MPScan RPM

[wheming]

Looking over some log info from Mini's SDAC runs.
I am wondering if the RPM reading is accurate.

What is the best way to check that MPScan is getting the RPMs correct?

My rev limiter was set to 6016 (REVLMT6) and 5800 (REVLMT5), and it seemed like i hit rev limit a couple times due to the tach not responding great.

[ShelGame]

Looking over some log info from Mini's SDAC runs.
I am wondering if the RPM reading is accurate.

What is the best way to check that MPScan is getting the RPMs correct?

My rev limiter was set to 6016 (REVLMT6) and 5800 (REVLMT5), and it seemed like i hit rev limit a couple times due to the tach not responding great.

MP Scan reds what the ECU tell it. What portion do you think is inaccurate? It's possible that some data is 'lost'. The fastest the ECU can send data out is still slower than the time it takes to ECU to run thru all of the code. So, it's possible that the RPM could 'spike' and cause a rev limit; and you would not 'see' that particular RPM in the data. Especially at higher RPM.

For example, the RPM is calculated every time there is a distributor interrupt. Which means, every time the shutter crosses the HEP. At 6000rpm, that is 400 interrupts per second. I think at best, if you only logged RPM, you would still only be able to get about 200 samples/second from the SMEC. So, you'd miss half of the data. If you're logging more channels, the rate for RPM will be even lower, as that 200 sample limit is for all data.

[wheming]

For instance i have my staging limiter set to like 3100 rpm. When i look at logs, i never see the rpm near that even during several seconds of log. I can see there being some lag due to protocols and transfer rate, but sure after 3-4 seconds i should see the rpm log at least one rpm event at 3000rpm. I only see like 2600-2700.

And at my shifts over 6000, i only see a highest logged rpm of maybe 5200-5300 rpm.

[wheming]

Maybe these observations are actually normal, but i don't have enough cal experience to know.

[ShelGame]

Looking at an Autometer type tach? How are you noticing the difference?

[wheming]

The tach is a speedhut tach. But even before installing i noticed the discrepancy. My staging limiter is 3100rpm but never see close to 3000 when reviewing log. About 2700 is the most ive logged staging. And it has bounced of the staging limiter as evidenced by the Turboflags.

[ShelGame]

SMEC, right? I actually have the opposite happen. I always blow thru the staging limiter. What are your settings?

[wheming]

I left the other settings as you had them. Just changed the rpm settings. Yes, SMEC.

[wheming]

Here was that bin:
https://drive.google.com/file/d/0B5l...ew?usp=sharing

[wheming]

The log files were here:
https://drive.google.com/folder/d/0B...o2VHJKYWs/edit