E85 mod for L86 engine

[LDM]

Finally was able to do the E85 conversion on my 2018 Sierra 6.2 on Sunday after receiving the fuel line I needed.  Everything went together just fine although I had to length my connection harness to make it go to where I needed it to for the sensor.  After uploading my e85 enabled tune with Tunercats OBD2 (yes, I have a Roadrunner for the 411 PCM and the full version of TunerCats OBD2 RT Tuner), I was able to see about 8.6-9.0 alcohol content in my current tank of gas.  I plan on filling up with E85 when I get down to less than 1 gallon and then will see how the truck both performs and how much it costs per mile to operate.  Right now E85 is around 20%+ less expensive than 91+ premium here so depending on the trade off in fuel economy it may end up being cheaper to run.  Also interested to see the data logs for any performance difference as the L83 gets a good 20+ HP and TQ when using E85 in the flex fuel vehicles.  Still not sure why GM didn't make the L86 flex fuel in the first place, since the only thing it lacks is the alcohol sensor and the few things in the tune enabled for use.

[SC88]

I've been thinking about doing the same, Where did you get your kit from?

[CamGTP]

It going to perform just about exactly the same once the alcohol content is over 60%.

 

I'm running E64 right now and can get it to around E70ish depending on the month and it runs the same with my truck.

 

It will help a little more if you modify the spark tables and lean out the commanded AFR/Lambda once it's running on higher blends of E.

Edited June 1, 2022 by CamGTP

[jrmcswain]

Wonder how E85 would complicate the Whipple set up. Tuned for 93 octane, but the retailer stopped carrying it.

[CamGTP]

If it's got factory injectors, you won't have enough injector for E85.

 

They are basically maxing out the stock injectors on a whipple kit and you don't have 30% more headroom beyond that for ethanol blends.

[jrmcswain]

16 minutes ago, CamGTP said:

If it's got factory injectors, you won't have enough injector for E85.

 

They are basically maxing out the stock injectors on a whipple kit and you don't have 30% more headroom beyond that for ethanol blends.

Good to know. I believe they are the stock injectors.i know the cam lobe for the fuel pump pumped more fuel. So it makes sense the injectors are maxed out. 

[CajunFries]

9 hours ago, jrmcswain said:

Good to know. I believe they are the stock injectors.i know the cam lobe for the fuel pump pumped more fuel. So it makes sense the injectors are maxed out. 

Run LT4 injectors and HPFP along with 535 in tank. Should be good for 650 on E. Maybe a lil more if you only run E60 (which is about where it is most balanced between power and MPG). 

[swathdiver]

Uncle Sam's incentive for FlexFuel vehicles ended so GM stopped offering it.  

[Black02Silverado]

8 minutes ago, swathdiver said:

Uncle Sam's incentive for FlexFuel vehicles ended so GM stopped offering it.  

Which to me is wrong, not like they didn't have the parts and the fuel is still available.  Why not continue to have it on the vehicles and let the consumer decide whether or not to buy it.

[KARNUT]

1 hour ago, Black02Silverado said:

Which to me is wrong, not like they didn't have the parts and the fuel is still available.  Why not continue to have it on the vehicles and let the consumer decide whether or not to buy it.

Probably because with E-85 the 5.3 got real close to the 6.2 in TQ and HP. Someone noticed. Can’t have that. 

[Grumpy Bear]

     I tired E-85 two summers ago and couldn't make it pay based on pricing. Currently however pricing has been favorable and now on my fourth thank. Blending to 50% and that is paying off on a price per mile basis. Thing is E-85 pricing is all over the map and varies by over $2 a gallon so I have to be very mindful of my stops and range for this to work. All of this based on 87 octane pricing. If I had a 6.2 that required the octane I think I could make this pay all day every day. In fact I'm sure of it. 

 

 

[swathdiver]

3 hours ago, Black02Silverado said:

Which to me is wrong, not like they didn't have the parts and the fuel is still available.  Why not continue to have it on the vehicles and let the consumer decide whether or not to buy it.

 

The extra $20 in parts hurts Mary's bottom line and switch to EVs.

[LDM]

18 hours ago, SC88 said:

I've been thinking about doing the same, Where did you get your kit from?

No kit, I just bought the alcohol sensor, a plug for the sensor, and the fuel line.  Wasn't overly expensive, the sensor was around $50, the plug around $25, and the fuel line around $30.  I also had to buy the VDF file and the security seed key for my OBD2 Tunercat program, which was $80 and $45 as well.  But now I can also tune my truck and any other 2014-2019 truck (although 17+ all require a $45 security seed key as well) so its worth it.  And now I can do all the other tuning on the truck, except for the TCM since Tunercat doesn't support the T87A yet. 

[LDM]

4 hours ago, Grumpy Bear said:

     I tired E-85 two summers ago and couldn't make it pay based on pricing. Currently however pricing has been favorable and now on my fourth thank. Blending to 50% and that is paying off on a price per mile basis. Thing is E-85 pricing is all over the map and varies by over $2 a gallon so I have to be very mindful of my stops and range for this to work. All of this based on 87 octane pricing. If I had a 6.2 that required the octane I think I could make this pay all day every day. In fact I'm sure of it. 

 

 

Yeah, if I could run 87 without any issues then it wouldn't be worth it.  The cost difference around here is about 20% for E85 vs premium, so depending on the mileage it may come out ahead.  I don't plan on tuning the truck just to run on e85 so I can always switch back to premium if I find out it doesn't work out for cost saving.

[Black02Silverado]

Price here for E85 just recently is a good $1.25 difference between it and 93.  Well worth it cost per mile.