MPG & DTE

[CDsDontBurn]

With our cars (v8) getting roughly 19MPG (mixed driving), what's the expected Distance To Empty? Doing the math on 16 gallons worth of consumption, that distance should be 304 miles.

This is great and all, but I'm at 198 miles and am down to 1/3 tank left from full. Does this marker really mean that I should be able to get another 100 (+/-) miles worth of driving before having to fill up again?

 

[XR7-4.6]

I don’t think I ever touched 19mpg mixed, before mods I think my mixed average was more like 16-17. Plus I don’t know your fuel formulations there but the E10 junk we have foisted upon us has a noticeable drop in range over real gasoline too.

 

[CDsDontBurn]

Hmm .

I only have two Fuelly entries so far and it puts me at 15MPG.

So I guess the real question is, under what circumstances is "19MPG mixed" expected to happen. Because if I'm going to be getting 15MPG, then I'm going to be at 240 DTE (~16gal consumption).

Is this 15MPG a more accurate representation of our (v8) cars?

And then, what is the optimal MPG cruise speed for our cars?

I'm all sorts of wrong here with what I was expecting out of fuel consumption .

 

[XR7-4.6]

If you did mostly highway driving cruising at like 60-70mph max I could see 19 mixed with a very small ratio of city driving, these cars absolutely can pull off mid 20s on the highway to bring that mixed number up, but if it’s 50/50, or you like to cruise at 80+ or you have a heavy foot in city driving, or encounter a lot of stop and go traffic you’re just not going to get stellar mileage.

 

[1997ThunderbirdLXV6]

I'm at 198 miles and am down to 1/3 tank left from full.

Well, if you assume a range of 300 miles, then yeah, one third of that would be another 100 miles on top of those 200-ish.

The fuel gauge is divided into quarters, so I'm guessing you're seeing the needle slightly above the last quarter. It all seems pretty normal.

V6 here, so my specific fuel economy doesn't apply, but a few general observations:

• The fuel gauge seems to travel through the first quarter slowly, through the second quarter fast, and then through the final two quarters sort of slowly again.
• Fuel economy can be fantastic on long road trips. I get 400 miles on a fill-up without even trying; I doubt the V8 is much worse.
• City fuel economy can be horrendous; expect low teens.
• "Mixed" driving, what is that anyway? My overall average is low 20s, which is a mix of highway and country roads with very little city. I'm guessing 19 sounds right for the V8.

Is it an old wife's tale that you shouldn't let your tank drop below one quarter because the fuel cools the pump?

Since the car is new to you, I would just monitor miles divided by gallons at the next few fill-ups. Get a feel for it. By all means, drive until the fuel light comes on a few times to ascertain range.

All in all, fuel economy is no worse than many modern cars (=SUVs). Just without the versatility; I can live with that.

 

[theterminator93]

On the Mark I trust the fuel economy readout because it's almost always right on when I fill up. IME optimal cruise speed is about 40 MPH. Instant fuel readouts usually are in the mid 30s. At 50 it drops to about 30; 60 is 28-29, 70 is 26-27 and 75 is usually 25-26. A/C can drop it 5-10%. In the winter these all drop 15-20% on average - more if it's really cold.

On the Cougar (again, v6) a 400 mile round-trip on one tank was the best distance I recorded, on 15.8 gallons.
On the 98 the longest distance on a tank I can find was 425 miles on just under 16 gallons. My average long-distance tanks are high 300s which I've recorded numerous times; rarely do I make it to 16 gallons in a single fill.
Usually in the T-bird I'm filing up between 300 and 350.
My best highway MPG was recorded in the 96 - unsurprisingly, perhaps, due to its 3.07 rear. On that car I recorded many >400 mile tanks - the best I can find was 452 miles on a tad under 16.7 gallons.

Don't put too much faith in the fuel gauge... mine doesn't budge off "F" until it's already consumed 3-4 gallons. By the time it gets to 1/8 tank I know there's only about a gallon left.

Here's all my MN12s/FN10s Fuelly data:

 

[MadMikeyL]

Driving around town in the 97 I usually get around 18mpg. On the highway I typically get 22mpg cruising around 90, which goes up to around 24mpg if I drop it down to 80. And I’m definitely a lead-foot! If you’re only getting 16mpg in a stock car, I would suspect some kind of fuel issue, either a vacuum leak, or a dirty MAF, or bad O2 sensor, something like that.

 

[1997ThunderbirdLXV6]

if I drop it down to 80.

I don't think I've ever dropped it down to 80.

