100 MPG per Quarter Tank,

[BADFISH6]

I shift between 2.5k-3k and recorded 123 miles for a half tank. I think thats about 16 mpg and as i said i get max 18mpg. I usually drive very short distances, not normally longer than 7 or 8 miles. Could this account for my terrible gas mileage?

 

[djpatm]

Well quarter tank left and I'm at 281 miles. Dammit I AM making it too 300 lol

 

[Wagonbacker9]

I shift between 2.5k-3k and recorded 123 miles for a half tank. I think thats about 16 mpg and as i said i get max 18mpg. I usually drive very short distances, not normally longer than 7 or 8 miles. Could this account for my terrible gas mileage?

definitely. if you're driving that short of a distance, your car isn't reaching its optimal operating temp and thus isn't running efficiently, plus if its that short I'd bet its a lot of stop and go too.

 

[djpatm]

So I think I figured it out... I filled up I'd say a quarter of a quarter or half of a quarter away from the Empty line. I got 311.2 MILES on the tank and put in 50.99 LITRES (I imported my car from the states) and that was till the second auto-off, click thing. Exactly like the time I filled up before when I started counting. So my calculations should be pretty close to perfect.

Anyway, 50.985 litres equals 13.47 Gallons so my MPG =

23.1 or 10.18 L/100km

Holy ****! Thats pretty suprising consedering I was hardly driving like a grandma. Is there some huge flaw in my math? This is City driving roughly 12-25 miles a day. Alot of stop go to. No way... something must be off right? Jesus. Haha I love this car!!

 

[Mgkdrgn]

I've never gotten more than 28mpg in my MS6 (calculated after a single full tank). I always fill up to the top and run to 20-40 miles past the warning light and I usually get between 360-400 miles per tank.

I'm always curious as to whether those claiming better mileage are running on smaller tires...because even the same tire size can differ enough to throw your calculations off.

I'm on the stock tires/rims, and if I'm on a long trip (fairly flat terrain) I can beat 28 by about .5. (example trips, Columbia SC to Washington DC, speeds sustained up to 80 mph, probably avg 70 or so).

On trips to Knoxville from Columbia, SC (over the Smokies) I do about 26 and some change, same speed range.

 

[chuyler1]

The times I've gotten 27-28 are similar to what you speak of. Highway driving...but staying out of boost as much as possible by using the cruise control between 65-75mph.

 

[sykopat]

Alright, a little update about my issue.

I just did about 150km (93miles) of highway-only, cruising at less than 3000RPM, more around 2600-2800rpm...
Then, I drove for the whole week, with practically no traffic, mornings and evenings, for about another 200km (124miles), always shifting below 3000RPM.

Right now, I have less than a quarter of tank left, and only 360km (224miles) done so far. I really don't think I'll get to 450km (280miles), even if I drove it the whole time like a 90year old grandma. I really don't get it.

A friend of mine is doing nearly 700km with a full tank when doing mostly highway travelling with his Mazda6i 2.3L, 4cyl. Obviously, he's not as heavy as we are, but still.

Honestly, it seems to be a lot worse than most of the guys here. I'm really thinking about bringing the car in to have it looked at. My best gaz consumption on highway seems to be 18-19mpg...

PS: By the way, my work is about 13miles from my home, with about 5miles city, and 8 miles highway.

 

[djpatm]

Yeah that seems pretty bad. Get it checked.
I remember when the auto tranny in my parents pathfinder went wacko we were get 24 L/100km. Thats 9 MPG.

It was terrible lol.

I've been driving pretty hard i my speed6 lately and I've done 200 miles on half a tank.

 

[Igve2shtz]

Sykopat, there are a few other things to consider.
1.) Temperatures -Colder temperatures eat more fuel because the engine runs richer during warm up periods. With fall here, and winter coming, gas mileage typically declines 10-15% in colder weather.
2.) Cold Starts - Do you do lots of short driving? for example, what about going out to lunch during work, say to a Mcdonalds that is only 2 miles away. Short trips that dont allow the engine to fully warm up before shutting off will destroy fuel economy
3.) Shifting - You say you shift before 3000 rpm, but that isnt always the best case. Sometimes shifting early makes you give more gas when you are lower in the RPM range eating some gas. Sometimes shifting at 3500 rpm is better if you are trying to accelerate to keep up with traffic because it prevents the engine from lugging.
4.) Coasting to a stop light with the engine still in gear is a good way to improve mileage. I am not a proponent of constantly downshifting (i think it does more harm than good on the tranny), but if you are doing 50 mph in 5th gear and you see the light ahead is red, just coast in gear, and then put it into neutral around 30 mph. Coasting while in gear causes the injectors to shut off saving increasing gas mileage.
5.) Also, remember in your friends 6i that we have atleast 200 pounds on him, and also, AWD which accounts for around a 10% decrease in fuel economy. And he has a bigger fuel tank. I think regular 6's have around 18 gallons (68 liters) vs. our 15.9 gallons (60 liters)

That is all I can think of now. Take that into account. And good luck on your quest for MPG.