1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Too underdriven?

Thread Tools
 
Search this Thread
 
Old Jan 7, 2004 | 03:34 PM
  #1  
hornbm's Avatar
Thread Starter
FD > FB > FC
Tenured Member: 20 Years
 
Joined: Oct 2002
Posts: 3,873
Likes: 3
From: Bothell, WA
Too underdriven?

I have the racingbeat under drive main pulley, and the dual belt alternator pulley. Ever since I put on the alternator pulley, my charging at idle has really taken a hit. Used to be right around 14 volts, now I'm around 13.5. The guages even brighten up when I rev the engine.

Anyway, the only reason why I wondering is because I got my alternator used (80amp Second gen)and I have no idea how old it is. The bearings in it squeel just a little if you spin the pulley by hand.

Could this be a sign that my alternator is going out, or do I need to lay off the under driving?
Reply
Old Jan 7, 2004 | 03:39 PM
  #2  
Rotofire's Avatar
Yea, I'm working on it...
Tenured Member 10 Years
 
Joined: Dec 2003
Posts: 1,220
Likes: 0
From: Click click fucking click, Africa
alt is going, that's my opinion, the bearing i don't see how they have too god awful much about the lights brightening and what not.
Reply
Old Jan 7, 2004 | 04:28 PM
  #3  
Anex 570's Avatar
It Runs!
Tenured Member 15 Years
 
Joined: Aug 2003
Posts: 955
Likes: 2
From: PA
Also check your battery, if its more then about 2 years old, it could be just going itself, because thats what contains the charge from your alt. Its pretty messed up about the whole thing, but are you lights at regular brightness then really light up when you hit the gas?
Reply
Old Jan 7, 2004 | 05:50 PM
  #4  
GavinJuice's Avatar
Leave A Message
Tenured Member 05 Years
 
Joined: Sep 2003
Posts: 1,454
Likes: 1
From: MN
your pretty much running off of your alternator when the car is running. Do you have a load on your charging system ie., car audio? That alone will slowly kill your alternator.
Reply
Old Jan 7, 2004 | 06:07 PM
  #5  
wwilliam54's Avatar
it WILL run
Tenured Member 10 Years
 
Joined: Dec 2002
Posts: 2,017
Likes: 1
From: Raleigh,MS
get a buick alternator
Reply
Old Jan 7, 2004 | 07:00 PM
  #6  
cdrad51's Avatar
Lorem ipsum dolor sit ame
Tenured Member 10 Years
 
Joined: Nov 2003
Posts: 3,262
Likes: 1
From: The Net
My car tends to do the same, though I don't have underdrive pulleys. All lights will brighten up if I rev the car. However voltage will be at about 14 volts. Battery is new so it's now an issue, even though I'm aware is mostly up to the alt when the car is running. I only have about 400 watts on the stereo system, would that be enough to kill the alt?
Reply
Old Jan 7, 2004 | 09:01 PM
  #7  
wwilliam54's Avatar
it WILL run
Tenured Member 10 Years
 
Joined: Dec 2002
Posts: 2,017
Likes: 1
From: Raleigh,MS
Originally posted by cdrad51
My car tends to do the same, though I don't have underdrive pulleys. All lights will brighten up if I rev the car. However voltage will be at about 14 volts. Battery is new so it's now an issue, even though I'm aware is mostly up to the alt when the car is running. I only have about 400 watts on the stereo system, would that be enough to kill the alt?
stock alt is 60amp

wouldnt help, you need to check your grounding
Reply
Old Jan 7, 2004 | 11:17 PM
  #8  
eddierotary's Avatar
back with rotaries
Tenured Member 20 Years
iTrader: (7)
 
Joined: Nov 2001
Posts: 2,239
Likes: 1
From: Watertown, NY
the RB pulleys doesnt supposes to reduce the speed of the alternator and the water pump? theres your answer in idle is so slow that only outputs 13.5 volts. that why is like that. maibe im wrong but that what i believe
Reply
Old Jan 7, 2004 | 11:33 PM
  #9  
Directfreak's Avatar
I am a Jeeper Now.
Tenured Member 20 Years
iTrader: (2)
 
Joined: Dec 2001
Posts: 9,371
Likes: 4
From: 3OH5
Underdrive Pullies suck on street driven cars - period.
It may not be the source of your problem, but it is definately a contributor.
Reply
Old Jan 7, 2004 | 11:39 PM
  #10  
hornbm's Avatar
Thread Starter
FD > FB > FC
Tenured Member: 20 Years
 
Joined: Oct 2002
Posts: 3,873
Likes: 3
From: Bothell, WA
yeah i didnt really have a choice as far as the pulleys go, all racing beat pulleys are underdrive. I needed the dual belt alternator pulley and the timing marks on my stock main pulley were wrong.


