MicroSquit Conversion, Giving this a try Options

[Mblizzard]

I am pretty happy with my stock FI. But after seeing some of the setups at Okteenerfest, I thought this might be worth trying.

The stock system is not easy to modify and get things running correctly. I spent a lot of time making minor adjustments by trial and error. While I am not looking for huge HP gains or anything, it is pretty clear that the mods I have could potentially benefit from a bit more precise control.

Going to start with fuel only at this point to get things going and see where it leads me. Any help or suggestions for set up would be appreciated.

[Mblizzard]

Ok let’s be clear. I am not no wiring expert! But as I understand things the micro squirt controls the injectors by providing ground. Meaning the controller switches ground on an off as needed to fire the injectors. Because I have low impedance injectors I have to use resistors. Below is the guidance from the manual on how to wire.



Based on this it shows the resistors on the controller side which is ground. (IMG:style_emoticons/default/WTF.gif)

This can’t be correct can it? Especially when it stats than an individual resistor is required for each injector.

The resistors have to go on the 12v wire don't they?

[N_Jay]

Ok let’s be clear. I am not no wiring expert! But as I understand things the micro squirt controls the injectors by providing ground. Meaning the controller switches ground on an off as needed to fire the injectors. Because I have low impedance injectors I have to use resistors. Below is the guidance from the manual on how to wire.



Based on this it shows the resistors on the controller side which is ground. (IMG:style_emoticons/default/WTF.gif)

This can’t be correct can it? Especially when it stats than an individual resistor is required for each injector.

The resistors have to go on the 12v wire don't they?

The order of devices in series is immaterial.

Question, how much voltage and current at are the injectors designed for?
What is the current the MS is designed to sink?

[Mblizzard]

Ok let’s be clear. I am not no wiring expert! But as I understand things the micro squirt controls the injectors by providing ground. Meaning the controller switches ground on an off as needed to fire the injectors. Because I have low impedance injectors I have to use resistors. Below is the guidance from the manual on how to wire.

Based on this it shows the resistors on the controller side which is ground. (IMG:style_emoticons/default/WTF.gif)

This can’t be correct can it? Especially when it stats than an individual resistor is required for each injector.

The resistors have to go on the 12v wire don't they?

The order of devices in series is immaterial.

Question, how much voltage and current at are the injectors designed for?
What is the current the MS is designed to sink?

Lets say the injector resistance is around 2.5 Ohms and I am adding another 3 Ohms so that would be about 2 amps based on 12V.

[N_Jay]

Ok let’s be clear. I am not no wiring expert! But as I understand things the micro squirt controls the injectors by providing ground. Meaning the controller switches ground on an off as needed to fire the injectors. Because I have low impedance injectors I have to use resistors. Below is the guidance from the manual on how to wire.

Based on this it shows the resistors on the controller side which is ground. (IMG:style_emoticons/default/WTF.gif)

This can’t be correct can it? Especially when it stats than an individual resistor is required for each injector.

The resistors have to go on the 12v wire don't they?

The order of devices in series is immaterial.

Question, how much voltage and current at are the injectors designed for?
What is the current the MS is designed to sink?

Lets say the injector resistance is around 2.5 Ohms and I am adding another 3 Ohms so that would be about 2 amps based on 12V.

So are they looking for 2A at about 6V?

Does anyone have the actual specs?

[Dtjaden]

Ok let’s be clear. I am not no wiring expert! But as I understand things the micro squirt controls the injectors by providing ground. Meaning the controller switches ground on an off as needed to fire the injectors. Because I have low impedance injectors I have to use resistors. Below is the guidance from the manual on how to wire.

Based on this it shows the resistors on the controller side which is ground. (IMG:style_emoticons/default/WTF.gif)

This can’t be correct can it? Especially when it stats than an individual resistor is required for each injector.

The resistors have to go on the 12v wire don't they?

The order of devices in series is immaterial.

Question, how much voltage and current at are the injectors designed for?
What is the current the MS is designed to sink?

Lets say the injector resistance is around 2.5 Ohms and I am adding another 3 Ohms so that would be about 2 amps based on 12V.

So are they looking for 2A at about 6V?

Does anyone have the actual specs?

The specs are clearly stated in the appropriate Megasquirt manual, MS2V3 Hardware Manual.
http://www.msextra.com/doc/pdf/MS2V30_Hardware-3.4.pdf
While the specification is 7 amps at 12V (6 volts does not come into this at all) per channel for the output transistors they don't want to drive them at full rating. The manual clearly states the resistor values (both resistance and wattage) and has a wiring pictogram.

As was stated earlier the resistor could be on either side of the injector although their diagram shows the resister installed between the injector and the MS controller. The controller does pull the injector lines to ground. With the resistor values suggested by the Megasquirt manual the current is kept under 2 amps.

Microsquirt is electrically a Megasquirt II version 3