Logging on C125 - need some insight please

[FoxSTI]

I know it sounds like a pointless question but I want you feeback.
I am considering unlocking my dash for data logging. What would be some useful items that are typically logged?

Is the logging on the dash mostly used for things related to driving? (track mapping, throttle, braking).
I would like to log more "useful" car vitals so that in case of a issue, I can go back see what happened or caused it.

I had a situation in the past last track day, were the car did something funny at the end of the straight (it cut boost on me) and ideally I would like to go look at a log to see what too place.

So I am not sure if the logging on my C125 can be used for that purpose so if I should look else where (another device).
In addittion, I have a COBB accessport for my car which can log virtually anything on the car as a result of their extensive ODB2 PID request decoding. The project is that there is not track mapping or time associated it with which would make it very hard to go back and try to find a problem...

I am just looking some guidance and insight.

PS: does the C125 have a gyro or G sensor on board?

[greenamex2]

You log whatever you want for whatever you need the data for.

On my car I will have the M130 logging fairly detailed engine data to check the engine condition, tuning etc. It will hold 8-10 hours worth.

The CDL3 dash will be logging basic driving related data for track driving analysis.

The M130 could probably handle all the logging requirements with it's 120MB, and perhaps once the engine is fettled I can swap things around a bit. Such is the flexibility of Motec and CAN.

[FoxSTI]

^ Thank you for your repl. This is in line with my original thoughts before posting, dash was for track mapping and driving metrics and that something else would log car concerned metrics (boost, afr, timing, etc).

The challenge I have is that I am running a factory ecu and it's connected via odb2.

Does your ecu keep a timestamp so that both logs can be combined for analysis?

[greenamex2]

Yes the Motec dashes keep a timestamp

So...you have your factory ECU connected to the C125 via the OBD port with the C125 configured to read what it can over CAN (having a Motec ecu, not sure what the OBD template gives you, from a brief look a while back...quite a bit!). All this can be logged.
You have the internal G sensor in the C125 also being able to be logged.
Hopefully you also have the GPS add on logging GPS data, also giving you track mapping, lap timing etc.
And you also have the option plug in further sensors directly into the dash.

That should keep you busy for a while. Certainly enough for engine health and driver analysis. And then later on you can add sensors via various routes if the desire/budget take you.

[David Ferguson]

Logging data systems answer questions. So your example of "What was occurring with your engine?" is the type of questions it can answer -- what data to you need to see to help you understand that happened?
-- RPM
-- Throttle Position
-- Manifold Pressure
-- Battery Voltage
-- Exhaust Lambda
-- Inlet Temperature

Maybe you want to verify
-- Fuel Pressure?
-- Ignition Timing?
-- Fuel Trim

It takes time to learn how to navigate data -- your Cobb access probably has the data, you just need to search through it. If the problem happened only at the end of the longest straight, then find what the top speed was on the straight, and look at all the places in the log were you were close. That would be each lap. Look for differences between laps -- RPM, Lambda, etc.

Of course this would be much easier with MoTeC I2, and your GPS L-10 which can break the data into laps, and easily overlay laps to compare.

Here is something I wrote a while back (ok, like 15 years ago!) to help folks understand how data acquisition is used in racing, and what sensors you might want to have depending upon what questions you want to answer:

http://veracitydata.com/how-will-a-data ... my-racing/

[FoxSTI]

Dave as always you are very helpful.
have the lap info and track sections make it very easy in my mind to see where and what the problem was which is why I really do not think the accessport is the answer in my case. Although it can log EVERYTHING and everything table on the cars ECU its lacking some real indication of when and where things too place. Not only that, since I am running and factory ECU and I have yet to figure out how to tap into the cars CANBUS messages, (my dash is using the ODB2 protocol) I cannot use both C125 and Accessport as the same time (which is kind of sad). Even for tuning, I need to disconnect the C125 to log on the Accessport.

I will read you paper tonight. Thank you for posting it.

[FoxSTI]

Dave, good read and I am glad it echoes my original train of thought.
So to everyone who wants to comment:

My concern is to monitor the car to ensure its working well under stress and that if something "funny" happens I can go back to see what is "could have been"

I think what is really throwing me off is that fact that the accesport allow me to log everything by tapping into the stock sensors and ECU and additional parameters. Since I will not be using it for track day logging let us pretend I only have the C125 and my car with the ODB2. These are the thing I think I should monitor and that I currently cant with the C125 which I am hoping is generic enough but useful enough for my purposes. Please feel free to add.

1- RPM (OBD2)
2- Speed (OBD2)
3- TPS (OBD2)
4- Gear Selection (calculated for now) (OBD2)
5- Gear Selections (Hall sensor of somehow in the future) (A/V)
6- MAP / Boost Sensor reading (OBD2)
7- MAF Sensor reading (OBD2) <- provide engine load via maths?
8- Engine Temp (OBD2)
9- Oil Temp (A/V)
10- GPS / G sensor

Below is what I don not implemented but I think would be useful (please comment) I am just not sure how this can be done.
The accessport logs this information via ODB2 (maybe its CAN).

11- Wastegate/EBC duty cycle? (maybe its done by reading a voltage from the EBC and using an A/V I/O)
12- Injector duty cycle ? (not sure how)
13- Knock ? (not sure how)
14- Timing advance? (not sure how)

Is this too many vitals to log?

[greenamex2]

The OBD template seems to also include "Ign Advance", so that is one done!

For the rest, you can probably do some of it with adapters, possibly CAN based (Plex knock monitor), but it might be easier and cheaper going to an after market ECU in the long run.

[David Ferguson]

You can actually use the speed inputs on your C125 to measure the injector duty cycle and boost controller duty cycle by splicing into their wiring.

I have successfully done this using a C125 with a factory ECU being run in an enduro racing and we were able to calculate fuel usage from the injector pulse width & RPM.

[FoxSTI]

You can actually use the speed inputs on your C125 to measure the injector duty cycle and boost controller duty cycle by splicing into their wiring.

I have successfully done this using a C125 with a factory ECU being run in an enduro racing and we were able to calculate fuel usage from the injector pulse width & RPM.

Speed inputs are the ones labeled SPD1..etc? what makes those special Dave?