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MaxxECU Questions and Support/Purchase: Post them here
- Thread starter WillettRun?
- Start date
- Joined
- Jan 24, 2009
- Location
- KC, MO
that's fine
bobxyz
Board Member
- Joined
- Aug 29, 2014
- Location
- Boulder CO
Does MaxxECU support direct 12volt input signals, such as "AC Switch On" and "AC Compressor On"?
The help docs show a +12V signal being used with an Analog "AIN x (0-5V)" pin. Is this correct? What about connecting a +12volt signal to a Digital DIN pin?
What are the high/low voltage thresholds used for DIN pins? and for AIN pins when configured as digital?
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1/10/25 Edit: I guess I need to answer my own questions. This is not an official MaxxECU answer - use at your own risk. Maybe @WillettRun? can provide an official confirmation?
I ran some benchtop voltage-current curve traces of a few inputs on a MaxxECU Mini (HW rev 11) and, based on the knee at 5 volts in the curves, I believe that both the DINx digital inputs and AINx analog inputs are 12volt tolerant. The knee implies that the input is properly diode-clamped to a max of 5volts on the PCB.
I ran these measurements with the DINx internal pullup resistor disabled. When enabled, the pullup draws a max of 2.0mA when the input is grounded.
For the DINx digital input thresholds, there's a ~1volt hysteresis - the measured Vin,low-to-high threshold is 3.92volts and the Vin,high-to-low threshold is 3.03volts. I think the DINx inputs are implemented using continuous ADC sampling within the box, and that the hysteresis is done in firmware.
For the AINx analog input thresholds, when in Digital Input mode, there's no hysteresis and the high/low threshold is at 3.0volts. In analog mode, the ADC range is 0v to 5v (inputs larger than 5v are reported as ADC=5.00v).
The help docs show a +12V signal being used with an Analog "AIN x (0-5V)" pin. Is this correct? What about connecting a +12volt signal to a Digital DIN pin?
What are the high/low voltage thresholds used for DIN pins? and for AIN pins when configured as digital?
---------------------------------------------------------------------------------------------------------------
1/10/25 Edit: I guess I need to answer my own questions. This is not an official MaxxECU answer - use at your own risk. Maybe @WillettRun? can provide an official confirmation?
I ran some benchtop voltage-current curve traces of a few inputs on a MaxxECU Mini (HW rev 11) and, based on the knee at 5 volts in the curves, I believe that both the DINx digital inputs and AINx analog inputs are 12volt tolerant. The knee implies that the input is properly diode-clamped to a max of 5volts on the PCB.
I ran these measurements with the DINx internal pullup resistor disabled. When enabled, the pullup draws a max of 2.0mA when the input is grounded.
For the DINx digital input thresholds, there's a ~1volt hysteresis - the measured Vin,low-to-high threshold is 3.92volts and the Vin,high-to-low threshold is 3.03volts. I think the DINx inputs are implemented using continuous ADC sampling within the box, and that the hysteresis is done in firmware.
For the AINx analog input thresholds, when in Digital Input mode, there's no hysteresis and the high/low threshold is at 3.0volts. In analog mode, the ADC range is 0v to 5v (inputs larger than 5v are reported as ADC=5.00v).
Last edited:
rb92673
racecar
- Joined
- Jan 17, 2017
- Location
- San Clemente
@WillettRun? Nice job on Randy Pobst's car. I wish my former racecar cold started like that. New owner of car is looking to put a B6304 in it, starting NA, but eventually turbo, with a 8HP70. It will be for endurance racing. Any suggestion on which MaxxECU to use?
Blockheadsquarewheels
New member
- Joined
- Nov 27, 2019
Anyone use maxx with distributor ignition? What did you use for an amplifier/powerstage? The one in the maxx site looks slick and small. I know wasted or sequential is better, but maintenance aside, is a distributor really that bad?
I live in a state where keeping a stock looking ignition system and hiding a mini in an empty LH box would be smart for...... esthetics
I live in a state where keeping a stock looking ignition system and hiding a mini in an empty LH box would be smart for...... esthetics
OttoB
Well-known member
- Joined
- Aug 2, 2006
I have Bosch double amp in Volvo B4204 (Four cylinder whiteblock) but that is Waste Spark application. But normal Volvo LH2.4 amp will be ok. Then another project is Chevy TPI V8 with Maxxecu's own small amplifier, but it will take some time until the sparks start to fly.
If you are limited to have a stock appearing engine room, it would be a safe guess that you are not having over 350 HP, and for that level distributor is more than enough.
Blockheadsquarewheels
New member
- Joined
- Nov 27, 2019
Could you explain this more?
