External voltage regulator mod question

[Reaper1]

I'm thinking more and more about adapting an external regulator to my car. However I have a question about this.

After discussing the possibility of changing the voltage target in the SMEC/SBEC calibrations (which CAN be done), it was stated that this can yeild a permanent code and CEL, even though it is working fine. I REALLY don't want that, hence my interest in going to the external regulator.

However, if the voltage target is changed in the code itself and it throws a code, what happens when you go external, which will be over the voltage target in the cal anyway? Also, what prevents the ECU from throwing the code when you bypass it with the external regulator? If I do this I REALLY don't want that CEL on al the time, especially when I swap my good cal in that has the CEL/knock mod done.

Can anybody that has done this mod to an SMEC/SBEC car comment on this, give me advice or feedback? Thanks!

[turbovanman²]

Rob will be able to answer about the code and the possibility of turning the light off but if you go external, you will get a code, regardless of the set voltage.

Why do you want to go external?

[Reaper1]

Partly because I'm paranoid about the internal regulator in our cars. Partly because I keep having issues related to low voltage (even though the alternator is fine, the battery is fine, and the connections and wiring all check out).

If the issue with the code and light coming on with the change in the voltage target in the cal can be corrected, I'll go that route and have Rob burn me another chip and try that first.

[turbovanman²]

Partly because I'm paranoid about the internal regulator in our cars. Partly because I keep having issues related to low voltage (even though the alternator is fine, the battery is fine, and the connections and wiring all check out).

If the issue with the code and light coming on with the change in the voltage target in the cal can be corrected, I'll go that route and have Rob burn me another chip and try that first.

Weird, maybe its related to your LC1 problems?

I assume you've checked everything but you must have a wiring or computer issue, millions of us use the stock setup with no problems. Are you using an UD pulley? What exactly happens to the voltage?

[Reaper1]

Weird, maybe its related to your LC1 problems?

I assume you've checked everything but you must have a wiring or computer issue, millions of us use the stock setup with no problems. Are you using an UD pulley? What exactly happens to the voltage?

The LC-1 issue is part of the reason I want to do this.

Yes, I'm running an UD pulley. Typically I only really have an issue at idle when my fan kicks on, or I have my stereo, headlights, blower motor, ect. on all at the same time at low rpm. Anything above standard idle and I don't have a charging issue.

My other thought is that even though I don't have a fueling problem, I'd like to get more voltage at the fuel pump. With the Chrysler charging target at only 13.5-13.7V we are not goving the pump the voltage needed to attain its full potential! It's not that I really NEED more fuel right now, it's the fact that when under load it will draw more current due to the low voltage to produce the same output. This will farther hamper my voltage issues.

Not that it's terribly accurate, but my stereo head unit has an option to display voltage. According to that my voltage oscillates slowly (meaning about 5 seconds) between I think 12.5-13.2, but is a bit more steady when at higher rpm. If I'm at idle and have things going as mentioned above then I've seen it drop to 11.7. Now, I don't know how accurate, or what sample rate that thing has, so it could be WAY off. I'm going to hook my volt meter to it to really see what I've got and report back later tonight.

[DOHCRT]

Well the underdrive pulley is probably the culprit here. It is turning the alt slower for a given engine rpm so the voltage output will be lower. Get rid of it and all of your problems will probably disappear. An alternator can only put out so much juice at idle, so with all of those accessories on at the same time go figure. Hell the non-turbo "L" bodies headlights used to flicker with the fan and or A/C on at idle due to the smaller alternator.

For the fuel pump, wire in a relay to send battery voltage direct to the pump, then you will always have 13+ volts there.

The voltage you are seeing at the head unit seems reasonable considering the UDP and voltage drop to the head unit.

[Ondonti]

I don't think anyone runs a pulley as small as the 3.0 guys and the only thing we ever see is headlights dimming if the idle bogs down.
I will eventually get a small pulley on my megasquirted car but I don't forsee a problem with maintaining voltage. When you have a problem that nobody else has, its probably not due to a part that everyone is using.

More then likely you have some bad wiring (or a mistake) or something on its way out.

When you ground a wideband to a different location then your ecu, your readings become suspect. Something as simple as that makes a wideband give you bunk results.

If your radio has a ground that is higher resistance then the ground on another device that looks at voltage, you are going to get different results. The Wideband and ecu need a common ground when running megasquirt so you can trust your datalogs to represent what was actually measured by the wideband device, not whatever the ECU was able to figure out with its better/worse ground. That assumes your wideband device is calibrated correctly.

