So far I’ve cleared about 4 tanks of fuel at a steady 33.5MPG in my Volkswagen, the little tricks I’ve been using to bump up the mileage from an average of 28MPG have pretty much become second nature.
1. Slow down. I’ve been able to conclusively prove that speed over 50mph in my car directly affects the fuel mileage. At 50mph, I can generally pull anywhere from 35-37MPG. At 65mph, I generally get 32-34MPG. I also make a point to use the cruise control to adjust and maintain my speed. The car’s computer and throttle controls are far better on the MPG rating than my size 13.
2. No jackrabbit starts. Sure, if I’m getting on a highway, or hopping onto a congested roadway – I may need to give it more gas than I’d like – but I’m not going to impose my driving habits on other drivers. Still, I’m not againt doing 64mph in a 65mph zone (in the slow lane) just so I can maintain a consistant speed. Now my Scangauge doesn’t read much MPG when I’m performing a slow start – but a jackrabbit start generally gets me 3-5MPG where a slow, gradual start gets me anywhere from 16-20+. It adds up and helps the overall average.
3. Coast downhill. Now pretty much any time I drive downhill – my MPG is increasing. It increases even more when I’m going 50mph+ and turning only 750RPM (instead of 2500-3000). Again, it drives the average MPG up for the tank. Just a piece of the puzzle. Depending on the conditions, I may coast for just about every downhill grade, but I mainly stick to the significant grades where I can maintain the legal speed limit and not have to touch the gas pedal at all. Also key is rev-matching when re-engaging the clutch. My theory – if you just engage the clutch you’ll slow down and lose momentum, forcing the use of the engine to bring the vehicle back up to speed. By rev-matching, you’re bringing the engine RPM’s up to a proper level which uses less fuel than if the engine was under load.
4. Run the engine only when the car needs to move. Unlock the car, roll down the windows, set the seat belt and pick a radio station. Put the car in gear, and THEN start the car – and drive. At a long stop-light, I shut the motor off and let the car sit without running, only starting it when the light is about to turn green. One thing I have done on occasion – but do NOT recommend doing – is coasting with the engine off. I do NOT do this at any speed greater than simply rolling. Anyone who does this at normal roadway or highway speed is a moron – stopping a car without power brakes is EXTREMELY DIFFICULT. I have on occasion been on a downhill offramp with heavy traffic, and instead of idling the engine for 15 minutes – I shut the car off and just roll, using the e-brake to stop the car until I get close enough to actually moving that firing the engine is justified.
5. Tire pressure, tire pressure, tire pressure. Maintaining at a MINIMUM the factory tire pressure is ESSENTIAL. At any pressure below the recommended PSI you are WASTING GAS. My previous numbers which were in the area of 34-37MPG (for a full tank) involved the tires being accidentally over-filled by the place that rotates them. My front tires were about 5lbs over full which decreased the rolling resistance, but IMHO would likely contribute to early tire wear. I’m sticking with the stock numbers for now.
14.5 gallons of fuel @ 28MPG = 406 miles to empty.
14.5 gallons of fuel @ 33.5MPG = 485.75 miles to empty.
Now I drive about 14 miles to and from work each day. That extra mileage is the difference between filling up once a week and filling up twice a month. Normally, I fill up when the fuel light glows – which means I have 2 gallons of fuel left, so I’ve gone from filing up at 300-350 miles to 400-450 miles. With the current cost of fuel – every mile counts, and I’m saving money every time I turn the key.
Lastly – if you have any interest in improving your MPG – pick up one of these. It’s a ScanGauge 2, I got mine from ThinkGeek.net for $150, and it was worth the investment to visually and accurately explain how to improve my MPG.