Brain fart regulator question Options

[mb911]

So was noticing I have less voltage while the car is running. I am use to seeing 13/14 volts as the pretty much normal. I have a fairly new marchel alternator and this year I am seeing 13v on the high side. Now I do have more electrical items, wide band o2, mega squirt, and active exhaust. Regulator going bad? Pictured in upper left. Hmm maybe I have them on the wrong pins? Might have messed that up?

[technicalninja]

Not sure if this will help...

The late model Miatas have a generator and the voltage regulator is the ECU.

Megasquirts can be arranged to provide this. You end up setting a "target voltage" in parameters in the squirt.

Don't know if this is applicable to a Porsche generator but the hard work may have already been done.

If you want to try it look to the Mazda solution for directions/ideas.

"Late" Miatas mean NB1s and NB2s for me. So, the years I'm referring to are 99-05.

I think some of the NAs pre 99 also did this as one of the old school mods to make this work was installing a 90-93 alternator in the newer model.

After they figured out how to work it in the squirt no one puts the old alternator in anymore.

[mb911]

Not sure if this will help...

The late model Miatas have a generator and the voltage regulator is the ECU.

Megasquirts can be arranged to provide this. You end up setting a "target voltage" in parameters in the squirt.

Don't know if this is applicable to a Porsche generator but the hard work may have already been done.

If you want to try it look to the Mazda solution for directions/ideas.

Hmm that’s interesting and good to know. I am learning MS right now. It is an amazing ECU for the money

[ClayPerrine]

Not sure if this will help...

The late model Miatas have a generator and the voltage regulator is the ECU.

Megasquirts can be arranged to provide this. You end up setting a "target voltage" in parameters in the squirt.

Don't know if this is applicable to a Porsche generator but the hard work may have already been done.

If you want to try it look to the Mazda solution for directions/ideas.

Hmm that’s interesting and good to know. I am learning MS right now. It is an amazing ECU for the money

You can control an alternator with Megasquirt. I have it in process for my 4.0 engine. It can't be done with the later internally regulated alternator, but it can be with the external regulated alternator.

From the MS3Pro manual:

High speed feedback field control: A different method of closed loop alternator field control, similar to an
electronic version of a points type regulator. The MS3Pro monitors the battery voltage at 20 kHz and switches
the field off if it is above target voltage, and switches the field on if it is below target voltage. Often easier to
set up than closed loop field control, as there are no PID parameters to tune - you just need to select this
mode and set a target voltage.
If the ECU is controlling the field coil directly, we recommend running the output through a solid state relay or external
power transistor. Many alternator field coils may require 10 amps or more, which is more than the MS3Pro’s
recommended output current.

You can replace the voltage regulator with a solid state relay, and use the Megasquirt to control the relay. the DF wire should be connected to pin 87 of a Bosch solid state relay, and pin 30 connected to the battery positive post. Pin 85 would connect to the ECU and pin 86 would connect to ground (I think...It may have to connect to 12v. Consult the Megasquirt manual). The programming should be fairly simple.

You will have to make the generator light trigger from the ECU if you want to have it work.

If you do it, let us know how it works.

Clay