Gas and performance 93 vs 89 no differance
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From: Oklahoma
The only time I've seen pinging were a short period last summer on one tank of gas. And it didn't happen until about a month after my fillup (so the gas was old). On the other hand, my pickup can ping at times of the year unless I use 89 or better.
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From: Northern Burbs, Chicago
This topic usually comes up in every car forum, from BMW to Honda. It is recommended to use premium, but I think another variable to consider is the brand of gas as well.
Ex. Shell Premium vs. Clark Premium
I'm sure Shell adds better detergents to the premium than Clark.
One question I had is since I live in the Midwest, all our fuel has 10% ethanol. Would this skew affect the octane rating vs. a blend that does not have 10% ethanol, or is it so small that it would not have an affect?
Also, in the winter my gas mileage drops considerably even though I drive slower. Here in IL I know the stations modify the gas for winter conditions. Does anyone know what is done to the gas in the winter?
Ex. Shell Premium vs. Clark Premium
I'm sure Shell adds better detergents to the premium than Clark.
One question I had is since I live in the Midwest, all our fuel has 10% ethanol. Would this skew affect the octane rating vs. a blend that does not have 10% ethanol, or is it so small that it would not have an affect?
Also, in the winter my gas mileage drops considerably even though I drive slower. Here in IL I know the stations modify the gas for winter conditions. Does anyone know what is done to the gas in the winter?
Originally Posted by Kimbo80
One question I had is since I live in the Midwest, all our fuel has 10% ethanol. Would this skew affect the octane rating vs. a blend that does not have 10% ethanol, or is it so small that it would not have an affect?
Also, in the winter my gas mileage drops considerably even though I drive slower. Here in IL I know the stations modify the gas for winter conditions. Does anyone know what is done to the gas in the winter?
Also, in the winter my gas mileage drops considerably even though I drive slower. Here in IL I know the stations modify the gas for winter conditions. Does anyone know what is done to the gas in the winter?
The primary additive in winter gas is oxygenates. The oxygenates reduce cold start emissions. The downside is lower fuel MPG. Winter fuel teamed with extended cold starts will typically result in 15-20% lower MPGs in the winter.
Originally Posted by rAizE2k
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.
If you use less than 91 you will almost be guaranteed engine pinging/knocking.
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From: New Jersey
i could care less about power because I dont go past 4k rpm much. I stay with premium because the lower octane i hear can do damage to sensors since they work harder to keep car up to par. I currently have a maxima but similar VQ engine. I also feel a difference in power but never really looked at gas mileage.
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I just started this same experiment. Around here super (93 octane) is $0.30-$0.40 more than regular (87 octane) - note I only use Mobil gas (Speedpass, brilliant idea). I've always owned cars that require super so I was used to paying the premium, but after reading that the G35 can adjust timing, etc to work with 87, I decided to give it a shot since it's saving me as much as $7 per fill up.
As far as I can tell performance-wise, no difference. I'm sure you can use a dyno or what not to perhaps find some minimal difference, but if I can't tell seat of the pants, then it's good enough. This is not some max-performance sports car, so I could care less if I'm losing 10% of my HP (which I doubt). In the grand scheme, it's still a slow car with super or without and I'm fine with that.
Jury is still out on the mileage, I'm on my second tank of regular and want to average out over a few tankfuls, but so far, it looks to be no change.
As far as I can tell performance-wise, no difference. I'm sure you can use a dyno or what not to perhaps find some minimal difference, but if I can't tell seat of the pants, then it's good enough. This is not some max-performance sports car, so I could care less if I'm losing 10% of my HP (which I doubt). In the grand scheme, it's still a slow car with super or without and I'm fine with that.
Jury is still out on the mileage, I'm on my second tank of regular and want to average out over a few tankfuls, but so far, it looks to be no change.
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From: Sunny CA
Originally Posted by rAizE2k
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.
If you use less than 91 you will almost be guaranteed engine pinging/knocking.
But I agree, long term effects are really unknown. I really doubt engineers put in the recommendation just to make oil companies richer. But I suppose some take conspiracy theories more seriously than others. Me, I go by the manual at least until I meet an expert on Nissan engines who knows more than the manufacturer.
Sport Z ran 10% less whp on a dyno with 87 vs. 91 in a Murano. Sounds conclusive to me. Sure, most of that 10% is at WOT near redline, so not much time to do an accurate by-my-butt-dyno.
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Originally Posted by DaveB
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.
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.
i used premium gas for the first year I owned my car, then switched to 87 ... made absolutely ZERO difference
no change in MPG (AVG 20ish) and no sluggish performance and no knocking.
still using 87 because I don't race or drive my car very hard.
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Originally Posted by DaveB
Na, the engine will run fine on 87 octane. The difference is your MPGs may be worse and you'll have less power. The thing is, most people that run 87 octane in these cars typically don't drive the cars hard. Light pinging isn't a huge problem and I've experienced pinging when running certain makes of 91 octane fuel including Quik Trip and Shell V-Power.
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Originally Posted by GR8NISS
Should I switch to 87 then? California $3.00 a gallon for premium right now!
run ur current tank as low as possible, then add like 1 gallon of 87 and see if you notice any problems