Nissan 370Z Forum - 370z requires premium fuel?

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Just a note for the people using E10 gas and don't drive their car often you lose about 2-3 octane rating if you let it sit in your tank for a few weeks especially when its humid.

Quote:

Originally Posted by Crash (Post 26884)

Nope. It just runs with fewer knocks.

100 octane is really meant for MUCH higher compression engines or forced induction.

or aggresive timing

Quote:

Originally Posted by tvfreakazoid (Post 28742)

WOW you guys use a lot higher octane than compared to America. wish we had higher octane more available her in Cali. Well we do have them available, but not as many and there expensive as hell.

Actually, no, they don't. European/English gas is about the same octane as we have in the US. Like miles vs. kilometers, there is a difference in how octane is presented at the pump. In Canada & Europe, they use the straight "research-octane-number" or "RON". In the US, we use the "AKI" or (R+M/2) measurement. Nitty gritty details can be found elsewhere, but basically..

91/92 octane Euro/UK = 87 octane US
95 octane Euro/UK = 91 octane US
98 octane Euro/UK = 93/94 octane US.

So don't think we have "crappy" gas here in the US because of the octane ratings. It's simply not true. That said, there are some stations in Europe (Shell V-Power?) that sell 100 octane gas, and that equates to like 95 octane in the US, which is a notch better than what we (generally) have here. And it is true that some Euro-spec vehicles may require this, which must be slightly detuned for the US market.

Similarly, it's like how vehicles in the UK seem to get better MPG than they do in the US (for Top Gear UK fans, this is relevant). They actually do get better MPG, but it's not the technology, it's simply the size of the gallon. An imperial gallon is 4.5L whereas a US gallon is 3.8L.

If you want to save on fuel costs have several maps available. I have a friend that tuned his car(he is a genius at tuning) for different octanes including 87. He uses the 87 map for driving back and forth to work and running errands. He switches to the other maps depending on what kind of racing he is doing on a particular day and what octane he has available from the track. So his range is from a few hundred whp to over 500 whp.

Quote:

Originally Posted by Augustus (Post 1636890)

A few points...

Technically, premium gas isn't required in a (stock) Z. Required as in the engine will explode if you don't use it. Per the manual, you can use 87 octane, but it's not recommended and you should avoid "spirited" driving if doing so. Using 87 in a high-compression engine means you'll get more knock. Knock = bad. Now in any modern car, the knock-sensors will detect knock and pull the timing before you even hear it. Retarded timing = less power and likely less MPG. Bad.

In my experience (based on owning several 'premium-recommended' cars over the years and being stuck at some podunk gas station that only had 87 a handful of times), running lower-octane gas in a premium-recommended car is a zero-sum game. It will cost you $3 less to fill up, yes, but you're going to see a decrease in MPG that's >= the cost you saved to fill up.

Bottom line, just put premium in you Z. It's a sports car. If you can't afford premium, buy a different car.

Actually, no, they don't. European/English gas is about the same octane as we have in the US. Like miles vs. kilometers, there is a difference in how octane is presented at the pump. In Canada & Europe, they use the straight "research-octane-number" or "RON". In the US, we use the "AKI" or (R+M/2) measurement. Nitty gritty details can be found elsewhere, but basically..

91/92 octane Euro/UK = 87 octane US
95 octane Euro/UK = 91 octane US
98 octane Euro/UK = 93/94 octane US.

So don't think we have "crappy" gas here in the US because of the octane ratings. It's simply not true. That said, there are some stations in Europe (Shell V-Power?) that sell 100 octane gas, and that equates to like 95 octane in the US, which is a notch better than what we (generally) have here. And it is true that some Euro-spec vehicles may require this, which must be slightly detuned for the US market.

Similarly, it's like how vehicles in the UK seem to get better MPG than they do in the US (for Top Gear UK fans, this is relevant). They actually do get better MPG, but it's not the technology, it's simply the size of the gallon. An imperial gallon is 4.5L whereas a US gallon is 3.8L.

Excellent post. Do you have any insight as to why most gas stations in the western states typically offer 91 as the highest octane rating? I've heard so many different reasons, ranging from altitude above sea level to emissions regulations.

Dead thread batman!!!!

Quote:

Originally Posted by mantella87 (Post 1636999)

AFAIK, it's simply because of the altitude. "Octane" measures the resistance to pre-detonation. The higher the rating, the harder it is for the gasoline to self-detonate (due to high compression ) before the spark plugs fire. This is knock. So... at higher altitudes, decreased oxygen levels mean your engine can't develop as much compression as it can at sea level (right?), which means there's less chance that pre-detonation can occur. So you can safely use lower-octane gas so long as you're at altitude. At least in the case of normally aspirated cars, stock cars. Note, I wouldn't fill up with 85 octane at 6K feet then drive down to sea level. That's asking for trouble. ;)

Not sure what happens if you have an aggressive tune. This might be a problem. Even more so if it's a turbocharged car which can (somewhat) compensate for the altitude.