We spoke about lightening driveline components to increase fuel economy in the driveline section. Another benefit to reducing weight in the rotating components of the vehicle is quicker acceleration and increased power. Driveline components such as the driveshaft, differential gears, flywheel, and axles all rotate in an effort to propel a car forward. The heavier or more massive these objects become, the more difficult it is to accelerate them. It robs more horsepower to rotate a heavy object than a lighter one.
Reducing weight in any of these driveline components can greatly improve vehicle acceleration and quarter mile times. This is the reason so many LT1 and LS1 engine Camaro and Firebird owners who race at the track have made the modification of a lightened aluminum flywheel. By replacing their stock steel unit with an aluminum one they save anywhere from 7 to 20 pounds of weight in their driveline. Improvements with this mod have been shown to yield up to half a second improvement in their quarter mile times!
There is more than one type of lightened driveshaft to choose from when modifying your vehicle. Most factory units are made of cast iron or steel. Aluminum and carbon fiber shafts make a great lightweight upgrade. Not only do they reduce weight in the driveline, the carbon fiber more so than the aluminum, but they also provide additional benefits. For example carbon fiber drive shafts have the ability to absorb a significant amount of vibration from a vehicle’s driveline and dissipate that vibration within the carbon fiber material. This includes vibration from your transmission or wheels that travels back through the driveshaft. Carbon fiber has the ability to deform and absorb some of the vibration, whereas a steel shaft would pass that vibration on to the rest of the vehicle. In fact many people report, after installing aftermarket carbon fiber driveshafts that the smoothness of their vehicle’s ride improves quite a bit. Aluminum also has the ability so absorb some driveline vibration as compared to cast iron or steel but nothing to the extent of which a carbon fiber shaft will absorb.
Lightweight aluminum axles and wheels can contribute to a lighter driveline as well. In fact many stock factory vehicles are now using aluminum rims in their designs for weight reduction. Lightweight axles are a little harder to come by and not used often. They can be quite expensive and difficult to find for a specific make and model of vehicle. However some companies make custom units to fit your needs. One of the drawbacks to using aluminum wheels or axles however, is that they have an easier ability to become damaged in an accident.
At MPGEnhance we have tested a lightened aluminum driveshaft and flywheel in a late 90’s LT1 motor Firebird. The flywheel we installed was 7 pounds lighter than our stock flywheel. The difference in performance and acceleration was phenomenal! The flywheel modification provided a much more pronounced effect than the aluminum driveshaft especially in lower gears, 1st, 2nd and 3rd. We do not have any dyno results or before and after quarter mile time runs.