My external regulator works great, but when I originally wired up megasquirt it was a piggyback install.
Not really sure what you really want since you already know all the answers :P
I don't know what your wideband issue is but as long as everything is properly wired and grounded, the voltage regulator is not a big deal. I think you are just bringing up fuel pump output as a mental reinforcement that its not a waste of your time to go external. Making up reasons

If you keep the OEM ECU, I see no point in adding something else that can fail. If you want to ditch the ecu, then its obviously a necessity.

My real question on an external is installing it inside the cabin to avoid heat vs installing it super close to the alternator to have minimal wiring and maybe see it control voltage a bit smoother.

Mine fluctuates about between 14.6 and 13.8 (but never very far at one time) when driving hard and barely moves when cruising. Whenever your RPM's are changing its constantly trying to correct the voltage back to nominal. The faster rpms change, the more it hiccups.

Voltage changes like that are scary because that can change injector output and fuel pump output enough to hurt something when you are on the edge.

[Reaper1]

I don't think anyone runs a pulley as small as the 3.0 guys and the only thing we ever see is headlights dimming if the idle bogs down.
I will eventually get a small pulley on my megasquirted car but I don't forsee a problem with maintaining voltage. When you have a problem that nobody else has, its probably not due to a part that everyone is using.

More then likely you have some bad wiring (or a mistake) or something on its way out.

When you ground a wideband to a different location then your ecu, your readings become suspect. Something as simple as that makes a wideband give you bunk results.

If your radio has a ground that is higher resistance then the ground on another device that looks at voltage, you are going to get different results. The Wideband and ecu need a common ground when running megasquirt so you can trust your datalogs to represent what was actually measured by the wideband device, not whatever the ECU was able to figure out with its better/worse ground. That assumes your wideband device is calibrated correctly.

My external regulator works great, but when I originally wired up megasquirt it was a piggyback install.
Not really sure what you really want since you already know all the answers :P
I don't know what your wideband issue is but as long as everything is properly wired and grounded, the voltage regulator is not a big deal. I think you are just bringing up fuel pump output as a mental reinforcement that its not a waste of your time to go external. Making up reasons

If you keep the OEM ECU, I see no point in adding something else that can fail. If you want to ditch the ecu, then its obviously a necessity.

My real question on an external is installing it inside the cabin to avoid heat vs installing it super close to the alternator to have minimal wiring and maybe see it control voltage a bit smoother.

Mine fluctuates about between 14.6 and 13.8 (but never very far at one time) when driving hard and barely moves when cruising. Whenever your RPM's are changing its constantly trying to correct the voltage back to nominal. The faster rpms change, the more it hiccups.

Voltage changes like that are scary because that can change injector output and fuel pump output enough to hurt something when you are on the edge.

I've had 2 8V cars with UDP's now. BOTH always had issues at idle keeping up with accessories running. The first was an '84 Laser XE. I honestly thought it was due to the age of the car and the archaic electronics, so I figured I'd try it on my '88. I actually have the EXACT same issues. There are times that even with everything off, if my radiator fan comes on at idle, it will throw the CEL due to low voltage! This is expecially true if I'm running the blower motor! Rev it a little, and everything goes back to normal.

I have the WB grounded to a common ground block under the hood that is directly wired to the battery. Only the power comes from the radio, which I'm going to correct.

You are probably right in the fact I'm trying to justify the change to the external regulator. For now I plan to stay with the stock SMEC set-up. If I figure out how to do custom cals, I probably won't deviate. If I DO decide to go stand-alone it will be with MS.

I understand your thoughts on the VR being too hot, but where I was going to mount it (if I decide to go that route) wouldn't be that bad.

I'm not really on the edge, but I do wish we could keep a more steady voltage output for your stated reasons. I'm going to go all theoretical and add complexity again for a moment, so feel free to slap me back to reality! LOL I understand the battey is only used as a back-up power source and as sort of an electrocal damper in the charging system once the engine it running. However, batteries doe not do well with very fast changes and are slow to take up slack. What it we uses a capacitor in the system that is regulated to be this buffer? I think a more steady output could be had, and spikes in the system would be greatly reduced.

What's your thoughts on that?

[turbovanman²]

Chris, I mentioned about swapping your alt pulley in another thread, I had the same issue running an UD pulley, at idle, the voltage would drop. Its much better now with the new pulley and in the cal, I raised the idle a 150 rpm, so now, no more charging issues at idle, even in winter with everything turned on.

Agreed with Vic on hard wiring the fuel pump.

[Reaper1]

Yeah, I think I remember you saying it was a Toyota Celica pulley? Also that it would have 1 more groove than stock for the 8V, but is perfect for the TIII. Am I remembering that correctly?

I've got a shop here in Daytona Beach that builds custom alternators, maybe I can swing by there and see if I can't find a pulley that'll work.

