wolfmanjack210

Perfect conditions. Sunny, dry, and temperature around 17 deg C (62 F).

mtrsprt

91 octane is considered premium and any vehicle/engine that "requires" it for normal engine operation, is going to run the most advanced timing possible for max efficiency/power.

There is no passenger production vehicle that requires anything more than 91 octane. 93 octane however, is just a bonus for those that may be running forced induction, or engine hardware changes that may cause the engine to be more susceptible to pre-detonation/knock over the original engine design.

Germany also uses higher octane fuels more commonly. In such testing of high end/high compression sports/sporty cars, they have found that there were increases in power when running even higher octane levels than 93, because the engine mapping calculates engine load, and determines even more ignition timing can be commanded.

wolfmanjack210

Unfortunately here in Toronto Canada I have not come across octane ratings higher than 91 that don't use ethanol. One of the reasons I use Shell is because their premium fuel does not contain ethanol. I'm not sure if this still applies, but I remember reading back in 2008 that our ECU's were optimized not to run fuel containing ethanol. Possible engine lopping / eratic behaviour could result. Ironically, look were my engine is now...

mtrsprt

The 10% ethanol addition is far too diluted to have any negative effect on engine operation. If anything, other than the downside of slightly less fuel economy, it actually helps keep combustion temps cooler, and oxygenates the burn better. There have been studies shown that a 10% ethanol addition to fuel will actually increase power output levels over non ethanol addition mixtures. The difference in VERY slight @ 10% however...

wolfmanjack210

Totally agree with what you are saying. I will also add that running higher octane than what the engine is designed for will actually produce less horsepower. If I recall correctly, the additives used to increase the octane rating, actually lower the energy density of the fuel.

mtrsprt

You are correct. Running any higher octane than needed, will indeed hinder performance.

Example:
John Doe's completely stock G37 coupe ran 101.6mph in the 1320. Three times in a row.

John decided to toss some 110 octane in the tank thinking he was going to blast off like a rocket.

John then made three back to back passes, and trapped 98.9mph.

John went home confused and starting purchasing products to clean his injectors, and do a tune-up.

eksigned

iTrader: (1)

did you figure out why your car was sputtering? are you SURE your car was stock prior? the ses doesn't really come on for much (usually non-serious) ie typically bad O2 sensors. seeing that your car was shuttering, and then the ses light came on, i can't image it'd be "bolt on" related, rather something with the ecu (ask infiniti to reprogram?). throttle flaps being stuck wouldn't really cause a shutter (and the cars new).................bad fuel, maybe, wet maf sensor on your intakes...............sometimes bad vac lines cause shuttering? say if they sucked something up (not sure if our cars have direct vac lines)...? eek...sorry hope you figure your problem out!

DarkGOne

So 91 is the mid level Gas? so no reason to put high level in?

I live in MD area and its goes 87-89-92 there is no 91

lier200a

iTrader: (1)

In Canada, we have 87-89-91.

I think Husky offers 93 here in Canada.

wolfmanjack210

I can't say for sure that the car has always been stock as I bought the car used from Infiniti. I was told the car had never been titled and was driven by an Infiniti Canada executive. The car belonged to Infiniti Canada.

Your right about the SES light. On my 2008 the light never came on once in 4 years.

wolfmanjack210

Update for the day. Have started the car six times today. All was good until the last start in the downtown area. Drove through the city and parked the car for about 30 min. I started the car and it began to sputter. This time it was mild but it lasted for about 2 min even after I drove off. As i accelerated from a stop sign not to far away the engine continued to sputter. I pulled over and waited 1 min. After a couple of mild revs all was good again???

daren_ipl

iTrader: (1)

some petro canada gas stations in toronto have 94

Goonz

iTrader: (9)

nice!!

Wyldfyer

Im a little confused why this hasn't been taken to the dealer yet. The time spent driving and reporting back to the forums could cost you more money. Use that warrantee, Bro! LOL

I hope it ends up ok. it sounds very fishy for such low miles.

Also, our cars would run just fine even on 89, although I would stick to premium for best PERFORMANCE... performance being the operative word. It wouldn't hurt a thing running 89 so the gas octane rating isnt an issue unless it was contaminated.

wolfmanjack210

The next morning after the sputtering upon startup happened I took the car to the dealer. The issue is that of replication. They were not able to replicate the sputtering startup. Also the SES light conveniently turned itself off. Apparently no codes were found in the ECU. This is very strange as the question would be what caused the SES light to come on? And why wouldn't it store the error codes for later retrieval. I'm starting to wonder whether they even plugged into the ECU.

At a compression ratio of 12.5:1 I'm not sure I would be running 89 octane. With a fresh engine perhaps you'd get away with it as the carbon deposits are at a minimum. As the engine ages these glowing carbon deposits inside your combustion chamber can cause pre-ignition; immediately deadly for engines. Detonation (usually deadly over prolonged periods of time) is also more likely at lower octane ratings. I haven't read my IPL 2011 manual on this matter. However on my 2008 G37S it specifically says not to use anything lower than 91. In an emergency use whatever octane is available and only fill to the 1/4 mark and don't push the engine. As soon as premium is available top it up. Also I paid for 348 hp, why settle for a smaller number.