Which gasoline for my 4.6L

[shagnat]

I have a gas station near me that sells 87 octane without ethanol. No premium w/out ethanol.

So, do you guys think I'd be better off with the 87 octane w/out ethanol or use premium with ethanol?

I don't much care about the 7 horsepower increase with premium, so with that information, what opinion do you guys have?

 

[AC/DC Fan]

I run the cheap stuff.

 

[NSXNEXT]

I have a gas station near me that sells 87 octane without ethanol. No premium w/out ethanol.

So, do you guys think I'd be better off with the 87 octane w/out ethanol or use premium with ethanol?

I don't much care about the 7 horsepower increase with premium, so with that information, what opinion do you guys have?

If I were you I would run a few tanks of each with similar driving patterns. Monitor the difference in mpg between regular and premium and the answer will be there in the numbers.
Sometimes the price difference between reg and prem are made up in better mpg.

 

[stuofsci02]

If I were you I would run a few tanks of each with similar driving patterns. Monitor the difference in mpg between regular and premium and the answer will be there in the numbers.
Sometimes the price difference between reg and prem are made up in better mpg.

Contrary to what most think makes sense you will get better mileage with 87 octane if you car can run it and does not seriously retard the timing due to knock sensor.

Higher octane is more resistance to knock, but actually contains less overall energy.

 

[Flgatorfan]

My car knocks under hard acceleration with 87. I didn't think that was supposed to happen.

 

[brfatal]

Of course it does. Th ECU will try to advance as far as it can until it detects knock via the knock sensor. When you run 87 it will knock sooner than on 93. When it does it will pull timing and start to advance timing again until it knocks again. This will happen over and over again. This is why some cars are "premium required" rather than "premium recommended". Usually cars that are the latter don't advance timing as quickly, but either way you are always going to develop knock with 87 if you push the car.

 

[topspeed]

I've tried both for extended periods and find no difference in performance. I'll stick with 87 octane.

 

[Mark_888]

Even though I think there are clearly measureable (although maybe not noticeable) advantages to premium gas with the Genesis V8, the fact that the 87 octane has no ethanol pretty much would seal the deal for me.

 

[EXBMWGUY]

Even though I think there are clearly measureable (although maybe not noticeable) advantages to premium gas with the Genesis V8, the fact that the 87 octane has no ethanol pretty much would seal the deal for me.

Agreed!

 

[shagnat]

I too like the "no ethanol" gasoline, but, it's $3.66/gal vs Premium w/ethanol at $3.63/gal. The 3 cents/gal isn't an issue, just trying to compare the two choices.

But, you guys think the "no ethanol" would be the better choice?

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[brfatal]

Cars now are designed to run with ethanol. It's not as big of a deal as with older cars. Running no ethanol is more stickin it to the man than anything else.

Despite stuofsci02's comment, you'll get the best gas mileage on whatever octane the car was intended to run with. I have a feeling that would mean 93. Why not test it yourself? You'll need to run a few tanks of each in a row to get a good comparison. The 1st tank of gas of each will not be the same results you'll get in the others.

 

[Mark_888]

Cars now are designed to run with ethanol. It's not as big of a deal as with older cars. Running no ethanol is more stickin it to the man than anything else.

Despite stuofsci02's comment, you'll get the best gas mileage on whatever octane the car was intended to run with. I have a feeling that would mean 93. Why not test it yourself? You'll need to run a few tanks of each in a row to get a good comparison. The 1st tank of gas of each will not be the same results you'll get in the others.

I disagree with your first point. Modern engines are designed to tolerate 10% ethanol, but once it gets much above that percentage then problems will occur with most current engine designs. So that leads me to the conclusion that even 10% has some drawbacks with regard to engine reliability.

You are completely wrong on the second point. In the "old days" it was true that engines were designed for a single octane rating, but with modern engine designs controlled by computers, many engines can vary various different things to adjust to the amount of octane in the gas. The Hyundai Tau V8 is specifically designed to handle either regular, mid, or premium, and to obtain increased HP and better MPG with the higher octane fuels. That does not mean HP and MPG can increase indefinitely for gas with more octane than premium, but within the octane ranges of 87-93 it is designed to make the best use of whatever octane level is present in the gas.

 

[brfatal]

I disagree with your first point. Modern engines are designed to tolerate 10% ethanol, but once it gets much above that percentage then problems will occur with most current engine designs. So that leads me to the conclusion that even 10% has some drawbacks with regard to engine reliability.

You are completely wrong on the second point. In the "old days" it was true that engines were designed for a single octane rating, but with modern engine designs controlled by computers, many engines can vary various different things to adjust to the amount of octane in the gas. The Hyundai Tau V8 is specifically designed to handle either regular, mid, or premium, and to obtain increased HP and better MPG with the higher octane fuels. That does not mean HP and MPG can increase indefinitely for gas with more octane than premium, but within the octane ranges of 87-93 it is designed to make the best use of whatever octane level is present in the gas.

On the 1st point I have nothing to refute what you said, other than that items like fuel lines, injectors, etc are all now built to accommodate ethanol where before they did not since it was never part of regular gas.

As for the 2nd, you're both saying exactly what I said and then throwing words in my mouth. I said that the car is mostly likely optimized for 93, so it will get better gas mileage on premium than regular. I never said anything about timing advancing indefinitely. Abiet many cars will continue to advance with octanes higher than 93 (Audis, VWs, and Subarus will keep advancing to take advantage for up to 95-98 octane)

 

[Mark_888]

As for the 2nd, you're both saying exactly what I said and then throwing words in my mouth. I said that the car is mostly likely optimized for 93, so it will get better gas mileage on premium than regular. I never said anything about timing advancing indefinitely. Abiet many cars will continue to advance with octanes higher than 93 (Audis, VWs, and Subarus will keep advancing to take advantage for up to 95-98 octane)

What I said is that the Tau engine is not optimized for any specific octane, so long as the octane is within an acceptable range (and at least 87). The fact that it gets better MPG with higher octane does not mean it is optimized for that specific octane, it just means that there is a positive correlation between octane and fuel mileage (the higher the octane the better the mileage). The real reason for this is that the higher the octane, the higher the HP, which translates into better mileage at a fixed RPM and fixed gear ratio. This should not be surprising, since the higher the octane, the more compression can be achieved, if the engine is flexible and intelligent enough to adjust it. But I guess this all just semantics, and we agree on the end result.

 

[shagnat]

My personal findings are the 87 octane w/out ethanol seems to give me better gas mileage. About horsepower, what's the difference between 368/375't in no drag races, so it doesn't matter to me.

Hope this helps someone else too.

 

[rve]

368/375

 

[AgentSmith007]

378/387 - 2011

 

[shagnat]

378/387 - 2011

Can you post a pic of your steering wheel badge? Or PM it to me, either way? I'm still debating on whether to stick the wing on top of the flying H.

 

[AgentSmith007]

Can you post a pic of your steering wheel badge? Or PM it to me, either way? I'm still debating on whether to stick the wing on top of the flying H.

shagnat,

It looks like in the picture that homeofstone already posted in the thread that you started. Scroll down to post #6.

http://www.genesisowners.com/hyundai-genesis-forum/showthread.php?t=11830

I like it. And it only cost me $10. I didn't want to spend $250 or whatever the price is on steering wheel air bag assembly to get wings emblem.