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Old 05-17-2022, 08:10 PM   #1 (permalink)
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2019 Civic Si, shift points?

Any thoughts on sifting techniques for small turbo 4 bangers? It seems to not mind being short sifted, even as low as 2000 rpm.

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Old 05-18-2022, 12:02 AM   #2 (permalink)
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I don't have a 'small turbo 4 banger' but my N/A three-cylinder XFi has a shift light that prompts you to short shift. Any tachometer with a shift light should give the same functionality.
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Old 05-21-2022, 10:19 PM   #3 (permalink)
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The K series in my Insight delivers the best fuel economy when I shift extremely early. Basically, if I'm above idle in the next gear, I'll get better economy by shifting at that point. Dropping it into 6th at 27mph and cruising along at 800rpm ends up being better at the pump than holding onto the gear longer.
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Old 05-22-2022, 01:42 AM   #4 (permalink)
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There is no one-size fits all shift point template. If you're accelerating using 25 horsepower, your most economical shift points will probably be lower than if you're accelerating at 50 horsepower or 75 or 100hp. Studying a BSFC map can help you see when to shift at various loads.

A scangauge can help, but the numbers on the display lag what is happening in real time
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Old 05-23-2022, 09:39 PM   #5 (permalink)
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With a turbo engine I would drive with some instrumentation to start with so you build muscle memory for various rpms and torque request. You basically just do not want the engine to run super rich at high boost, and you might be surprised how easily it will get to the enrichment zone if you haven't watched a lambda gauge.

Shift point is mostly unimportant as long as you keep the engine efficiency high as much as possible. That means a little below the highest torque you can get while still running stoichiometric, and use as high of a gear as needed to avoid running at low load.

If that wasn't concrete enough, get Torque + an OBD scanner, stick your smartphone on the dash, and learn to back off if the AFR drops below 14.7.

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