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Alternator Question

  • Thread starter Thread starter m0squ1t0
  • Start date Start date Oct 19, 2013
M

m0squ1t0

Member
Feb 3, 2011
103
2
19
Oct 19, 2013
#1
  • Oct 19, 2013
  • #1
My 2002 Gt is not keeping charge due to my steeda UDPs. I was told I need a higher amp alternator to compensate. What size is stock? What size do I need? I don't have anything crazy in my car, no amps subs etc... Thanks!!
 
M

m0squ1t0

Member
Feb 3, 2011
103
2
19
Oct 20, 2013
#2
  • Oct 20, 2013
  • #2
Anyone? I really need some direction...I have found out that the stock alternator is 110 amps so I need to know what size to replace it with to avoid having the battery drain on me.
 

COramprat

...I can take it. I think.
20+ Year Stangneter
Mar 2, 2003
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Sea of Tranquility
Oct 20, 2013
#3
  • Oct 20, 2013
  • #3
The PA alternator are 130 amps. What specific issues are you having now?
 

99Blownstang

Member
Feb 15, 2012
107
6
19
Oct 21, 2013
#4
  • Oct 21, 2013
  • #4
My opinion is that under drive pulleys are a joke. I have ran them and they just cause overheating problems
 

Mattstang04

15 Year Member
Sep 15, 2006
1,152
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St. Louis, MO
Oct 21, 2013
#5
  • Oct 21, 2013
  • #5
Has the alternator been tested to ensure that it is operating correctly? Could just be a case of an alternator going bad.
 
M

m0squ1t0

Member
Feb 3, 2011
103
2
19
Oct 21, 2013
#6
  • Oct 21, 2013
  • #6
the battery and the alternator have both been tested. I was told both are good. I was also informed that the underdrive pulleys are causing the alternator to not properly charge the battery enough because if I sit at a red light while its raining with my radio, lights and windshield wipers on the battery gauge drops unless I rev my engine in neutral. I don't have anything crazy in my car I have a replacement deck with the factory equivalent speakers.I've never had any overheating problems.
 

Mattstang04

15 Year Member
Sep 15, 2006
1,152
144
104
St. Louis, MO
Oct 21, 2013
#7
  • Oct 21, 2013
  • #7
Maybe try putting the stock pulleys back on and see if that fixes it. If it does, I would weigh the advantages of underdriven pulleys versus having to fix the issue. I had pulleys before my blower install. I was not impressed by any change they made.
 
M

m0squ1t0

Member
Feb 3, 2011
103
2
19
Oct 21, 2013
#8
  • Oct 21, 2013
  • #8
Stock pullies are a no go. Car came with the UDP system.. This is a problem that is new not something that has been around...could this be a programming issue?
 

COramprat

...I can take it. I think.
20+ Year Stangneter
Mar 2, 2003
8,474
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Sea of Tranquility
Oct 21, 2013
#9
  • Oct 21, 2013
  • #9
While the alt and battery my have tested OK I'm betting they are at the minimums. I had UD pullies on my old car and had frequent power issues. I eventually did away with them.
 
M

m0squ1t0

Member
Feb 3, 2011
103
2
19
Oct 22, 2013
#10
  • Oct 22, 2013
  • #10
I don't have thoriginal pullies, so for now thats a no go. Could i go with a higher amp alternator?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,349
18,084
224
Massachusetts
Oct 24, 2013
#11
  • Oct 24, 2013
  • #11
Higher amp alternators are not the cure because they still require a minimum RPM in order to create power.

The issue here is that your current alternator is spinning too slowly to produce a proper charge. Going to a higher amp alternator may not fix the issue of your accessory belt is still spinning too slowly to fix that issue.

You have 2 solutions:

1) find a set of stock pulleys and swap them back on

2) Find a stock alt pulley, or an aftermarket alt pulley that will fit of larger diameter in order to OVERDRIVE the alternator and compensate for the slowed down accessory system.

A 3rd option is to find an aftermarket alternator that produces full power at a lower RPM than stock. You'd need to know crank pulley size and alt pulley size and do a little bit of math to calculate if this will work.

Option 1 is prob the easiest
 
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