Average mileage on a tank of gas

[sdg3205]

How many miles do you normally get on one tank of gas in the following situations:

1. City only?
2. Highway only?
3. A mix of city and highway?

[Ozzie]

Edit: Sorry, you were asking for miles, my numbers below are mpgs. The most I've let myself see has been 230 miles on the odometer, could have probably done more, but at a reading of 220 miles on highway driving, I typically start looking for a gas station. Based on mpgs below, you can calculate miles based on approximately a 10 gallon tank - but you'd be slurping from the bottom of the tank by then.

My experience:
1. 17-19 mpgs ...depending on how much fun i want to have, or had, driving OR traffic.
2. 27 mpg ..steady 65mph cruise for several hours
3. low 20 mpgs

This all assumes, in my case, spec idle, spec A/F mix, good plugs/rotor/cables/coil/injectors, and my car is standard tranny.

[DMC3165]

With my D I do a good mix of city and highway. From full to empty it's pretty consistent at about 250 miles.

[Jacko]

About 250 miles on a tank for me, too.
I seem to get about 25 MPG no matter how I drive ... within reason....:driving1:

[Bitsyncmaster]

City driving makes a big difference where you live. Highway expect high 20s for a 5 speed and low to mid 20s for an auto.

It also depends how low you let it get. Driving in the mountains I would fill it at 1/4.

I have only let the low fill light come on once.

[DeloreanJoshQ]

I was able to achieve 30.25 all highway driving on the flat I-70 highway from Columbus to Dayton, OH...this even with performance camshafts! I also did not have the A/C on.

On the way back I got around 27 highway with the A/C running...

[sdg3205]

Thanks folks.

I'm running this tank down to the bitter end to see what I get. I dont think my Lambda system is working properly.

[stevedmc]

My mileage is going to be a little different since I am carbureted but I estimate that I got 27 mpg last night on the highway cruising around 70 mph. This is with a manual transmission and with the AC running.

The reason it is estimated is because my speedometer is off and needs to be re magnatized. My speedometer said I drove 96 miles and Google Maps said 107 miles.

[David T]

250 is a good rule-of-thumb and is what I use when planning. Depending on the type of driving it can be stretched to 300 but remember that the automatics get slightly less. And if you have any non-original things attached or have a lot of stuff on the luggage rack the range will be less. 300 miles divided by 12 gallons = 25 MPG. If the car is not in good tune the mileage can be significantly less. 250 miles at 50 miles per hour is 5 hours. By then most people will want to have a pit stop. If not for gas then for other things. Especially if you have a female passenger. The gas tank is supposed to hold 12.5 gallons. Now, if you are driving the Delorean with 2 motors you will be stopping a lot more often!!!!
David Teitelbaum

[Rad Dad]

I keep wondering why the constant reference to "10 gallon" tank. My tank, and yours - I might add - holds 13.2 gallons. At an easily achievable 24/25 mpg on the highway, that means a range of 300+ miles. I do understand using 250 miles for a safe cut off point, but driven reasonably*, you can stretch that to 300 miles. I have done that on more than one occasion.

Dick

*I drive a twin turbo D and that is the mpg I get on the highway at a constant 70 mph.

[Dangermouse]

Oh dear,

I start looking for gas stations at around 100 miles. Mine is all suburbs commuting and my GasBuddy app tells me I average about 13.5 mpg

[vwdmc16]

i always can get 280+ miles a tank gotten 310 once and that took 13gal to refill so it was really at the end and ive still never seen the warning lamp illuminate

[awildermode]

Oh dear,

I start looking for gas stations at around 100 miles. Mine is all suburbs commuting and my GasBuddy app tells me I average about 13.5 mpg

If it makes you feel better, I am getting about the same. 12-13 MPG

[Sidaries]

Usually my car has 23 mpg, but if everything goes well it has 30 mpg and on car shows 15 mpg.
The more I traveled with one tank of gas was around 300 miles, but I prefer to fill it after 200-230 miles latest.

[David T]

You should always be keeping track of the gas mileage. It should be over 20. If it is below that or it suddenly changes it is a good indicator that something is wrong. Very common for the Lambda system to be non-functioning and to compensate someone messes with the mixture screw and richens the mixture to make up for the lack of the additional fuel that would have been provided by the Lambda. That and a lot of vacuum leaks. I use the 12.5 gallon # . That still leaves a little more if you "overfill". What you are doing is filling the hoses leading into the tank, they can hold a lot of fuel but if you have ANY leaks you will know it! Turbos will use more fuel than normally aspirated cars but only if you use the turbos. If you stay off them the mileage will be equal to an original 5-speed. When planning a caravan you always have to plan conservatively just in case someone has really low MPG or doesn't fill up or has a luggage rack with a lot of stuff on it, etc. I once got 350 out of a tank but that was all highway driving and I had a small can of gas just in case. I knew the car was in good tune and running well.
David Teitelbaum
David Teitelbaum

[Bitsyncmaster]

Your city MPG is so dependent on how you drive and how long you idle. Stop signs, traffic lights, warming up engine for testing something all reduce your measured MPG.

Do you drive around town in fourth gear? You need to drive in the highest gear as soon as possible.

Do you floor it when you start moving?

I have about 50 miles on my car that has used a half tank right now. I'm testing my Idle ECU and that uses a lot of gas with zero miles clocked.

[stevedmc]

Guys, keep in mind that a demagnatized speedometer can cause you to think you are getting low mpg. I used to think I was getting between 20 - 25 mpg and as it turns out I was wrong. My speedometer is about 10 percent off and this was affecting my cauculations.

For me 96 miles on the odometer is actually 107 miles (verified by Google Maps). I got 27 mpg on my last fillup and this was driving at 70 mph. If I had slowed down it would have been even better.

Disclaimer: I've got a carb

[David T]

If you suspect your speedometer is not accurate you can always cross-check it with a GPS or the mile markers on the highway nad a stop watch. If the speedometer is not accurate it can be recalibrated. Speedometers can be off because of old lubrication, the spring loses some tension, the magnet loses some power, there is slippage in the cables (the dust cover is slipping). At 60 MPH the cable should be turning 1000 rpm's. That is where shops calibrate to and speedometers are most accurate. Makes the math easy.
If the odometer is off the speedometer will be off too.
David Teitelbaum

[dmc6960]

Guys, keep in mind that a demagnatized speedometer can cause you to think you are getting low mpg. I used to think I was getting between 20 - 25 mpg and as it turns out I was wrong. My speedometer is about 10 percent off and this was affecting my cauculations.

For me 96 miles on the odometer is actually 107 miles (verified by Google Maps). I got 27 mpg on my last fillup and this was driving at 70 mph. If I had slowed down it would have been even better.

FYI, you have another problem than just a demagnetized speedometer. The odometer is directly driven off of the cable input. The magnets only control where the needle points. If you odo is off, you may still have a speedometer problem, but you may also have an input problem as well. Could be dustcap, angle drive, lambda counter, or the cables.

[NVAPILOT]

I get about 20 miles for every 3.78 liters

Automatic trans

[stevedmc]

FYI, you have another problem than just a demagnetized speedometer. The odometer is directly driven off of the cable input. The magnets only control where the needle points. If you odo is off, you may still have a speedometer problem, but you may also have an input problem as well. Could be dustcap, angle drive, lambda counter, or the cables.

The dustcap is new and the cable it connects to is firmly installed. The angle drive is new, the lambda counter has been bypassed with a long speedo cable. There isn't much left other than the speedometer itself.

I have a spare speedometer sitting around the house that I am going to hookup one day to test my theory but I highly suspect the problem is with the speedometer itself.

[Bitsyncmaster]

As Jim said the odometer has no calibration inside the speedometer head. It's all gears. Do you have standard size tires on the front?

[dmc6960]

I highly suspect the problem is with the speedometer itself.

Which it very well could be, but just so you know, its not JUST the magnets.

[content22207]

Road & Track measured the following speedometer errors on a factory new DeLorean in 1981 (Gold Portfolio p. 85):
- 60 MPH indicated, 57 MPH actual (5% error)
- 80 MPH indicated, 75 MPH actual (7% error)

Bill Robertson
#5939

[stevedmc]

I'm running Primewell 195 60 R12 tires in the front.

[Bitsyncmaster]

Road & Track measured the following speedometer errors on a factory new DeLorean in 1981 (Gold Portfolio p. 85):
- 60 MPH indicated, 57 MPH actual (5% error)
- 80 MPH indicated, 75 MPH actual (7% error)

Bill Robertson
#5939

The MPH is adjustable in the unit. The odometer is not.

My car indicates a few MPH lower than true speed.

[dmc6960]

I'm running Primewell 195 60 R12 tires in the front.

12" rim? Not 14"?

[content22207]

It's a new mod I've worked up -- Austin Mini rims up front to eliminate that silly nose high attitude created by factory front springs.

Bill Robertson
#5939

[dhaney]

I too run my fuel tank all the way to empty pretty regularly. Once I get to about 300 miles I start looking to fill up.

My car is an automatic and I drive as hard as anyone, DPI Josh can verify this, and yet I get between 24-26 mph on the highway and about 20-22 in town.

fwiw - A couple of years ago I paid to have my speedometer/odometer cleaned, old warn parts replaced and the unit recalibrated for a cost of about $50.

Dan

[content22207]

When Louie Golden and I drove to New Orleans last year, we passed through a stretch of Alabama that did not have a single gas station for at least 60 miles. We zoomed the GPS out, and there were no 2 lane roads anywhere close by. Nothing but woods. We both commented that if the tank had been run down to just a couple of gallons, we would have been sweating bullets in fear of running dry.

My practice is to start looking for an inviting gas station when the tank drops to 1/2, which is about the distance from one state line to the next, and 3-4 hours of travel time (by which time I'm ready to get out and stretch).

Bill Robertson
#5939

[stevedmc]

12" rim? Not 14"?

I checked the tire size a few hours ago in the heat. The heat must be getting to me. I will check again before I drive home.

[stevedmc]

I just checked and I do have 14 inch tires in the front. There isn't much left to blame other than the speedometer itself.

[Bitsyncmaster]

I too run my fuel tank all the way to empty pretty regularly. Once I get to about 300 miles I start looking to fill up.

My car is an automatic and I drive as hard as anyone, DPI Josh can verify this, and yet I get between 24-26 mph on the highway and about 20-22 in town.

fwiw - A couple of years ago I paid to have my speedometer/odometer cleaned, old warn parts replaced and the unit recalibrated for a cost of about $50.

Dan

You must not drive in the mountains.