To make the poll even more useful, i would recommend that the "brackets" be sthg like
less than 250
250 - 275
275- 300
300 - 325
325 - 350
350 - 375
greater than 375

As the average seems 300 miles to the tank, the above would provide a more accurate picture than simply 0 - 150 ... which is a little pointless.

BTW, i get just less than 300 city driving and over 350 (driver only) on the highway.

P.S. My fuel guage doesnt seem very linear ... it hardly moves until i've driven 70 miles ... and moves faster and faster the more i drive... i.e. by half tank i have driven 200 miles, but at empty i have 300 only.... you guys have similar experience?

 

I've never had less than 350 miles to a tank when city driving and frequently get over 500 highway driving and on occasion 550 or higher. My gas gauge takes forever to come off full and moves down fairly quickly after it hits 3/4, which is no cause for alarm.

I can't believe the crappy fuel economy so many .orgers get. I would attribute it to fast acceleration, drving well over the speed limit, poor vehicle maintenance and under-inflated tires.

 

I get about 300 with all city driving and about 450 all highway. people are definately too much in the peddle, there is no reason to accelerate to 5000 rpm from every light.

 

yaeh i have the same thing happening to my fuel gauge

 

My commute to work for the week contains a 10mile drive around 35mph with only two stop lights. Traffic is mostly smooth flowing with the occassional brake pedal to slow down for those who make right turns onto the lane. Its the same way traveling back home. I normally shift at:

under 2,500rpm 1-2
2,000rpm 2-3

I skip 4th gear and head to 5th when I'm cruising and never get out of 5th unless the RPM is below 800rpm, that when the VQ starts to send resonance through the cabin and vibrates the coins in my ash tray.

 

The best way to check gas mileage is NOT from tankful to tankful, but by filling it twice before doing the math. The more miles you put on your odometer, the more accurate will be your gas mileage calculation.

For example, fill up your tank in the morning without overfilling it -- when it clicks off, thagt is the signal to quit.

Let the gauge run down to between 1/4 and E, and then add 10 gallons to your tank. Again, let the gauge run down to between 1/4 and E, but this time, fill up the tank in the morning like you did initially.

Read the mileage on your odometer, and divide it by the number of gallons it took to fill the tank the 2nd time PLUS the 10 gallons you added in between.

Your MPH will be a lot more reliable.

 

I get 400 before the warning light starts to fade on:

 

I got an 95 with 117K 2 months ago. No mods, no freeway driving, auto. 28 MPG. Figure it out. only going to 15 gallons gives me 400 on a tank. Come on over and I'll prove it.

 

400 divided by 15 is 26.6, not 28.

 

We have 18.5 gallon tanks. If we actually use 18 gallons, and go 400 miles, that is 22.2 mpg. Within advertised specs, if that involves only city driving--whatever that means.

We all know what highway miles are...sort of.

Now, what are we carrying in our cars? Do we drive alone? Do we have heavy subs in the trunk?

What kind and size of tires are we using? Inertia, rolling resistance...all factors.

How much do our cars actually weigh stock?

The 95 Max is a lot lighter than my 98 I30, so it should get better mileage than mine, all things being equal.


At what altitude are you living? Barometric pressure is also a factor, as is ambient temperature.

This may turn out to be a fairly meaningless exercise given that no two cars -- or drivers -- are the same.

Now, that you have all this data, what I would like to know is the median miles per gallon FOR EACH VEHICLE TYPE AND YEAR.

That would be a much more accurate measure than the bar graph, or the anecdotal reports.

 

Anothing thing to consider......

When you drive at high speeds, usually above 75mph, your fuel efficiency goes down. At 3k rpms on 5th gear, your car should be seeing that speed. Lead foot = more gas consumption.

In Los Angeles, I've noticed that most people are now maintaining the speed limit on the freeways. Why??? Because they want to save on fuel consumption. Makes sense!

 

Good point, Dr!

 

My gas milleage was 320 max, now it's 325 and i still have 3/4 from the last line.

 

Ditto on the gauge. From "How Things Work":

You may have noticed how your gauge tends to stay on full for quite a while after filling up. When your tank is full, the float is at its maximum raised position -- its upward movement is limited either by the rod it's connected to or by the top of the tank. This means that the float is submerged, and it won't start to sink until the fuel level drops to almost the bottom of the float. The needle on the gauge won't start to move until the float starts to sink.

Something similar can happen when the float nears the bottom of the tank. Often, the range of motion does not extend to the very bottom, so the float can reach the bottom of its travel while there is still fuel in the tank. This is why, on most cars, the needle goes below empty and eventually stops moving while there is still gas left in the tank.

There is another reason, and it is simple math:

Let's say you use 4 gallons of gas. With a nearly full tank of 18 gallons, a drop of 4 gallons is a 22% change in volume; whereas with a half empty tank of 9 gallons, a drop of 4 gallons is a 44% change. That's also the reason why the gauge moves faster towards the bottom versus the top!

 

I live in south Atlanta. I normally shift at 3500 to 4000 RPM. I have a dual ten MDF box and Rockford Fosgate Amp. Usually by myself. Have been with most of my mileage measurements. Drive a 97 SE. Keep my tires at 44 psi. I think barometric pressure is pretty consistenly at around 30" mercury. Near sea level I think. The weather does not really change my mileage. City/Highway mix I pretty much consistently get 20-21 mpg. I get about 24 or 25 at best with all highway. I'll stay at about 80 on the highway. My thing is that people report getting 450 miles in one tank, or even less than the whole tank say they drive just like I do. I have an evap canister and purge valve circuit fault or something on the emissions, but otherwise, the car is well-maintained. I haven't been able to spring the dough to fix stuff that is not supposed to really affect the function of the car. My car is registered in my mother's name in Alabama (has been since I got it in 2000) so I don't have to pass emissions tests. And it doesn't put out any visible emissions. And those devices are mainly for when you first start your car up and switch it off. So I'm not doing any really largescale polluting nearly like the clunkers I see every day.

 

That math is wrong. Percentage change works both ways. If the needle is at 1/8th tank and drops down to 1/16th tank that's a 50% change but that's only few millimeters of change in the needle position. So what?

 

Yeah I was wondering too. I mean percent change in what? Percent of the original or percent of whatever the instantaneous amount is? You would think that the designers of the gas guage would calibrate it such that the amount of gas/needle position would each change linearly. I have always just assumed that they are both slightly less accurate as you approach their limits.

 

Did you read the "How it works" article above? The needle movement on the gauge is linked to the movement of the top part of the float relative to the sensor. As the article said, when the tank is full, the top of the float drops down to the level of the sensor only after the gas level has changed sufficiently enough to allow it to move.

What makes a float, er..."float?"

The pressure exerted below the float by the density of the gasoline keeps the float from sinking due to the air pressure above. However, the ratio of gasoline pressure to air pressure does, in fact, change as the level of gasoline declines because the density of air and gasoline are different -- as well as the fact that air can be compressed very easily wheras gasoline cannot.

Consequently, because of changes in pressure, the float does not move in equal increments (linearly) from full to empty.

Air temperature also affects air density (and air pressure). That is the reason why, on very hot days, your tank may appear to have more gasoline than it really does. That "Whoosh" you hear (and smell) when you remove the gas cap is proof that the air pressure inside the tank was greater than the air outside it.

Since air pressure (P) is directly related to air volume (V) or P = k/V, where k is a constant, any increase in air pressure will result in a decrease in air volume, and that decrease will be NON-LINEAR.

Do the math, if you don't believe me.

Now, if the air volume in a gasoline tank decreases as air pressure increases, then what do you suppose happens to the gasoline's volume??

You choices are:

(A) Remains constant
(B) Increases
(C) Decreases
(D) All of the above


PS: As for the percentages I listed, I was talking about "percent change in volume."

(18-4)/18 versus (9-5)/9.

 

Yeah man I read the article, and it did not explain any non-linear relationship between the gas gauge and what the float does other than what happens at the limits, i.e., when the gasoline level falls the height of the float from full and when it falls the length of the float when the float is completely descended. BTW, I have never noticed any difference in reading my gauge on hot or cold days. Maybe I have just never tried to see it, but I haven't noticed it. My gas mileage is so predictable (20-21 mpg, which is my complaint) that I just get gas around 320 miles on the trip odometer and don't even pay attention to the gauge most of the time.

 

If you have an auto tranny, and 20-21 is what you get in town, then you are getting the Nissan specs here. If your tranny is manual, well, then I see your beef.

What you might want to try is to check your gauge on a cool day, which given that we're into a summer-like pattern, would mean a rainy day. Fill up your tank on a rainy morning, wait until the gauge hits 3/4, and then fill it up again.

Write down how many gallons it took.

Now, do the same on a really hot day.

You should get very different readings. If not, then your gas cap may be venting a lot more than most.

A lot of people in this thread talked a lot about why the gas gauge seems to move faster towards the bottm than the top, and I was simply positing a scientific reason for it.

If you don't notice it, then that is a good thing, actually. How many miles you go on a tank is still the best measure.

BTW, this hot, sticky weather really kills gas mileage...for most cars.

 

I make a 1000 mile round trip about once a month. W/ the cruise on 78 mph, I get 31.8 mpg and can get 500 miles out of a tank before fillup. Use NGK Iridium IX, K&N, and 93 octane super from either BP, Sunoco, or Mobil.

 

WTF? That reads like some word problem.

I think the answer is billy will get to the train station at 5pm.

I consistantly get 29-31mpg when I goto Michigan from KY. I use the "old fashion" method of checking gas mileage. After 22 years of driving, I'm not going to word problems to check.

 

330 per tank

 

got 435 on my last tank, typically i get around 390-400 with mixed highway and city driving

 

Well, while driving with my dad we usually get around 24-26 mpg, but almost all are highway miles, when driving in the city Max gets around 22-23. (5 spd) So usually over 450 miles per tank. I'm not driving yet, but the Max gets passed down to me next year.

 

I'm getting about 250-270 per tank.

 

i get around 375 miles /tank ..75% highway
in pure city driving around 300 miles

 

i think another important issue to this may be the octane rating cuz at least in cali, that ive noticed, we only have 91 as the highest. also if you have bigger than stock rims.
unless you get jet fuel

 

What's your method? Measuring how much you siphon from your neighbor's tank, minus the amount left over in your mouth?

 

I routinely get 450+ before I fill up again and even then, the indicator is at the last second to last hash mark and I only take in 14.5-15 gallons. It helps that I only have highway driving to do.

 

What is the 'old fashioned' method of checking gas mileage? What more accurate method can there be than measuring from fill-up to fill-up, or fill-up to fill-up to fill-up, like that other due was suggesting?

Also, you guys getting 400 or 500 a tank, what is your driving style? You drive like grannies? I shift at 3500 to 4000 RPM fairly consistently. I've been trying to do it around 2000 to 2500 lately, after reading another post. But when I do that, driving the car is sooooooo boring. No fun at all. Almost defeats the purpose of having a 5speed (which is not the gas mileage for me, it's the increased performance). Also, I think my clutch has been conditioned (worn) to where I can't shift as smoothly at lower RPM. I actually have to shift a little more slowly to avoid a jerk. I'm guessing the engine speed has to slow down before I pull of the clutch so that they sync up faster. I asked before if a worn clutch affects mileage greatly, but no one answered. I travelled about 170 miles Saturday, pretty much all interstate except for maybe 15 or 20 miles, and I got 24.07 mpg. I staid at about 80 and didn't have to slow down and speed up again very much. AC was on.

 

My car sees 3K+, at most, once a day, if that. But when I do break 3K, it's on the way to redline. My car does ~2500rpms at 75mph and I generally cruise at 60mph (local speed limit is 55) so I'm below 2K most of the time. It's an eight mile highway drive to work and ten mile highway drive to the store for me.

 

Great post!!

I drive like a freakin' lunatic with the AC set on 480 Kelvin, and I'm lucky if I bust 20mpg (19.6 to be exact).

All ah do is drive back 'n forth to the liker store. Ain't gone nowhere yet so's ah don't know whut I'd get on the highway.

 

I don't know how you do it. It would be so hard for me to do that. 3K once a day keeps you from the gas station away.

I just don't feel like I'm driving anything if I do that. But I think I'm going to keep trying. Except on the way to work or wherever else I may be heading when I'm not on time.

 

I force myself to do it because I'm going to have this car for another five years or so and I want it to last. I just broke 80K a few days ago which isn't too bad for a nine year old Max. But when I do get on it, this car flies. The VI is possibly the best mod I've done to this car from that standpoint.

 

Where do you get a VI, who puts it on, and how much? Is this the MEVI I've read about that you're referring to? Is the improvement mainly in gas mileage or performance?

EDIT: BTW, I've pu 25K on w/in the last year and my car still runs great (126K currently). Like I said, the clutch is getting old, but the engine and transmission are all good. I'm going to see 200K before I cave and get another car. Maybe I could find a 6speed G35 w/ aero kit for around 25K by then. (Then Nissan will have a rwd V8 max and I'll still be behind.)

 

Got the VI from a fellow org member. He and I installed it. Total cost was around 180 with RPM switch. And this is the 00VI, not the MEVI. It's a performance mod but I've found that my performance mods actually help my mileage as my car becomes more efficient. I just have to keep my foot off the gas.

 

my milage sucks but i think its due to a bad knock sensor...i get 258...if im lucky.

 

Bad knock sensor shouldn't hurt gas mileage at all, but bad O2 sensor(s) will definitely.

 

typically anywhere from 360-400.

Thats a lot of cruising at low speeds, little start/stop and not much highway.

Edit- 96 Max SE. 155,000 miles.