Catatafish,
To judge exactly what affect a specific local standard would have, you would have to do extensive and expensive testing. Since many of the standards are designed to help more complete combustion (reducing CO and hydrocarbon emissions - perfect combustion of hydrocarbon fuel (gas) results in only two products: water and CO2 [carbon dioxide]). Theoretically, the more complete the combustion, the more energy recovered and you should get more power and/or better gas mileage. As today's engines get better, in terms of reduced emissions, there's been an improvement in power and gas mileage for a given size engine. The environmental improvements have come via much better capability to control the combustion process; using multiple sensors and controllers and a computer to instantly analyze input data and adjust fuel/air mixture, spark timing, etc.

 

Marty, Catafish,

I suppose you know how difficult it is to even get to the plugs
in a 2K Maxima. I suspect is it just as difficult or more to get
to our G35 plugs. If I could easily pull and replace my plugs,
I would do it myself every 25K miles or so. The 2K Maxima
appears to be a real bear! Does anyone know how to access
the G35 plugs?

2003 TwBlue 5AT Sedan, sunroof,
Graphite Leather, splashguards, HKS exhaust,
14 wire Grounding kit, 350Z duct, Stillen CAI
Underbody rear diffusers, Drilled alum pedals

 

cato,
LOL, I can't even find them so I'm sure it's a blast to change them .

Marty,
Thanks so much for sharing....great info to know.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

One last question. I don't know how much you know about the point of sales part of gas, but my brother refuses to use anything other than a brand name gas station such as Shell, Texaco or Mobile. I, on the other hand, feel that Sam's gas is just as good. Excluding your Stop and Rob gas stations, is there an actual difference or is it just marketing? This is assuming that the gas stations we are going to are not dishonest. And thanks for your very informative answers.

 

Excellent info here guys!!!
Being the son of 2 petro engineers and former part owner of a large filling station, I can attest that there are 2 schools of thought, and neither is truly correct.
The first says "gas is gas," and is technically right. The major difference being the additive package added WHEN THEY FILL THE TRUCKS! They used to send "pigs" down the pipeline to separate grades, but don't even do that anymore. Now they just sell off the mixed middle grade to agri- or industrial use.
The other school of thought is that gas from a certain region is "better" than others. This is also true to a point. In certain areas, (Cali, Great Lakes, parts of the East coast) the retailers are forced to sell a product called RFG or reformulated gasoline. This can contain oxygenates such as the aforementioned MTBE, or alcohol, or several other additives to supposedly reduce certain types of emissions.
Adding this to the changing seasonal blends, one can understand the confusion revolving around gas.
The most surprising thing I read on this thread was the DESIRE to come to Illinois to buy gas.......I would run the other way as fast as I could. I saw a 6 whp difference between RFG and good gas purchased in Wisconsin on a Chevy small block. Others have complained of poorer mileage with RFG as well.
Marvin....the only difference being additive packages, you will be ok using Sam's brand. They do sell below retail to put other stations out of business, so please consider before purchasing gas from a hypermarketer (as they are called).
As long as you buy from a busy station that changes their moisture-trapping filters often, you should be OK.
As far as stations being dishonest, it is a HUGE fine to mis-market gasoline. Illinois has roving vans that sample and test the grades and volumes to make sure you are getting what you pay for. I don't know about enforcement in other states.


'04 G35X Graphite/graphite, NAV, wood, premium

 

Marvinclt,
I agree with ChicagoX, that you should buy the cheapest gas within any octane grade. The unbranded stations typically buy on what's called the spot market. They bid on gas available in their area, coming from refinery "x" in their region.
Our G35x gets a mix of octanes; if I'm filling up, I put in 87 or 89 octane, my wife tends towards 91. We both try to use the cheapest station around; independent of brand. I have never found the need to put any extra additives, to clean the jets, etc. in any car I've owned (including a Mazda 626 turbo I owed for 155,000 miles. I never had to touch the engine or turbo, except for plugs.

 

All I can say is I've noticed from the few cars I've owned... gas is like our diet... if you're a vegetarian and one day you try some chicken your body will react to the different food... much like gas... if you use Mobil, 76, BP, whatever... what you start with should be what you use... your car will get used to it and your results will be more likely than not consistant... I religiously use 76 and on occasion should there not be a 76 (or partner company of) where I'm in need of gas, I'll fill up with Mobil or Chevron... try to stay with the mother companies... Arco, USA, etc. buy oil from the cheapest supplier during that time period creating an inconsistancy.

-Kawika


P.S.
For those who care. I drive a Silver Sedan 6MT CA license plate "KRZ HAYN" = "Krazy Hawaiian". A "Shaka" is always welcome.
Eibach Pro-kit
Z-tube
JWT Pop-charger