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Discussion Starter · #1 ·
It's not my intent to start a thread for or against ethanol fuels. I don't want to debate what you may have read, or the food supply, or other stories of ethanol. I want to discuss ethanol E10 and E15 in a 1.4L turbo without increased injectors and with a stock tune. Is it equal to mid grade, and how is knocking effected?

I just filled with my first tank of E15, and I normally run 89 Octane E10.

Has anyone noticed the coolant temperatures actually running slightly lower with the E15? I know the car drops coolant temperature when coasting under Fuel Cut off conditions, so maybe that's a combination of what I'm seeing.

We're also probably off winter gas where I live onto the summer blend, which should help fuel economy. I need a few hundred more miles to do some hand calculations on mileage, but based on the over optimistic DIC cluster, this appears to be one of my better tanks in the vehicles life.. 150 miles in with a DIC display of 43 mpg.

I've done two data logs using the Torque app, and it doesn't seem to be knocking that much. There's an area on my drive home from work that records knocking even with 91 octane, and I'll have to run a few more tanks of E15 and then go back to the 89 E10 to compare.

This fuel is from a local independent station, who sells E85, E30, E15, E10 and E0, diesel, and propane. I don't know if the E15 product comes in blended to the station, or if it's blended at the pump. There's a lot of fuels at this little station to have separate tanks for each, so I suspect there might be some blending. In this case it could be possible that if the blending is off using a higher quality of gas as the blend base stock this maybe showing a difference.

Fuel trims on Torque remain 0-4% for short term and long term fuel trims, so it doesn't appear that this fuel is significantly leaning out my engine.

So far I'm impressed, anyone else do some data monitoring with E15?

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Discussion Starter · #2 ·
The first tank of E15 was 10.5 gallons E15 mixed with balance of tank 89 E10. Mileage upon fill of the second tank via the pump shutoff method and hand calculations was 35.7 mpg.

Car was driven in hot 80F+ temperatures and was very smooth. I did run air conditioning for about 30 miles in this weather. This is comparable to the fuel efficiency seen with the 89E10 that I've always used without air conditioning.

Seemed to drive better than it does with straight tanks of 87E10.

Second fill up of 88 E15 has been done. This tank is closer to 88 E15 with no significant blending differences due to other fuel being in the tank.

I have not seen wild swings in the long term fuel trims. Upon driving long term fuel trims swing between +5 to -5. Even near zero when driving. I believe this shows the fuel system is tight, with no unmetered air, or fuel getting in.

Car seems to be holding 6th gear longer before downshifting. This could be leading to longer periods of fuel cut off allowing the engine coolant temperature to fall. Or it might simply be the additional ethanol, but I don't think 5% more ethanol would lower coolant temperatures a measurable amount.

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My comparisons, but with the caveats of: 2014, Completely stock car, 6MT, and PA has lots of hills and the temperature changes hour to hour, lol

I tried 88 E15 (Sheetz) over the winter, seemed to run slightly better than 87 E10, mileage was about the same. But the up and down winter we had in PA makes it hard to judge for sure. I also had plug issues. I was getting anywhere from 30-32 mpg DIC (29-31 calculated) running either one. After I changed my plugs, I noticed a flat spot in the RPM range. So I decided to try 93 E10 (Sam's club only has 87 and 93, for a really good price). Now I'm up to 35-36 DIC (34-35 Calculated). So the cost was offset by the increase, and more importantly, it runs WAY better. I want to try some E15 again, but it will be tough to give up the better power. I'm honestly surprised by the difference.

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Discussion Starter · #5 ·
I'm on my 4th or 5th tank of this now. I've switched to Kwik Trip vs. the local independent stations that blend at the pump. Kwik Trip offering the E15 as Top Tier detergent.

Still running well. Last week ran in 95F heat with air conditioning running hills. No significant issues.

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Discussion Starter · #7 ·
It's in my signature. 2012 1.4L Automatic 73,000 miles.. Cars love Kwik Trip..

