Do Rogues respond better to premium fuel (higher Octane)

I feel I got better fuel mileage using premium fuel.

But I also notice less noise on acceleration too.

Is there any correlation to the type of fuel I'm using or am I imagining things.

Do any of you swear by high octane fuel or am I wasting money.

You are wasting your money. The QR25DE motor is optimized for 87 octane fuel.

philipa_240sx wrote:You are wasting your money. The QR25DE motor is optimized for 87 octane fuel.

What do you mean by optimized?

It performs better with 87 octane ?

Or there isnt any difference in engine performance with a higher octane?

I should have explained a bit better....

Octane rating refers to the fuel's ability to avoid detonation. Detonation occurs when fuel is compressed or heated excessively and it ignites too early in the combustion cycle. Detonation is quite violent and can destroy a motor. Higher octane fuels actually burn slower and require higher temperatures and pressures to detonate.

When a high octane fuel is used in a high compression motor ie. the VQ35DE in the 350Z, it allows the engineers to increase ignition timing and compression to produce more power. To get maximum performance, you should use the high octane fuel the mfg. recommends.

When you use a high octane fuel in a motor designed for 87 octane, you get little if any benefit. The motor does not have high enough compression or the programming needed to get the extra power from the fuel.

High octane fuels do not produce more power by themselves, the engine has to be designed to take advantage of it. Any differences you are noticing are either due to other factors, or in the case of 'smoothness' it's the simple fact that high octane fuels burn more slowly.

I have experimented a bit with both Octane values and Gas brands and have been using 89 Octane Chevron for some time now.

I do not have any tools to quantify delta in performance of different Octane rating/ Brand combinations other than MPG values and 'feel' in accelaration and engine sound pattern of engine .

With 89 Octane Chevron I get One MPG extra over Chevron 87 Octane which compensates for 10 Cents additional price for Premium and both me and my wife found acceleration / Engine Sound pattern and over all feel is better with 89 Octane.

BTW I am getting 24 MPG in 90 % City Driving (cery conservative driving habits) which I guess is good mileage.

There are some circumstances where higher octane fuels 'may' improve fuel economy slightly. Here is why:

Hot weather and/or heavy loads can produce a mild pre-ignition or engine knock condition. A mild knock condition is normal.

Modern engines including the Rogue use a very sensitive knock detection system. When engine knock occurs, the engine computer will change the ignition timing to reduce the knock/pre-ignition and to prevent engine damaging detonation. The downside is a reduction in fuel economy and power... usually by a few percent. By using a higher octane fuel under these conditions, you can sometimes get a bit better fuel economy.

More information of fuel recommendations can be found in your user manual on pages 9-3 and 9-4.

Personally, I have never noted an improvement in fuel economy by using higher octane fuels. But each situation is different. If you wish to experiment, I would do the following:

1) Try to keep your driving habits similar between fill ups. Always use the same brand of fuel for comparison, just change grades. If possible try to use the same gas station location. Perform the test during summer when gasoline formulations are kept constant and the weather is consistently warm.

2) Fill up with 87 octane and keep track of your mileage. I would go through 2-3 tanks of fuel to get a good average.

2) Fill up with the next highest octane. ie 89 octane. Go through 2-3 tankfuls of fuel and average your results.

If you note an improvement in fuel economy that justifies using higher octane fuel at the higher price, then go for it.

I may be nuts but I FEEL a difference in acceleration and it sounds quieter.

I buy the cheapest gas. Here in Iowa, that's a 10% ethanol blend. No problems after 1 year.

I have been using Shell 87 octane but the Husky station closer to me is now selling 90 octane 10% ethanol blend for the same price as regular 87 octane gas. So I will be using the 90 octane ethanol blend from now on.

I'm rolling with 87 octane.

i tried 87 for a few tanks and then 93 for a few tanks and didnt notice a difference.

I'm on my third tank using the highest octane fuel at Shell.

And you guys may think I'm nuts but I have noticed over the time since going from regular to super a few things.

a) My car is quieter, now I bought my car brand new about a month and a half ago so its either the fuel or the possibility that as time goes on and components are breaking in the car is getting quieter.

b) I do feel a bit more giddy up on this fuel too.

So, again you guys may find facts that state there are no advantages to higher octane fuel but I am getting a better feel with that fuel and I'm sticking with it.

Again, it may be the car feeling better and quieter due to break in, I'm at 2300 kms but who knows.

My Rogue has used Regular 85 Octane gas since it was new. Since I live at a higher elevation (around 5000 feet) we get 85 instead of 87. Sometimes I get 10% ethanol, and sometimes not. Car runs great.