it really won't matter if you mix different grades.

But I always use 93 oct.....its maybe 20cents more.(a whole $4.00 difference for 20 gallons of petro)

 

well when the G is geting 13mpg like mine does right now,,,I dont really want to spend $4 extra for this gas cow if I dont have to.......

 

Repeated use of lower octane rated fuel can cause detonation on higher compression motors.

Key work CAN!!!

I ran 89 in mines after the hurricane and did not see a difference but better safe than sorry. I ran 89 in my 2003 Acura TL for week and immediately I heard knocking..so that just goes to show you

 

I feel so exclusive now...with 4 year old car which costs about $17,000 USD...

 

lol no ****,,,, people on here talk about their G's like they are some rare Ferrari or something when in fact its a cheap Entry Level Lexury sports car.

 

true but some people make them even cheaper appearing with their grapefruit launcher ebay mufflers.

 

hahahahahaha, sLOL

props on that one...

i use chevron 91 because i dont like to hear knocking when i walk away from my car...

 

I don't know how many times I have to say this, but once again, 87-89 octane will not harm these engines. Lower octane fuels aren't "dirtier" either. Like someone pointed out earlier, octane is a fuel's resistance to detonation (ie it's resistance to burn). The higher the octane, the harder it is to burn. High compression motors, like the VQ35, create high combustion chamber temps, therefore it is recommended to use higher octane fuels. That doesn't mean it's required though because the engine's knock sensor can yank timing and richen the A/F ratio if it hears knock/detonation (even when you can't hear it).

In the winter, especially in an area that experiences sub 40 degree temps, you're not going to notice much difference because the engine typically runs a bit cooler and the intake temps are far lower. For every 10 degree drop in temps, you gain about 1% in power to a degree. However, I have found that these motors don't seem to feel as strong in sub 30 temps, especially the 0 to 10 degree weather I'm getting in Kansas City.

In the warmer months, I can guarentee you that you will slower running sub 91 octane on the track. Will you feel it? Probably not because most of the detonation will be experienced in the longer gears like 3rd where the G-forces are very minimal. Why in the longer gears? Just like in forced induced cars, more heat is generated the longer the car remains in a particular gear. It's also why many poorly tuned turbo cars wreck their motors in 4th and 5th gears.

On a Sunday cruise on highway, even in the hot weather, you won't feel a difference in power, and most likely won't a difference in MPGs because you're not running the span of the powerband.

I do wish Nissan would get off their *** and bring direct injection to the States though. They had the technology in Japan since the late 1990s and Stateside Toyota/Lexus' have it and the advantages are clear. You can run high compression (10.5:1+) on 87 octane, make killer power numbers, and improve MPGs by 15%. Add 91 octane and you'll gain an instant 10whp. This makes me even more interested in purchasing an IS350.

 

huh? what? using a higher rating will not get rid of that noise... it's coming from your exhaust as the metal cools... lmao.

 

^LOL, WHS!!

 

the dealer put 87 in my car when i first got it...i heard knocking...continued to use 87 for a month...still happened...switched to 91 and it was gone...

keep in mind i always used chevron. just reporting my experiences.

 

your opinion doesnt make sense. it doesnt increase horsepower, it increases the gas's resistance to detonation. yet, you said we are trying to kep our cars from knocking and then making the computer retard the timing and lose power. uhmmm hello... the whole point is the fact that if you lose lesser octane fuel theres a decrease in performance. we aint being dicks.. we are just keepin it real. why ask why? try bud dry!

 

no... its a piece of sh**

 

I dont know what this means, but when i put 89 in my car, the rpm jumps to about 1,000 upon ignition, and when i put in 94, it jumped to around 2,000.

Anyone experiencing the same thing?

 

It doesn't matter if you don't get performance increase, you will most likely damage the engine if you use a less octane gas for a long period of time. Our engines are made for 91+.

If you use less than 91 you will almost be guaranteed engine pinging/knocking.