Thread: EPA may fine VW
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Old 09-28-2015, 03:15 PM   #64 (permalink)
COcyclist
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Join Date: Dec 2007
Location: NW Colo
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TDi - '04 VW Golf
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Quote:
Originally Posted by Daox View Post
I had a question from a coworker. Has anyone seen a comparison of the current gen TDIs actual emissions vs the last generation? He is wondering how much worse 40 times EPA actually is vs the older engines.
In my opinion, no. The older engines surely made more NOX. A diesel that is tuned for power and efficiency has high combustion temperatures and makes NOX. Adding EGR reduces NOX and has been phased in over several generations of the turbo diesel. The latest TDI uses low pressure and a high pressure EGR circuits to further lower oxides of nitrogen or NOX. Some TDI owners have removed or eliminated EGR through a "tune" (off road only). This keeps sooty, hot, dirty exhaust gas from being run through the intake in which protects the longevity of the engine, makes more power and improves mpg.
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https://ecomodder.com/forum/showthre...tml#post621801


Quote:
Originally Posted by freebeard View Post
The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.

Last edited by COcyclist; 09-28-2015 at 05:22 PM..
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