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Old 01-05-2015, 01:54 PM   #5 (permalink)
Focus-Ak
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Join Date: Sep 2014
Location: Alaska
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n/a - '05 Ford Focus ZX3
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Quote:
Originally Posted by Vekke View Post
Here is one constant power curve for 1.2 TDI with some reference points on my Audi A8 project with vaious gear and Cd ratios. ... [chart] ... You can clearly see that if you just lower your drag your engine efficiency will get worse. that is the reason why you should always match your gear ratios when you lower your drag figures.
Or another way to look it is that the engine is now over-sized. So if there were more time and $ for the project, a re-engining may be productive both in improving engine efficiency and in reducing weight. (Which in turn means a slightly smaller engine is needed, which means less weight, which means ... which is why aircraft design, for example, is an iterative process).

Interesting curves and data points. Thanks for posting this.
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