View Full Version : Question about gas

04-09-2009, 05:29 PM
So I usually fill up with premium (91) at 7-11 or Petro Canada but last weekend my friend showed me a Shell or Mohawk that sells 94 with 10% ethanol mix. I have a few questions about this.

Whats the deal with ethanol? From what I've managed to find, all gas has ethanol in it but different stations use a different amount, Petro Canada apparently using quite a bit. I also read on an older car like my GT4 that ethanol can be corrosive. Any truth to this?

My first thoughts were to fill up with 94 as soon as possible, since the 3SGTE is a turbo charged, high performance engine it would be better suited to the higher octane gas. I just want to make sure and see what you guys think.

The way I see it, if I'm filling up at Petro-Canada and they use a 50/50 ratio of ethanol than 94 octane with 10% ethanol at shell is the obvious choice.

04-09-2009, 05:50 PM
I wouldn't use it. iirc, you have to replace pretty much all the o-rings in the fuel system if you want it to not corrode. Just run premium.

04-09-2009, 06:00 PM
Most places already use up to 30 percent ethanol, already, I dont know if Id cry about a 50/50 mix, I have yet to read about a single case of trouble of people running mixes like that, or even running E85, which is more corrosive than what youd be running.

I dont know if Id run it ALL the time, but every so often if I wanted to turn the boost up and have some fun, Id go for it.

04-09-2009, 06:03 PM
Here's the low-down, and I'm taking this from wikipedia and stripped down to what is relevant and thrown in my 2c where I wanted.

Fuel Economy

In theory, all fuel-driven vehicles have a fuel economy (measured as miles per US gallon, or liters per 100 km) that is directly proportional to the fuel's energy content. In reality, there are many other variables that come in to play that affect the performance of a particular fuel in a particular engine. Ethanol contains approx. 34% less energy per unit volume than gasoline, and therefore in theory, burning pure ethanol in a vehicle will result in a 34% reduction in miles per US gallon, given the same fuel economy, compared to burning pure gasoline. This assumes that the octane ratings of the fuels, and thus the engine's ability to extract energy from the fuels, are the same. For E10 (10% ethanol and 90% gasoline), the effect is small (~3%) when compared to conventional gasoline, and even smaller (1-2%) when compared to oxygenated and reformulated blends. However, for E85 (85% ethanol), the effect becomes significant. E85 will produce lower mileage than gasoline, and will require more frequent refueling. Actual performance may vary depending on the vehicle. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles resulted 25.56% lower than unleaded gasoline.


Pure ethanol has a octane rating of 105 PON (129 RON), whereas Canadian 91 PON fuel has a RON of 96. This is why companies like Husky/Mowhawk offer the higher 94 (PON) instead of the typical 91 (PON).

Before this comes up: Canada uses PON, Japan uses RON. Your JDM engine IS NOT TUNED FOR 100 OCTANE!

Anyways, higher octane fuel allows you to up the boost and timing and make more power, even though ethanol releases less energy per unit. The higher octane will more than make up for it.

Fuel System Problems

Several of the outstanding ethanol fuel issues are linked specifically to fuel systems. Fuels with more than 10% ethanol are not compatible with non E85-ready fuel system components and may cause corrosion of iron components. Ethanol fuel can negatively affect electric fuel pumps by increasing internal wear,. cause undesirable spark generation, and is not compatible with capacitance fuel level gauging indicators and may cause erroneous fuel quantity indications in vehicles that employ that system.

Using 100% ethanol fuel decreases fuel-economy by 15-30% over using 100% gasoline; this can be avoided using certain modifications that would, however, render the engine inoperable on regular petrol without the addition of an adjustable ECU. Tough materials are needed to accommodate a higher compression ratio to make an ethanol engine as efficient as it would be on petrol; these would be similar to those used in diesel engines which typically run at a CR of 20:1, versus about 8-12:1 for petrol engines.

ChrisD's Experience

I have been running E10 for several years now with zero issues. I find that it significantly reduces detonation/knock over traditional 91 octane fuels such as Shell and Petro-Canada. I can safely run more ignition timing and boost without issue, and thus make more horsepower.

No troubles at all with my Walbro fuel pump or fuel lines, hoses, etc.

As for fuel economy, I have no idea since I didn't buy a GT4 for that!


04-09-2009, 06:12 PM
Looked it up for reference

Husky / Mowhawk uses E10

Petro-Canada uses E10 ONLY in "selected markets". Most markets use no ethanol.

Shell Canada does not claim or market the use of ethanol in their fuels

04-09-2009, 07:02 PM
They have had 10% ethanol in gas here in the US for a very long time. I have use it for years and have never had a problem with any of my cars. They have all been older vehicles too.