145 amp alternator enough, multiple fans
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This source says the maximum rpm for a typical automotive alternator is 18K rpm. And it explains what happens inside the alternator when it is spun over its maximum rpm limit.
PowerMaster is a good source for larger pulleys.
https://www.hotrod.com/articles/0206...ur-alternator/
now that I’ve established the need for a bigger (AD244 case) truck alternator along with the “how to make it fit” , I’m trying to determine if the stock truck alternator at @ 145 amps will be enough.
Im running:
- 4 Spal fans, 16”, 9” & two 10” pushers.
- Holley ECU
- dual squash 340 fuel pumps
still have AC & amps for stereo ( which I can easily keep out of the equation)
Optimus yellow top is in great condition.
Anybody have experience with this kind of load ? do I need to go bigger with say a Mechman 200+. I’d like to avoid that if I can.
Im running:
- 4 Spal fans, 16”, 9” & two 10” pushers.
- Holley ECU
- dual squash 340 fuel pumps
still have AC & amps for stereo ( which I can easily keep out of the equation)
Optimus yellow top is in great condition.
Anybody have experience with this kind of load ? do I need to go bigger with say a Mechman 200+. I’d like to avoid that if I can.
He told me he can build me something, it would cost more than any other alternator, but I'd be coming back for another one real soon.
.
As I stated I'm running the Escalade 145 amp alternator for the additional amperage but there must some kind of control on my 4th gen.
The amp output seems to vary being in the 12.5-13 volt range at idle but once moving into the 14+ volt range.
The amp output is also 14+ at start up but drops off after driving at idle, I just assumed the ECM is exciting the field when needed since it hasn't caused any problems lol.
The amp output seems to vary being in the 12.5-13 volt range at idle but once moving into the 14+ volt range.
The amp output is also 14+ at start up but drops off after driving at idle, I just assumed the ECM is exciting the field when needed since it hasn't caused any problems lol.
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From: PDX-OR-USA
Use a dedicated HEAVY wire from the Battery to the fuel pump relay and for the relay to the pump.
I'd go 10 or 8 gauge, with a 50A to 80A relay. Use high stand count copper wire,, not the cheap stuff.
Home run the fuel pump ground back to battery Negative. Your battery should be able to provide >
800 amps for the time it takes to make a 1/4 mile run.. If your on the dyno ,, you may need a second
battery paralleled on because of the extended higher RPM pulls. I used to use a pair of 6V Golf cart batteries
with 00 jumper cables to the cars battery to make darn sure we had a rock solid 13.7 V no matter what the car was doing.
I've measured a few pumps at 50+ amps of draw when they are at full pressure and volume. Duals make it even worse..
At 6500 a MSD can pull > 50 A as well...
I'd go 10 or 8 gauge, with a 50A to 80A relay. Use high stand count copper wire,, not the cheap stuff.
Home run the fuel pump ground back to battery Negative. Your battery should be able to provide >
800 amps for the time it takes to make a 1/4 mile run.. If your on the dyno ,, you may need a second
battery paralleled on because of the extended higher RPM pulls. I used to use a pair of 6V Golf cart batteries
with 00 jumper cables to the cars battery to make darn sure we had a rock solid 13.7 V no matter what the car was doing.
I've measured a few pumps at 50+ amps of draw when they are at full pressure and volume. Duals make it even worse..
At 6500 a MSD can pull > 50 A as well...
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From: PDX-OR-USA
Oh and yea,, the later cars almost all have a voltage control circuit(Under many names) to cut the alternator at lower RPM's to reduce load on the engine at idle to make them "cleaner.. "
I you park at night at a white garage door at idle and turn your headlights on,, you'll often see a flicker about every 3 minutes or so thats the alternator kicking to charge up the battery..
I you park at night at a white garage door at idle and turn your headlights on,, you'll often see a flicker about every 3 minutes or so thats the alternator kicking to charge up the battery..
This is good stuff.