I'll do the fuel pump soon. I just want to fix this problem and get the car tuned back up. I HAVE to do a compression test on it because I think the engine is finally getting tired. It still has really good pep, but it just doesn't seem like it's got the bit it used to. I wish I could find my notebook I wrote all my specs in for it over the years. Each time I did a tune up and such I always did a compression check, just to keep track of it. The bottom end is the original stuff...all 200,000+miles of it and I've pushed it pretty hard over the past few years. Another though is maybe the valve springs are wearing out. I don't know how old those are as this head is a stock rebuilt unit, but I'd assume the springs were just reused. I'm also going to check cam timing and ignition timing.

[turbovanman²]

Yeah, I think I remember you saying it was a Toyota Celica pulley? Also that it would have 1 more groove than stock for the 8V, but is perfect for the TIII. Am I remembering that correctly?

I've got a shop here in Daytona Beach that builds custom alternators, maybe I can swing by there and see if I can't find a pulley that'll work.
.

If you have the Nippo alt, then yeah, a 2000 Toyota Celica, the extra grooves don't matter, it will still work with your belt.

[Reaper1]

Yup, that's what I remember. I'll do some looking today!

[Reaper1]

I was thinking about this a bit the other day...what if a resistor was put inline in the computer's sensing circuit to artificially lower the voltage it sees to force it to feild the alternator more and raise the charging voltage?

[turbovanman²]

I was thinking about this a bit the other day...what if a resistor was put inline in the computer's sensing circuit to artificially lower the voltage it sees to force it to feild the alternator more and raise the charging voltage?

Not sure that would work, but it could. Is yours your own cal? if so, you can alter the factory turn on point and raise the voltage, going to do that mod next.

[RoadWarrior222]

Wouldn't want to do that with the resistor, would need to be a small value, then in hot weather would be of higher resistance, causing even higher charge voltage, such that your battery gets cooked. Need a negative temp co-efficient thermistor, or a resistor "corrected" by one.

[Reaper1]

Not sure that would work, but it could. Is yours your own cal? if so, you can alter the factory turn on point and raise the voltage, going to do that mod next.

The one I have in there is a FWD S5. I have a nice ShelGame cal as well, but until the car is tuned back up, I'm not putting it back in.

I've heard from ShelGame that you *can* raise the turn on value and that it does work, but it turns the CEL on because the voltage the cal sees interferes with something else and it thinks there's a problem. I thought I had read that somebody had figured that problem out, but I'm not 100% sure. I just don't want to have the CEL on all the time #1 because it's annoying, and #2 because that cal has the knock/CEL mod done to it and if the darn thing is on all the time I won't be able to use it.

Wouldn't want to do that with the resistor, would need to be a small value, then in hot weather would be of higher resistance, causing even higher charge voltage, such that your battery gets cooked. Need a negative temp co-efficient thermistor, or a resistor "corrected" by one.

I understand what you are saying, but this resistor would be pretty darn small. Whe're talking about lowering the sensed voltage by about .5V! That's not a lot at all. I know that sounds pointless, but when others that run external regulators indicate that they have very good luck with things running at 14.2V instead of 13.7V, it makes me think that this is worthwhile. I'll do some research on it if I get a chance. I think it *might* work, but you're correct, don't want to fry anything due to temp varience changing resistance either. Thanks for the sanity check!

[RoadWarrior222]

use a silicon diode, drops 0.6V 1N4001 or similar.

[Reaper1]

AH! Good thinking!

[turbovanman²]

The one I have in there is a FWD S5. I have a nice ShelGame cal as well, but until the car is tuned back up, I'm not putting it back in.

I've heard from ShelGame that you *can* raise the turn on value and that it does work, but it turns the CEL on because the voltage the cal sees interferes with something else and it thinks there's a problem. I thought I had read that somebody had figured that problem out, but I'm not 100% sure. I just don't want to have the CEL on all the time #1 because it's annoying, and #2 because that cal has the knock/CEL mod done to it and if the darn thing is on all the time I won't be able to use it.

Gotcha. Contact Stratman, he's done the mod, he'd know for sure.

Did you find a pulley yet? Raise your idle by 100-150 rpm, that helps a ton too.

[JDAWG]

Sorry late to the thread, not sure how much all this would help being as you have an underdrive pulley but
here is an adjustable external alt
http://cpgenerator.com/voltageregulators.html
about half way down
I would also upgrade all you charge wires to 2 gauge or bigger, they are really terrible from the factory, just doing this on my daytona I picked up over a volt, dont forget the one on the back of the intake
lastly go to car-part.com and look up a alt from a 02 or so durango with the 5.9, there is a 160amp version, mine was $50 shipped, you will just need the plug off of a 'newer' car/truck, should be able to chop one off at the junkyard, you didnt say you were running a big stereo or anything but it couldnt hurt
the adjustable reg and wire upgrade should help you out the most though