Just wondering what my voltage should be at wot?
- Thread starter spooldup
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V6 Kompressor
New member
I have installed the Red-Tops in a fleet of ambulances, and they have given flawless starting performance for over a year now. The last set of batteries installed were A/C delco's commercial duty batteries and they lasted about 1 year before they were wasted. All but one ambulance has two of these and 1 has 3 of these installed. Of course the delco's didn't like being installed in a ford, but the engines are all navistar's...
:grin:
:grin:
No ATR pulleys here- don't they only show hp gains over 5000rpm like other perf. pulleys? With the ATR batt. relocate kit putting it where I can't see it I wanted a solid reliable sealed batt. and optima was it. The reason my wot voltage went up I believe was regardless of what was draining the batt. before,a stronger batt. would have the ability to maintain output voltage despite being under a load. I've heard from several mechanics that like the AC, the alt. is cut out at WOT to reduce engine drag. Didn't get any farther on it than that,but you may want to look into it.
Jeremy
Jeremy
InvisiBill
Active member
The red top Optimas are made for starting, while the yellow tops are the deep cycle ones that are used in a lot of stereo installs. With the engine running, the battery is a load, so a bad one could be sucking power away...
Isn't the alternator just a shaft with a pulley on it? I don't think there is a way to cut it out, unlike the AC's clutch...
I'm still looking for one of these: http://www.eau.com/sw/batt/ Apparently StreetWires was bought out though, and the rep for the local shop said they haven't been able to find ANY, anywhere in the country... I've still got to check with QuickCar and see if they have any, or a replacement... http://www.negia.net/~phase/ca_fx1050.htm is the personal page of one of SW's tech guys. He mentions that these are designed to withstand high G accelerations. Not like we'd ever need anything like that. =)
Isn't the alternator just a shaft with a pulley on it? I don't think there is a way to cut it out, unlike the AC's clutch...
I'm still looking for one of these: http://www.eau.com/sw/batt/ Apparently StreetWires was bought out though, and the rep for the local shop said they haven't been able to find ANY, anywhere in the country... I've still got to check with QuickCar and see if they have any, or a replacement... http://www.negia.net/~phase/ca_fx1050.htm is the personal page of one of SW's tech guys. He mentions that these are designed to withstand high G accelerations. Not like we'd ever need anything like that. =)
Mephisto
These trucks are cursed
would getting one of those MSD ignition thingies raise the voltage that much to make it worth buying?
if you got a constant 13.5 with it at WOT, versus not having one and the voltage dropping to 12.9, would that really make that much of a difference to justify getting one?
if you got a constant 13.5 with it at WOT, versus not having one and the voltage dropping to 12.9, would that really make that much of a difference to justify getting one?
I.bill- the alt. depends on a certain amount of voltage recycled into itself to continue putting out.A trigger if you will. I was told that a simple but unexplained mechanical process in the alt. is the reason, though I'm not sure. Have heard it several times, though.
Neal- how many of our critical sensors would give false results if their output was cut by .6VDC? .6V equates to like %17 to the TPS. I know ECM depends on % not V, just an example.
J
Neal- how many of our critical sensors would give false results if their output was cut by .6VDC? .6V equates to like %17 to the TPS. I know ECM depends on % not V, just an example.
J
Most of the sensors operate on a 5 volt system as regulated by the ecm. So even if the ignition voltage varies, the sensors should still see the same five volts.
I feel that the reason for the voltage drop at WOT is that the same circuit (ECM B) that supplies the ignition voltage to the ecm also supplies votage to the injectors. When you are at WOT, the injectors are running near static, meaning open all the time. therefore, the injectors are pulling much more current through that circuit under this condition. using Ohms law (Voltage = Current x resistance), we can see that when the current goes up due to the static condition of the injectors, any resistance within the circuit shows up as a voltage drop, hence lower ignition voltage at the ECM ignition fed terminals. This is what I believe that Datamaster is reading (ignition voltage at the ECM). So now we look at where the resistance is in the circuit. Well its an ignition voltage, meaning its powered when the switch is turned on, so the current path goes through the ignition switch. It also goes through the harness connector at the firewall twice, supply in and then back out. Also goes through the ecmb fuse, fusebox and the connector at the ecm. All these connections and switches add a resistance to the circuit and since they are in series, the resistances add. Its no wonder why we have such a voltage drop starting at the alternator and going to the ecm. I have been considering trying a relay setup to eliminate some of the inherent resistance of the circuit, but time has not permitted trying it out yet.
I feel that the reason for the voltage drop at WOT is that the same circuit (ECM B) that supplies the ignition voltage to the ecm also supplies votage to the injectors. When you are at WOT, the injectors are running near static, meaning open all the time. therefore, the injectors are pulling much more current through that circuit under this condition. using Ohms law (Voltage = Current x resistance), we can see that when the current goes up due to the static condition of the injectors, any resistance within the circuit shows up as a voltage drop, hence lower ignition voltage at the ECM ignition fed terminals. This is what I believe that Datamaster is reading (ignition voltage at the ECM). So now we look at where the resistance is in the circuit. Well its an ignition voltage, meaning its powered when the switch is turned on, so the current path goes through the ignition switch. It also goes through the harness connector at the firewall twice, supply in and then back out. Also goes through the ecmb fuse, fusebox and the connector at the ecm. All these connections and switches add a resistance to the circuit and since they are in series, the resistances add. Its no wonder why we have such a voltage drop starting at the alternator and going to the ecm. I have been considering trying a relay setup to eliminate some of the inherent resistance of the circuit, but time has not permitted trying it out yet.
mrweelr
New member
Daron - I'm getting my volt readings from Datamaster. The reason I'm replacing my ignition module is because it's cheap and it's the only ignition component left that I haven't replaced. Some guys are replacing their distributors hoping for better spark but I didn't want to go that far yet.
InvisiBill
Active member
But the actual mechanical, spinning parts of the alternator are bolted directly to the pulley, aren't they? So even if there was something to cut the output, wouldn't the physical drag on the engine from spinning the alternator still be there? Whereas the AC clutch actually disconnects the pulley from the other parts, so the engine has less mass to spin... Right?
Worked on a T-3 at the power plant yesterday and asked my escort about it. He'd said that the alternator should spin pretty freely of the belt.The drag associated with it is from the opposite magnetic fields inside the alt. Their alternating polarity exites the atoms, creating a charge(he kinda lost me while I was trying to translate it into auto talk since he only knew power,not cars).By removing the current trigger the electromagnets have no magnetism to transfer,eliminating much of the drag.
Jeremy
Jeremy