C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

alternator upgrade?

Thread Tools
 
Search this Thread
 
Old Oct 2, 2014 | 11:55 PM
  #1  
Bigeddie's Avatar
Bigeddie
Thread Starter
Burning Brakes
10 Year Member
 
Joined: Jun 2013
Posts: 798
Likes: 26
From: salinas CA
Default alternator upgrade?

i will be installing electric motors to operate the headlights along with a sound system with a 12 inch sub and 6 speakers(,maybe just 4). that being said i was thinking of going with aluminum rad and dual electric fans and I'm guessing i will definitely have to upgrade the alternator. My other future upgrades that will happen will be installing better brighter headlights maybe some HID'S...
Reply
Old Oct 3, 2014 | 04:29 AM
  #2  
76CSRvette's Avatar
76CSRvette
Burning Brakes
 
Joined: May 2014
Posts: 1,094
Likes: 16
From: Los Angeles California
Default

You should up your amps on alternator or do the cs1... upgrade. As they will help keep the load on although down. My lights use dim down alot at night with electric water pump and fans switched to a 105amp 1 wire and added relays to headlights helped out some
Reply
Old Oct 3, 2014 | 07:08 AM
  #3  
jb78L-82's Avatar
jb78L-82
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Default

I had a high output 100 amp 12SI alternator for years but the gen light would flicker at idle with my Hella Euro Halogen headlights (100 watt highs) so I switched to the much more modern and efficient GM CS-144 (140 amp stock charging rate) a few years ago. Generally its not a great idea to up the amps in the Stock 10/12SI alternator housings since the fan will not sufficiently cool the alternator at high amp loads, will not provide high amps at idle (they require some revs for high output) and were never designed for high amp output (my stock 12Si was rated at 63 amps). I went with the CS-144 140 amp alternator since it has a much bigger housing for cooling, was designed for stock OEM 140 amps, has a much bigger cooling fan, Charges like a champ at idle (I believe, not sure now, but 60 amps at idle), and fits perfectly in the stock location. You will need an adapter wire to go from the CS-144 to the stock wiring plug (easy and cheap). I did not upgrade the wire from the alternator to the battery since my total draw is only about 80 amps but you should with your setup. I paid $170 for the CS-144 new..not rebuilt.



Last edited by jb78L-82; Oct 3, 2014 at 07:10 AM.
Reply
Old Oct 3, 2014 | 10:54 AM
  #4  
ezobens's Avatar
ezobens
Drifting
10 Year Member
 
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
Default

Originally Posted by jb78L-82
I had a high output 100 amp 12SI alternator for years but the gen light would flicker at idle with my Hella Euro Halogen headlights (100 watt highs) so I switched to the much more modern and efficient GM CS-144 (140 amp stock charging rate) a few years ago. Generally its not a great idea to up the amps in the Stock 10/12SI alternator housings since the fan will not sufficiently cool the alternator at high amp loads, will not provide high amps at idle (they require some revs for high output) and were never designed for high amp output (my stock 12Si was rated at 63 amps). I went with the CS-144 140 amp alternator since it has a much bigger housing for cooling, was designed for stock OEM 140 amps, has a much bigger cooling fan, Charges like a champ at idle (I believe, not sure now, but 60 amps at idle), and fits perfectly in the stock location. You will need an adapter wire to go from the CS-144 to the stock wiring plug (easy and cheap). I did not upgrade the wire from the alternator to the battery since my total draw is only about 80 amps but you should with your setup. I paid $170 for the CS-144 new..not rebuilt.

A super easy upgrade and a better way to go than the 1-wire stuff everyone seems to be going to these days.
Reply
Old Oct 3, 2014 | 12:51 PM
  #5  
lionelhutz's Avatar
lionelhutz
Race Director
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Default

Originally Posted by jb78L-82
I had a high output 100 amp 12SI alternator for years but the gen light would flicker at idle with my Hella Euro Halogen headlights (100 watt highs) so I switched to the much more modern and efficient GM CS-144 (140 amp stock charging rate) a few years ago. Generally its not a great idea to up the amps in the Stock 10/12SI alternator housings since the fan will not sufficiently cool the alternator at high amp loads, will not provide high amps at idle (they require some revs for high output) and were never designed for high amp output (my stock 12Si was rated at 63 amps). I went with the CS-144 140 amp alternator since it has a much bigger housing for cooling, was designed for stock OEM 140 amps, has a much bigger cooling fan, Charges like a champ at idle (I believe, not sure now, but 60 amps at idle), and fits perfectly in the stock location. You will need an adapter wire to go from the CS-144 to the stock wiring plug (easy and cheap). I did not upgrade the wire from the alternator to the battery since my total draw is only about 80 amps but you should with your setup. I paid $170 for the CS-144 new..not rebuilt.
too

At the very least use a CS-130.

