With gas prices approaching $4 a gallon, drivers are challenging themselves to find new ways to improve fuel economy. How we drive has a significant effect on our mileage: Slower speeds, going easy on the pedals and using cruise control each contribute to better fuel efficiently. Likewise, a well-maintained vehicle - with properly inflated tires, a good alignment and a well-tuned engine - helps stretch the gas tank further. While good driving habits (arguably the most effective and least expensive method) and careful maintenance have a positive impact on fuel economy, there are a number of vehicle modifications that can help drivers improve fuel efficiency. (For related reading, also take a look at 9 Easy Ways To Increase Your Gas Mileage.)
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- Real-Time Engine Monitoring
These devices plug into the vehicle's On-Board Diagnostic System (or OBD II; the updated on-board diagnostics standard in vehicles sold in the United States since the beginning of 1996) to provide streaming data ranging from battery voltage and coolant temperature, to its real-time fuel economy readout. Fuel economy instrumentation, such as ScanGauge's OBD II Computer or the CAMP2 from HKS, measure fuel quantity data from the vehicle's injection timing. The longer the injectors remain open, the more fuel is release.
How do these devices improve fuel efficiency? Simple. Drivers get instant feedback on how driving habits affect mileage. Gun it off the line and the display shows an immediate (and significant) drop in fuel economy. Drivers learn to accelerate smoother and drive a bit slower.
- Vacuum Gauges
A vacuum gauge is a low-cost, low-tech device that measures instantaneous fuel economy by monitoring the manifold vacuum. The concept is this: A higher manifold vacuum equates to higher mileage. Similar in appearance to other dashboard instrumentation, these dials let users know how well they are driving - in terms of fuel efficiency. Through practice and with the vacuum gauge's feedback, drivers learn to accelerate in ways that maintain high and steady gauge pressure.
- Grounding Cables
Grounding wires and cables are an integral part of a vehicle's electrical system. A vehicle depends on an electrical network, including fuses, relays and electrical wiring, to operate systems such as lights, fans, stereos, DVD players and air conditioners. All of these systems share a common ground, connected to the battery's negative terminal. As the connections wear out or loosen, resistance increases since the amount of conductive material decreases. As a result, everything in the electrical system has to work harder, leading to a variety of problems, including slower throttle response and decreased fuel efficiency. Quality grounding cables can improve your car's performance and gas mileage, for a relatively small investment.
- Pickup Truck Caps
The open bed of a pickup truck is a trap for wind. This reduces the truck's aerodynamics and can cause substantial drag, both of which reduce fuel efficiency. Truck caps improve aerodynamics, as do tonneau covers, which are low-profile bed covers that allow air to flow smoothly across the back of the truck. Some "ecomodders" - those who modify vehicles for fuel economy, rather than power and speed - have built custom aerodynamic truck caps that reportedly improve gas mileage by 13 to 20%. Slanted from the top of the truck's cab to the top of the tailgate, they greatly reduce drag by increasing aerodynamics. Visit http://www.ecomodder.com/ for ideas.
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- Weight Reduction
Every additional 100 pounds in a vehicle equates to a 1-2% increase in fuel consumption. The smaller the vehicle, the more it is impacted by any excess weight. Drivers can leave behind the golf clubs, box of tools, and any other unnecessary items that end up stored in the vehicle. A more extreme approach is to actually remove or substitute parts of the vehicle: taking off unused roof racks (reducing weight and drag), removing unused seats, replacing rims with lightweight alternatives, or replacing the spare tire with a can of tire sealant. In addition, filling the gas tank only partially, instead of all the way, reduces the overall weight of the vehicle. Fuel weighs about eight pounds per gallon; depending on the fuel tank capacity, that could mean driving around with 50 to 100 less pounds in the car.
- Fluid Mods
Using the lowest viscosity engine, transmission and differential oils recommended by the manufacturer can improve gas mileage because thinner oil reduces resistance. In addition, synthetic oils have more stable viscosities as temperatures change, further decreasing resistance. Synthetic oils are more expensive, but tend to last longer because they don't break down as quickly as conventional oils.
The Bottom Line
Back in the glory days of muscle cars, much time, money and heart were devoted to improving a vehicle's performance - in terms of how fast it could go. Zero to 60 in five seconds was much more important than miles per gallon. Times have changed, and now many car enthusiasts are more concerned with maximizing fuel efficiency, rather than muscle. Simple car modifications, such as ditching the roof racks and adding a vacuum gauge, can improve fuel efficiency, and are easy enough that even non-mechanics can attempt. Other projects, such as altering the vehicle's shape to increase aerodynamics - using space age designs that are likely to be seen on production cars in the future - are mostly reserved for DIYers, or those people who have the time and drive to work on custom modifications. Modifications can save money and fuel, and that's good for you, your car, and the environment.
Note: Caution should be exercised to avoid any modification that could affect the safety and/or handling of the car.
For additional reading, also take a look at 7 Tips For Finding The Cheapest Gas.