You should sell your car if you want to save money.

 

No it won't.

To the OP, do you drive aggressively or are you more of a mellow driver? If you drive easy you can get away with running regular.

The reason why certain higher performing engines require higher octane fuel is because the higher the octane, the slower the fuel burns. Higher performing engines typically imploy one of the following:

1. High compression ratio (i.e. when the piston is at its highest point, how much fuel and air is the cylinder compressing vs how much volume is in the cylinder when the piston is at its lowest point).
2. Turbocharged (fans compressing air via exhaust and shoving it in the engine)
3. Supercharged (fans compressing air via the engine and shoving it into the engine)

In all of these cases they involve compressing a lot of air. When you compress air, it gets extremely hot so the more compression, the hotter its gonna get in there (hence the use of intercoolers in some turbocharged and supercharged applications). When driving hard and that compression comes more into play, lower octane fuel will explode before its supposed to, resulting in something called knock (because it makes a knocking noise in your engine) or detonation. In the old days, too much of this would simply blow your engine, today the car's computer and knock sensors will basically retune your car and pull back the timing to save the engine, only draw back is, depending on the severity of the knock, your car will perform much slower, this is the "power decrease" that people will mention.

Its important to keep in mind that the octane in the fuel itself does not reduce or increase power, higher octane fuel doesn't release more energy than lower octane fuel so its impossible for it to increase/decrease power. I'm sure mislead folks just have a case of the Placebo effect whenever they make such claims.

The best type of fuel to use is the lowest octane available that causes 0 knock, but unless you have scanning tools that read the car's computer, you won't know what that is.

In most cases, in normal driving, regular gas will suit just fine. So go for it, get regular gas and drive easy. You'll get better mileage (because you'll be driving easier on the throttle...not because of the octane rating) and you'll save a buck or two every fill up.

 

why drive a 300hp g if you are just going to go easy on it all the time then?

 

I rarely drive mine hard.

Theres a lot more to a car than just how much power it makes.

 

Sorry dude, thats not true. The ECU has a part to do with it, as it will safe guard the motor if it detects lower octane. There may be other factors, as this isn't an area I know a lot about, but I do know the basics. High-performance engines typically have higher compression ratios and are therefore more prone to detonation, so they require higher octane fuel.

Take my car for example, or any boosted G35. If you run boost, and then run 87 octane and do whatever you want to the ECU to make it pull timing, you will possibly damage the motor and/or lose a hell of a lot of power. I know, because it has happened to me when my car would run lean under boost.

 

To add to what Canadian said-0My car hates California Mix 91. Can't imagine going any lower. Not so much of a performance issue. It's the detonation-
Never hear a ping if I run unleaded 100 which we have around here at a local 76 station.
I'm still trying to get it to run on 91 without detonation at lower rpm. Sort of scaring me actually.

 

ur car HATES it? uhm?

 

Uhm, that would seem to be the case. Seeing as it doesn't detonate on higher when the tank is filled with higher octane. Do you run 91 octane gas in California? Do you have any mods? What's your experience or advice. I'm ready to listen to anything at this point-

Jfisher, what can I do to "tune away" the detonation? Please share-
Edit, I'm obviously beginning to wonder if my car is experiencing other issues.

 

damn you need to pull that stick out of ur ***, i was just wondering what you meant by your car NOT liking 91 gas, yes i do run 91 gas on my car, havent had any problems, no engine mods yet, but plenty of people who do on their g35s run 91 gas and their car doesnt "hates" the gas

 

For optimal fuel economy, you should put in diesel.

 

You know someone will and destroy their engine and then you will feel bad...

That is so not right...

 

I think this is pretty simple. If you have a coupe or any other model that says Premium Fuel Only, then use 91 or better octane. Anything less is just until you can limp to a station that offers higher octane, and you should put as little fuel as possible to get to a better station.

If your car says Premium Fuel Recommended, it is your choice. If you drive it hard, go with premium. If you drive normally or cautious, regular or midgrade is fine unless you actually notice issues. 91 won't hurt, but you can save money with lower.

 

More reliable engine and "significantly" more horsepower? Do you have any data to back this up? And almost no car is an "investment" either, certainly not anything in the price range of the G.

I'm not saying it's OK to put regular in the car, and they should have done a search, but at least the OP actually has a G rather than just coming on here and trying to make people feel stupid with inaccurate statements.

 

lol

who actually pumps 91?

we get 93 here where i live.

 

The highest we get in my town is 91