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E85 for towing?

K85 Octane

K85 Octane

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Curiosity
Never owned a flex fuel vehicle till I got my van some months back. Planning to tow the Blazer to BB this year, wondering what’s the benefits of using 87 vs 91 vs E85. (Since I have access to E85)

DISCUSS!
:D
 
I have found e85 to get less mpg and the gain performance wise wasn’t that big to justify the cost of 91 or even 87 honestly.

I felt 91 over 87 was less money and actually got more performance cost wise.
 
No towing experience with e85 but my work truck seems slightly peppier, but worse mileage.
 
Ugh. A GM small block that is "flex-fuel" is not optimized for E85. What I mean is to take advantage of the Octane rating E85 has, the engine really needs a bump in compression. But since they wanted the engine to run any mix of ethanol up to 85% so they kept the compression down where it would be for gasoline only. What it equates to is you might feel a little bump in power, but it's going to use more fuel.

It's the stupid thing to have an engine to set up for both honestly. When ethanol has less power per gallon than straight gasoline you will end up using more of it. And the idiots in charge think by forcing us to E10-15 that it will reduce our dependency on foreign oil. No dipshits, we'll end up using more because of the dang corn fuel they keep forcing on us.

It's not to say E85 is bad. When used in a dedicated application it's awesome. The guy I helped run a car at a local oval track switched to E85 over the track standard race fuel and that engine picked up a lot of HP all the way through the curve. He swapped the carb out for one built to use E85 and the jetting was 15-20 numbers bigger than what we ran for race fuel. We even increased the size of the fuel lines to make sure we could keep the monster fed.

Getting back to the original question. Don't bother trying to tow with it. The cheaper cost of fuel per gallon gets lost in the fact you'll end up using more to go the same distance.
 
ZooMad75 said:
Ugh. A GM small block that is "flex-fuel" is not optimized for E85. What I mean is to take advantage of the Octane rating E85 has, the engine really needs a bump in compression. But since they wanted the engine to run any mix of ethanol up to 85% so they kept the compression down where it would be for gasoline only. What it equates to is you might feel a little bump in power, but it's going to use more fuel.

It's the stupid thing to have an engine to set up for both honestly. When ethanol has less power per gallon than straight gasoline you will end up using more of it. And the idiots in charge think by forcing us to E10-15 that it will reduce our dependency on foreign oil. No dipshits, we'll end up using more because of the dang corn fuel they keep forcing on us.

It's not to say E85 is bad. When used in a dedicated application it's awesome. The guy I helped run a car at a local oval track switched to E85 over the track standard race fuel and that engine picked up a lot of HP all the way through the curve. He swapped the carb out for one built to use E85 and the jetting was 15-20 numbers bigger than what we ran for race fuel. We even increased the size of the fuel lines to make sure we could keep the monster fed.

Getting back to the original question. Don't bother trying to tow with it. The cheaper cost of fuel per gallon gets lost in the fact you'll end up using more to go the same distance.
Click to expand...
This is what I was trying to say but you said it best.
 
Yeah, I see a lot of people building and tuning for E85 because they have easy access to it. But like said already, those are dedicated engines that can use E85’s advantages.

Ok
 
K85 Octane said:
Yeah, I see a lot of people building and tuning for E85 because they have easy access to it. But like said already, those are dedicated engines that can use E85’s advantages.

Ok
Click to expand...
Works good in dedicated engines at the track. Great for power and octane, as well as heat control

The BTU output is significantly less than regular gasoline, so it’s normal to see 1.4:1 consumption or so vs gas to make up the BTU

Straight ethanol is a 1.7:1 factor and methanol 1.8:1


Worth noting that the stoic AFR using e10 should be 14.1:1 not 14.7
 
GM's first try at flex-fuel was really the best setup. They had it on GMT800 Tahoes/Yukons and expanded it to Fleet only 1/2ton trucks. They used a fuel composition sensor in the fuel line to detect the ethanol content in the fuel. So the computer knew the ethanol content of the fuel and proactively adjusted the fuel rate accordingly. It added complexity and possible fail points, but it worked well. Needless to say the engineers figured out how to do it without the sensor.

So how'd they do it? Simple, they watched the pre-cat O2 sensors. Higher oxygen content meant more oxygen in the fuel so it must be ethanol right? So based on this reactive assumption the computer would deliver more fuel. They knew based on Oxygen content how much of a percentage of ethanol was in the fuel. Here's the problem the whole operation is hinged on accurate reading from the pre-cat O2 sensors. A vacuum leak or fouled O2 sensor will fool the computer into thinking the higher oxygen content is actually ethanol when it isn't. The computer doesn't know any better and starts adding fuel delivery based on the new data. Again, it's a reaction to assumed data that the extra O2 is actually from the fuel. We all know what assume stands for right?

It really means one should pay closer attention to the pre-cat O2 sensors. Shoot nobody replaces them until they start tripping codes. Myself included. The problem is when the O2 sensors naturally start fouling out say north of 100k miles. When the sensors foul out they tend to read incorrectly and start making the system think you are running ethanol when you aren't. Typically it will manifest itself with fuel mileage slowly getting worse. It's gradual and if you aren't a nerd like I am that tracks every tank, you will take longer to notice it. Once the computer is assuming you are running 30% or more ethanol you'll start to feel the pinch harder at the pump. Keep going and then you'll start tripping rich fuel trim codes and turning the SES light on. That is where most people would bring them in.

With the scan tool we could go in and see what the computer thought the alcohol content was. I've seen it as high as 65% even though there isn't an E85 station in the entire county we were located in. The customer confirmed they have been getting fuel locally too. We did have a way to test the actual alcohol content if the customer couldn't give is a straight answer where they got fuel. We could reset the value but it usually took a couple tanks of fuel before it was doing it again. We'd replace the pre-cat O2's and clear the codes and send them on their way.


We had another customer with a flex-fuel Impala that lived outside the county we were in and had access to E85 and used it regularly. They lived up near Cripple Creek with a home elevation over 9,000 feet. Every fall when it started getting cold up there she complained the engine was hard to start first thing in the morning. It started better when it warmed up. She brought it down to us and we had the car for a week attempting to start it first thing in the morning cold. It lit off as soon as the key bumped the starter. We were at half the elevation she was. My ace figured it out after doing some research. E85's lesser volatility combined with the high elevation and cold temps were causing the hard start condition at home. After talking with the customer more and explaining it, she switched to regular gasoline in the fall and didn't have another problem.
 
they did it on early 90's something sister 4 door car to the Beretta, i forget the model name. Super POS we had 3 in or fleet, used as pool cars. Any time some rented one it came back on hook. One we had the heads off , burnt valve, My coworker had the job. he pushed out of stall after disassembly, waiting on heads to be machined. I was looking at 1 cylinder, and asked whats that? A crack ? He looked at and accused me of drawing it on the cylinder wall, lol. It was a vertical crack in the cylinders. All three of went to salvage inside of 4 years. This is when we kept sedans for 15 to 20 years.
 
I just buy based on price. When E85 is 25% cheaper or more, it becomes more economical. Do think about your range when towing, since it is reduced the same as your MPG. If your engine is seeing reduced timing (i.e. knock retard) due to high temps and loads, the high octane of E85 will help (usually over 100) - that's the potential performance improvement.
 
Corn is at record high prices right now, so I can't imagine Ethanol being overly cheap. That being said, they have not stopped production at the ethanol plant by my house.

Martin
 
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