E85...any reason Not to use it?

[Fless]

As I understand it the ethanol mix is done as the local station's tanks are being filled. They do the same thing we do, mix at the tank. I could be wrong.

 

[HiHoeSilver]

I live in Michigan, come winter E85 can drop as low as 61% ethanol. I've read about using E85 test kits (glass vial) is there an easier way to confirm the ethanol percentage?
Is there a website that lists when the E85 has the ethanol percentage lowered?

I don't run it in the winter here (Chicago) anyways simply because it doesn't like to burn cold.

 

[R3cord303]

On 93 Octane Gasoline, the last 14 tanks averaged 14.65 MPG or twenty-four cents a mile.

On E30, the last 20 tanks averaged 15.18 MPG or sixteen cents a mile.

While we're talking ethanol, the last 25 tanks of E85 averaged 12.01 MPG when not towing or twenty cents a mile.

Ohh, does it mix well? I guess so, have not experienced any adverse effects.

Do you spend a lot of time on the highway? I've been mainly in town and see about 13.7 MPG but if im on the highway for a couple weeks I'll be up at 14.1 MPG using 87

 

[swathdiver]

I live in Michigan, come winter E85 can drop as low as 61% ethanol. I've read about using E85 test kits (glass vial) is there an easier way to confirm the ethanol percentage?
Is there a website that lists when the E85 has the ethanol percentage lowered?

See I read that winter blend E85 is not supposed to drop lower than 71%! That's the problem with it, the numbers are not consistent. I don't know, the guy who blends at the Sunoco I go to for E30 obviously could do a better job of it, or maybe cycle the tank more often, if there is such a thing to keep it mixed? I dunno.

 

[swathdiver]

Do you spend a lot of time on the highway? I've been mainly in town and see about 13.7 MPG but if im on the highway for a couple weeks I'll be up at 14.1 MPG using 87

Yes. Soon after the cats were replaced last year we took a day trip down to the keys and the truck averaged 17.01 MPG over 359 miles. There was a bit of stop and go in there too.

These are the MPG numbers from running multiple 2-way averages in each 5 mph increment. Also have numbers for E85 @ 80% and 71%. Not done with E30.

Well, here's one of the E85s:

 

[swathdiver]

As I understand it the ethanol mix is done as the local station's tanks are being filled. They do the same thing we do, mix at the tank. I could be wrong.

Possible. I asked the owner of the Sunoco that sells E30 and he mixes it from his E85 and 87 tanks with a blender pump as he called it.

 

[R3cord303]

Yes. Soon after the cats were replaced last year we took a day trip down to the keys and the truck averaged 17.01 MPG over 359 miles. There was a bit of stop and go in there too.

These are the MPG numbers from running multiple 2-way averages in each 5 mph increment. Also have numbers for E85 @ 80% and 71%. Not done with E30.

View attachment 224043

Well, here's one of the E85s:

View attachment 224044

Wow that's fantastic information. Very cool to see how the MPG drops off as your speed increases. IIRC you fight twice as much air for every 10 mph you go up in speed. Do you have AFM deleted?

 

[swathdiver]

Wow that's fantastic information. Very cool to see how the MPG drops off as your speed increases. IIRC you fight twice as much air for every 10 mph you go up in speed. Do you have AFM deleted?

AFM has all the latest parts but is turned off now in the tune by BlackBear. I was working with Justin last year to see if we could get 1 mpg back between 65 and 70 on gasoline but no joy so far. Last time was too much timing (lots of KR) and then I switched her back to Ethanol and these last three tanks were out of convenience. Not in any hurry.

I'm often tempted to turn it back on and tweak it, but I would have to get EFI Live or HP Tuners and do it myself. No disposable income right now with another kid about to head to college and a new car payment very likely in the near future. So I leave it alone lest I break something!

 

[R3cord303]

AFM has all the latest parts but is turned off now in the tune by BlackBear. I was working with Justin last year to see if we could get 1 mpg back between 65 and 70 on gasoline but no joy so far. Last time was too much timing (lots of KR) and then I switched her back to Ethanol and these last three tanks were out of convenience. Not in any hurry.

I'm often tempted to turn it back on and tweak it, but I would have to get EFI Live or HP Tuners and do it myself. No disposable income right now with another kid about to head to college and a new car payment very likely in the near future. So I leave it alone lest I break something!

Good to know. Glad to see MPG is still very possible on the highway with it turned off. As soon as I can afford it I'm getting an HPTuners kit and turning AFM off on mine. Hate it. Only ever stays on at highway speeds for about 3 seconds. Its on in town more but it shakes the whole vehicle a little bit. Makes it feel like the transmission is shifting.

 

[swathdiver]

Good to know. Glad to see MPG is still very possible on the highway with it turned off. As soon as I can afford it I'm getting an HPTuners kit and turning AFM off on mine. Hate it. Only ever stays on at highway speeds for about 3 seconds. Its on in town more but it shakes the whole vehicle a little bit. Makes it feel like the transmission is shifting.

When it was working it was seamless, never felt it. I figured if we could get each cylinder to make another 5-6 horsepower and torque, then the duty cycle would increase to K2 levels; from about 10% to 50%. Cam, exhaust and heads and tuning the ethanol tables could all contribute to bringing those numbers up, probably just tuning and a cam.

When AFM first came out, there were a bunch of guys with Avalanches using HP Tuners that were tweaking the system on their stock motors to get 21-23 MPG. One of the key parameters was vacuum if memory serves. If you google around you can find those posts.

