how many gallons does a 1983 rx7 tank hold. and whats the mpg on it.

 

14-14.5 I think. MPG depends. Stock ones get around 23-28 range and most seem to be right around 25 if all stock.

 

ok thaxs i have that size tank but ive done the math and i only get about 15 mpg any idea whats wrong

 

Explain how you did the math. The only correct way to do that is to divide the mileage traveled since the last fillup by the number of gallons it takes to fill the tank. You can't just divide the mileage traveled by the supposed number of gallons based on the position of the needle on the fuel gauge. Most fuel gauges are notoriously inaccurate.

Having said all that, fuel mileage depends on a number of things, not the least of which is ones driving style. If you are heavy on the gas most of the time you will use more fuel. In addition, there are engine tuning and other conditions that can adversely affect fuel mileage. Is your air filter clean? Is the air-fuel mixture correct throughout the range of throttle settings? Are spark plugs fouled? And so on.