alternator output question
- Thread starter sy2185
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B.A.M.F. BMW Tech
Re: alternator output question
around 140-160a
i'm not sure but this is a good guess.
sy2185 said:
around 140-160a
i'm not sure but this is a good guess.
Jer
Don't taze me bro!
Re: alternator output question
It's 105 amps but at idle it's closer to 60 amps. I just popped a new 200 amp alternator in this weekend along with a 4 gauge alternator/battery wire I made. Should be able to run all my electronics as well as the stereo and all the lights at night at a stoplight w/o draining the battery all the way.
It's 105 amps but at idle it's closer to 60 amps. I just popped a new 200 amp alternator in this weekend along with a 4 gauge alternator/battery wire I made. Should be able to run all my electronics as well as the stereo and all the lights at night at a stoplight w/o draining the battery all the way.
crashing_sux
Blow Me?
Re: alternator output question
While we're on idle questions I have one I've been wondering about for a while. I have a stock alternator with an underdrive pulley and of course have voltage issues at idle. From what I hear either putting the stock pulley back on or going to a higher output alternator will fix the problem so here's my dilema. The underdrive pulley may have been a mistake but a previous owner put it on for a reason, to free up some power, so what would be a bigger hp drain, spinning the stock alternator the stock speed, or spinning a bigger alternator a reduced rpm with the underdrive pulley?
While we're on idle questions I have one I've been wondering about for a while. I have a stock alternator with an underdrive pulley and of course have voltage issues at idle. From what I hear either putting the stock pulley back on or going to a higher output alternator will fix the problem so here's my dilema. The underdrive pulley may have been a mistake but a previous owner put it on for a reason, to free up some power, so what would be a bigger hp drain, spinning the stock alternator the stock speed, or spinning a bigger alternator a reduced rpm with the underdrive pulley?
Jer
Don't taze me bro!
Re: alternator output question
You're talking about very low numbers either way. I would get rid of the under drive pulley and put a stocker back on. If the alternator is struggling to keep up with normal requirements how do you think your other accessories are handling? You might free up some power but are probably losing it on the top end anyway as the electrical/ignition struggles on these vehicles to keep up with the demands. Just my opinion.
crashing_sux said:
You're talking about very low numbers either way. I would get rid of the under drive pulley and put a stocker back on. If the alternator is struggling to keep up with normal requirements how do you think your other accessories are handling? You might free up some power but are probably losing it on the top end anyway as the electrical/ignition struggles on these vehicles to keep up with the demands. Just my opinion.
crashing_sux
Blow Me?
Re: alternator output question
I guess that's possible although it seems to keep up just fine once the rpm's get over 1000.
I guess that's possible although it seems to keep up just fine once the rpm's get over 1000.
Re: alternator output question
our ecms contain certain tables such as F33 that are directly affected by high/low "voltage"....also voltage dwell and recovery times are factored in as well.....i would try to keep voltage as consistent as possible as it could directly affect fueling and or spark, depending on your chip's calibration of course....this should have big effects on performance.....my white ty used to audibly ping and fall on its face under load....it ended up being a failing alternator in my case.... voltage was fine at idle but would take a nosedive under a certain load or boost....
our ecms contain certain tables such as F33 that are directly affected by high/low "voltage"....also voltage dwell and recovery times are factored in as well.....i would try to keep voltage as consistent as possible as it could directly affect fueling and or spark, depending on your chip's calibration of course....this should have big effects on performance.....my white ty used to audibly ping and fall on its face under load....it ended up being a failing alternator in my case.... voltage was fine at idle but would take a nosedive under a certain load or boost....
Re: alternator output question
Before you go through all that, have you upgraded any of your stock wires (known as the big 3, the ground from the batt to the firewall or where ever its grounded at, the line going from the alt to the battery, and the one going to the ground on the block)? if not, you may have lots of corrison on the stock parts. Try cleaning the stockers up/ making new ones out of 4awg cable(unless you have a big system, in that case bump up to 0/1 awg). This should help some, and if this IS whats causing the problem, moving to a bigger alt with the stock pully isn't going to help one bit.
If that doesn't clear it up, you can swap on the stock pullie and test the voltage with a simple DMM to see. You'll be looking for 13.8v (at least) at anything above idle, and at least 12.6v at idle as most alternators suck at idle no matter what they are rated for. Also, with some the larger alternators, you'll be eating up 7-8 hp to turn them I belive.
Before you go through all that, have you upgraded any of your stock wires (known as the big 3, the ground from the batt to the firewall or where ever its grounded at, the line going from the alt to the battery, and the one going to the ground on the block)? if not, you may have lots of corrison on the stock parts. Try cleaning the stockers up/ making new ones out of 4awg cable(unless you have a big system, in that case bump up to 0/1 awg). This should help some, and if this IS whats causing the problem, moving to a bigger alt with the stock pully isn't going to help one bit.
If that doesn't clear it up, you can swap on the stock pullie and test the voltage with a simple DMM to see. You'll be looking for 13.8v (at least) at anything above idle, and at least 12.6v at idle as most alternators suck at idle no matter what they are rated for. Also, with some the larger alternators, you'll be eating up 7-8 hp to turn them I belive.
