Bingo! You are right on the money! Our newer engines are designed to automatically retard the timing when a lower octane gas is introduced to a high compression engine. Under high acceleration, the octane rating does make a difference, and if you switch to a lower octane you might notice a loss in power, and not much else. There should be no pinging as prevalent in our older cars that required high test years ago. I have switched to 89 instead of 93... but not 87 and driving conservatively there is absolutely no difference whatsover. The idle is smooth, and the temperature is the same. Temperature can be affected with the change and that is why I mentioned it. Lower octane in a High compression engine can sometimes lead to higher running temperatures. Not the case with my G35 and so I will not pay sometimes 20 cents more for the high test when the 89 does the same job. Please note again..... If you drive aggressively, you need high test! We don't know what in the long term will occurr by straining the engine to adapt to the lower octane in this scenario. Just my opinion.. but I'm an old timer and with prices eventually getting to $5.00 and I 'm sure much higher.... I'm going to keep my foot very lightly on the gas pedal.

 

Instead of risking detonation on your high compression motor by switching to a lower octane fuel, why not try a few hypermiling techniques to get a better fuel mileage?

 

Price | Gallons | fillups/year | $$/Year | Diff/year vs reg unleaded
3.97 | 20 | 52 | 4128.8 |
4.1 | 20 | 52 | 4264 | 135.2
4.25 | 20 | 52 | 4420 | 291.2

buying a bicycle…. Refil tank every other week instead of every week:
3.97 | 20 | 26 | 2064.4 | -2064.4
4.1 | 20 | 26 | 2132 | -1996.8
4.25 | 20 | 26 | 2210 | -1918.8



My experience.... bought a bicycle, ride it to/from work (14 miles a day) cut gas in half.... way better choice than cheap gas! can make a few payments with those numbers.... just think how much I can save when the price hits $15/gal next week.... haha.... Good Luck! Oh, looks like the $300 for the bike was worth it.... and I am getting in shape so the ladies look even if I'm not in the G!


Guess you could just be easy on the right foot... but then why buy a G?

 

hmm.. again to all the people complaining about the gas, i feel you, i curse up a storm everytime im at the gas station, i mean a$$hole prices, n a car that loves 2 eat up gas, but eh.. it pays to play..

 

Its more important to find a pump that actually doesn't cheat you.

I routinely pump at 14.0-15.0 gals per fill up. or roughly 320 miles.

But I found this pump near my house that somehow always gets me to fill up 16+ gal, always higher then I normally would pump elsewhere.

Tried it for my other cars and same thing. So it kinda confirms my suspicion that some pumps lag or "cheats"

 

http://en.wikipedia.org/wiki/Octane_rating

 

i just took my g in to the dealer and was told i had spark knock wich is what happens due to lower octain or quality of the gas i allways put 91 octain from chevron but now im gonna try some other brands to see if it goes away but the knocking happens at idle and it starts to bug so much for chevron having good gas lol

 

dude i live in miami and gas is horrible like $4.40 for premium i was putting mid grade for a couple of weeks and it ran fine, but as soon as i read all the threads decided not to take a chance over a couple of bucks. Effectively i put the premium and it rides by it self you barely tap gas and its already taking off. so yea man just put premium and save money on dumb trips.

 

Yes, they do need at least mid grade (91octane)

 

Not really. I spend about $1000/month for gas (Both my wife and I have 80+ miles per day commutes. My wifes is probably closer to 100+ per day, becuase she has to drive around to multiple different offices)

An extra 2 bucks per tank, with our driving still only amounts to $32/month, or $16/month for each my wife and I.

I have saved more money than that by simply packing my own lunch rather than going out to lunch.

If $16/month is going to make or break your budget, than you have other financial issues that need to be rectified first. For example, since my wife's main office is next to the train station, I started carpooling with her, and have her drop me off at the train station, and I take that to work. She needs to drive for her work, and my work is still 30 miles roundtrip from her work.

Just that alone, means I can save about $500/month in gas, if I carpool everyday. (But I can't, so my savings is less) But I calculated that each day that I carpool, I save about $20 in gas if you take into account the all-day train pass. Coupled with me not being able to drive out for lunch, I save an additional $5-10. And this is per day.... Much more savings than simply putting in 87 octane gas.

 

I have two cars and here's your answer. My 2k max had received premium until last year. Bought my G35 last year and I dropped back down to mid-grade on my Max, no major problem. Efficiency went down to under 20MPG, no problem. This year I've been super busy driving alot so, I dropped down to regular. My car has been making some hellacious knock and had been hard going up hills. Today I filled-up with midgrade, problem solved. Our engines specifiaclly require a higher grade of gas than cheaper cars. It's your car, do what ya wanna. I'm not going to ruin my engine for a couple of bucks per week.

 

Its so funny when people(who dont know about cars, and don't really look at the whole picture) go "OMG you have to put premium in your car, its so much"
then when you tell them its only a $4 difference to fill your tank with 91 instead of 87 they're like "NOWAY''.........YESWAY lol

 

1+ I agree with you 100%, especially the bolded area.

There's so many other ways of saving money, which isn't much to begin with, than going with lower grade fuel.

.

 

Cheap compared to my $5.00/gallon in Cali

 

^Yeah dude. Here in the Bay Area we're hitting $4.69 for premium as of yesterday. No doubt it will hit $5.00 within a few weeks.