The VW and Audi TDi diesel vehicles are probably the most economical cars on the road, getting about the same or better economy than the new hybrids. They are the best way to go when looking to save money on fuel. The VW TDis especially are growing in popularity in the U.S.. There are some complaints though. Like not having the power needed to pass someone on the road. This has all changed in recent years. There are several upgrades that can be made to the TDis to improve power, and to actually improve fuel economy even more. I will touch on these subjects briefly. The first TDi Performance mod that comes to mind is an upgraded chip or tuning box. Both of these items, the VW performance chip and the VW tuning box change how the fuel is delivered to the engine. For a VW performance chip to be installed, the TDis computer must be removed and sent to someone who can solder in the new chip with the new program.
A VW tuning box will simply be connected under the hood where it can intercept the signals going to the engines ecu and alter them. Most people will say that the upgraded chip will do the most for you, but the tuning box is the more common upgrade just because it is so much easier to work with. Also the tuning boxes are well liked because they can be removed and have no trace of ever being there so that warranty work can be done. The TDi Performance upgrade that comes to most peoples minds first is the cold air intake. An upgraded cold air intake in a VW TDi will add approximately and additional 5-10% increase in power and economy. Cold air intakes are sealed away from the hot engine air. Cold air takes up less space, so in turn more air is able to occupy the same area because it is cold and not hot. That is a pretty good jump and the cost for the upgraded air intake is minimal. One of the drawbacks is that upgraded air intakes are not available for all of the TDi models or year groups.
There are also performance drop-in filters for most of the TDis that will increase airflow slightly, and add a little power and economy. The next thing that comes to peoples minds is an upgraded exhaust system for their TDi. The only problem with that is the lack of mods for the TDi exhaust. There are currently no major companies that manufacture full TDi exhaust systems to my knowledge. A mufflerectomy where the muffler and resonator are removed and straight pipes are put in their place to reduce restrictions on exhaust air flow. This doesnt really give a measurable power or economy increase, but does give a throatier sound that some are looking for and the reduced back pressure will add to engine longevity. People will replace the muffler with a new muffler that is able to vacuum the exhaust out the tail pipe. Another common upgrade for the VW TDi is upgraded injector nozzles. Upgraded injectors or injector nozzles and an improved spray pattern than the stock injectors and when required are able to flow more fuel. They greatly add to performance and add a little economy too. They are also an inexpensive upgrade, and high on the bang for your buck scale. There are also other things such as propane injection or water methanol injection that will add power and economy but I wont go into detail as they are not common mods for the TDis. Also with any modifications, a set of gauges should be added to monitor the VW TDis engine parameters and to make sure that things are functioning properly.
The 2014 Passat line-up will feature four engine options, including the gasoline 2.5-liter inline five cylinder, the new 1.8-liter TSI turbocharged four cylinder, the 2.0-liter TDI Clean Diesel, and a powerful 3.6-liter VR6. The refined 2.5-liter five-cylinder engine features chain-driven double overhead camshafts, four valves per cylinder, and practically maintenance-free hydraulic lifters. It makes 170 horsepower and 177 lb-ft of torque and is available with a five-speed manual gearbox as standard or with an optional six-speed automatic. Volkswagen pioneered the use of small displacement, highly efficient direct-injection and turbocharged engines in the U.S., starting with the EA113 engine in the 2006 GTI and Jetta GLI. Now, beginning with the SEL Premium trim, the 2014 Passat will feature a new EA888 Gen 3 turbocharged and direct-injection four-cylinder engine that is made in Silao, Mexico. This 1.8-liter engine will produce 170 horsepower and 184 pound-feet of torque—the same power, but seven pound-feet more torque, delivered lower in the engine speed range than the 2.5-liter five-cylinder used in the current Passat.
