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Old 05-29-2009, 03:16 PM   #2 (permalink)
EcoModding Lurker
Join Date: Nov 2008
Location: Annapolis, MD
Posts: 27

Mom's Taxi - '05 Toyota Sienna LE 8-passenger
90 day: 22.59 mpg (US)

Diesel - '09 VW Jetta TDI
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Why swap the stock wheels/tires? I was shocked to learn that my stock Jetta 16" wheels weigh a hefty 43lbs each!

btw- Does anybody know how much the internal tire press monitoring devices weigh per wheel?

So my Motegis could potentially reduce my VW unsprung mass by as much as 9lbs per wheel!

Here's a list of mods I have completed and a few I have in mind for my Diesel Jetta:

1. Installed Vortekz vortex generators to reduce pressure drag. As per tuft testing, these have cleaned-up the flow a bit.

2. Inflated tires to 90% of 51 psi maximum.

With these two simple mods I have been able to achieve up to 53mpg during easy hwy driving (+40mpg city).

Other mods in mind:
Eibach sport springs to reduce vehicle reference area

On a side note, VW does an awesome job of covering most of the underbody of the Jetta. Surprisingly, many of the underbody panels are dimpled (think oversized golfball)- which encourages early transition to a turbulent boundary layer.

VW already uses full synthetic oil and tranny fluid. My VW is a 6spd manual.

Any tips/info to increase my Diesel's FE would be greatly appreciated.
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