What is better, E10 93 Octane or R90 gas?

S

Ssg Ken

Member
Joined
Mar 8, 2009
I now have a gas station near me with 93 Octane pure gasoline but what if I need gas and have to choose the lesser of two evils; pure 90 Octane gas or 10% ethanol 93 Octane? Which to use?

The 93 Octane gas is near a lake. E10 is bad for boat engines. E15 coming next year to a station near you thanks to the President.
 
Go for the higher octane. If it's straight gasoline, even better.

The E10 93 octane will run ever so slightly leaner.

Stay away from the 90 octane stuff.
 
BEATAV8 said:
Go for the higher octane. If it's straight gasoline, even better.

The E10 93 octane will run ever so slightly leaner.

Stay away from the 90 octane stuff.
Click to expand...
Not sure I understand why pure 93 is better than E10 93?

Everybody that runs the stuff claim that E85 is the hot ticket for octane equivalent.

If that's true wouldn't a little bit E10 be just a little bit better than straight?

I know for a fact I can run just a little more boost on E10 93 than I can on pure 93.

Sent from my DROID RAZR MAXX HD using Tapatalk 2.
 
Ssg Ken said:
I now have a gas station near me with 93 Octane pure gasoline but what if I need gas and have to choose the lesser of two evils; pure 90 Octane gas or 10% ethanol 93 Octane? Which to use?

The 93 Octane gas is near a lake. E10 is bad for boat engines. E15 coming next year to a station near you thanks to the President.
Click to expand...

The 10% ethanol is to help keep the fuel from freezing..


Clint

Posted from the TurboBuick.Com mobile app
 
Ssg Ken said:
In 2009 87 gas was $2.79 but I saw E85 For a dollar less.

This a joke right?
Click to expand...

Here in NC, E85 is about 20 cents cheaper than 93. For the most part E85 is cheaper than 87, but you also get lower MPG. I have estimated a 7 MPG drop between E85 and 93. This is not an accurate number as somehow I find I have a heavy foot when on E85 :)
Every gas station I come across seem to have 10% Ethanol now. Can't remember the last time I saw straight 93?
Take a look at this website, maybe you can find more gas station near you with no ethanol.

http://pure-gas.org/
 
vacuum 6 said:
Octane is octane whether 10 or 15% ethanol. Watch your tune.


Walter
Click to expand...
x2. If it gets a 93 rating,it has a specific resistance to auto igniting. What ever the ratio of this to that,it won't auto ignite until x. Because it won't auto ignite until x,it gets a rating of 93. Or,octane is octane.
 
I'm going to provoke some more thought on this one and say it Depends on what your chip programmer had in mind when figuring fueling. Remember that your chip is programmed for a mass of fuel to be injected. Also remember that it takes approx 30% more E85 to make the same power as 93 gas.

If your chip is programmed based on 93 octane E10, and you run pure 93, you will run a tad rich.

If your chip is programmed for pure 93 and you run 93 octane E10, you will run a tad lean.

In this case, I'm sure the difference is negligible but it's still noticeable.

Say your chip is programmed to run pure 93. The programmer has told it to spray X amount of fuel at WOT. If you stick 90% 93 and 10% E100 in the tank, it'll really take (0.9X) + (0.1X + 0.03X) = 1.03% or 3% more than what it's used to.

True that octane is octane, but running gasoline requires much less fuel than E85.

I ran into this when I was mixing E85 with 93 to kill some KR. I thought I was increasing octane (which I was), but I didn't take into account the additional fuel requirements. It still all turned out good.

E85 is a blast.


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earlbrown said:
^how dare you bring hard numbers and science to a ethanol fuel post!!! :)
Click to expand...

Just tryin to help the OP out.

Ken, if you're running a modern chip (bob's or Eric's), the. They've taken into account the 10% ethanol in your fueling. If you run pure 93, it'll likely run rich and therefore have less power, BUT it will be "safer" IF you don't fiddle with boost.

Also keep in mind that the fueling may not be perfect for your vehicle (hence the adjustability features in the chip), so you still may have to play with it a little (giggity).

One guy's opinion and advice:
1) run the fuel that your chip programmer set the fueling up for
2) if you stray from it, always err on the side of caution so as not to lean it out.

I ain't no expert! Just been learnin' from this here "forum thingy" on this so called "worldwide web contraption"!!!


Posted from the TurboBuick.Com mobile app
 
I run the factory chip @ factory boost. When I saw E85, I was in corn country at a grain elevator. None nearby that I have seen here. Octane is a ratio. I looked it up as chem class was a long time ago but it is still the same.

The name "octane" comes from the following fact: When you take crude oil and "crack" it in a refinery, you end up getting hydrocarbon chains of different lengths. These different chain lengths can then be separated from each other and blended to form different fuels. For example, methane, propane and butane are all hydrocarbons. Methane has a single carbon atom. Propane has three carbon atoms chained together. Butane has four carbon atoms chained together. Pentane has five, hexane has six, heptane has seven and octane has eight carbons chained together.
It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.
 
I think a lot more than just compression ratio comes into play. Take modern engines for example. My Ecoboost twin turbo V6 comes with a compression ratio of 10:1, is turbocharged to the tune of 12# of boost, and is perfectly happy on 87 octane. But these modern engines have a very sophisticated knock sensing routing and are likely pulling timing as needed for each cylinder. They tell me I can make more power if I run 93. Maybe so, I can't feel it in the but dyno, and running 93 makes absolutely no difference in fuel economy.
 
As mentioned earlier, the octane rating is the octane rating, regardless of the blend. Running straight gas would give slightly better fuel econ (MPG) and slightly richer WOT, running E10 blend will have the opposite effect, slightly worse fuel econ and slightly leaner WOT.

If you want to run E85 then you will definitely have to do a conversion. A Powerlogger, a laptop computer, large injectors, a turbotweak E85 chip, and a strong fuel pump setup with excellent "hot wire" wiring are all musts. With a stock turbo you could use 80lb injectors and have a great running setup with excellent drivability and run A LOT more boost than the 93 octane would allow. Ofcourse this only means something if you have an E85 station nearby. Here in northern Illinois I have about 10 E85 pumps within 5 miles. The only good thing about Illinois if you ask me!
 
TurboDave said:
I think a lot more than just compression ratio comes into play. Take modern engines for example. My Ecoboost twin turbo V6 comes with a compression ratio of 10:1, is turbocharged to the tune of 12# of boost, and is perfectly happy on 87 octane. But these modern engines have a very sophisticated knock sensing routing and are likely pulling timing as needed for each cylinder. They tell me I can make more power if I run 93. Maybe so, I can't feel it in the but dyno, and running 93 makes absolutely no difference in fuel economy.
Click to expand...

Direct injection plays a big part in ecoboost strategy. Not a fair comparison to our sfi engines. Direct injection is to fuel injection what fuel injection was to carburetors. One way they are the same though is that 93 octane will have no performance improvement over 87 without more boost. You may be surprised how far you can push the tune even on 87.

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