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Old 05-16-2019, 02:39 PM   #12 (permalink)
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Dark Egg - '12 VW Touareg TDI Sport AWD
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Originally Posted by Frank Lee View Post
Such a unicorn would need a really whack BSFC curve.
I agree, I think it is more a result driven by want. You want it to do better at the higher speed so the testing never gives the lower speed a real chance at success. More speed takes more power, more power takes more fuel, it's just physics. At speeds under 45 with different gearing and such where aero doesn't have as big of an effect I can see it, but once the car is in it's highest gear whatever that just off idle rpm is will be it's highest economy. If there was some problem with the tune or motor, again possible, maybe you are overcoming a vacuum leak or rich idle condition. Tuned for economy and in perfect mechanical condition, top gear, just off idle.
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