I thought the CS-144 is rated for around 80-90A at idle, assuming about a 3:1 drive ratio.

Besides upgrading the charging wire also look at the wiring method so your can make proper use of the remote voltage sensing capability of the alternator.
Reply
Old Oct 3, 2014 | 05:06 PM
  #6  
jb78L-82's Avatar
jb78L-82
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Default

Originally Posted by lionelhutz
too

At the very least use a CS-130.

I thought the CS-144 is rated for around 80-90A at idle, assuming about a 3:1 drive ratio.

Besides upgrading the charging wire also look at the wiring method so your can make proper use of the remote voltage sensing capability of the alternator.
Thanks for the clarification on the CS-144 idle amps!
Reply
Old Oct 5, 2014 | 12:45 AM
  #7  
bluegtp's Avatar
bluegtp
Drifting
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2004
Posts: 1,628
Likes: 293
2020 C3 of the Year Finalist - Modified
Default

I've seen my new cs144 (with fbody serpentine setup) has put out 107amps at idle with a weak battery.

Reply
Old Oct 5, 2014 | 08:54 AM
  #8  
gearbreaker's Avatar
gearbreaker
Advanced
 
Joined: Nov 2013
Posts: 94
Likes: 1
From: leesburg va
Default

I put a mean-green on my wrangler 10 years ago to handle the winch, air pump, extra lights and such. still working great.

http://www.mean-green.com/
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Oct 5, 2014 | 09:48 PM
  #9  
68post's Avatar
68post
Burning Brakes
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2012
Posts: 788
Likes: 100
From: Indianapolis IN
Default

http://www.qualitypowerauto.com/catalog.php?item=12

Here's a site with options and prices, ( I have no experience with this company ).
Reply
Old Oct 6, 2014 | 12:25 AM
  #10  
REELAV8R's Avatar
REELAV8R
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Default

http://www.ebay.com/itm/GM-CHROME-120-AMP-1-ONE-OR-3-THREE-WIRE-SBC-BBC-CHEVY-ALTERNATOR-ES-1001-C-/350970868932?pt=Motors_Car_Truck_Parts_Accessories&hash=item51b77e74c4&vxp=mtrNot sure why a guy needs to pay more. I have one of these, three wire works good warranted for life.:
Reply
Old Oct 6, 2014 | 04:28 PM
  #11  
lionelhutz's Avatar
lionelhutz
Race Director
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
Default

Originally Posted by REELAV8R
Not sure why a guy needs to pay more. I have one of these, three wire works good warranted for life.:
What is the current draws in your application?
What is the rated idle current of that alternator?


My CS-144 will still maintain 14.4V at dash volt-meter at idle with 330W of high-beams, electric fan, electric fuel pump, EFI etc all powered. About 50A worth of load total.
Reply
Old Oct 6, 2014 | 04:33 PM
  #12  
jb78L-82's Avatar
jb78L-82
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Default

Originally Posted by lionelhutz
What is the current draws in your application?
What is the rated idle current of that alternator?


My CS-144 will still maintain 14.4V at dash volt-meter at idle with 330W of high-beams, electric fan, electric fuel pump, EFI etc all powered. About 50A worth of load total.
Exactly! The reason I went with a CS-144 140 amp alternator on my 78 was the Hella Euro Halogens that draw 320 watts when on-that's just for lights, nothing else (100 watt high beams and 60 watt lows on the high beam setting). A 12/10 Si alternator cannot provide enough amperage at IDLE.
Reply
Old Oct 6, 2014 | 04:45 PM
  #13  
REELAV8R's Avatar
REELAV8R
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Default

Originally Posted by lionelhutz
What is the current draws in your application?
What is the rated idle current of that alternator?