 

[Generalee0527]

My experience w/ '97 sport bought new I have never gotten less than 20 mpg. I recall shortly after break-in that I got like 410 miles from a full tank while all interstate. 377k miles later and I get 23-24 every tank full and I cruise at 65 on open roads but will air it out when I feel like it and mileage drops maybe a 1 mpg. Only things that are not stock are k&n air filter, 2000 mustang 4r70w trans, synthetic diff oil. 37 psi in tires.

 

[1997ThunderbirdLXV6]

, synthetic diff oil

Which one? I want to change mine, but 80W90 seems to be all conventional (?).

. 37 psi in tires.

You're practically hovering. No wonder you get those MPGs.

 

[theterminator93]

One thing I will add is that "in town" driving can vary a lot. Suburbs with a mile or so between stops/traffic lights? Urban sprawl with traffic lights every 500-1000 feet and extended idling periods?

"In town" around here is suburban with relatively few traffic lights; I get about 20 MPG in the cars. As soon as I hit "the city" it drops from there. 15 or so is my guess.

 

[Grog6]

Guys, y 'alls mileage is low, compared to my experience. I always got 360+ miles off a refill, over 400 if I had to stretch it. I got 20 mpg hooning lazarus to death.
Edit:
I realize, there are differences; All my driving was interstate, 80+.

 

[MadMikeyL]

Which one? I want to change mine, but 80W90 seems to be all conventional (?).



You're practically hovering. No wonder you get those MPGs.

75w90 synthetic is fine as a replacement for 80w90 conventional.

 

[1997ThunderbirdLXV6]

"City" for me really means city. I owned a 2000 Continental and a 2006 Crown Vic living in NYC. 12-14 mpg.

 

[Chingon1]

I usually get around 14MPG mixed driving, mainly city. I’m going to attribute it to my kinda heavy foot and the heavy saleen wheels.

I have pulled off around 300niles to 16gallins when I was doing alot of highway driving.

This is with 3.27 gears out back.

 

[XR7-4.6]

I usually get around 14MPG mixed driving, mainly city. I’m going to attribute it to my kinda heavy foot and the heavy saleen wheels.

I have pulled off around 300niles to 16gallins when I was doing alot of highway driving.

This is with 3.27 gears out back.

Yep that’s mine. The good news is no matter how hard I drive I never get LESS than that lol

Gears make very little difference in mpg in mixed/city driving. 3.08s, 3.55s and now 4.30s it’s pretty much the same as ever. Wide tires are what really kill it, but worth it

 

[Chingon1]

@XR7-4.6 your currently running 4.30’s?? Godamn haha that’s pretty cool, what does your first gear top out at?? Now that I’m boosted I surprisingly still get 14MPG a lil less if I’m REALLY on it

 

[XR7-4.6]

@XR7-4.6 your currently running 4.30’s?? Godamn haha that’s pretty cool, what does your first gear top out at??

Hard to tell with all the wheelspin but 35mphish lol

 

[CDsDontBurn]

Driving around town in the 97 I usually get around 18mpg. On the highway I typically get 22mpg cruising around 90, which goes up to around 24mpg if I drop it down to 80. And I’m definitely a lead-foot! If you’re only getting 16mpg in a stock car, I would suspect some kind of fuel issue, either a vacuum leak, or a dirty MAF, or bad O2 sensor, something like that.

I like to cruise at 80. The car doesn't have any codes currently and I'm running my Torque app on most drives to monitor engine temps (I don't like the accurately inaccurate temp) and nothing has come up yet. Of course, that's not to say that the MAF is dirty or whatever, because it could be.

I do have a bit of a lead foot though. I hate being behind slow drivers on the freeway who prevent me from driving my cruise speed. But still, 15MPG? Still doesn't seem right.

 

[dDUBb]

I like to cruise at 80.

I hate being behind slow drivers on the freeway who prevent me from driving my cruise speed.

I cruise around 70 mph .. I hate drivers on the freeway flying by me at 80 mph. What's the big hurry, late for work ? Wake up earlier.

But still, 15MPG?

22 mpg in my Dodge truck with boxes in the bed loaded with tools and a rack strapped up with copper pipe. 266 miles to go with a little under half a tank left. Oh and yes 61 degrees is accurate.

 

[CDsDontBurn]

I hate drivers on the freeway flying by me at 80 mph. What's the big hurry, late for work

Stay in the slower lanes and we won't have a problem!

It's not a big hurry. It's just my norm. 90+, then I'm in a hurry.

 

[XR7-4.6]

2/3rds of traffic is doing 80+ on the expressways here, even the semis. going slower than that just makes the drive super stressful

 

[Jae 'Bird]

2/3rds of traffic is doing 80+ on the expressways here, even the semis. going slower than that just makes the drive super stressful

That's something I agree with, even if the speed limit is x but literally everyone is going faster, it puts you in more danger to be driving the "speed limit" because then there's people flying around you and one wrong move and they hit you, matching the flow of traffic is important.

 

[dDUBb]

Stay in the slower lanes and we won't have a problem!

No. This is why i dont even look in my rear view mirror. I dont care for people who cant follow the speed limit are the same ones who cut me and semi trucks off in traffic.

matching the flow of traffic is important.

Not when your speed exceeds the legal limit. Tell that to the highway patrol and they will still give you a ticket.

Slow the fuck down people.

 

[1997ThunderbirdLXV6]

Having grown up in Germany, I have to say that speed limits for me are just that: limits. Not speed targets, not speed recommendations.

As teenagers, on Autobahn sections without speed limit, sure, we'd floor it. But when there were speed limits, we'd follow them. And that's how I operate today.

If I'm below the speed limit, I stay to the right. If I'm at the speed limit, I don't worry about the lane I'm in (though I stay to right mostly by force of habit). In Germany, you must stay right unless you're actively passing another vehicle; passing on the right is prohibited.

Since passing on the right isn't prohibited here, the traffic flow is a bit more dynamic.

 

[theterminator93]

I tend to avoid going more than 5 over the posted limit. I never slow down for speed traps; never been stopped by one either. I always have a laugh when people going 10-15+ over the limit mash the brakes when they see cops; I often cruise right past them at my original speed while they go exactly the speed limit (or less) as they drive past the speed trap.

 

[XR7-4.6]

Speed limits are all psychological. 10 over is the norm, but if they set the limits to where most people (including police) actually naturally drive people would be doing 10mph over that. As long as you’re not weaving through traffic like a BMW owner the likelyhood of you getting picked out of the hundreds of other vehicles going the same speed is slim.

Having grown up in Germany, I have to say that speed limits for me are just that: limits. Not speed targets, not speed recommendations.

As teenagers, on Autobahn sections without speed limit, sure, we'd floor it. But when there were speed limits, we'd follow them. And that's how I operate today.

If I'm below the speed limit, I stay to the right. If I'm at the speed limit, I don't worry about the lane I'm in (though I stay to right mostly by force of habit). In Germany, you must stay right unless you're actively passing another vehicle; passing on the right is prohibited.

Since passing on the right isn't prohibited here, the traffic flow is a bit more dynamic.

Actually here it is by law, left is supposed to be passing lane. Half the drivers don’t care or are oblivious to it and cops rarely enforce it but it’s also the law.

 

[KevinVarnes]

If I'm below the speed limit, I stay to the right. If I'm at the speed limit, I don't worry about the lane I'm in (though I stay to right mostly by force of habit). In Germany, you must stay right unless you're actively passing another vehicle; passing on the right is prohibited.

Since passing on the right isn't prohibited here, the traffic flow is a bit more dynamic.

I don't know if that is entirely correct. I believe you are supposed to keep right except to pass, but I'm sure it differs from state to state. I would also bet that passing on the right is illegal as well.

I was driving home from working on cars late at the shop one Friday night/Saturday morning. It was maybe 3AM. There was NOBODY else on the road. I was driving in the left lane because the right lane was full of potholes. I had a cop pull me over for driving in the left lane when the right lane was available. Now, we all know he just needed some semi-legitimate reason to pull be over because he thought he had an easy DUI. If only they would enforce that all the time. The worst is the two lane (in each direction) road in the town I live in. You'll get a car in the slow lane going 55mph and then somebody doing 55.1mph in the fast lane that takes them three miles to overtake and then they still camp in the fast lane.

 

[Jae 'Bird]

No. This is why i dont even look in my rear view mirror. I dont care for people who cant follow the speed limit are the same ones who cut me and semi trucks off in traffic.



Not when your speed exceeds the legal limit. Tell that to the highway patrol and they will still give you a ticket.

Slow the fuck down people.

I guess I meant within reason, by "speed limit" I mean if the average traffic speed is just a little bit higher, hell even police here get fed up with people doing exactly the speed limit, I see em passing people all the time and not because they are responding to anything either. I always hoon responsibly (my car isnt fast enough to hoon at all)