Eddie, your probably right, I mean the pulleys arent helping anything, but I dont know if the alternator is adding to the problem. Basically what DF said.

Is anyone else using both under drive pulleys?
Reply
Old Jan 7, 2004 | 11:44 PM
  #11  
Directfreak's Avatar
I am a Jeeper Now.
Tenured Member 20 Years
iTrader: (2)
 
Joined: Dec 2001
Posts: 9,371
Likes: 4
From: 3OH5
The one Manntis sells is a double Alternator pulley, and is NOT underdriven.

NOTE:

1) A 2nd Gen (TII) Alternator wouldn't hurt One Bit
2) Replacing all the lighting in the car with High Intensity LED's will significantly reduce the electrical drain at night as well.

Last edited by Directfreak; Jan 7, 2004 at 11:46 PM.
Reply
Old Jan 7, 2004 | 11:51 PM
  #12  
hornbm's Avatar
Thread Starter
FD > FB > FC
Tenured Member: 20 Years
 
Joined: Oct 2002
Posts: 3,873
Likes: 3
From: Bothell, WA
Hey I have a second gen 80 amp alternator right now, but its N/A. Do you know what the difference between the N/A and the TII ones are?
Reply
Old Jan 8, 2004 | 03:22 AM
  #13  
eddierotary's Avatar
back with rotaries
Tenured Member 20 Years
iTrader: (7)
 
Joined: Nov 2001
Posts: 2,239
Likes: 1
From: Watertown, NY
i dont think theres a difference betwen them. the sec gen forum may can answer that
Reply
Old Jan 8, 2004 | 09:09 AM
  #14  
Directfreak's Avatar
I am a Jeeper Now.
Tenured Member 20 Years
iTrader: (2)
 
Joined: Dec 2001
Posts: 9,371
Likes: 4
From: 3OH5
FB = 50 Amps?
SE = 55 Amps (Could be series III)
FC N/A = 70 Amps
TII = 80 Amps
Cosmo = 90 Amps
FD = 100 AMPS
Reply
Old Jan 8, 2004 | 10:39 AM
  #15  
Halfbridge12aT's Avatar
Banned. I got OWNED!!!
 
Joined: Jan 2004
Posts: 4
Likes: 0
From: Welland, Ontario, Canada
FD alternator sounds really good right now i bet i can run my two 15" rockfords off that no problem
Reply
Old Jan 8, 2004 | 04:06 PM
  #16  
wwilliam54's Avatar
it WILL run
Tenured Member 10 Years
 
Joined: Dec 2002
Posts: 2,017
Likes: 1
From: Raleigh,MS
ask rotary dankusagain about putting in a buick alt

they are like 50$ tops and put out 150 amps
Reply
Old Jan 8, 2004 | 06:24 PM
  #17  
silverrotor's Avatar
Moderator
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Mar 2002
Posts: 7,592
Likes: 5
From: Toronto, Corporate Canada
Yeah, you can't go wrong with the FD Alternator.
https://www.rx7club.com/showthread.p...hreadid=172766
Reply
Old Jan 8, 2004 | 10:51 PM
  #18  
hornbm's Avatar
Thread Starter
FD > FB > FC
Tenured Member: 20 Years
 
Joined: Oct 2002
Posts: 3,873
Likes: 3
From: Bothell, WA
S5 N/A alternators are 80 amp as well....
Reply
Old Jan 8, 2004 | 11:05 PM
  #19  
rotarydankus again's Avatar
Senior Member
Tenured Member 05 Years
 
Joined: Nov 2003
Posts: 260
Likes: 0
From: hutchison ks
dude 13.5 at idle is nothin to complain about , check you specs thats above factory idle spec, more along the lines of 1500rpm or so, besides to get rite down to it voltage is irrelevant as long as it s around 13 its amps output that matters. ive got 120 amps , it kicks out 60 amp at idle but only around 13 volts,At full load it sees 95, thats all loads +electric fan hybrid ign, after market f/p, defrost high heat you name it head lites everything. the only time i see 14 volts is rite off idle no load. and your lites wont brighten with engine speed if you relay the headlites and get the load off of the lite switch . voltage drop across the low beem curcuit is uasually around 2 volts . so the lites werent gettin the 13.5 even, after relay conversion they are within .2 volts of alt out put voltage, alot brighter,
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
ioTus
1st Generation Specific (1979-1985)
13
Mar 8, 2013 09:23 AM
F1blueRx7
2nd Generation Specific (1986-1992)
3
Oct 1, 2005 11:10 AM




All times are GMT -5. The time now is 04:34 AM.