Aim Lambda sensor channel noisy?

[Blair Robertshaw]

hello all,

We have recently switched to AIM data systems. We have noticed that the Lambda channel is very noisy (trace is all over the place) and are wondering if it is the sample rate. We have tried a few changes but still very noisy.

Application: Suzuki GSXR 1000 / F1000, Aim EVO 4 logger, uses new K line adapter for RPM

can anyone confirm what the data sampling rate might be set at in order to see a smoother data trace? and any other Lambda system set tips are also appreciated. thanks.

[David Ferguson]

So to be clear, you are using an Aim LCU-One, with the data coming over the CAN expansion? Or are you using the version with the Analog output, or something else?

What rate are you sampling at now?

[Blair Robertshaw]

hi, thanks for the reply. yes, CAN expansion and current sample rate 10 Ten x PS

[David Ferguson]

You can change the sampling rate from 1hz to 50hz using Race Studio 2, under the Channel Expansion tab when configuring your Evo4.

At 10000 RPM there are about 333 exhaust pulses per second (assuming your sensor is located downstream of the exhaust collector), so even at 50 hz there will be some aliasing.

I would probably try logging at the 50hz rate to see if there was a pattern I could discern (ie, is one cylinder running rich or lean leading to a noisy signal due to aliasing problems). Then try filtering in the analysis software. Compare that to logigng at say 1 or 2 hz. Which one is more usable for you?

Note that if you could be synchronized with the exhaust pulses at 50hz you would be able measure every single combustion event at 1500 RPM. What do you see when logging at 50hz and idling?

I am willing to take a look at your data if you want to send it to me.