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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-

Mileage Figure

  • Thread starter Thread starter hoopty5.0
  • Start date Start date Oct 29, 2014
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hoopty5.0

mechanicus terribilis
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#1
  • Oct 29, 2014
  • #1
For those that don't follow my build thread, I've been painstakingly revamping my '90 coupe since I sold my truck. The premise was I could pay cash for it, drive it daily, AND it would get better mileage. That last part has been a bit of contention with the wife lately, but couldn't prove otherwise until I fixed my speedometer.

Recently, I did fix it..... Sort of. It has the wrong gear and reads 7-8 mph slower than the GPS app on my phone, but works great otherwise.

After filling up Sunday, I reset the trip odometer. I did quite a bit of driving Monday, usual trip to work/home yesterday and this morning. The tank is now just a hair above the red E line and the odometer shows 223 miles.

Here's the question - If the odometer is 7-8 mph slow, about how many miles is it NOT accounting for? Would it be a safe assumption that I have gone an honest 250 miles? More?


At any rate, I think it's an excellent figure, considering I commute 50 miles daily in Houston traffic. I did do a lot of driving Monday mid-day, but the rest could be considered a healthy mix of traffic and highway miles. Assuming 12 gallons, 250 miles shakes out to 20.8 mpg. Not bad for a worn out 302!
 

Mintsick

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#2
  • Oct 29, 2014
  • #2
Hard to say for sure since the speedo being off is a percentage not just a static 7mph, but if it were static 7mph off you really travelled 252 miles.
 

hoopty5.0

mechanicus terribilis
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#3
  • Oct 29, 2014
  • #3
Mintsick said:
Hard to say for sure since the speedo being off is a percentage not just a static 7mph, but if it were static 7mph off you really travelled 252 miles.
Click to expand...
True. But either way, the figure is around 20ish mpg, would you agree?
 

90lxwhite

I'm kind of a She-Man
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#4
  • Oct 29, 2014
  • #4
Justification to appease the gods...
 
H

h2v7

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Oct 29, 2014
#5
  • Oct 29, 2014
  • #5
I fill up my gas tank and then drive 100 miles and fill again
I must do this because my gas guage is broken
I usually put between 9 and 12ish gallons to fill back up

So i get around 10mpg
Sheeeeeet
 

hoopty5.0

mechanicus terribilis
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#6
  • Oct 29, 2014
  • #6
h2v7 said:
I fill up my gas tank and then drive 100 miles and fill again
I must do this because my gas guage is broken
I usually put between 9 and 12ish gallons to fill back up

So i get around 10mpg
Sheeeeeet
Click to expand...
Time for a tuneup mayne. Mine ran like it had a 3/4 race cam in it when I first got it. Gauges are easy and cheap to fix as well.
 

FoxMustangLvr

I love my Pimp
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Oct 29, 2014
#7
  • Oct 29, 2014
  • #7
Back when I had my 88' LX with basic bolt ons and 245/50/16's all around I averaged 20 mpg so you're right where you should be, at least until you start sup'ing up that engine for mo' powa!
 

hoopty5.0

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#8
  • Oct 29, 2014
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FoxMustangLvr said:
Back when I had my 88' LX with basic bolt ons and 245/50/16's all around I averaged 20 mpg so you're right where you should be, at least until you start sup'ing up that engine for mo' powa!
Click to expand...

Better HCI = more efficient flow = better mileage - heavy foot = wash.
 

A5literMan

At least it is lumpy...
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#9
  • Oct 29, 2014
  • #9
I always averaged around 18-19mpg when I dd a fox. I had a heavy foot though. If you're truly getting 20 I feel that's pretty darn good. My daily avg's about 15 right now 99 Yukon with a 5.7
 

hoopty5.0

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#10
  • Oct 29, 2014
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A5literMan said:
I always averaged around 18-19mpg when I dd a fox. I had a heavy foot though. If you're truly getting 20 I feel that's pretty darn good. My daily avg's about 15 right now 99 Yukon with a 5.7
Click to expand...
I had an '06 F-150 King Ranch and sold it because it got terrible mileage and the equity paid off a lot of bills. I do have a heavy foot, but I'm learning to control it. Somewhat.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
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#11
  • Oct 30, 2014
  • #11
I couldn't average 20 MPG with mine unless I rolled it down a hill for 300 miles.

But, that's what daily driver's are for
 

FoxMustangLvr

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#12
  • Oct 30, 2014
  • #12
Mustang5L5 said:
I couldn't average 20 MPG with mine unless I rolled it down a hill for 300 miles.

But, that's what daily driver's are for
Click to expand...

Well the nice thing about Texas is that its flat there, unlike the women
 
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jrichker

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#13
  • Oct 30, 2014
  • #13
I get 14.6 MPG on a 12 mile each day commute on city streets. It' just enough time/distance to get the heater or A/C working comfortably.
 
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Dave2000GT

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#14
  • Oct 30, 2014
  • #14
My '92 vert clocked in at 27.2 MPG highway on a 200 mile trip (Pacific Northwest so it's not a prairie flat drive either). Not sure why, that car was a freak. It did 13.8 1/4, stock everything on the motor, just subframes and underdrives.

By comparison, my SSP Coupe averages 11-12 mpg. However, most of my drives are like 10 miles or less and involve multiple trips to 6k rpm burning rubber the whole time.
 
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hoopty5.0

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#15
  • Oct 30, 2014
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I'll order the 23 tooth speedo gear I need so I can get a more accurate assessment and will update. I'd be willing to bet the figure will be close, but somewhere closer to 17-18 as this week was more highway driving than I usually see.
 

stykthyn

I want to measure mine. It doesn't look that tall.
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#16
  • Oct 30, 2014
  • #16
In heavy stop and go traffic I avg 13-14mpg. On the hwy at 80mph I got close to 24.
 

Micheal Nadeau

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#17
  • Oct 30, 2014
  • #17
With 4.10 gears, I get between 21-22 mpg.
 

RangerJoe

I leave the horn on while driving
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#18
  • Oct 31, 2014
  • #18
I normally see 14 miles per gallon with the 4.10s. But that is also cruising around town and driving spirited. The best I have got was a little over 18mpg on an interstate trip.

Joe
 

hoopty5.0

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#19
  • Oct 31, 2014
  • #19
Has anyone that posted a number got a nice set of heads and intake, as in better than a GT40? I don't think you'd see a difference in stop/go traffic with them, but I'd bet highway would be a noticeable difference.
 

A5literMan

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#20
  • Oct 31, 2014
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hoopty5.0 said:
Has anyone that posted a number got a nice set of heads and intake, as in better than a GT40? I don't think you'd see a difference in stop/go traffic with them, but I'd bet highway would be a noticeable difference.
Click to expand...
Nope. E7's on all mine. I do agree with you that an upgrade to aluminum heads would improve highway totals. Just the weight difference and more efficient design should be worth a little?
 
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