Gas Mileage

[LowR3V'in]

ya it turns on at 1.6.
16.4gal tank so run it to the light and fill up.
run it back down to the light and count the trip.

will give you your actual mpg not some estimate.

m30 turbo on e85 i estimate about 13mpg based on the couple times
i like to fill. usually when the needle's on "empty", yet only 12gals go in.

[r-mm]

I have never seen a fuel lite on in my 89 - is there not one? Does it come on @ reserve?

[LowR3V'in]

the light does not turn on when empty btw.

[dnguyen1963]

i think a better question is from full tank to when the gas light turns on how many miles?

Just a word of caution...the fuel pump requires gas to lubricate and keep itself cool. If you guys keep running the tank down to empty, your fuel pump will not last. I wonder if this is the reason why there are so many posts about fuel pump making whiny noises.

[LowR3V'in]

i think a better question is from full tank to when the gas light turns on how many miles?

[pj29]

My odometer doesn't work, but if I guess I get no more than 19-20. Mostly highway driving at around 80 mph. 86 mile round trip commute and I am hard pressed to get much more than 3 trips on a full tank.

[Sonny]

Gas Mileage

The fox body was at least as aerodynamic as the E30, and I'm sure the gearing is way more favorable, hence the better highway mileage. Highway is just gearing and aerodynamics for the most part. That E30 sticker is also for an autotragic, which is at least 5-10% worse than a manual.

You can see how the Mustang is penalized for the larger engine with the city driving. It is 1mpg lower, despite being about the same weight as an E30, even though the E30 has an automatic too.

Is the build quality what brings the reason for a 2x price markup? I honestly feel like if I drive both cars into a curb at 40mph the bmw would be the only to make it.

[earthwormjim]

The fox body was at least as aerodynamic as the E30, and I'm sure the gearing is way more favorable, hence the better highway mileage. Highway is just gearing and aerodynamics for the most part. That E30 sticker is also for an autotragic, which is at least 5-10% worse than a manual.

You can see how the Mustang is penalized for the larger engine with the city driving. It is 1mpg lower, despite being about the same weight as an E30, even though the E30 has an automatic too.

[Sonny]

Saw this original sticker from an 89 fox body mustang 5.0 on BaT today. Same/Better than the ‘90 beemer with half the displacement?! And half the price. And no I do not want the mustang despite all that.

[ATTACH]127641[/ATTACH]

It’s double the price to, that is insane, how could it be $15k and the bmw $30k? Without inflation either

[r-mm]

Gas Mileage

Saw this original sticker from an 89 fox body mustang 5.0 on BaT today. Same/Better than the ‘90 beemer with half the displacement?! And half the price. And no I do not want the mustang despite all that.

[packratbimmer]

Are you running stock tires/wheels?

[nrubenstein]

Am I lucky to be reaping in 30 mpg usually. Cruise control managed to clean and get working and at 65mph I can hover at 40mpg for an hour straight on the interstate. Before cruise control I still managed 30mpg++

I bet you’re running oversized injectors, or the wrong OBC. Or both.

The E30 has the aerodynamics of a brick (which were pretty good for its time), so highway fuel economy, which is heavily influenced by aero is not great.

40mpg sustained is simply not plausible.

[dnguyen1963]

The gauge is useless for telling average mileage, it's not a linear scale either. You're also not accounting for the massive amount of fuel that is wasted while warming your car up, and I doubt you are monitoring it during stops. It doesn't even seem accurate to me, it underestimates fuel consumption during warm up, so I have no idea what its actually measuring. The gauge claims I get the same mileage at 60mph on a flat road when the engine is cold, as when it is hot. It's certainly not measuring actual fuel usage.

If I use my OBC to measure fuel consumption after the car has warmed up, I can get pretty close to 30mpg on my drive. It's the warm up period, and stop lights, which drops my average down to 24mpg or below.

OBC calculations are pretty close to what I've measured looking at distance driven vs. fill up volume.

Yeah...I just tried to replicate what Sonny was reporting when he set the cruise control at 65 mph.

[earthwormjim]

Well, I tried to reproduce what Sonny reported here this weekend. This was what I found. Setting the cruise control at 65 mph on a flat road and calm day, the mpg needle actually got very close to 40 mpg. I could travel this way for about 20 min and get between 30 - 40 mpg until I got tired and stepped on the gas. It is possible to see those numbers from the gauge, but I do not know the actual mpg without knowing the distance and the actual volume of gas used.

The gauge is useless for telling average mileage, it's not a linear scale either. You're also not accounting for the massive amount of fuel that is wasted while warming your car up, and I doubt you are monitoring it during stops. It doesn't even seem accurate to me, it underestimates fuel consumption during warm up, so I have no idea what its actually measuring. The gauge claims I get the same mileage at 60mph on a flat road when the engine is cold, as when it is hot. It's certainly not measuring actual fuel usage.

If I use my OBC to measure fuel consumption after the car has warmed up, I can get pretty close to 30mpg on my drive. It's the warm up period, and stop lights, which drops my average down to 24mpg or below.

OBC calculations are pretty close to what I've measured looking at distance driven vs. fill up volume.

[ELVA164]

I get mid to high 20s with my 3.73 in my 325i. I can do better but it's boring so I don't.