What Grade of Gas are you using.

[G37 Man]

Car calls for 91Octane,what is everyone using,less or more and can you feel the difference?

[G37sdr1ft3R]

im using 91 .. have been using it since i got my car, if you use anything less then 91 octane you will lose 20% Horsepower so if you dont care about having that extra speed then it doesnt really matter =)

[Kendahl]

Premium (91 octane) only. After spending forty large on the car, I'm not about to pinch pennies on fuel.

The manual specifies 91 octane. In an emergency, you can mix it with just enough regular to get you to a station that sells 91 octane. Then, fill up with 91 octane.

[RedG37SNC]

Never seen 91 it's either 89 or 93 in Charlotte, using 93 always.

[Magellan]

Car calls for 91Octane,what is everyone using,less or more and can you feel the difference?

Feel the difference? That’s the wrong question. It should be: After driving your car for a few years using a lower grade fuel than the manufacturer recommends, what damage to your engine have you suffered?

[ArEs23x]

Your car deserves only the best so I always use 91 even after i know im leasing cuz who knows whether they might pin it on you later for ruining the engine using lower grade gas

[redhed]

what damage to your engine have you suffered?

probably none since the ECU adjusts spark timing to accomodate lower octane fuel...

[Magellan]

These threads on using a lower octane gas are a bit tiresome to me. Even if there’s no eventual damage to your engine (in IMHO that’ s still a possibility) other than a performance loss due to the adjusted spark timing, do the math on the annual cost:

If 91 costs twenty cents more per gallon than 89, and you drive 15,000 miles per year averaging 24mpg, then you’re spending an extra $125 per year for premium gas.

Now I doubt if there are any G37 owners, who probably paid $40K plus to have a 330hp performance vehicle, who are willing to loose some of that performance to save $125 per year. I bet we spend more than that for popcorn at the movies.

[nKhona]

Even more tiresome are threads where people think putting higher octane gas in vehicles that only require 89 is better or gives more power. (Hint: It doesn't. Use what the manufacturer recommends.)

[RedG37SNC]

From the manual:

VQ37VHR engineUse unleaded premium gasoline with an octanerating of at least 91 AKI (Anti-Knock Index)number (Research octane number 96).If premium gasoline is not available, unleadedregular gasoline with an octane rating of 87 AKInumber (Research octane number 91) may betemporarily used, but only under the followingprecautions:c Have the fuel tank filled only partially withunleaded regular gasoline, and fill up withunleaded premium gasoline as soon as possible.c Avoid full throttle driving and abrupt acceleration.However, for maximum vehicle performance, theuse of unleaded premium gasoline is recommended.CAUTIONc Using a fuel other than that specified couldadversely affect the emission control system,and may also affect warranty coverage.

Octane rating tipsUsing unleaded gasoline with an octane ratinglower than recommended above can cause persistent,heavy spark knock. (Spark knock is ametallic rapping noise.) If severe, this can leadto engine damage. If you detect a persistentheavy spark knock even when using gasoline ofthe stated octane rating, or if you hear steadyspark knock while holding a steady speed onlevel roads, have an INFINITI dealer correct thecondition. Failure to correct the condition is misuseof the vehicle, for which INFINITI is not responsible.Incorrect ignition timing will result in knocking,after-run or overheating. This in turn may causeexcessive fuel consumption or damage to theengine. If any of the above symptoms areencountered, have your vehicle checked at anINFINITI dealer or other competent service facility.However, now and then you may notice lightspark knock for a short time while acceleratingor driving up hills. This is no cause for concern,because you get the greatest fuel benefit whenthere is light spark knock for a short time underheavy engine load.

[redhed]

yeah, my 2006 coupe manual says the same thing. it (the manual) also says that it's okay to use 87 or higher octane in the 2006 automatic sedan, but that you'll get better performance from high octane.

so, here is the puzzler....the 2006 automatic versions of the coupe and sedan have the exact same hp/torque ratings, yet you are required to use high octane in the automatic coupe???? this flat out tells me that 87 or higher is fine for the automatic coupe too...i won't make a judement call on the manual coupe since it's engine/fuel system is slightly different...

btw, my dad's 2007 maxima with the very similar 3.5l engine says 87 or higher octane in the owner's manual, but on the fuel filler door it says premium is recommended...so go figure!

[djkymar]

using 94 only since i got the car and you can feel the power

[Magellan]

using 94 only since i got the car and you can feel the power

Are you sure? As I understand it, the purpose of premium fuel is to prevent knocking at an engine’s higher compression ratio. If 91 does it, what more would 94 do? Try putting in aviation fuel (I think it’s around 100) and let us know if your teeth rattle from the acceleration.

[TnBill]

PLEASE don't listen to these self-proclaimed "experts"! Type in GOOGLE "premium gas" & READ the 1st 3 or 4 articles.

Do not overlook the article by the PORSCHE:

All Porsche engines are designed for premium, too, but it's not available everywhere. "Our cars must be able to drive all over the world, and so we are able to run on regular," says Jakob Neusser, director of powertrain development at Porsche's research and development center in Weissach, Germany. "You don't have to feel that a mechanical problem or anything else will happen" using regular gas, even in the highest-performance, regular-production Porsches.

Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.

Most of the folks here who SAY they know something refuse to admit they are talking out of their ***.

TRUST but VERIFY.

[RedG37SNC]

Interesting read, although the conclusion I came out with is to still use Premium for the G37. Your right that the engine will adjust to avoid pre-ignition but the cost is fuel economy. Considering this engine was designed for premium and the difference in cost in minimal and results in better fuel economy and performance it's worth it.

[G37 Man]

Talked to Infiniti service Mechanic and put the question to him.He said You can run 89 Octane gas but when the weather warms up run the higher Octane of 91,that higher Temp was over 90F.

I'm sticking to 91 but just wanted to get some input on what others were hearing and doing.

[pippen99]

A salesman told me the same thing back in 03 when I bought my first coupe. He said the dealership uses 87 or 89 until the hot summer months.

I have used 92 in all 3 of my Infinitis. I fortunately have 2 gas stations in my vicinity who charge only a .10 differential for premium.

[redhed]

i've generally put 89 octane (10 percent ethanol) in my g and haven't had any performance issues whatsoever. i tried one tank of 87 octane but could definitely tell the power was down...car ran fine just wasn't as spunky.

where i live there is a 35 cent difference per gallon between the 89 and 91 octane...which over time adds up! although i suppose i'm taking a bit of a mpg hit with the 10 percent alcohol so maybe it's a wash...? i should probably check to see what kind of mileage i get burning the high octane vs the 89 octane 10 percent ethanol.

[TESLAASTRO]

I found your post insightful Bill.....I've always used regular in all my leased vehicles because, hey, they were leased.....with my new G37 i decided to use Chevron 93 because A) I purchased the vehicle B) the difference in cost over a year (10,000 miles / 18 mpg x extra $.20 per gallon =extra $111 per year, which is negligible)....C) since I'm giving this car to my kid in 4 years, why not give the car the best available fuel.......

also, I figure that if the car gets slightly better mileage and performance, that extra cost is offset.....

[jcox265]

only use premium fuel unless you have to use a small amount to get you somewhere that has premium fuel. higher octane fuel burns cleaner and it is a cleaner fuel in general. not running the right fuel for several years will increase engine wear and tear and will leave nasty carbon build up on your valves.

[redhed]

it's funny how the oil companies have convinced many people that they should put "premium" fuel in their vehicles. i mean, afterall, it's called "premium" right? the word "premium" by itself suggests this fuel is not only high octane...it's better for me, my car and my dog!

[Magellan]

In my day we used to call it “High-Test.” It cost 30 cents per gallon, and if we filled up (with any grade) we often got free dishes and some blue stamps.

Anybody remember blue stamps? You got a stamp for each 10 cents of purchase and put them in a special book. When you filled up a few books you took them to a special Blue Stamp store and exchanged the books for merchandise.

[330badboyg37]

These threads on using a lower octane gas are a bit tiresome to me. Even if there’s no eventual damage to your engine (in IMHO that’ s still a possibility) other than a performance loss due to the adjusted spark timing, do the math on the annual cost:

If 91 costs twenty cents more per gallon than 89, and you drive 15,000 miles per year averaging 24mpg, then you’re spending an extra $125 per year for premium gas.

Now I doubt if there are any G37 owners, who probably paid $40K plus to have a 330hp performance vehicle, who are willing to loose some of that performance to save $125 per year. I bet we spend more than that for popcorn at the movies.

Ive been using the Shell v Power top stuff is that good to use?

[330badboyg37]

using 94 only since i got the car and you can feel the power

what gas station offers the 94?

[rn79870]

We hashed this over pretty thoroughly in the G35 forum. There are some G35 drivers who have used 87 octane for 50,000+ miles with no problems. However, the G37 has slightly higher compression, and therefore a greater chance of having a problem with the lower octane.

I only run 91 octane in my G35 but could get by with a tank or two of 87. I would not run anything less than 91 in a G37 though. The G35/37 share the same manual, and mine clearly makes a difference between the 2 cars and the use of 87 octane. Use 91 or better and be safe.

[hyekid10]

Are you sure? As I understand it, the purpose of premium fuel is to prevent knocking at an engine’s higher compression ratio. If 91 does it, what more would 94 do? Try putting in aviation fuel (I think it’s around 100) and let us know if your teeth rattle from the acceleration.

honestly.. there is a difference between 91, 94, and 100 (race fuel) which is called around my area .. tri state..

regular 87.. i used on my old g35 (i have a 37 now) and the only difference i felt was the delay in the acceleration..

as i filled up wit "super"(94) i felt as my rpms would shot up higher very fast and id kick it..

and for the "Race fuel" .. it basically kept my cars RPMs high like ready to fly or some****.. so there is quite a difference pal..

and if for people that wanna now how much "Race fuel" is.. i paid 7 dollars a gallon on a empty tank so i paid 49 dollars for 7 gallons not even half tank.. and it was major difference..

[Magellan]

Sorry, I don’t believe you’re getting any more horsepower from higher octane fuels. You may think so, but it may be mostly wishful thinking. The octane rating of any automobile fuel is to prevent knocking. As the compression ratios go up in certain engines, the octane rating must also go up, as per the following:

http://auto.howstuffworks.com/question90.htm

So putting higher than 91 fuel in your G37 really does nothing other than contributing to an oil company’s profits at the expense of your own.

[rn79870]

Sorry, I don’t believe you’re getting any more horsepower from higher octane fuels. You may think so, but it may be mostly wishful thinking. The octane rating of any automobile fuel is to prevent knocking. As the compression ratios go up in certain engines, the octane rating must also go up, as per the following:

http://auto.howstuffworks.com/question90.htm

So putting higher than 91 fuel in your G37 really does nothing other than contributing to an oil company’s profits at the expense of your own.

I would agree in theory with this. Using lesser octane will result in your computer retarding the timing and therefore less power. Using a higher than recommended octane will not cause the timing to advance past a pre set limit. 91 octane allows reaches that limit.

Higher octane fuels have LESS energy in them than lower octane. Seems opposite of what you would expect, but it is true.

Racing fuels are great, for engines with 12 -13 to 1 compression running 36-40 degrees total advance. Not in a 37 with 10.6 and probably 32-33 degrees total advance.

Anything more than 91 is a waste. Anyone paying 7 bucks a gallon for fuel is wasting money in an Infiniti.

[TESLAASTRO]

I like Chevron's 93.....it has Techron (whatever that is)...and I like those cute cartoon cars they have....win/win

[G37 Man]

Correct me if wrong but not only are you looking for the octane but also the additives that some brands of gasoline are adding.

are the cheaper stations,no brands putting them in or enough of it?

There is a special rating that gas gets which is posted on the pump which talks about this I believe?