 

[R3cord303]

When it was working it was seamless, never felt it. I figured if we could get each cylinder to make another 5-6 horsepower and torque, then the duty cycle would increase to K2 levels; from about 10% to 50%. Cam, exhaust and heads and tuning the ethanol tables could all contribute to bringing those numbers up, probably just tuning and a cam.

When AFM first came out, there were a bunch of guys with Avalanches using HP Tuners that were tweaking the system on their stock motors to get 21-23 MPG. One of the key parameters was vacuum if memory serves. If you google around you can find those posts.

My tahoe used to be my grandfathers. Its got 218k on the clock so im not shocked that its a bit more lurchy. He has a 13 now and its a little bit more... fluid? Doesnt work very well on his either. Family rented a 2016 suburban though and it got 21 mpg with 600 pounds of american and all their luggage at 75 mph. Couldnt feel it with the newer engine.

 

[swathdiver]

My tahoe used to be my grandfathers. Its got 218k on the clock so im not shocked that its a bit more lurchy. He has a 13 now and its a little bit more... fluid? Doesnt work very well on his either. Family rented a 2016 suburban though and it got 21 mpg with 600 pounds of american and all their luggage at 75 mph. Couldnt feel it with the newer engine.

Mine has all the latest parts including the new VLOM and the lifters from the Gen V motors. Still has original motor mounts as best I can tell too. I figure the smoothness was because of the upgraded parts.

 

[R3cord303]

Mine has all the latest parts including the new VLOM and the lifters from the Gen V motors. Still has original motor mounts as best I can tell too. I figure the smoothness was because of the upgraded parts.

I didn't realize there was a set of updated AFM parts! Good to know.

 

[gooffeyguy]

I just started an experiment today. I needed to get gas, it had been a couple weeks since I filled up. I last had 93 octane in there and my alcohol % was at 8.5. My DIC showed that I had used 23.6 gallons, so I figured I would put in 12 gallons of E85 and 12 gallons of 87 octane. The E85 was $2.419 and the 87 was $2.579 and actually only took 10.4 gallons. On the way home from the station my alcohol % was fluctuating between 33 and 38. I'll see what it stabilizes out to. I paid in total $57.23 for 22.43 gallons of gas ($2.55/gal) for hopefully somewhere around 96 octane while the cost of premium 93 octane was $3.069/gal. I also want to see what the mileage is like.

Does anyone know at what alcohol % the computer runs the higher E85 spark tables?

 

[swathdiver]

I just started an experiment today. I needed to get gas, it had been a couple weeks since I filled up. I last had 93 octane in there and my alcohol % was at 8.5. My DIC showed that I had used 23.6 gallons, so I figured I would put in 12 gallons of E85 and 12 gallons of 87 octane. The E85 was $2.419 and the 87 was $2.579 and actually only took 10.4 gallons. On the way home from the station my alcohol % was fluctuating between 33 and 38. I'll see what it stabilizes out to. I paid in total $57.23 for 22.43 gallons of gas ($2.55/gal) for hopefully somewhere around 96 octane while the cost of premium 93 octane was $3.069/gal. I also want to see what the mileage is like.

Does anyone know at what alcohol % the computer runs the higher E85 spark tables?

My rough calculation is that it should settle at about 36% and the octane rating would be 95.52. This assumes the 87 is at 8% and the E85 @ 80%.

@randeez Randy knows the tables off the top of his head and how they work. Fun stuff Tom!

 

[R3cord303]

My rough calculation is that it should settle at about 36% and the octane rating would be 95.52. This assumes the 87 is at 8% and the E85 @ 80%.

@randeez Randy knows the tables off the top of his head and how they work. Fun stuff Tom!

Is there a way to show alcohol content in the DIC?

 

[gooffeyguy]

My rough calculation is that it should settle at about 36% and the octane rating would be 95.52. This assumes the 87 is at 8% and the E85 @ 80%.

@randeez Randy knows the tables off the top of his head and how they work. Fun stuff Tom!

Actually, my calculations seemed a bit off and I looked at the receipt for the 87 and the pump over charged me.

Price per gallon showing on pump was $2.579 and total gallons pumped was 10.434 and I was charged $28.20.

Should've only been charged $26.91
Looks like it charged me $2.70/gal

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[swathdiver]

... and the pump over charged me.

Cash and Credit pricing?

Is there a way to show alcohol content in the DIC?

That would be cool but I doubt it. I drag out the Tech-2 every time. Hey Tom, do you watch your LTFTs head to 25%??? That got me going the first time I saw that but realized that since it hadn't set off a code, it must be learnin'.

 

[randeez]

short answer... with any amount of E content it alters the spark. more likely to stay in the high octane table as it will resist knock.
ethanol has a spark table that it adds(or subtracts) to the base table depending on %.

you can download hptuners (or efilive) free, find a few tune files around to poke around with to get an idea

 

[gooffeyguy]

Cash and Credit pricing?



That would be cool but I doubt it. I drag out the Tech-2 every time. Hey Tom, do you watch your LTFTs head to 25%??? That got me going the first time I saw that but realized that since it hadn't set off a code, it must be learnin'.

I pumped the e85 from the same pump and it showed the correct total.

I haven't watched my LTFTs. I have them displayed at the bottom of my TorquePro screen, but I just forget to look at them at times.

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18