I have a 97 DelSol Si approxiamtely 117000. When I drive around town I average 30mpg. On the highway driving approximately 75 in Fl. I average 26mpg. Driving the highways in Ga. and NC I average 31mpg. Can someone possibly explain the big differences in my MPG?

 

Exactly how are you calculating your mpg?


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10 gal fuel = 300 miles around town
10 gal fuel = 260 miles on Florida Hwy
10 gal fuel = 320 miles on Ga & NC Hwy

 

Are your driving habits changing?

I have never seen someone get less mpg on the highway then around town.

 

I think sometimes Hondas like ours get a little bit worse mileage on the high way because they rev pretty high at 80 miles an hour. It all depends on several factors. Is there more traffic in Florida where you're usually driving? Do you drive differently?

Also, some gas pumps click off at different "full" levels than others. I have an 11 gallon tank. Some pumps may fill it to 10.5, others to 10.7 before clicking off, which is when I always stop filling. This could change perceived mileage.

 

^truth about being in high rpms on the highway. my coupe has a b16 in it and on the highway im limited to about 240-260 miles to the tank, but thats only if i stay around 80mph, which keeps me pegged at ~4600rpms. now if i drive at 70 or less, under 4k, my mpg goes up to near 300. but i dont drive until im on the redline, which btw gives you approximately another 1.5 gallons of fuel in my car atleast, i try to get gas before my needle touches the red E line. i then calculate for the 8.4 gallons it takes to get to F rather than the 10.2 if i run almost bone dry.

 

Here is a method I use to calculate my mileage more accurate than just looking at the fuel gauge and miles.

1. Fill up the tank and reset the miles to zero.
2. Drive the car til the fuel gauge reaches half tank.
3. Go refill and look at the pump to see how many gallons you just put in.
4. Divide the number of miles on your cluster by the number of gallons you just put in the tank.

I think that should give you a better estimate. Also, I think the weather can be a factor on how fuel economy.

 

Mountainous Highways?

 

Heavy lead footed rapid acceleration??