MoTeC Global Forum

New to the M150 world and was told that I should be wiring nitrous solenoid and shift actuators to the M150 instead of the PDM. It was told to me that if i needed actuation in the milliseconds, that is should come from the M150. I believe they said it needs to be wired into the half-bridge ports. Question is, how many amps can each port handle. We are using the nitrous only to spool turbo. Thanks

You will find this information in "M1 ECU Hardware" manual, found on this page:

https://www.motec.com.au/downloads/down ... pdrawings/

Under the "M1 ECU Hardware Tech Note".

Spoiler alert:
Half Bridge Outputs...
• 12 Amp low side driver and 9 Amp high side driver.
• RMS current 4 Amps.

Thank you David. For installs you have done, how may half bridge ports have you used for nitrous solenoid control?

Unfortunately I don't have any Nitrous experience. But I've controlled plenty of solenoid valves with a half-bridge for variable cam timing, and sequential gearbox shift actuators. And I've used Full-Bridge configurations for drive-by-wire throttles.

The main limitation you may have is the firmware -- try to setup what you want and configure the outputs -- that will tell you what is possible, and identify any limitations.

Hi,

Normally each solenoid is connected to a single output, and the recommended method to power them is to supply switched 12V+ to the solenoid, and then have the M1 low side (switch to Ground) drive the output. This is done as the M1 can low side switch a higher amperage than it can supply. If you are using the Half Bridge outputs, they must have a switched power supply to the device under control, other wise it is possible to have a parasitic power draw through the M1.

Most of the solenoids that I have used have a current draw below 2A, this means that you can also use the unused Ignition and Injection outputs to drive the solenoids if needed. The timing resolution on the low side outputs is also finer compared to the Half Bridge outputs. (o.1us to 0.25us)

You could switch the Nitrous through the PDM, I do not believe that the timing for this is that critical that the response time of the PDM will affect its operation, but having setup a system that used the PDM to drive the shift actuators, I can tell you that the shift actuators will definitely suffer being switched through a PDM.

Thanks Sean. WE are using the PDM15 to power the solenoid. I assume this would be considered a switched power supply. We are planning to use the Nitrous to help spool turbo and then shut off once boost target is acquired. Communication through CAN-BUS will be quick enough? Sorry don't know much about the M1 and CAN-BUS communication protocol. My main concern is damaging the unit. I don't want to put the ground to 1 low side that can't handle the amperage demand of the solenoid. Manufacturer said 15amps. So if for what ever reason the CAN-BUS communication reaction time wasn't fast enough, how many low side outputs would I have to use so I wouldn't damage the unit. I'd assume two for safety measures? Thanks

That must be a big solenoid.

For a current load like that, I would use a single 20A PDM output to directly control the solenoid as none of the M1 outputs are capable of supporting that current load continuously, nor can they be grouped together to distribute the load. The PDM - M1 CAN communications will be responsive enough for switching this solenoid on and off.

Speaking from experience nitrous manufactures typically have no idea how many amps are being pulled. Check the solenoid for yourself.

Another thing to note if you are running this output from the PDM, ensure that you have the latest PDM firmware and set the default sate against the output as off in the case of a can bus timeout.
The last thing you want is for the nitrous solenoids to activate, due to a can config or timeout issue and stay on!