Originally Posted by chef73
I have a 2010 Jetta Sportswagen and it barely gets in the 30 range during the winter is there anything i can do to improve the gas mileage for the winter like using a fuel additive
Forget the air intake. Your "baby" breathes fine. There's really not much you can do but get the car to warm up faster. This must be your first diesel: speak in terms of fuel ecomony, fuel mileage not "gas" mileage.
Like Derrel says, a TDI takes a long time to reach operating temperature in cold weather. Even in the Valley of the Sun, it takes my TDI about 7 miles at 45 mph before the temp gauge registers normal when the ambient temperature is in the 40s. At 7 miles my MFD average MPG is in the low 30s. My guess is the oil is still not up to operating temperature after 7 miles. It takes me about 15 miles before the average MPG climbs into the lower 40s. So, short trips in frigid weather will have a significant impact on MPG. My guess is that if your trips are short in duration you could easily see a 10 to 15% drop in fuel economy during Ohio winters.
Also, the winterized fuel in OH will probably cost you about 2-3% or so in MPG due to reduced energy content in winter vs summer fuel assuming the winter fuel is cut with kerosene.