Need to justify washing your Pontiac at every opportunity to your family? Tell them a good, clean paint job that is highly waxed (like on this 1965 Pontiac Grand Prix belonging to Lou Grassi,) will decrease fuel usage at high speeds.
Keep Good Records
Since your goal is to improve the distance your Pontiac travels on a gallon of gasoline, it is important to keep accurate records to chart your progress. A simple notepad in the glove compartment is all that is required.
A good idea is to indicate the type of gas and brand used, driving conditions, gallons consumed, and the rate of consumption. This may sound rudimentary, but to calculate fuel mileage, divide the number of miles driven by the gallons consumed. Keeping a small calculator with the notepad makes this less burdensome.
The question now becomes, what pump reading should be used? A general consensus of the industry is that a vehicle should be fueled at the slowest pump setting to limit aeration. The reading used and recorded should be the "click-off" gallons, not the "top-off" value. Some may argue that varied pumps may shut off at a different in-tank pressure, and this is true, but over time the data will balance out. So do not be too disappointed or excited if your first few readings seem excessively poor or frugal. After a while, you will see a trend and determine the true fuel economy. The top-off reading will only add range to the fuel tank and is unreliable since it will vary with each fill-up.
A simple notepad entry would be:
- 342 miles, 17.1 gallons, Mobil regular,
- 20 mpg, highway 65 mph,
- 80 degrees F, very windy
Another important aspect of recordkeeping is knowing your vehicle. Though not common, there are gas station pumps that are either intentionally or accidentally calibrated incorrectly and read higher gallon amounts (we never had one that read in our favor, though!). For instance, the author knows that with his economy car, when the low-fuel light illuminates, the gas tank will take between 9.2 and 9.6 gallons. This was determined by accurate record keeping and more than 572 fill-ups to date (the vehicle has over 200,000 miles). On an inconsistent basis, a local gas station's pump would read a sale of 10.6 to 11.1 gallons when the low fuel light was not even evoked (the car should have taken about 8.0 to 8.5 gallons).
Another instance was when traveling out of state and the low-fuel light just illuminated about five miles before the gas stop. The pump shut off at 13.2 gallons. The problem being, the car has a 12.8 gallon fuel tank! Errors such as these are not only fraudulent because you are being charged for fuel you never received, but can really wreak havoc with fuel-mileage calculations.
Everyone recognizes there are different grades of gasoline, and you may find your Pontiac gets better fuel mileage on a higher octane, but that is not always the case. There are a lot of rumors in the industry about super having less energy content when measured in Btu's than regular, but that is not a blanket statement. According to the chemists at Texaco, it all depends on how the octane was achieved. Some premium-grade fuels may have a slightly lower energy content when compared to regular, but others may not.
The benefit of octane is the ability to run a more aggressive ignition advance curve. If you have a newer Pontiac with a knock sensor, then a fuel-economy gain may be realized if detonation were occurring on the lower grade of fuel. The ignition timing was retarded by the engine-management system. Older carburetor- equipped Pontiacs would not have this ability, and the driver would have to listen for knock. Once again, it is important to know your vehicle. You may find that with premium fuel, the ignition timing can be advanced 2 degrees and gain a slight fuel economy advantage, but the higher cost may impact the cost-per-mile, where it is less expensive to run the regular grade at a higher consumption rate.
Under examination, you will find the highway speed at which your Pontiac runs the most efficiently. Do not just assume that slower is more frugal, especially if you have an overdrive automatic transmission and lock-up torque converter. For example, a car may get better fuel mileage at 68 mph than at 63 mph, but do worse at 70 mph.
Knowing how the gasoline industry works is also important in obtaining good fuel economy. Even if you purchase only one brand of fuel, each load that comes to the gas station is not exactly the same as the one before or after it. The density of the fuel and thus the Btu content is affected by the refinery where it was produced, the ambient temperature of the day it was made, the crude oil used, and so on. You will find a certain brand and/or tank full may produce either poor or exceptional results. Low-density fuel will be consumed at a higher rate and impact fuel mileage more than weather conditions. It is not uncommon for a tank full of low-density fuel to alter fuel mileage by 5 mpg or more. You may also come to recognize your car does not do well on a certain brand of fuel, while it seems to like others. It all goes back to knowing your Pontiac and keeping good records.
Not Just For Hot Rods
Doing your best to improve the fuel economy of your everyday car is just as much fun and important as the same quest with your toy. All of the information provided by HPP can be applied to any vehicle, make, brand, or style. Driving for fuel economy not only becomes a challenge with its own rewards, but provides the satisfaction of saving money and doing your part to reduce America's dependence on foreign oil and to lower air pollution. If that's not enough, possibly your efforts will save enough money to allow you and the family to attend one more Pontiac show this season. What better way is there to enjoy your Pontiac!