Help configurating PLX data logger
 

I am in the process of configuring a PLX M-500 for data logging and was wondering if anyone on the board has already done this. If so, I would appreciate knowing the specifics of where you "tapped" the sources for: boost, RPM and MPH. Can you splice into the wires on the back of the gauges to connect to the controller? Also, if you created a voltage mapping of all of the gauges, I would appreciate it if you could mail me your configuration (or send a print screen of the configuration).

Thanks in advance,
David
1986 911 Turbo

David,

Can you post the instructions or a link?

I tend to favor making little plug-in adaptors and custom wiring sub-harnesses rather than cutting into the Factory harness.

What is your intended use for the data?

As it stands now, you want:
Manifold pressure - boost and vacuum (from gauge)
Engine RPM (from tach)
Vehicle speed (from speedometer)
Oil pressure (from gauge)
Engine oil temperature (from gauge)

Some other useful parameters to measure are:
Intake air temperature after the intercooler.
Exhaust temperature ahead if the turbo.
Cylinder head temperatures.
Detonation (knock) sensing.

Of course this list is endless but other useful info is:
Atmospheric conditions (air temp, humidity, barometric pressure.)
Chassis dynamics (2-axis accelerometers.)
Throttle position.
Brake pressure.
Steering position.

Data acquisition is very useful, particularly when you are pushing the envelope.
There is also the problem of having too much information where “you can’t see the forest for the trees.” Good, easy to use software is a must.

Check this thread:
http://forums.pelicanparts.com/porsche-911-technical-forum/186805-cht-probe-placement.html


Best,
Grady

Grady,

Thanks for your response. PLX's website is: http://www.plxdevices.com/ . My intent is just to use the data logger to help tune and monitor my engine. At the moment I am only interested in tracking (in addition to AFR which is working fine) RPM, MPH and Boost. Later on I may add EGT and intake temperature.

Thanks,
David

David,

I went here for the installation instructions:
http://www.plxdevices.com/InstallationInstructions/M-400_500PlugPlay_Install.pdf

You will need to determine the range of voltage at the input of your gauges; less than 0-14V is my guess. The logger clips anything above 5V. You can deal with this using a pair of resistors as a voltage divider. To do this properly, you need to know or measure the input impedance (resistance) of the analog inputs. They are probably very high impedance, in which case you can possibly ignore that consideration.

I don’t see any instruction on how to attach one of the two “frequency” to measure RPM.
I assume the electronic speedometer shouldn’t be any problem.

Hopefully you got a more detailed instruction manual than the above lame 2-page PDF download.

Best,
Grady

No additional instructions came with the equipement, that is why I am seeking help.

Thanks for your advice,
David

David,

Pack it back in the box and return it for a full refund. That is outrageous to ship a product like that to a consumer with no instructions.

There are plenty of other manufacturers who take care of their customers.

Best,
Grady