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While I wrote a thread before about switching over to ethanol fuels, and it was deleted by the OP, I still think it was valid.
When I had my 2011 Cruze Eco, I often suffered from low performance on 87 oct fuels when the outside temperatures were above 85F; and unacceptable performance above 100F.
The quickest solution was to enable higher octane fuels, however, they were quite expensive; now that premium fuels are more than $1/gal more than regular.
And while premium fuel did keep performance relatively in check during hot summers, it also degraded performance when the temps were below 85F.

I quickly got tired of this, and this, together with the bi-annually recurring coolant leak, caused me to sell this car, and go for a Fiesta ST.
This car has a 1.6 liter engine, that runs cooler overall, has less aero drag than the Cruze (it's smaller), and lighter by about 500LBS.
But it's still basically the same engine, tuned slightly differently, with a bit less low end torque, trading for much more mid range punch (200HP, 200+LB FT of TQ).

That being said, the Fiesta ST forum people referred me to adding a gallon to 2 gallons of E85 to a tank.
Though my fiesta is not suffering from timing lag due to heat soak, I do notice an increase in performance adding 50% of E15 to the regular 87 oct (E10) tank!
More pull.
I also tried E30, but found this not to work well with the car.

At the time of writing, I had looked up a chart, and it seems like Chevrolet supported E15 from 2012 onwards, so if you have a 2011 model, it might run better with E15, but perhaps not for long.
Mostly fuel lines, and fuel systems are affected by the corrosion of Ethanol.

If you have a 2012 model or after, you should have no problems running up to E15.

My experiences stem from my Fiesta ST; which recommends no higher than E20 in the tank.

I tried regular with E15 on a 50-50% base, and had best results there (about 5% more HP).
Likewise MPG dropped by 10%.

Ethanol fuels lower engine temperatures. This works really well on turbo cars. However, overall engine temps should remain unchanged, since the engine temp sensor is measured from the water cooling circuit, which depends on the thermostat.
Since Chevy Cruzes always show a slightly below the middle temperature on the needle, I doubt that this would change with E15.
However, the core of the engine will run cooler!

Now, the 4 options for boosting summer performance (and hot day performance) would be:
1- A blend of High octane fuels (91-93 Octane) with E85.
2- Hi Octane fuels (91-93 Oct) no Ethanol. Good performance, best fuel mileage.
3- Fuel E15, slightly better performance, lowest fuel mileage.
4- Mix of 87 Octane with E15, or 87 octane with a gallon of E85.

You'd have to find out where your car is running the best.
According to what I read, Ethanol contains some liquid oxygen in the fluid, so it will lean out the mixture.
This Oxygen attracts Hydrogen, and creates water in the fuel; which leans out the mixture even more.
Not only that, but it also is thicker in substance than gasoline, causing the injectors to spray a percentage less of fuel than with regular fuel.
Some turbo cars, running slightly rich from the factory, might run better with this leaner mixture, meaning better the higher the Ethanol percentage is in the fuel.
There's a sweet spot, where your stock car runs best with; and usually that's between E0 and E15.

For option number one:
My recommendation is to stay below 1 gallon of E85 per tank, as this will get you anywhere between E10 and E15, depending on the ethanol levels in your base blend.
E85 + High Octane fuel = Best performance, slight drop in fuel economy.

Number 2:
91 - 93 Octane fuel is the most expensive, and only benefits under hard acceleration. It generally performs poorly in colder climates. Some cars prefer this over Racing fuel (E0).

Number 3:
Most cost effective! Quite often E15 is cheaper as a blend, than buying 87 octane and E85 together.
This also shows a drop in gas mileage when just cruising or not taxing the engine, both on turbo and N/A cars.

Number 4:
In my case, 50% of 87oct + E15 is the perfect balance between cost, MPG, and power. It boosts power by a few HP, cost is just a few cents over E15, and in most cases,
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