Mileage Figure

[hoopty5.0]

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]

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]

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.

True. But either way, the figure is around 20ish mpg, would you agree?

 

[90lxwhite]

Justification to appease the gods...

 

[h2v7]

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]

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

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]

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]

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!

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

 

[A5literMan]

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]

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

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]

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]

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

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

 

[jrichker]

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.

 

[Dave2000GT]

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.

 

[hoopty5.0]

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]

In heavy stop and go traffic I avg 13-14mpg. On the hwy at 80mph I got close to 24.

 

[Micheal Nadeau]

With 4.10 gears, I get between 21-22 mpg.

 

[RangerJoe]

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]

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]

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.

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?