I have an Escalade AD144 145A alternator. I haven't logged voltage to see if it drops off at 7000. I'm trying to remember if I put it in after I did my last bout of tuning on the car or before. Hmm. But I know I wasn't having any problems when I was logging 7k RPM.
I thought my stock AD130 was shitting the bed from the high RPM. And I needed more for my stereo setup. But now with a pair of Stealth 340 pumps, SPAL Fans, IGN-1A Coils... it might really **** the bed. I'll have to look at getting a 3.5" alternator pulley to go with my ATI balancer.
I have an Escalade AD144 145A alternator. I haven't logged voltage to see if it drops off at 7000. I'm trying to remember if I put it in after I did my last bout of tuning on the car or before. Hmm. But I know I wasn't having any problems when I was logging 7k RPM.
I thought my stock AD130 was shitting the bed from the high RPM. And I needed more for my stereo setup. But now with a pair of Stealth 340 pumps, SPAL Fans, IGN-1A Coils... it might really **** the bed. I'll have to look at getting a 3.5" alternator pulley to go with my ATI balancer.
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From: Norn Iron
I spoke to a Mechman technician......he told me if I use anything larger than about a 145-160 amp....which could be made........That will not last more than a few hundred miles ON A CAR THAT RACES in any way. He said its the high RPM bursts that kill high output alternators. I told him I'll hit 6700 rpm regularly......he said forget it.
He told me he can build me something, it would cost more than any other alternator, but I'd be coming back for another one real soon.
.
He told me he can build me something, it would cost more than any other alternator, but I'd be coming back for another one real soon.
.
Even years ago with a stock GM item I'd have seen as much as 7300 when racing...again, never any problems. After a few years it did fail, but nothing lasts forever.
Bullshit...I see 7k regularly with my 170A and zero problems. Although after having problems with some cheap ebay replacement alternators, I opted for their 170A along with a slightly larger pulley as I was intending try and get a usable 7500rpm.
Even years ago with a stock GM item I'd have seen as much as 7300 when racing...again, never any problems. After a few years it did fail, but nothing lasts forever.
Even years ago with a stock GM item I'd have seen as much as 7300 when racing...again, never any problems. After a few years it did fail, but nothing lasts forever.
Most people that race don't have their A/C, stereo and other non-essential items running when they do a hard run....so the alternator is not putting out much.
I was looking into a 310amp custom built amp so I can run a stand-alone electric A/C motor to act as a Killer Chiller....so I wouldn't be tapping into my factory A/C system for super-cooling the fluid. The stand-alone motor takes 110amps alone to run.....then with having to run everything else....Mechman and other shops said it will not last long putting out 255 amps during high rpm runs.
They're the experts, not me......thats what they say.
.
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From: Norn Iron
Most likely not putting out 170. Put it to the test, see whats it real output is. And the guy meant if you are fully loading it up to its max....at high rpm, they will not live. Try maxing it out at 170.....BYE-BYE.
Most people that race don't have their A/C, stereo and other non-essential items running when they do a hard run....so the alternator is not putting out much.
I was looking into a 310amp custom built amp so I can run a stand-alone electric A/C motor to act as a Killer Chiller....so I wouldn't be tapping into my factory A/C system for super-cooling the fluid. The stand-alone motor takes 110amps alone to run.....then with having to run everything else....Mechman and other shops said it will not last long putting out 255 amps during high rpm runs.
They're the experts, not me......thats what they say.
.
Most people that race don't have their A/C, stereo and other non-essential items running when they do a hard run....so the alternator is not putting out much.
I was looking into a 310amp custom built amp so I can run a stand-alone electric A/C motor to act as a Killer Chiller....so I wouldn't be tapping into my factory A/C system for super-cooling the fluid. The stand-alone motor takes 110amps alone to run.....then with having to run everything else....Mechman and other shops said it will not last long putting out 255 amps during high rpm runs.
They're the experts, not me......thats what they say.
.
Can you even list all the items needed to draw that much current ?