My CS-144 will still maintain 14.4V at dash volt-meter at idle with 330W of high-beams, electric fan, electric fuel pump, EFI etc all powered. About 50A worth of load total.
48 amps @ 600 rpm. Mine is actually 105 amp rated not 110 amp. Works good with 30 amps worth of fans, lights an ac running.
Reply
Old Oct 6, 2014 | 06:59 PM
  #14  
jb78L-82's Avatar
jb78L-82
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Default

Originally Posted by REELAV8R
48 amps @ 600 rpm. Mine is actually 105 amp rated not 110 amp. Works good with 30 amps worth of fans, lights an ac running.
What voltage does it show with a 48 amp draw at idle? My 12Si 120 amp alternator would not provide 13/14 volts at idle with big loads…no problem above 1,000 RPM. Running 10/12SI high amp alternators are notorious for burning out at high amp loads for long periods of time since the casing and fans are inadequate to cool the unit with those loads. There is a reason GM went with different alternator designs when they upped the amperage ratings.
Reply
Old Oct 6, 2014 | 10:15 PM
  #15  
mikep3's Avatar
mikep3
Burning Brakes
15 Year Member
 
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Default

I had a 100 amp 10si, my 15 amp e-fan and ac would kill it at idle. With head lights on the gen light would be on. I installed a CS130 and it never has dropped below 14 volts, fan ac and headlight. The CS130 looks the same size as the 10si.
CS130 alternator gets my vote.
Reply
Old Oct 7, 2014 | 10:01 AM
  #16  
REELAV8R's Avatar
REELAV8R
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Default

Originally Posted by jb78L-82
What voltage does it show with a 48 amp draw at idle? My 12Si 120 amp alternator would not provide 13/14 volts at idle with big loads…no problem above 1,000 RPM. Running 10/12SI high amp alternators are notorious for burning out at high amp loads for long periods of time since the casing and fans are inadequate to cool the unit with those loads. There is a reason GM went with different alternator designs when they upped the amperage ratings.
Found my paperwork for the alternator. I guess it's actually a 110 amp unit. According to the documentation it supplies 65 amps @ 600 RPM. So a little better than I remember.
At idle I show 13.5 volts or so on the gauge (hard to tell with the installed gauge but you can see the voltage drop with the load of the fans) with fans running and maybe slightly less with lights and A/C on.
Never have seen the ALT/BAT light come on at idle. Been running it for 3 years with no issues yet.
All it needs to do is provide more than battery voltage to keep battery charged.
Reply
Old Oct 7, 2014 | 11:20 AM
  #17  
jb78L-82's Avatar
jb78L-82
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2007
Posts: 7,445
Likes: 971
From: Tennessee/Rhode Island
Default

Originally Posted by REELAV8R
Found my paperwork for the alternator. I guess it's actually a 110 amp unit. According to the documentation it supplies 65 amps @ 600 RPM. So a little better than I remember.
At idle I show 13.5 volts or so on the gauge (hard to tell with the installed gauge but you can see the voltage drop with the load of the fans) with fans running and maybe slightly less with lights and A/C on.
Never have seen the ALT/BAT light come on at idle. Been running it for 3 years with no issues yet.
All it needs to do is provide more than battery voltage to keep battery charged.

Very good. That's nice that it provides that amperage at idle and it is working fine for you. Sure as heck can't beat the price! Unfortunately my 120 amp alternator would not and my gen light would flash at idle with the lights on, otherwise I probably would have left it alone until it stopped working. I went with the CS-144-140 amp alternator since it was reasonably priced for a new unit, charged like a champ at idle, was designed for high amperage as a stock unit with stock amperage rating, and I liked the bigger more efficient housing and fan for cooling the unit. At full amperage load with everything running in the car, the unit is not even at half its amperage rating-should last a long time, hopefully.

Last edited by jb78L-82; Oct 7, 2014 at 11:22 AM.
Reply

Get notified of new replies

To alternator upgrade?

Old Oct 7, 2014 | 01:06 PM
  #18  
flyinrazrback's Avatar
flyinrazrback
Racer
10 Year Member
 
Joined: Apr 2004
Posts: 293
Likes: 1
From: AR
Default

Originally Posted by REELAV8R
GM Chrome 120 Amp 1 One or 3 Three Wire SBC BBC Chevy Alternator ES 1001 C | eBay
Not sure why a guy needs to pay more. I have one of these, three wire works good warranted for life.:
I just ordered one to give it a shot.
Reply
Old Oct 7, 2014 | 08:20 PM
  #19  
REELAV8R's Avatar
REELAV8R
Le Mans Master
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
Default

Originally Posted by flyinrazrback
I just ordered one to give it a shot.
3 wire version? I hope.
Reply
Old Oct 7, 2014 | 08:34 PM
  #20  
flyinrazrback's Avatar
flyinrazrback
Racer
10 Year Member
 
Joined: Apr 2004
Posts: 293
Likes: 1
From: AR
Default

Originally Posted by REELAV8R
3 wire version? I hope.
Yes
Reply



All times are GMT -4. The time now is 01:13 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE