gas mileage

<font face='Comic Sans MS'>I averaged 15-1/2 MPG (3:50 gears) on my trip to the 45th last year. That included running 70/75 MPH where we could. My running partner 65Hipo, same setup, I believe got the same.

For our trip to the 40th, the result wasn't that different. For that do I plugged a 3:00 into the rear end (65Hipo stuck with the 3:50) and realized an astonishing 16-1/2 MPG [Blocked Image: http://s4.tinypic.com/30w2jyw_th.jpg]

most of the time I get 18 to 20 mpg driving at 55 - 65 mph w/ 3.00:1 gearing. Basically stock internals 289 Hi-Po with a Vintage Paxton.

Without the Paxton I averaged 22.4 mpg during a 1500 mile trip to New Mexico in May of 2009. Speeds were generally not under 75 mph. Occasionally I would go 85 mph for long stretches.

Z.

17 mpg in fourth gear at 70 mph, 3,300 rpm.

10 mpg in all gears with my foot stuffed in it on back roads!

According to my log book which goes back to day one she averages 12 to 15 in normal driving, best of 18.3 on a long trip. Stock motor, 4sp, 3:50 gear. Still seems to get close to that but I don't keep very close track of it. Here is a sheet from 1972, gas was around 40 cents!

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On highway running 70 to 75 was 18.2 MPG and have not checked around town but would be considerably lower as I tend to accelerate a little too fast at times.

Jack

Finally someone else with documentation. My current log is my computer. Several years back (1992, I just looked), I set up a spreadsheet to track my mileage on a 1979 Dodge 360CID E200 Van (It was 12.3 overall ave when I sold it in 1999) and my 1969 VW Baja (20.5 mpg today, but it ain't stock). I've added the five Mustangs to the spreadsheet as I bought them and, although I've not taken a long highway trip (1000 miles or more) in any, the car with the best milage was in a 65 GT Fastback (15.5 mpg) that I used as the check car in a 150 mile long rally I organized. It's now at 14.1 mpg ave. The other two cars (I sold two) are: 66 "A" code hardtop semi-daily driver - 12.1 mpg; 66 K GT Fastback 10.5 mpg. It's the crappy gas we have here in California. They currently get driven about every two to four weeks about five miles just to keep them running. The best I ever got in a Mustang was 18.1 mpg driving from the East Coast to California in 1967 in a 1966 "A" code Fastback, 4 speed. I maintained a 66.1 mph ave as well. The car weighed in at 4,250 pounds (empty weight was 2,820 at the Connecticut dragway) when I weighed it at a NY State weigh station on I-80 West of Albany. I did this because everything I owned, all 1,430 pounds, was in the car.

Jim

Just a thought, but you may want to consider the accuracy of the gauge. Since I put a new tank and sender in mine, it does not read like the original (that I should put back in I guess). When I show a 1/4, it fills with only 8 gal. Your gauge may be dropping faster than the the gas in the tank.

To hi-jack the thread, I guess the tank could be my problem, but I would I'm inclined to think sender. Any body with a similar problem?

Accuracy of the gauge? Not hardly. I fill up the car always, and drive until I estimate a 1/2 tank was used (100-120 miles, and I nhave never run out of gas - my father taught me well). The only gauge that would be in question is the odometer, and that I check using GPS. Fuels is measured at the pump, which in California, is under government inspection.

I've had a couple of fuel level sender problems; open coil, gas in the float and a bent arm (previous owner). The resistance of the sender should be about 80 ohms. The sender needs to be out of the car for this resistence check, plus a visual check of the coil for wear and the float for "float". The arm adjustment might take a couple of fill-ups and removals for adjustment.

Jim

Forget about using a gas gauge. I agree with Jim, the only practical way to measure fuel consumption is to completely fill the tank each time.

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....and I have never run out of gas - my father taught me well). <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana" size=2 id=quote>

How does that work when you're a teenager with a girlfriend:)

Grow up, get married and get responsible. Oh, stop whining about "it", and just do "it".

Jim

my daily driver right now is a ford 2006 f350 with a diesel. i get about 14 around town and about 15 on the highway at 65 mph. some of you guys are getting better that that with hotrods. when i get done with my 65 if it gets 10 mpg with the way i drive that will be o.k. with me. cant expect good gas mileage form a hotrod and yes a hipo 289 is a factory hotrod engine as is the boss 302,boss 351,boss 429 , 428 cj , etc. the only way to accuratly measure gas mileage is to fill the tank to the top of the filler neck. write the mileage on the odometer down and drive around untill close to empty and refill all the way to the top of the neck subtract new mileage fron old mileage and divide the mileage by the gallons it took to fill up the second time. 195 miles divided by 14.5 gallons = 13.44 mpg. of couse that really getting close to walking with a 16 gal tank !

Edited by - stickshift on 12/04/2010 21:00:58

Edited by - stickshift on 12/04/2010 21:03:09

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...the only way to accurately measure gas mileage is to fill the tank to the top of the filler neck. write the mileage on the odometer down and drive around until close to empty and refill all the way to the top of the neck subtract new mileage from old mileage and divide the mileage by the gallons it took to fill up the second time.

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Of course, that assumes your speedometer and odometer are dead on accurate. <img src=images/icon_smile_wink.gif border=0 align=middle>

What does the speedometer have to do with miles per gallon? It's the odometer that counts, and again, I use my GPS to see what the actual mileage is. The GPS unit also tells me how fast I'm going so I can verify that I'm speeding.

Jim

In the original post, he said it "used a 1/4 tank of gas", thats what my gas guage comment was addressing. The gauge may move a 1/4 but that doesn't mean he used 4 gallons of gas. (Of course, he didn't say how far he went on any given outing, but it's implied he isn't going very far, and that he is actually using a 1/4 tank. Just wanted to throw in another angle.)

True, indicated speed has nothing to do with MPG, but if the wrong speedo gears are in the car, the speedometer AND odometer will both be wrong. For what it's worth, most speedo's read faster than actual speed, and that is by design. The odometer would be accurate though. New cars are far more accurate, to within 2 MPH at 60, but through the 80's-mid 90's, it could have been off by up to 10%. 60's-70's were no better I would guess. Ford published a service info stating this fact.

I like the idea of the GPS, will have to do that next summer to check my speedo/odo combination.

Edited by - 289kford on 12/06/2010 10:58:24

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What does the speedometer have to do with miles per gallon? It's the odometer that counts, and again, I use my GPS to see what the actual mileage is. The GPS unit also tells me how fast I'm going so I can verify that I'm speeding.

Jim

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OK...GPS wasn't mentioned in the original explanation of how to calculate the <i>exact miles traveled</i>. As was mentioned above, the odometer is driven by the speedo cable (and gear) that connects to the transmission. Unless the odometer is known to be accurate, the true mpg calculation will be incorrect using the "conventional" calculation method based on odometer readings. Even with the correct speedo gear (and rear axle ratio), different tire size (diameter) will influence odometer accuracy.