Extra RPM signal

[billman]

Hi, i want to monitor the RPM of my turbocharger as it has a built in Hall sender. How can i do this? Can i use a spare input on VEMS?

thanks

[lugnuts]

Connect it to the wheel speed input and calibrate the input to real 1 km/h per 1000 rpm.

What turbo and sensor do you have? The Honeywell sensor has an adapter in addition to the sensor itself.

[billman]

my ecu does not have wheel input is an older version. i have other inputs like

pin1 mcp3208 pin6,ch5
pin2 mcp3208 pin7,ch6
pin3 mcp3208 pin8,ch7
pin4 EC36 pin 34 (power out)
pin5 EC36 pin 36 (power out)
pin6 GND

[lugnuts]

So you have an Audi 5 cylinder PnP ecu then?

There is a speed sensor input on the Audi harness, you'll just have to pick to use it for the turbo or the vehicle speed.

[GintsK]

Lugnuts, if sensor has no any electronics then direct signal probably will be with too high frequency. Assuming 150000rpm*6blades=15kHz
In this case some signal converter required. It can be frequency divider for use with speed input or frequency->voltage converter for use with analogue input.

[lugnuts]

Yes, I was wondering if he had an adapter or not. The 1.1.84 fw had a divider function (max /16) and two speed inputs,
but the rate will still be too fast.

[mattias]

From what I've read (google) most of the turbine speed sensors divide the frequency, just for the reason that the actual frequency is too high. So it's perfectly possible to use such a sensor on the wheel speed input.

A frequency-voltage converter would solve any issue and make it possible to use an analog 0-5 Volt input instead.

I don't think the older Audi PnP boxes have the wheel speed input wired on the board (to the "PS/2" input) with adequate protection, I know the newer ones have them but I've yet to see the correct configuration settings (if any exists) to make the speed useful.

[billman]

it is older PnP box without the wheel speed signal. The sensor counts shaft rotation and not blades.

[mattias]

At least one typical Garrett sensor sends one pulse per 8 blades, then you use a factor depending on the blades on your compressor wheel.

[billman]

it send one per rotation. It reads on the shaft and not on the impeller. Is there any standanole or someking of a multimeter thingy that can simply count?