stoich to E10 ratings of 14.1 since 2014ish. The way the computer can still try to achieve stoich is through fuel trims. It can sense that something is different with the E85 mix that some people run but it can't tell the actual alcohol content. Fuel mileage is still going to be less because of the fact that the computer is smart enough to use the fuel trims to make it run good.

 

Saying 10-15% increase in power is a stretch. I'd have to go back the wiki page for exact numbers but I believe GM rated the GEN V 5.3 engine at 355hp and 383hp on E85. That is an increase of only 7-8% and that is on real E85. The torque increase is the roughly the same at 6-7%.

Hey bud, I appreciate your energy content on this e85 topic, but we need to square some things here. More on that below.  First things first, the e85 mixing it really does run good at 50-50 mix (93 gasoline and e85).  This is producing an e48 blend roughly.   No engine knock at all, none whatsoever.   If the worse thing that is happening is running rich (Lambda is less than 1.0) that's not at all bad. Engines are designed to run rich all the time, under load, under WOT, in cold temps.  

Now, a few things to clarify from what you're saying.  Let's take a walk around the engine shop, shall we?  

1) "GM has also been setting stoich to E10 ratings of 14.1"   <-- GM doesn't set stoich.  Stoich is the property of the air content in the fuel itself.  GM sets +/- fuel trim for driving conditions.  The stoich of pump gasoline is 1:14.7, one gram of fuel, 14.7 grams of air

2)  "The way the computer can still try to achieve stoich is through fuel trims. It can sense that something is different with the E85 mix that some people run but it can't tell the actual alcohol content"   <-- The O2 Sensor on the Exhaust manifold is what reads the oxygen content.  If the oxygen is too high, it reports back to the computer, which is then going to send more fuel (Trim up +)

3) Guess what -  e85 has the highest content of oxygen of any fuel source.  The Stoich property of e85 is 1:9.765, 1 gram of corn fuel, 9.765 grams of air.  That might seem confusing, counter intuitive, but realize the lower the ratio gets, the closer to 1:1 parts of fuel and air, essentially we're getting much more air content, with e85.

4) So what does the engine (GM's computer) do when it senses too much air, via the 02 sensor?  It sends more fuel.   That's why I'm getting 14mpg with the 50-50 mix, versus 22mpg with straight gasoline.  In order to optimize the ideal amount of fuel,  we need to think in terms of Lambda readings (not Stoich)   Lambda is the post combustion ratio of what is actually occurring.  Our 02 sensors, I have no idea if they are wide-band, or narrowband. I'm guessing they are narrowband, so they aren't giving the most optimized measurement. 

5) Optimized for what you ask?  Detonation, at full compression (not too soon, not too late) 

6) For today, is all of this optimized?  Hell no it's not, that's why I'm not running full 100% e85.  The only way any of us is going to be able to optimize it, is getting (1) new sensor, that is a wide-band 02, and a tune that can be set to those updated readings, calculating Lambda.

7) What are those readings going to be?  They are not going to be Stoich pre-set A/F RATIOS. That's not the right way to work with e85.  You need to be using LAMBDA.  A combination of post combustion (wide-band 02 Sensor reading) that accurately tells the PCM,  either too much oxygen a.k.a "lean" (lambda > 1.00) or too little oxygen a.k.a "rich" (lambda < 1.00), and to adjust trim (precisely how much to adjust) and to optimize performance based on the fuel type.  ADD a pre-combustion e85 sensor, that will tell the computer the exact fuel content e85, e70, e48, going into the engine, prior to combustion - so that you can get the ideal detonation at full compression  (no knock, no pre-detonation) just pure, clean, cold, optimized power. 

In the meantime, is this 50-50 thing generating more HP,  cleaner burning fuel, cooler engine temps for longer engine life?  YES, ALL DAY LONG. 

 

Edited October 30, 2019 by Doolin-Dalton

[CamGTP]

Here is just a little proof that "GM does set the stoich ratio to 14.1".

 

I understand the 14.7 parts air to 1 part fuel for 100% gasoline, it's just that they do not use 100% gasoline in the calibrations anymore because everything can be up to E10 at the pump on regular 87 octane.

 

GM doesn't set a +/- for the fuel trims, there is no table within the calibration for that.

 

As said the 02 sensors/fuel trims only report what is going on in the exhaust. These are narrowband o2 sensors and .450mv is what we consider to be stoich. The sensors will show it swinging lean and rich of that value and the trims will show you the work being done to reach that. Be it a negative value or trimming fuel or positive value of adding fuel in real time on the fly.

