Alternator selection
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 17
Likes: 0
Alternator selection
Hey Folks! I just acquired a 86 vette and need some help choosing a alternator. At idle the cluster is dimming out pretty bad. probably doesn't help that the car also is running a MSD ignition. (Full specs below if that helps). As far as the amperage, I see alternators ranging from 100-200+ Amps. I know how to test for draw, but that doesn't tell me how hefty of an alternator I would need to stop the dimming. Can someone point me in the right direction? Thanks!
1986 Vette , 6spd Richmond, