I keep reading that for highest performance you must use 91 grade, which makes sense. It is also stated that you can use 87 grade and it will not be harmful, just somewhat less potent. It seems that in most circumstances, then the 87 makes sense--if truly not harmful. Sometimes I wonder exactly how far apart these grades actually are and if one isn't almost the other. Any thoughts?

 

Hey bro, My owners manual says to "use unleaded Premium Gasoline with an octane rating of 91" (for the Coupe).
If 91 is unavailable, then 87 can be used teporarily but only if you can refill with Premium soon after , and full throttle driving is avoided.
Don't cheap out on gas.....Your engine won't like it.

BTW-- welcome to our site bro, and congrats on your new ride.

<font color=red>GSM</font color=red> <font color=black>Silverstone Coupe</font color=black>

 

It's probably wise not to mess with the gas. Keep it at 91 or higher.

2003-G35C-5AT Laser Red/Black/Prem/Tint/6 Spoke Chrome/Black Badged/Lo-Jack

 

Like the manual says, no big deal with the lower octane stuff. The engine will not be damaged by it.

 

It cost about $3.60 more to fill 18 gallons of gas with 91 or better assuming 91 is 20 cents more than 87. Don't be cheap.

Life is too short to argue on the Internet!

04' 6MT Coupe (on order)

 

Where on earth do you get 91 octane gas?
Around here (East Coast), the basic choices at virtually ALL stations is 87, 89 or 93. Sunoco has 94 (instead of 93), but from my experience it's no better than say, Amoco's 93 (best pump gas on the planet, IMHO). Nowhere have I ever seen 91.
And for the record, my baby sees ONLY 93 or better. I think once my wife put in regular (87) by mistake, and that was the last time she got behind the wheel. The G was coughing, spitting, and knocking like crazy on regular fuel.

2003 G35 Coupe 6MT Leather
Premium, Aero
"There is no spoon"

 

California and most South Western States.

 

If ur willing to spend around 40 G's for a car dont be cheap on gas it makes no sense. If u wanted to use the cheap stuff u should have bought a Honda

03 6mt black/black
All the goodies inside and out

 

Lower octane may make it ping when you floor it. Incomplete combustion is only a problem if it becomes chronic. Use the highest octane you can get.

 

Modern cars have knock sensors. If you use fuel that is lower than recommended (like 87 octane), you should not even encounter any knocking/pinging unless you're wide open throttle under heavy load. And if that should cause knock/ping, then the knock sensors will detect it and retard timing to eliminate it.

If the question was 87 octane fuel hurting your engine, then no, it will not do any damage, just as it says in your owners manual. However, under certain circumstances, you may lose a few horsepower at wide open throttle using the 87 octane fuel, due to the retarded ignition timing.

 

Anothing thing to think about-- Engineers that design engines/fuel systems know that there will always be people that will put 87 octane fuel in their tanks, regardless of warnings in the owners manual/fuel door etc.... With this in mind, they MUST make even a high-compression engine run normally on the 87 octane fuel, with no damage at all. Think about it-- if they didn't, then there would be all kinds of warranty claims on damaged engines due to low octane fuel use. And that would cost the manufacturer big $$$$$.

That's why it's okay to use 87 octane fuel in your car if you want to.

 

Hey bro, 91 octane is available in Ontario Canada, along with 87, and 89. Sunoco offers 94 I believe, but at a Super Premium cost.
Is using a fuel with an octane above the manufacturer's recommendation beneficial? Anyone???????? Or just a waste of dough?
Going below 91 (on the Coupe) would be bad, but going above. hmmmmmm?????????

<font color=red>GSM</font color=red> <font color=black>Silverstone Coupe</font color=black>

 

I saw a test somewhere forgot where I saw but they put 100 octane in a 350Z auto track and manual track and both cars yielded a about a 4hp gain for auto and about 6hp for manul. Prior to reading that I put 100 octane at this 76 gas station in Brentwood and man it was freakin expensive like 4 dollars more than 91so I only put like $20 worth and all I can say was the car drove a little smoother in higher rpms and the car shifted a little better in auto which felt faster.

 

Deadman, Brentwood CA? That's just a skip for me.

03.5 Coupe - Black/Willow, 6MT, Premium, Navi, Aero, Sat