 

The main problem I have with people running these mixes is that there is far more to the picture than just what the o2 sensors do. When the E85 sensor shows a higher alcohol content in the fuel, it's changing the commanded stoich or lambda value in the tune. Which also changes the injector functions and timing, it would also change the timing and commanded fueling under certain loads and full throttle. That is stuff that can't be controlled when it doesn't know what is going on.

 

 

[CamGTP]

Thanks for taking me around the shop though, sure did get learned.

 

I mean I've only been tuning with narrowband and wideband o2 sensors for like 8 years now, I think I got most of this down.

Edited October 30, 2019 by CamGTP

[swathdiver]

On 10/24/2019 at 3:57 PM, Mountain boy said:

As I understand it neither the 5.3 or 6.2 can run e85. The reason being is ethanol absorbs water if it is in the station storage tank for extended periods especially this time of year. Once it absorbs the water it turns into a white sludge  and can clog things up. I am not a scientist this is what I was told.

Government benefits to automakers for producing FlexFuel vehicles expired in 2016.  You can safely run E15/Unleaded88 in it or any other auto produced since 2000.

 

In time some tinkerer will find out and announce whether the computers contain the FlexFuel tables and ability to add Alcohol Content Sensor (Fuel Composition Sensor) like the L83s.

[swathdiver]

3 hours ago, TXGREEK said:

I’ve been adding 6 gallons of E85 then filling the rest up with super, ZERO problems

 

Also run mixes and get my best fuel efficiency and savings with an alcohol content between 16% and 22%.  E85 mixed with 93 usually yields 95 or 96 octane.  Pumping E85 with E15 is much less expensive and still delivers 91 octane.

[Doolin-Dalton]

 

9 hours ago, CamGTP said:

Thanks for taking me around the shop though, sure did get learned.

 

I mean I've only been tuning with narrowband and wideband o2 sensors for like 8 years now, I think I got most of this down.

I know that Cam, didn't believe otherwise.....I learn from it just as much as sharing the info, and from what I learned in tuning my Honda, Lambda is the measurement to use regards to e85. 

 

Back to Chevrolet land, I'm eagerly awaiting  (1) an e85 sensor (2) HP Tuner for our 2019 Trucks so that I can run full out e85.  Until then, I don't believe spiking Gasoline with e85 is hurting anything.   There is obviously a question of how much, I've taken it to 50-50 with positive results.  Reluctant to go any higher than that, without the sensor and tune.

 

My 2016 Silverado ran full e85 and it was amazing.  My Honda Civic was gasoline only, but I tuned it for e85 using HondataFlashpro and an e85 Sensor,  it too was amazing.  It's not just #s and charts, you will feel the difference in the vehicle. 

 

 

 

 

 

 

Edited October 30, 2019 by Doolin-Dalton

[Black02Silverado]

I can say this much.  When I did run E85 100% in my 2002 Silverado I would get a CEL and the code was for it running lean on banks 1 and 2.  So ever since then I only go as high at 50/50 and have not had any issues since. 

 

I was lucky to be able to add a sensor to our 2016 Suburban really easily and had Black Bear tune it.  It runs great and I sent him a log file after mixing in some E85 and he came back saying it was showing a 35% ethanol level and everything looked good.  Now with a 32 gallon fuel tank and E85 being $1.98 a gallon it doesn't hurt as much to fill up as it would with 93 at $3.00 a gallon.

 

Doolin and Cam, thanks for the post and great info.  I'm learning more every time I get on GM-Trucks. 

[KARNUT]

My last new truck 2014 ran noticeably different on E-85. It needed less throttle input seemed to shift better. I liked the option to use reg gas on trips. I always had caned tunes since they were available. The combo of transmission tuning, 50 percent TM, higher shift points and E-85 really woke up my truck.


Sent from my iPhone using Tapatalk

[Taz56]

12 minutes ago, KARNUT said:

My last new truck 2014 ran noticeably different on E-85. It needed less throttle input seemed to shift better. I liked the option to use reg gas on trips. I always had caned tunes since they were available. The combo of transmission tuning, 50 percent TM, higher shift points and E-85 really woke up my truck.


Sent from my iPhone using Tapatalk

100% agree. I used it as often as I could in my 2014 5.3L as well. Here in Calgary Alberta there is only one station that carries it, a city of over 1.2 million and we get one pump LOL. But I used it all the time when I was in the city and then Premium when on the road..... Made a big difference and I am pissed off it is not an option for my 2019 6.2L