E85...any reason Not to use it?

[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