Loving my E85 right now

[opfor2]

Like stated in the title, I'm loving having an E85 capable Tahoe right now with the fuel prices being $ 5.59+ a gallon in Riverside County, CA., and E85 is $ 3.15 a gallon. It just sucks that I'm only getting like 10.85 miles per gallon on it. Oh well....

 

[Dustin Jackson]

Is it actually cheaper per month to run a Tahoe on E85 VS Premium? I haven't seen the math yet

 

[Onlyone]

It’s usually a 30% mileage decrease, so if it’s over 30% cheaper then it’s more cost effective to run E85. Ish

 

[mikez71]

Is it actually cheaper per month to run a Tahoe on E85 VS Premium? I haven't seen the math yet

Yep.
Was $3 e85 vs $5 91 octane, 10 vs 12 mpg.

Now e85 is $4 a gallon, 91 is $5.50. Still cheaper.

 

[Dustin Jackson]

I did run E85 a month ago and ever since then I have been able to fill up my gas tank all the way without the pump clicking

 

[intheburbs]

It’s usually a 30% mileage decrease, so if it’s 30% cheaper then it’s more cost effective to run E85. Ish

You doing that new math?

If E85 is 30% cheaper, but mileage goes down by 30%, then it's neutral. No difference.

 

[Onlyone]

You doing that new math?

If E85 is 30% cheaper, but mileage goes down by 30%, then it's neutral. No difference.

Sort of. Lol. I think in my mind I was trying to explain the break even but it came out wrong. I meant to say OVER and it just didn’t get into the post.




fixed it.

 

[Dustin Jackson]

@Onlyone No worries man I think we all knew what you were getting at lol.

For me I think the mileage difference between E85 and Premium is greater than just 2mpg. I will use your 30% rule of thumb to figure out if it would be worth it because I live in Northern California so gas prices are similar to the example given earlier in this thread.

I think with e85 I was getting about 12mpg @ 70mph and with premium I usually get about 16mpg.

 

[Marky Dissod]

Is it actually cheaper per month to run a Tahoe on E85 VS Premium? I haven't seen the math yet

It’s usually a 30% mileage decrease, so if it’s over 30% cheaper, then it’s more cost effective to run E85. Ish

That's thinking in the short term.
Thinking in the very long run, doesn't E85 burn cleaner / leave less carbon deposits than 91?

 

[Onlyone]

Yes. It cleans very well and leaves virtually zero carbon deposits. There is anecdotal evidence that extremely short drives, without getting to operating temps could degrade your oil, as with any fuel. Regular oil changes will negate that potential.

 

[opfor2]

Yes. It cleans very well and leaves virtually zero carbon deposits. There is anecdotal evidence that extremely short drives, without getting to operating temps could degrade your oil, as with any fuel. Regular oil changes will negate that potential.

What would on consider "Short Drives?"

 

[Onlyone]

What would on consider "Short Drives?"

Drives that don’t get up to operating temps.

 

[iamdub]

@Onlyone No worries man I think we all knew what you were getting at lol.

For me I think the mileage difference between E85 and Premium is greater than just 2mpg. I will use your 30% rule of thumb to figure out if it would be worth it because I live in Northern California so gas prices are similar to the example given earlier in this thread.

I think with e85 I was getting about 12mpg @ 70mph and with premium I usually get about 16mpg.

E85 has 27% less energy, so it takes 27% more of it to equal E0. Most fuels are at least E10 and most E85 is actually much less, in the 50s to 60s percentiles. So this narrows that 27% spread. It's just easier to quick math it at 30% and figure for the worse. You can expect a max of 30% reduced fuel economy (actually ~25%). But, if the price of E85 is around 30% (or ~25%) lower than 91-93 E0/E10, then you're coming out ahead, never mind the cleaning benefits.

Estimating an actual of less than 85% ethanol and, therefore, not losing the full 27%, lets rough it at a 25% loss in MPG. That 12MPG on E85 is right in line with your non-E85 16MPG. I'm sure that E85 was more than 25% cheaper than 91-93 E0/E10.

 

[iamdub]

Drives that don’t get up to operating temps.

And remain there long enough to get a sufficient amount of the water in the oil to steam out of it so it doesn't collect and dilute the oil.

 

[swathdiver]

Both my 5.3 Yukon XL and 6.2 Sierra show a 21% difference between running 93 and E70/E85.

 

[Dustin Jackson]

@swathdiver Interesting so your results suggest that E85 only needs to be 21% cheaper to run for it to break even, if E85 is 30% cheaper than 91 then I would be saving money running E85.

Does running E85 have any downsides of running it? Does it shorten the life of components?

You guys about sold me on E85, I'll look into getting a fresh set of O2 sensors because I understand that's how the Tahoe reads ethanol content.

 

[Marky Dissod]

Does running E85 have any downsides of running it? Does it shorten the life of components?

So long as you let the engine spend at least 30min or more at operating temp, the only downside I can think of is that ethanol cold winter startups take up to two seconds longer than gasoline cold winter startups, even given the fact that E85 in winter is really E50 or some lesser percentage.

 

[swathdiver]

@swathdiver Interesting so your results suggest that E85 only needs to be 21% cheaper to run for it to break even, if E85 is 30% cheaper than 91 then I would be saving money running E85.

Does running E85 have any downsides of running it? Does it shorten the life of components?

You guys about sold me on E85, I'll look into getting a fresh set of O2 sensors because I understand that's how the Tahoe reads ethanol content.

Just shorter range per tank of fuel. The engines love the stuff and once adapted to it after 5 or so tankfulls, even the transmission performs better.

In cold weather, the first remote start usually stalls on E85, the second attempt takes hold. We've also had E85 sit in a near empty tank for months, make only short runs down the street, etc. No issues with water or whatever people complain about.

Just make sure you have OE oxygen sensors that are under 100K miles or so or convert to an actual sensor like Chris did.

 

[avalonandl]

I was getting 11.4 mpg on E85.

 

[the 18th letter]

Just shorter range per tank of fuel. The engines love the stuff and once adapted to it after 5 or so tankfulls, even the transmission performs better.

In cold weather, the first remote start usually stalls on E85, the second attempt takes hold. We've also had E85 sit in a near empty tank for months, make only short runs down the street, etc. No issues with water or whatever people complain about.

Just make sure you have OE oxygen sensors that are under 100K miles or so or convert to an actual sensor like Chris did.

If you haven't been running E85 prior to 100k is it best not to run it after unless O2 sensors have been changed?