Wednesday, October 24, 2012

VW Jetta TDI Performance & Economy Upgrades

"What fuel economy gains can I expect from this upgrade on my diesel?"  That's a question we hear many times every day, so we've decided to do some rudimentary tests for some of our most popular aftermarket diesel performance parts and report the results back to you via this blog.  



Let's start by looking at a 2012 VW Jetta 2.0L TDI Sedan with an automatic transmission.  Our test car is basically brand new, with less than 250 miles on it.  The first thing we wanted to do is establish a baseline mileage reading on the bone stock vehicle.  To do this we used a trip of approximately 217 miles from St. George Utah (elevation 2941) to Ely Nevada (elevation 6427).  On August 9th 2012, we filled the fuel tank and took a picture of the odometer.



With 244 miles on the odometer, we hit the road with a full tank of diesel with no additives.  Temperature that day was about 100 degrees Fahrenheit in southern Utah.  With 3 people and luggage for a weekend trip, we had about 800 pounds in the car.  The drive is mostly in rural, farmland, or even high Great Basin desert terrain, with minimal traffic and only a handful of stops.  The average speed on the trip was about 70-75 mph, and it seemed that if we had kept to about 65-70 mph our rpm's would have been in a better fuel economy "sweet spot."  However, we just wanted to get where we were going, so mileage wasn't worried about - we just went the speed limit, or maybe a little over. 

After getting to central Nevada, we refilled the tank.


The odometer was now showing 461 miles.  


The receipt from our fill up in Ely showed that we had used 6.022 gallons of diesel.

So the math works like this; 461 miles on the odometer minus 244 miles on the odometer at the start of the trip equals 217 miles traveled on 6.022 gallons of diesel fuel.  Dividing 217 miles by 6.022 gives us a final trip average of 36.03 miles per gallon.

Since this trip takes you up over 3000 feet in elevation we were interested to see what fuel mileage it would get on the return trip with lots of downhill stretches of road.  We're also curious to see what effect "breaking in the engine" over the next year will have on fuel economy.  

Join us for our next blog post where we show you the numbers from our return "downhill" trip with the stock Jetta TDI sedan at the end of the weekend drive.  Thank you.  And don't forget to shop Parleys Diesel Performance for all your VW TDI performance needs.

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