Buick is arguably one of the few car companies in business today that has remained true to its original business model over a century after it was created. Buick's earliest offerings were amongst the fastest and most luxurious on the road, as were the 1970 Buick GSX and 1987 Buick Regal GNX. Recent years have made it obvious to GM that performance comes in many measures, including fuel economy. This is especially true for Buick, which sells more than four times more cars in fuel-hungry China than in its American homeland, according to Car and Driver. Still, there's always some room for improvement.
Install a cold-air induction kit with high flow air filter, a set of tubular exhaust headers to replace the factory exhaust manifolds and a catalytic-converter-back ("cat-back") exhaust system. These enhancements will allow your engine to inhale more fresh oxygen per revolution, helping to burn fuel more efficiently to increase both power and fuel economy. Purchase and install an aftermarket computer chip to advance timing and lean out your air fuel ratio for a more efficient burn.
Remove your engine-driven mechanical cooling fan and mechanical water pump with electrically driven units. Replace your alternator and power steering pulleys with larger "underdrive" pulleys that slow the accessories to reduce horsepower draw (a.k.a. "parasitic drag"). This is where you can take advantage of GM's endemic platform and component sharing; many parts used on low-performance Buicks were also used on higher-performance Chevrolets and Cadillacs.
Install a Praxis air suspension in place of your stock springs. Praxis' proprietary piston design solves the biggest problem with traditional airbag suspensions: most get stiffer as they go up and softer as they go down, which is exactly the opposite of the ideal. The Praxis system will allow you to drop your car to an inch off the ground for an impressive increase in fuel mileage without compromising handling performance. You could also install a set of cheaper lowering springs or shorter struts, but you won't get the maximum fuel economy benefits since the car will still need to be high enough to clear speed bumps.
Install a full belly pan. A belly pan is a smooth piece of sheetmetal that covers the entire bottom of your chassis from bumper to bumper, increasing air velocity under the chassis and reducing drag. When combined with a lowered suspension a belly pan can significantly increase highway mileage and high speed stability.
Replace your hood and trunk-lid with fiberglass or carbon fiber panels (about 50 lbs saved). Expand your car's diet by installing a set of manually adjustable economy-car seats in place of the Buick's massively heavy power-adjustable units (about 100 lbs saved). Remove the full-sized spare from your trunk and install a lightweight dry-cell battery in place of your stock lead acid battery (about 80 lbs saved). these mods alone will shed about 230 lbs from your heavy Buick for an increase in fuel economy, acceleration, braking and handling. Continue cutting pounds wherever you can for yet more economy and performance. Some weight-shedding enhancement include lightweight forged wheels, a lightweight exhaust system, a smaller fuel tank, lightweight carpet, a carbon fiber rear seat padded with foam, crank-up windows instead of power units and Lexan in place of your side and rear window glass.
