What are the differences between Scaled RPM, HR RPM, & RPM?
- Thread starter Jeff S
- Start date
Craig Smith
That was easy!
- Joined
- May 25, 2001
I'll try to boil this down here. A detailed explanation would most likely cause my head to explode in writing it down, and you might get hurt reading it too. 
HR RPM is High Resolution RPM. It's basically the exact RPM signal seen by the ECU. The other two are derived from this value.
RPM is the HR RPM value rounded to the nearest 50 RPM. This is just a good round number for data logging, etc. It's not really pracical from an observation standpoint to be more precise than 50 RPM at a time.
Scaled RPM is a value that is calculated from HR RPM to provide the best resolution within your 3D tables based on the cell width you specify. That one may sound kinda funny, it's tough to explain. If you think of everything the ECU does internally as just manipulating bits, then think of scaled RPM as a number derived from making the each of the "bits" we have available represent the smallest number of RPM possible, which will maximize tuning resolution.
Ow. I think I'll end my day on that one. Night all.
HR RPM is High Resolution RPM. It's basically the exact RPM signal seen by the ECU. The other two are derived from this value.
RPM is the HR RPM value rounded to the nearest 50 RPM. This is just a good round number for data logging, etc. It's not really pracical from an observation standpoint to be more precise than 50 RPM at a time.
Scaled RPM is a value that is calculated from HR RPM to provide the best resolution within your 3D tables based on the cell width you specify. That one may sound kinda funny, it's tough to explain. If you think of everything the ECU does internally as just manipulating bits, then think of scaled RPM as a number derived from making the each of the "bits" we have available represent the smallest number of RPM possible, which will maximize tuning resolution.
Ow. I think I'll end my day on that one. Night all.
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