What type of fuel

[nricci]

Team,
My first post here.

I have a 2012 S4 that is 100% stock. Use the car as my daily driver when I'm not riding my bike. Car has 28k miles and works perfectly.

In the area I'm currently living I can find two types of fuel:

- 91 octane with 10% ethanol and
- 89 ethanol free.

I reckon both are not ideal. Best would be 93 non ethanol (I will keep dreaming) or maybe 91 non ethanol. But these are not available here. It is hard to even find 93 with ethanol around here!

So considering these two options, which one would you take? I know the manual says 91 minimum and this is what I've been doing. But since you're more experienced and know much more about this car and engine than I do, I was wondering: if you were in my position would you opt for the 89 non ethanol?

PS: I do not track/race the car.

Thanks for any input. It is really appreciated.

[Dr GP]

Running 89 octane will not hurt the car. Just diminish the performance SLIGHTLY. On the road you probably won't notice a significant . Computer will automatically adjust the timing for lower octane gas. i don't think the 10% ethanol will hurt the car either. You are right. In an ideal world we could get 91 or higher non ethanol gas. In my area we have predominantly all 10% ethanol gas. But premium is usally 93 octane. Occasionally run into 92 octane. Almost never see 91.

[mrmomo313]

I would opt for the highest available octane so the 91. Lots of the west coast guys are running that 91 craptane as well. If you fancy some more octane, mix some good e85 with the 91 to an e30-33 mix which will run nicely on the stock ecu

[eurotic]

I was thinking of asking a similar question. The best fuels I can get are:
91 no ethanol (Shell V-Power)
94 with 10% ethanol (Husky/Mohawk and maybe Petro-Canada)

I can't say I can feel a difference and any difference I think I might feel is probably in my head. Currently stock but plan to do stage 2. Any suggestions either way? What would I gain/lose from either?

[LINDW4LL]

91 is the clear choice due to higher octane. There's nothing wrong with 10% ethanol- in fact, it (ethanol) is actually helpful from a performance standpoint as it reduces knock and timing correction as compared to normal pump gas. Of course, there isn't too much benefit with only 10%, but still. The only con is that fuel economy is 2-3% worse with E10 as compared to 100% gasoline.

I take it from your post that you must not be located in Charlotte any longer?

I was thinking of asking a similar question. The best fuels I can get are:
91 no ethanol (Shell V-Power)
94 with 10% ethanol (Husky/Mohawk and maybe Petro-Canada)

Currently stock but plan to do stage 2. Any suggestions either way? What would I gain/lose from either?

94. See above. Your timing advance will be better with it as compared to 91.

[mrmomo313]

I was thinking of asking a similar question. The best fuels I can get are:
91 no ethanol (Shell V-Power)
94 with 10% ethanol (Husky/Mohawk and maybe Petro-Canada)

I can't say I can feel a difference and any difference I think I might feel is probably in my head. Currently stock but plan to do stage 2. Any suggestions either way? What would I gain/lose from either?

when tuned you'll make more timing with the 94 petro

It's not going to make much of a difference stock so just go with what's more convenient. I personally only run shell 93, 93+e85 or race gas in my car

[nricci]

91 is the clear choice due to higher octane. There's nothing wrong with 10% ethanol.

I thought non-ethanol fuel helps with engine longevity and overall reliability.

Not right?

[dls11b8]

I thought non-ethanol fuel helps with engine longevity and overall reliability.

Not right?

Based on the idea that ethanol has lower specific energy and higher octane, I would assume that it wouldn't hurt reliability and longevity. I'm no expert though, so that's just a guess.


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[nricci]

Based on the idea that ethanol has lower specific energy and higher octane, I would assume that it wouldn't hurt reliability and longevity. I'm no expert though, so that's just a guess.


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I was referring to corrosion and other issues in injectors, ducts etc.

[jimrobbington]

Based on the idea that ethanol has lower specific energy and higher octane, I would assume that it wouldn't hurt reliability and longevity. I'm no expert though, so that's just a guess.


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People purposefully ADD ethanol to BOOST performance via E85 mixtures. Of course 91 without ethanol is better than with as the latter began as a lower octane fuel to begin with most likely.

[Canadianwraith]

I was thinking of asking a similar question. The best fuels I can get are:
91 no ethanol (Shell V-Power)
94 with 10% ethanol (Husky/Mohawk and maybe Petro-Canada)

I can't say I can feel a difference and any difference I think I might feel is probably in my head. Currently stock but plan to do stage 2. Any suggestions either way? What would I gain/lose from either?

I run the 94 from Petro religiously

[cspcrx]

I am stock, minus intake, and only have access to the same fuels as you. What I do is mix in 3-4 gal of E85 with every fill up of top tier 91 octane 10% Ethanol. The car really seems to like it, especially as it gets warmer. Every summer, especially here in Phoenix, my car just looses all of its pep. Much less with this mix. I have been running it for over a year now and never had any codes or issues.

[waxxonMTL]

I run the 94 from Petro religiously

I was thinking of asking a similar question. The best fuels I can get are:
91 no ethanol (Shell V-Power)
94 with 10% ethanol (Husky/Mohawk and maybe Petro-Canada)

I can't say I can feel a difference and any difference I think I might feel is probably in my head. Currently stock but plan to do stage 2. Any suggestions either way? What would I gain/lose from either?

Also canadian.. I was having this discussion with my co-worker today because I'm getting EPL stg2 next week with 93 maps. However, from his standpoint, the quality of the shell v-power is the best available and offer better fuel economy and less corrosion/more clean engine and the latter which is like a 91 octane boosted with ethanol to make it to 94 rather than being a TRUE 94 octane.

So I'm glad this topic came out and sorry for bumping in the way ( maybe i should start another thread about canadian gas station ?) but I'm curious if I shouldn't just be better using the 91 v-power instead of the ''modified'' 94. or all this v-power is marketing hype ?

I guess the only way to tell is to get it datalogged and see how much knock is recorded with both type of gaz once my ecu has adapted to the tune ?

[LINDW4LL]

Also canadian.. I was having this discussion with my co-worker today because I'm getting EPL stg2 next week with 93 maps. However, from his standpoint, the quality of the shell v-power is the best available and offer better fuel economy and less corrosion/more clean engine and the latter which is like a 91 octane boosted with ethanol to make it to 94 rather than being a TRUE 94 octane.

So I'm glad this topic came out and sorry for bumping in the way ( maybe i should start another thread about canadian gas station ?) but I'm curious if I shouldn't just be better using the 91 v-power instead of the ''modified'' 94. or all this v-power is marketing hype ?

I guess the only way to tell is to get it datalogged and see how much knock is recorded with both type of gaz once my ecu has adapted to the tune ?

Your co-worker is overthinking it. At the end of the day, it is a "true" 94 octane fuel, regardless of the recipe. Corrosion isn't an issue on modern engines. He is correct on fuel economy, as E10 is 2-3% worse for MPG as compared to pure gasoline.

Shell is a reputable fuel, but real-world you're almost certainly never going to see a difference over any other equivalent octane top-tier fuel. I'd certainly never sacrifice octane points to fill with it.

And, feel free to log. I'm sure you'll see better timing with the 94.