Super or Regular - I can't tell the difference

[mfn1194]

I really cannot tell the difference in how my '03 G35 drives whether I use 93, 91 or 87 octane.

Maybe if i used a stop watch or something... But for everyday driving...it really seems the same. I also have not seen any evidence that the engine will last longer on Premium fuel. Nissan has used a version of this engine in Maxima's and Patherfinder for the last 10 years or so... It has a great track record of long term reliability.

Unless you are racing..... I cant tell the difference

[joe603]

There have been many posts like this, and the answer is this. If you don't use premium, your car will not perform as well as it could. The other cars you mentioned use a toned-down version of the VQ35. Like most new high performance vehicles, the G35's engine management system will regulate the fuel/ignition curves to compensate for the reduced octane. However, this will affect gas mileage and strait-line performance.

It's your car, put in whatever fuel you want, but the manufacturer recommends a specific type of fuel for a reason. With gas prices the way they are, don't you think that if the car could run efficiently with regular fuel, Infiniti would promote that fact as a selling feature?

[gjohnson66]

I've also had a buddy who ran his Z on 87 octane (I know, not exactly the same but bear with me) and he ended up shortening the life of his points and plugs. They came out looking rather coroded. In the long run, it's a small repair but (and I don't know about you) I'd rather not perform any repairs before I really have to.

As stated before, it's your car and you can do with it what you want, but it really can't live up to it's potential using sub-standard fuel.

[g35beaver]

According to my 2006 G35 Sedan Owner's Manual (page 9-3)

Sedan - Automatic transmission modelsUse unleaded regular gasoline with an octane rating of at least 87 AKI number. For improved vehicle performance, Infiniti recommends the use of unleaded premium gasoline with an octane rating of at least 91 AKI number.

Sedan - Manual transmission and Coupe models ("rev-up" engine?)Use unleaded premium gasoline with an octane rating of at least 91 AKI number.

Summary: Super is required for 6MT/Coupe but not for sedan. However, it is recommended by Infiniti for sedan.

[WESIDE]

Then think about the price difference. Whats another seven or eight dollars? Not much. Fill the G with the good stuff. You only going to give yourself a headache in the future. Just my 2 cents.. -Wes

[Omega-3]

And you get better mileage with Premium fuel

[lawson3]

I constantly use 87 octane with no problems,now i do have a 06 sedan,I acually think i got worse gas milage with a tank of 93 octane.using 87 octane i get approx 340 to 350 miles until fuel light comes on,thats pretty good as far as i can tell.

[joe603]

I noticed that too with my sport bike...using premium gas got WAY worse gas mileage. Turns out the manual recommended 87!? After I did the switch, I got an additional 5 mpg. Now the G35, thats different...but only with the rev-UP engine. If you have an auto, thats different.

[Q45tech]

Ethanolized Premium will get worse MPG than NON ETHANOLIZED REGULAR.

Premium usually has a higher percentage of deposit reducing detergents, useful as the miles pile up.

[infinititech1]

I noticed that too with my sport bike...using premium gas got WAY worse gas mileage. Turns out the manual recommended 87!? After I did the switch, I got an additional 5 mpg. Now the G35, thats different...but only with the rev-UP engine. If you have an auto, thats different.

you put 87 in your bike???

[Q45tech]

In cold weather you can often get by with lower octane, however summer heat may require MORE than any available at the pump!

[joe603]

you put 87 in your bike???

Yup, I had an 02 Honda Interceptor...manual said to use 87. I tried premium, and got crappy gas milage...switched to skunk gas, and she ran better!

[telcoman]

2006 G35 Sedan 6sp manualI now have over 20k miles on mine and have never used premium. I use 87 octane. Never had a problem and the car runs fine. Mileage is usually between 21.5 and 24 or 340 to 350 miles per tank.

TelcomanEast Brunswick,NJ

[redhed]

i have an '06 automatic coupe and i can only tell the difference between running 87 and 91 octane when i'm flogging the car. with 87 octane there just isn't as much urgency to the acceleration, which, i presume is do to the fact that the spark knock sensors are dialing back the timing.

as far as running 87 octane hurting anything...i doubt it. if you can run 87 octane (according to the '06 owner's manual) in the g sedan automatic...why couldn't you run it safely in the same rated g coupe automatic...?

[redhed]

I've also had a buddy who ran his Z on 87 octane (I know, not exactly the same but bear with me) and he ended up shortening the life of his points and plugs. They came out looking rather coroded. In the long run, it's a small repair but (and I don't know about you) I'd rather not perform any repairs before I really have to.

As stated before, it's your car and you can do with it what you want, but it really can't live up to it's potential using sub-standard fuel.

how old was that buddy's Z? when was the last time points were used...?

[Crashtest77]

Easy to do....ferrari = high octane fuel....you will see hp ratings and most of the times in the tuner mags,they will even tell you, done on 93 octane,or some skylines before they are brought over run on 103 octane or 101. High performance car, better fuel, it's easy. The ecu will adjust everything for it to run on that, but you won't get the numbers that they got when rating it. Not to mention it burns better,so yes,in fact it's better for your car. I'm sure alot of folks remember this ...G.I.G.O ....garbage in, garbage out......i'd never use 87 in my bike when I had it, always 93.... very easy folks.......93 octane for performance....and less gass mileage.....the lower grades cuts back on your performance but gives better gas mileage your call.

[Omegamerc]

I thought for cars 100+ octane was a big no-no because of knocking?

[Crashtest77]

nope, skylines before they come over run on 100+ octane before they get re done for us

[redhed]

Easy to do....ferrari = high octane fuel....you will see hp ratings and most of the times in the tuner mags,they will even tell you, done on 93 octane,or some skylines before they are brought over run on 103 octane or 101. High performance car, better fuel, it's easy. The ecu will adjust everything for it to run on that, but you won't get the numbers that they got when rating it. Not to mention it burns better,so yes,in fact it's better for your car. I'm sure alot of folks remember this ...G.I.G.O ....garbage in, garbage out......i'd never use 87 in my bike when I had it, always 93.... very easy folks.......93 octane for performance....and less gass mileage.....the lower grades cuts back on your performance but gives better gas mileage your call.

high octane fuel does not necessarily equate to high quality...it only equates to high octane.

and, if you are burning high octane fuel in a vehicle that can't take advantage of it...you are being wasteful.

[Crashtest77]

All vehicles can take advantage of it. You will get slightly higher hp numbers. Being that the g35 has an engine that can take advantage of it, means just that. It's drivers choice, infiniti makes the recommendation so you get the same numbers they do when you driver your car, and that ferrari thing was meant to illustrate the higher performance engine. Not saying our engine is in the same league,but it has the potential if people want to spend the money on turbos and forged internals. So yes, this engine can make use of it.

[redhed]

All vehicles can take advantage of it. You will get slightly higher hp numbers.

some, but not all. advanvces in electronic controls/sensors, engine combustion chamber design, and so forth, do allow many engines to accept anything above 86 octane...and make a little more hp/torque when high octane is used. but, many still do not. for example, my '05 f150 recommends 87 octane. it even explicity says in the owner's manual you are wasting money by using high octane because there is no performance benefit.

so, my point was if your vehicle was explicitly setup to use 87 octane like my f150, there is no reason to waste your money on high octane fuel.

[Crashtest77]

Haha redhead,it's a good thing we aren't talking about pickups though. We are talking about sports cars with engines that were meant to use this. The gains you see won't be on any car til you are normally wot anyway. The pressure in the manifold and the compression of these cars meant to use the higher octane gas will then be able to use the higher octane to the full potential,so no,if you aren't going to be using your engine like that,yes it is a waste,I however did not buy a coupe to sit in the far right hand lane.

[redhed]

Haha redhead,it's a good thing we aren't talking about pickups though. We are talking about sports cars with engines that were meant to use this. The gains you see won't be on any car til you are normally wot anyway. The pressure in the manifold and the compression of these cars meant to use the higher octane gas will then be able to use the higher octane to the full potential,so no,if you aren't going to be using your engine like that,yes it is a waste,I however did not buy a coupe to sit in the far right hand lane.

uh, but you said that ALL vehicles benefit from using high octane...that is NOT true!

[Crashtest77]

I give up redhead, you are right. All cars can use the premium gas,and yes,all cars will get a little bit more power, but that's at wot. So no,of your f150 it's pointless,but we aren't talking about your f150. We are talking about sports cars.

[redhed]

I give up redhead, you are right. All cars can use the premium gas,and yes,all cars will get a little bit more power, but that's at wot. So no,of your f150 it's pointless,but we aren't talking about your f150. We are talking about sports cars.

no, i give up. you are the one that introduced ALL vehicles into this discussion on high octane and it's benefits. from what i know about engine/ignition and fuel system design, i've never seen anything that suggests an engine optimized to run on 87 octane gets any benefit from burning high octane, whether it's idling or running at WOT...
Modified by redhed at 10:33 PM 2/20/2007

[Crashtest77]

haha, i will agree to disagree with you then.