Has any owner or organization tested different gas octanes in 2007+ G35 sedans to see the difference in gas mileage for each octane?

I have searched and read all the gas octane posts and I'm looking for actual test results.
Please use this thread for posting test results and other data.
I don't want this thread to become filled with opinions and arguement.

Thanks for any info in advance.

I have a 2008 G35x and I plan to own the car indefinitely. But, I use the car as basic transportation, so I am looking for the most cost effective fuel option.
I would only use a higher octane if it was necessary to prolong engine life or if increased mileage enough to compensate for the additional cost over regular fuel.

 

91 or 94 gives me 480 to 500km a tank with smooth acceleration above 160km/hr..... however, 89 gives 510 to 520 a tank with a bit more torque when take off.... Never try 87....
Test results based on 2 months of testing back and forth...

 

The answer to your question is no. There are no credible tests performed in acontrolled environment. However, using 87 in a vehicle that recommends premium can cause some expensive repairs 4-5 years down the road. The
VQ35 series of engines retard timing to prevent ping from using lower octane gasoline. 4-5 years down the road you may have to replace the knock sensor and possibly your 02 sensor which will cost somewhere in the ball park of $1200.

 

Or if you do it yourself...$100-$200. Changing those items aren't difficult...at least not in most cars.

 

or lease the car and not worry about the long run =X

 

This thread sucks, If $2 - $3 per fill-up is going to make or break the bank then sell the G and buy a prius.

 

Sometimes I get better gas mileage with higher octane, sometimes no. Too uncontrolled to test reliably.

This is on the 2004 Auto, which doesn't require premium.

 

Octane rating is independent of mileage. You'll have better luck comparing mileage of different brands.

http://www.weif.net/car/mileage.php

 

That's what I thought as well. No matter what the mileage is, our engine is designed for at least 91 octane fuel. Any lower will bring pings and poor performance.

 

gas mileage has absolutely nothing to do with octane rating. octane is simply this....the higher the octane, the slower more controlled the burn which means you are able to run more ignition advance. the more ignition advance the more peak combustion, hence more power. the lesser the octane, the less ignition advance before tdc due to the faster more uncontrollable burn.

 

I have more of an issue with 10% ethanol fuel. I get worse mileage with it.

 

Same here.

 

TT C6, you can easily gather some data by driving over a particular section of the freeway using cruise control when traffic is light. Take the average of both directions if you want to be really scientific to cancel out the wind effect. You just have to repeat the test after using up most of the tank and filling up with the second octane a few times.

 

Don't use 10% Ethanol. It's good for the environment, but until they start making engines that burn it at a rate similar to regular gasoline, you'll be paying more money in E-80 or whatever it is than premium over a month's time.

 

I am definitly with you regarding not wanting to use 10% ethenol, but here in florida it is getting hard to find stations that have 100% petrol.

As to ethenol being better for the environment, the jury is still out on that one. Sure it burns cleaner, but full ecological inpact might just be worse than fossil fuels when considering the full lifecycle from seed to energy.

What we need is a new breakthrough.