And an electric motor for a/c like that instead of just powering it off the engine is just daft, especially when there is a compressor setup already bolted to the engines to use that is easy switched off/on and it will be efficient.
As for experts....if they cannot build an alternator for you to race with...well, there are better "experts" out there.
I have a 25% off from Advance Auto, they have a new and a rebuilt 145, thought about getting one.
The new is prob from china, where maybe the rebuilt would be U.S. Not sure, but I figured the rebuilt
would be the better of the 2.
The new is prob from china, where maybe the rebuilt would be U.S. Not sure, but I figured the rebuilt
would be the better of the 2.
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The Nascar crowd regularly spin their engines way over 7K up to 9k plus dependent upon the track location where the engine reaches 9k and does so during each lap for 3-4 hours continuously.
So what rpm is the alternator spinning? Looks like not more than 18k according to Mclaren (same as what PowerMaster says is the safe maximum rpm an alternator should not exceed).
This statement is from the Mclaren site.
"Our alternators provide 140A in a 7lb package.
The alternator has a specially wound stator to yield a small, low weight package. An uprated rectifier assembly and internal fans minimize internal heating. The output is controlled by a solid state regulator inside the alternator. Stiff brush springs, the rectifier, a pegged stator and high quality bearings are used to ensure reliable operation at speeds up to 18,000 rpm. "
So looks like they have to use a larger pulley to maintain the 3 to one ratio in order to not exceed the 18k threshold. Also looks like they the don't need more than a 140A alt in the car with fans everywhere to keep things cool.
So what rpm is the alternator spinning? Looks like not more than 18k according to Mclaren (same as what PowerMaster says is the safe maximum rpm an alternator should not exceed).
This statement is from the Mclaren site.
"Our alternators provide 140A in a 7lb package.
The alternator has a specially wound stator to yield a small, low weight package. An uprated rectifier assembly and internal fans minimize internal heating. The output is controlled by a solid state regulator inside the alternator. Stiff brush springs, the rectifier, a pegged stator and high quality bearings are used to ensure reliable operation at speeds up to 18,000 rpm. "
So looks like they have to use a larger pulley to maintain the 3 to one ratio in order to not exceed the 18k threshold. Also looks like they the don't need more than a 140A alt in the car with fans everywhere to keep things cool.
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From: Norn Iron
The Nascar crowd regularly spin their engines way over 7K up to 9k plus dependent upon the track location where the engine reaches 9k and does so during each lap for 3-4 hours continuously.
So what rpm is the alternator spinning? Looks like not more than 18k according to Mclaren (same as what PowerMaster says is the safe maximum rpm an alternator should not exceed).
This statement is from the Mclaren site.
"Our alternators provide 140A in a 7lb package.
The alternator has a specially wound stator to yield a small, low weight package. An uprated rectifier assembly and internal fans minimize internal heating. The output is controlled by a solid state regulator inside the alternator. Stiff brush springs, the rectifier, a pegged stator and high quality bearings are used to ensure reliable operation at speeds up to 18,000 rpm. "
So looks like they have to use a larger pulley to maintain the 3 to one ratio in order to not exceed the 18k threshold. Also looks like they the don't need more than a 140A alt in the car with fans everywhere to keep things cool.
So what rpm is the alternator spinning? Looks like not more than 18k according to Mclaren (same as what PowerMaster says is the safe maximum rpm an alternator should not exceed).
This statement is from the Mclaren site.
"Our alternators provide 140A in a 7lb package.
The alternator has a specially wound stator to yield a small, low weight package. An uprated rectifier assembly and internal fans minimize internal heating. The output is controlled by a solid state regulator inside the alternator. Stiff brush springs, the rectifier, a pegged stator and high quality bearings are used to ensure reliable operation at speeds up to 18,000 rpm. "
So looks like they have to use a larger pulley to maintain the 3 to one ratio in order to not exceed the 18k threshold. Also looks like they the don't need more than a 140A alt in the car with fans everywhere to keep things cool.