I have used 2 amplifiers so far, they both had some issue. I have very nice 8.5mm wire, good plugs, and Bose blue coil so I think very solidly the amplifier is my weak point.
1. MSD 6al CDI box plugged into my LH2.2, it works good under 50%-100% throttle but I always got some misfire under light cruse throttle.
2. The stock Boch amplifier, had some issues with spark blowout if 14+ lbs of boost.
I have very nice 8.5mm wire, good plugs, and Bose blue coil so I think very solidly the amplifier is my weak point.
I am hoping the Maxxecu amplifier will perform better, plus its quite small and looks pretty.
The stock ignition amplifier is nothing more than a single or pair of FETs, think of it like a very fast solid state relay as they are the same design. These parts rarely go bad unless they are overheated.
The issue with a stick distributor is that the caps and rotor are wear items, and if the rotor is not aligned properly then you get accelerated wear on the rotor and cap. There are a lot of other things that can make the stock type system not work great either, the issue you have could easily be on the fuel side.
When you are running an aftermarket ECU, you can control the coil dwell very easily and slightly increase it for more spark energy. This will cause the coil to get hotter, and in some instances fail.
All this to say, many many people have used the stock ignition components with an aftermarket or stock ECU to very high HP numbers without issue.
OttoB
Well-known member
- Joined
- Aug 2, 2006
If you got spark blowout at boost the sparkplug gap might be too much.
Maxx Race installed, and tuned by local tuner. Whoohooo! Good so far.
Now, CAN.
The Maxx CAN dbc file (MaxxECU_Default_CAN_protocol_v1.3) has fields "User_Channel_1" through "User_Channel_12".
By default, they have some data on them, but I'm not sure what it is.
I can't figure out what these are or how to use or assign values of interest.
"User Channel" is not found in the help.
Oddly, there are 12 "virtual outputs" in Mtune, but assigning those to a function doesn't seem to show up in the "User_Channel" CAN data.
It' be great if I could use these "User_Channel_x" fields to assign values in MTune that aren't predefined in the .dbc, but maybe that's not what these are for?
Any help appreciated.
Now, CAN.
The Maxx CAN dbc file (MaxxECU_Default_CAN_protocol_v1.3) has fields "User_Channel_1" through "User_Channel_12".
By default, they have some data on them, but I'm not sure what it is.
I can't figure out what these are or how to use or assign values of interest.
"User Channel" is not found in the help.
Oddly, there are 12 "virtual outputs" in Mtune, but assigning those to a function doesn't seem to show up in the "User_Channel" CAN data.
It' be great if I could use these "User_Channel_x" fields to assign values in MTune that aren't predefined in the .dbc, but maybe that's not what these are for?
Any help appreciated.
bobxyz
Board Member
- Joined
- Aug 29, 2014
- Location
- Boulder CO
You can select the Virtual Outputs from the Output Config menu. The CAN User Channels are selected from the CAN - CAN settings / Data Transmission menu. It looks like there's a bug in the CAN settings GUI that only shows an empty box, instead of labeling it "select". Just click in the empty box next to each User Channel to configure it.
- Joined
- Jan 24, 2009
- Location
- KC, MO
Race unit, and convert it to drive by wire.
- Joined
- Jan 24, 2009
- Location
- KC, MO
Its tolerant. just don't blow the diode!
It would be cool if the DINs were floating, perhaps if they could be a zero or a 1.
You can only use 12+ on DIN's that have selectable internal pullup. otherwise, they are always pulled up to 5v and will not register a high signal.
- Joined
- Jan 24, 2009
- Location
- KC, MO
Yep, those are them. they are useful if you do not wish or require defining your own data.
DagazEnterprise
We Don't Roll
- Joined
- Dec 12, 2009
- Location
- New Hampshire
Question about the Mini, If i'm running an AEM UEGO wideband, can i use the output on that to communicate that info directly to the Mini?
- Joined
- Jan 24, 2009
- Location
- KC, MO
I recommend an AEMX wideband, and using CAN to communicate the lambda signal, so you dont eat up an analog input (they are precious on the mini)
I just installed an AEMX CAN wideband, and it's working just fine as a 2nd WB input to my Race. It's a bit of a struggle to get the non lambda fields understood (eg, status bits, and for Maxx to correctly use them for "2nd wideband " status, but the lambda CAN fields work as expected.
- Joined
- Jan 24, 2009
- Location
- KC, MO
Unfortunately, those advanced status bits are not supported. Perhaps one day we will get scripting.
That'd be awesome (scripting of some sort). I'm just going to CAN the status bits over to my AiM logger, and create warnings and popups there. Not ideal, but better than nothing. (I don't use Mdash in the car.)