370z requires premium fuel?

chubbs

Here in England our 'normal' fuel is 95octane - Nissan recommend 'super unleaded', which is 97 or 98octane.

I run my 350z with 98octane (super unleaded) - and tests in at least one car magazine have shown that 98octane increases the horsepower slightly and/or it's more economical than 95octane. Also, the owners' manual for the 350z warns you that you should only use 95octane if you really have to - is this the same for the 370z?

Personally, I wouldn't use anything but super unleaded and I assume it's the same for the 370z.

In addition, I assume that the ECU will adjust itself to account for different fuel types, as I believe it does in the 350z.

__________________
.

'03 Grey >>> '06 Black >>>'10 Silver >>> '16 Grey ^

Robert_Nash

Gasoline formulation varies a great deal between the U.S and the U.K. - it even varies here from season to season; region to region and perhaps even city to city.

__________________
Robert
-My Basset Hound Is Smarter Than Your Honor Student and Barack Obama -

chubbs

Thanks for that - your reply prompted me to Wikipedia 'octane rating' - and it's very interesting...

Octane rating - Wikipedia, the free encyclopedia

__________________
.

'03 Grey >>> '06 Black >>>'10 Silver >>> '16 Grey ^

tvfreakazoid

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.

__________________
Mudders milk

BalanBro

True, but the amount they pay for their regular gas is probably similar to what we would pay for race type fuel. We have it cheap compared to most of the world.

__________________
2012 Mercedes C63 AMG P31 Sedan, ROW, aFe, Eurocharged Dyno Tune. 438WHP/415WTQ
2010 SOLD: 40th Anniversary 370z

NBZ34

In Germany, right now they're paying around $8.50/gal

Venezuela on the other hand.... $.12/gal

Augustus

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.

mantella87

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.

Augustus

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.