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Old 01-01-2021, 05:58 PM   #4 (permalink)
Aero Wannabe
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Location: NW Colo
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TDi - '04 VW Golf
90 day: 51.96 mpg (US)
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Bad news for US (North America)

I followed the original Throttle Stop thread and assumed it would not work on the TDI since it is both drive-by-wire and turbocharged. I saw this thread and hoped it might give us another option besides A-B-A that Darrin has suggested for years. Alas, I tried it today without success.

I had the car mostly warmed up on a flat, straight road, at 70 mph, 16 degrees F with zero wind and speed and elevation measured by a Garmin on the dash. First, the Throttle Position Sensor on the ScanGuage (TPS) was useless as it just read 95 all the time unless I really stood on the throttle. I tried Load (LOD) but it was all over the place even with my right foot braced tightly on the footwell. I finally tried Gallons Per Hour (GPH) and was able to hold a fairly steady 1.66 @ 70 mph. However the windows up or down did not show a consistent difference in top speed.

I would say that for the most common small diesels in North America (Volkswagen Audi Group TDI) Throttle Stop testing may not be a viable option.

If anyone would like more info about A-B-A testing on my Golf TDI check out my Heresy thread.

EDIT: I just read a note from Julian that suggested that the test distance needed to be over the course of a kilometer. I may have to repeat the test under better conditions in the future. If anyone is attempting this with the TDI I still suggest bracing your right foot and using GPH on the ScanGuage
60 mpg hwy highest, 50+mpg lifetime
TDi=fast frugal fun

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; 01-01-2021 at 06:43 PM.. Reason: Recent PM from Julian
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