Poor RPM/Speed Data

[BLN355]

Just wondering what peoples thoughts are on my poor Data captured from my M800 Motec on my Turbocharged Holden V8.

RPM and Speed.jpg (360.78 KiB) Viewed 5222 times

The RPM and Speed are both logged 20 times per second (that appears to be the max i can set it at).

The RPM is taken from the Hall Effect Sensors in the Holden VT Distributor. The speed is taking from a factory VN/S Commodore Speed Sensor that is driven by the std gear arrangement on the back of a powerglide transmission.

I was thinking of installing a 32-1 or 60-2 Crank Trigger wheel and GT101 Sensor, and fit a 40 tooth wheel on the yoke coming out of the trans with a GT101 also.

Will this improve my signal quality ?

[Sean]

You can log those signals at up to 200 hz as far as I can see in the version of ecu manager I have here. Highlight the log rate in data logging setup and use the pg up key to increase.

Are you are using the distributor for the ref and or sync signals? Maybe you should log the sync relative position, that may help to give an idea if the dissy sensor is playing tricks. You could also do a ref sync capture with the engine running in that problem rev range.

Chopper wheel on the crank is always going to be a more accurate way of measuring rpm and of timing the engine. With the Holden, as you know, between the crank and the sensor in the dissy you have the timing chain, oil pump drive, cam, dissy gear etc etc. Lots of things that can make the timing wander.

Hope this is some help.