Brain fart regulator question Options

[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

[emerygt350]

A hair off topic, and not to hijack, but why is the vdo volt meter so wonky? Mine is running right off the battery but it still isn't reliable (it just doesn't respond to the brake/turn signals anymore).

I’m confused. So you want it bouncing around? (IMG:style_emoticons/default/confused24.gif)

If you are running it right off the battery it should be stable. The battery (in theory) is an infinite current source and its voltage should remain unaffected by minor loads like a turn signal bulb.

The OEM red / white wire that supplied the volt meter ran a convoluted route from battery to fuse 9, to the stop switch, and then to the volt meter and is subject to variance and voltage drops across lots of wire and the fuse. That red / white wire also went to a number of other locations that could load it down.

Easy enough to go back to original if you miss the variability dependent on load. (IMG:style_emoticons/default/shades.gif)

Yeah, I don't miss that, it's just that it isn't accurate. It's like it has to warm up or something. I will have the multimeter on the battery and it will be showing 13.7 and the gauge will be down around 12.5, and 5 minutes later it will be up at 13.5ish. eventually it gets its crap together but I can't really trust it. I cleaned up all the connections today and it's still like that. Maybe it's some kind of ballast to keep it from bouncing around?

[Superhawk996]

@emeryGT350

That doesn’t seem right. Let me check my gauge against bench power supply and DMM. Give me a couple days - away on vacation but I’ll post result when I get back.

[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

[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

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

1st thing is first and get a regulator on there and tune the car. Then I will tackle that. I am learning autotune now.

[technicalninja]

I'm in agreement!

I'd start with a stand-alone power generation system if I had the option.

Having less stuff in the squirt at initial light up is easier IMO.

If I continued to have regulator issues I would try to incorporate it into the squirt.

[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

1st thing is first and get a regulator on there and tune the car. Then I will tackle that. I am learning autotune now.

I would agree with that. Keep it simple at first, then add things like this later.

I honestly thought you already had it running well on the Megasquirt.

Clay

[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

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

1st thing is first and get a regulator on there and tune the car. Then I will tackle that. I am learning autotune now.

I would agree with that. Keep it simple at first, then add things like this later.

I honestly thought you already had it running well on the Megasquirt.

Clay

Decent not great. Was working on that and my voltage levels became subject and that reason for this post

[Spoke]

dF is weird as I get different values depending on what 12 pin connection I check.

What does the 12 pin connection have to do with DF? In the 914/4, DF goes between the alternator and the VR and goes through the 3 pin connector between them. That's it.

Did you do some tests on the 3 VR voltages while running? This can tell a lot about your system.

When running, measure these voltages at the VR:

D+ should be 13-14V
DF should vary between 5-10V depending on electrical load.
D- should be 0V

Also measure the battery voltage:
B+ should be 13-14V and follow D+

Measure all voltages with respect to a chassis lug, not the engine case.

For the field test, remove the VR and short DF to D+ then start the engine. This should force maximum voltage of about 16V on D+ and B+. Do this for a short burst as it's hard on the battery and alternator.

As an aside, my '86 930 was showing low battery voltage (12V) and slow starting. I bought a new battery and immediately got 13.5V steady. You mentioned you were going to replace your 10 year old battery. Did you replace it and did it make a difference?

[mb911]

dF is weird as I get different values depending on what 12 pin connection I check.

What does the 12 pin connection have to do with DF? In the 914/4, DF goes between the alternator and the VR and goes through the 3 pin connector between them. That's it.

Did you do some tests on the 3 VR voltages while running? This can tell a lot about your system.

When running, measure these voltages at the VR:

D+ should be 13-14V
DF should vary between 5-10V depending on electrical load.
D- should be 0V

Also measure the battery voltage:
B+ should be 13-14V and follow D+

Measure all voltages with respect to a chassis lug, not the engine case.

For the field test, remove the VR and short DF to D+ then start the engine. This should force maximum voltage of about 16V on D+ and B+. Do this for a short burst as it's hard on the battery and alternator.

As an aside, my '86 930 was showing low battery voltage (12V) and slow starting. I bought a new battery and immediately got 13.5V steady. You mentioned you were going to replace your 10 year old battery. Did you replace it and did it make a difference?

Changed battery, no change, did full load test and shot up to 15.5-16 volts short burst. Everything points to VR so ordered a new one. Waiting for that to be delivered

[JamesM]

This wiring picture just broke my OCD

[mb911]

This wiring picture just broke my OCD

What wiring no picture? No idea what you’re talking about. It’s a bunch of wiring in small space which includes MSD, ECU, wide band o2 . There is no other spot for it and I feel like it’s pretty straight forward

[mb911]

Well it was a combination of things. Ignition switch replaced (911 style), fuse panel needing cleaning, a few grounds cleaned up and all set now

[Superhawk996]

(IMG:style_emoticons/default/smilie_pokal.gif)

[SirAndy]

Well it was a combination of things. Ignition switch replaced (911 style), fuse panel needing cleaning, a few grounds cleaned up and all set now

I like happy endings (IMG:style_emoticons/default/w00t.gif)

[mb911]

Well it was a combination of things. Ignition switch replaced (911 style), fuse panel needing cleaning, a few grounds cleaned up and all set now

I like happy endings (IMG:style_emoticons/default/w00t.gif)

It’s amazing something so silly caused this but glad it’s taken care of now time to learn MS autotune.