Use what the manual tells you to use. I've got a V6 with 240 hp and it's the lowest grade. Unless you drive a friggin' Zonda, probably the same for you.
On a side note, I saw that the shells over on my side of town are offering their gasoline as "nitrogen-enhanced" now. Anything to that or just a fancy marketing ploy that'll last 5 seconds?
The octane requirements are based on the combustion characteristics of the particular engine. An engine with a higher compression ratio, or other means of acquiring higher pressure and heat-such as turbos or superchargers (more heat produced, higher chance of pre-ignition or spark knock), is often recommended/required to run higher octane. Most modern engines have knock sensors, however, and if a lower than optimum octane is used, and improper combustion occurs (causing pinging or knock), then the ignition timing can be r****ded to compensate. This usually has the adverse affect of lower power and fuel economy. Think of diesel engines. They don't use a spark from a spark plug to ignite the diesel (which is much less volatile than gasoline). They rely on the heat generated by the high compression ratio, meaning that the air and fuel mixture is squeezed so tight that it heats it to the point of combustion. If pressures are higher in one gasoline engine over another, the gasoline in the higher heat/pressure engine is more prone to being ignited by heat, rather than the spark-which is bad.
It's in the detergents they add to the gas from what I understand - I still haven't been able to figure out anything other than that. BTW, apparently they were giving away free gasoline at various Shells in Houston to celebrate the new formulation : http://finance.yahoo.com/news/Shell-Rolls-Out-AllNew-Shell-prnews-14563238.html
depends what kind of engine you have. If you have a v8 its normally premium. If you have a v6 you can use mid to get better performance but regular is fine
There isn't really much of a difference where the gas comes from. I believe all gasolines are pumped from the same pipelines. The difference is the additives that gasoline companies add to their gasoline therefore giving your engine better performance by having additives that clean the gunk left from the fuel such. Sometimes pumping from cheaper gas stations, some do add water to their fuel (or at least I heard they use too) which lowers gas mileage, screws with your engine in the long run. This is illegal. Do know, that I'm sure is just a few select stations that do this illegally. I know I did hear of those cases in the past. Not sure about now, but I rather go with the more known brands which add stuff to their gasoline for the sake of cleaning out things.
The different gases? There are different detergents in the gasolines from the different vendors, if that's what you're asking.
do you know which gas stations "add water"? i've been stopping by Krogers and Randals lately and RaceTrac because of their prices.. I think i'll stick to the bigger names from now on.
I heard that too. I'm not so much sure if that's just an old popular myth still or not. There's a gas station by my house that looks like a garbage dump but always has a discount of about 5-8 cents more than other stations in the area. Consequently, this is always the station I hesitate buying from unless I'm in a dire need for gas
Bingo. Really not hard to figure out. I have to use premium as I have a high rev engine in the Z that requires it.
This isn't like you can water down Kool-Aid. lol. Water in your gas line would be tracked down pretty easily when hundreds of customers report it. BTW, those dinky gas stations use the same gas everybody else uses. Walmart gas pumps, for example, are usually run by Murphy Oil. They may not all have the same detergents. If you want to be really anal about it, go with "tier one" gas : http://www.toptiergas.com/ http://www.toptiergas.com/retailers.html
the cheapest, 87 octane..thats all my car requires. Ocassionally I fill up with 91 chevron plus techron gas, just to clean the engine.
