jattdimax

Hey Guys,

I have 2009 Max, for about 2 months now and i've notice my gas mileage sucks.

From Canada, so excuse my kms/liters.

I know it has a 70 Liter gas tank, and i put in 91 Octane.

I only got about 500 km on a full tank, but that's also driving in winter -35 degree temperature.

Is this the regular or should I be getting more?

Any suggestions would be appreciated!

Thanks

Dudemaine

iTrader: (1)

No scientific data to back it up here, but I think the cold weather definitely attributes to the poorer MPG. I notice a difference myself, albeit not on a concerning level or anything, but I just notice a difference.

I fill up with 93 octane, every time, and I only fill up at Shell gas stations.

george__

iTrader: (1)

^
I get suck(er) mileage in the winter time.

I believe it is due to tires spinning more, car taking longer to warm up, gas stations supposedly use different formula in the winter etc

Dudemaine

iTrader: (1)

Nail on the head especially with the different formula bit. Haha I feel like such an idiot for not remembering that, but, yes, George is correct with the different formula (more additives in the winter = decreased gasoline quality) as compared to the summer.

Not to get too off topic here, but same rules apply with heating oil for homes which is why you always fill up in the dead of August and watch it last much longer compared to when you fill up in the dead of winter it doesn't last nearly as long (and yeah I know the differences etc I'm not a square bro, them's just the facts)

lightonthehill

Keep in mind that 'distance per tankful' is a totally meaningless number, especially with the 7th gen Maxima. On some 7th gens, the 'empty' light comes on with over a quarter tank of gas still in the tank. On other 7th gens, it comes on with the tank four-fifths (or more) empty.

Nissan does this for many reasons, including keeping the fuel pump (inside the tank) from overheating, and reducing the chances of running out of gas, which could damage the (expensive) catalytic converter.

The dash readout of fuel efficiency is usually fairly close, but not exact.

The only correct way to determine fuel efficincy is to record the distance driven and the fuel added to refill the tank, and do this over several tankfuls.

This is a 3600 pound car with lots of power. Stop and go and city driving can result in very poor fuel efficiency, well under 20 MPG. I get around 23 overall in mostly suburban driving, and between 27 and 29 on freeway trips. Some posters here have gotten 30 MPH on freeway trips. This is very good fuel efficiency for a 3600 pound car with almost 300 HP using a fuel system designed in 2006/07.

dr_2010SV

Are you driving on Winter tires?
I have mine on and can tell a big difference with the increase in the tires rolling resistance. They also have a softer sidewall and tread compound all of which can affect you gas mileage.

It's like trying to run with boots on compared to running shoes.

silberma

Winters cause the engine to ingest colder air so it takes more gasoline to heat the air to the proper combustion temperature. Cold air means lower air pressure in your tires. Did you check the tire pressure? Driving on ice and snow does not provide as much traction as on dry pavement, this has a detrimental affect on gas mileage. Colder oil is more viscous and the increased engine friction also affects gas mileage. You also use heated seats and steering wheels which use energy. So basically expect poorer gas mileage in the winter. The only thing you can control is the air pressure in your tires.

KGMtech

Umm, no.

Colder air is more dense, it has more oxygen than the same cubic measure of air at higher summer temperatures. More oxygen is better for power.
The Mass Air Flow sensor measures density by how much the heated resistor is cooled by the incoming air so that it can adust the fuel injectors accordingly.

The largest reason for burning more fuel in cold winter is increased friction - until all parts warm up to full operating conditions, then your point about using more electrical accessories in winter comes next.

LtLeary

What, no summer vs. winter formulae debate??

KGMtech

okay..."In this corner wearing teal is Winter..."

Yes the winter formula does reduce fuel efficiency, but the amount IIRC is not so significant compared to how extreme cold makes total driveline friction worse and also tends to make electrical accessory use spike. YMMV

boatguy272

I will say my 2010 gets worse MPG than my 2006 did

silberma

Think again,


Warm air is bad from a power perspective, but good for economy. The engine is combusting less fuel due to the warm air, improving fuel economy. During winter, the reverse is true--denser air encourages the engine to chuck in more fuel, boosting performance and harming economy.


Another factor is different gasoline formulation.
Gasoline doesn't vaporize readily at very cold temperatures. So oil companies formulate fuel differently for cold-weather markets in the winter. Unfortunately, the changes that provide better cold vaporization characteristics also result in less available energy for combustion. You won't get as far on a liter of winter gas as you will on a liter of summer gas


PS The ideal operating outside air temperature for your best MPG’s will be from 75°-85°. Once you start dropping below say about 68° the mileage decreases pretty rapidly.

stodge

I know I'm late to this conversation, but I live in Ottawa and this sounds about right. Economy drops like a rock in winter here, especially if you're doing lots of short journeys or stop/start driving.

KGMtech

So all those 'cold air intakes' and intercoolers to remove heat from intake air for turbocharged engines are total bunk in the pursuit of more power?

All things being equal, if due to more dense oxygen charge the engine can make more power from a smaller throttle opening, the engine will use less fuel.

I'm done on this thread.

silberma

If you read what I said carefully I indicated that colder air boosts power but harms gas mileage.

mrcmtl

Completely normal. During summer, I use to have around 12L/100km and now in winter I use 14L. So 14L/100km gives me exactly 500km on a tank. It also depends on how you drive and the traffic. I always get stuck in traffic and my computer tells me my average speed is around 20Km/h.