Windedv6
Ty n 10s
Re: alternator output question
The hp draw on an alternator, whether they are low amp or high amp output are affected by how much load you have on them. If you have no load the alternator would just spin freely. A 105 amp alternator and a 145 amp alternator will use the same hp if the load is the same. When racing turn off everything needed so that the minimum amount of hp is needed to run the alternator. One small difference is that we use a small case alternator. Most of the better 160 - 200 amp alternators use a large case alternator which has a slighter heavy armature that may use a touch more power to spin, but this is probably not measureable at our rpms. Overloading a alternator that is to small just causes additional heat that will trash the alternator quicker. Put a stock pulley on...or even an over size pulley to bring up the idle voltage.
John
The hp draw on an alternator, whether they are low amp or high amp output are affected by how much load you have on them. If you have no load the alternator would just spin freely. A 105 amp alternator and a 145 amp alternator will use the same hp if the load is the same. When racing turn off everything needed so that the minimum amount of hp is needed to run the alternator. One small difference is that we use a small case alternator. Most of the better 160 - 200 amp alternators use a large case alternator which has a slighter heavy armature that may use a touch more power to spin, but this is probably not measureable at our rpms. Overloading a alternator that is to small just causes additional heat that will trash the alternator quicker. Put a stock pulley on...or even an over size pulley to bring up the idle voltage.
John
Re: alternator output question
here's some measurements from my truck-key on,not running-
Datamaster voltage-11.9
cigarrette lighter volts-12.34
volts@batt. in bed-12.46
running at idle,acc.off-
DM-13.5
cig. lghtr-14.1
volts@batt-14.2
and at 2300 rpm-
DM-13.5
cig. lghtr14.15
volts@batt-14.3
These were with 2 6ga. jumpers from alt. to batt(checking my voltage drop/load) here's with out:
at idle acc. off-
DM-13.2
cig. lghtr-13.1
volts@batt-13.75
acc. off @2500-
DM -13.4
cig. lghtr -13.6
volts@batt -14.1
now w/o 2 6ga cables-
at idle all acc. on:
DM-13.0
cig. lghtr-12.4
volts@batt-13.5
and all acc. on@220rpm-
DM-13.3
cig. lghtr-12.35
volts@batt-13.8
I've got 2 8ga wires from batt. in bed to alt. plus extra ground to my ground bus under the truck,and 1/0 ga starter cable off a sol. in the bed to the starter-only hot when cranking. Sometimes when it stumbles while idling esp. at night I see the volts on the dm drop to as low as 11.9 or even a liottle below that during extended wot runs.
Thanks for any help.
Jeremy
here's some measurements from my truck-key on,not running-
Datamaster voltage-11.9
cigarrette lighter volts-12.34
volts@batt. in bed-12.46
running at idle,acc.off-
DM-13.5
cig. lghtr-14.1
volts@batt-14.2
and at 2300 rpm-
DM-13.5
cig. lghtr14.15
volts@batt-14.3
These were with 2 6ga. jumpers from alt. to batt(checking my voltage drop/load) here's with out:
at idle acc. off-
DM-13.2
cig. lghtr-13.1
volts@batt-13.75
acc. off @2500-
DM -13.4
cig. lghtr -13.6
volts@batt -14.1
now w/o 2 6ga cables-
at idle all acc. on:
DM-13.0
cig. lghtr-12.4
volts@batt-13.5
and all acc. on@220rpm-
DM-13.3
cig. lghtr-12.35
volts@batt-13.8
I've got 2 8ga wires from batt. in bed to alt. plus extra ground to my ground bus under the truck,and 1/0 ga starter cable off a sol. in the bed to the starter-only hot when cranking. Sometimes when it stumbles while idling esp. at night I see the volts on the dm drop to as low as 11.9 or even a liottle below that during extended wot runs.
Thanks for any help.
Jeremy
mrweelr
New member
Re: alternator output question
Hey Jer, where'd you get the 200amp alternator? I'm looking at upgrading my PowerMaster 140 to their 200, but the SOB is $500! Is that what you went with or some other source? This is my 2nd PowerMaster 140 that's started making noises and getting too hot.
Hey Jer, where'd you get the 200amp alternator? I'm looking at upgrading my PowerMaster 140 to their 200, but the SOB is $500! Is that what you went with or some other source? This is my 2nd PowerMaster 140 that's started making noises and getting too hot.
Crimson93Ty
PITA new guy
Re: alternator output question
Was it this one?
I'm thinking about getting one myself.
200 amp alternator for S,T series
Was it this one?
I'm thinking about getting one myself.
200 amp alternator for S,T series
Jer
Don't taze me bro!
Re: alternator output question
It's been a while now so I'm not 100% but I think that's the seller. It looks identical with the gold wheel and black fan but that's not saying a lot since a lotta alternators have that look. I really like the alternator and it's one of the better mods I did. I have a sub/amps/deck along w/a Taurus elec fan and a SPAL elec fan and methanol injection and MSD 6A and all sorts of things that like lots of clean power. I would recommend them if your power needs are higher than the stocker can handle.
It's been a while now so I'm not 100% but I think that's the seller. It looks identical with the gold wheel and black fan but that's not saying a lot since a lotta alternators have that look. I really like the alternator and it's one of the better mods I did. I have a sub/amps/deck along w/a Taurus elec fan and a SPAL elec fan and methanol injection and MSD 6A and all sorts of things that like lots of clean power. I would recommend them if your power needs are higher than the stocker can handle.