The alternator doesnt need to spin anywhere near max to operate correctly, so they'll spin it as slow as they need to given the application, and whether or not it charges at idle really doesnt matter a damn
Relatively speaking the only reason LS alternators rpm's would seem high, is because of that large crank pulley.
Look at any Jap car, including Hondas, many of which will see 8, 9000rpm with OEM reliability. Simple...crank pulley is smaller, hence alternator speeds are lower.
So if someone cannot build an alternator to handle 7000rpm at the engine, something is seriously wrong. All they need to do is fit a correctly sized pulley in relation to the crank pulley.
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I have a c5 alternator that I bought @ chelmsford auto electric. . They bench tested it @ 175 amps. My car has 4 fans. 2 for the rad, 2 for the heat exchanger. It hits 6500-7000 rpm all the time. Somtimes with the Ac on. The only issue I have is somtimes it will drop voltage @idle .my car idles at 750 rpm. If I rev it up to say 1k, it will charge. Eventually I’ll prob bite the bullet and get the 220amp powermaster @$379 ,since it’s supposed to have excellent output at idle.
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From: Wellington, FL
I picked up the alternator yesterday. Looks great. It bench tested at 253 amps., & while I can’t remeber the specs the guy told me that it really shines at low rpm & he spun it up & it held 14.1 V “all the way”. He was impressed with his own work, good enough for me.
This will be more than enough for my load & not break a sweat.
I could use use a little advice as it pertains to making room for the ProCharger pulley. As mentioned earlier in the thread the case of the larger alternator effectively moves dead center ( the alternator pulley) closer towards the drivers side which now encroaches into the fat hex head bolt on the SC pulley. It looks like the washer under the bolt also needs to be grinder a bit.
I picked up the smaller headed pulley bolt, Cap head, 7/16 x 20.
My Q: I’d like to avoid grinding the ProCharger washer ( which looks like it’s about 3/16” thick),
is there any issue using multiple thinner stainless steel washers to achieve the proper thickness ? Will I loose strength against the head unit pulley ?
This will be more than enough for my load & not break a sweat.
I could use use a little advice as it pertains to making room for the ProCharger pulley. As mentioned earlier in the thread the case of the larger alternator effectively moves dead center ( the alternator pulley) closer towards the drivers side which now encroaches into the fat hex head bolt on the SC pulley. It looks like the washer under the bolt also needs to be grinder a bit.
I picked up the smaller headed pulley bolt, Cap head, 7/16 x 20.
My Q: I’d like to avoid grinding the ProCharger washer ( which looks like it’s about 3/16” thick),
is there any issue using multiple thinner stainless steel washers to achieve the proper thickness ? Will I loose strength against the head unit pulley ?
Good discussion, thanks.
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
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Joined: Nov 2003
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From: Norn Iron
Good discussion, thanks.
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
If you will see prolonged high rpm's then yes slowing it down makes sense from a long term reliability point of view.
A few 1/4 mile passes at high rpm though ? not really prolonged use.
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Good discussion, thanks.
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
Couple questions...…
Is this issue just related to the large scale truck alternator?
Anyway, I ran the pulley diameters on the car I'm having issues with. We are at 18000 alt rpm at 7000 engine rpm which is where it sits most of the run.
Peaks at 19000 rpm.
So we need to either slow it down or buy a fancy high rpm alt.
And sure we need the current, it's a turbo car that has to support high current when the fuel pump hits full tilt.
Second question.....is it only us guys who take detailed data logs who see this?
Ron
Was at the local track last night. As it turned dark some of the racers turned on their lights. This track is poorly lit.
What I noticed in the water box when doing burnouts, when a couple cars who hit the rev limiter their lights would dim. One in particular the lights went completely out.
I suppose it could be a number of things to cause the lights to dim just when they hit rev limiter. Perhaps it was when the alternator maxed at 18k when the engine peaked and hit the rev limiter. Or maybe little batteries to save weight.
BTW - these weren't Mustang and Camaro street cars. The cars were built the for drag strip only running mid to low 9/s and high 8's..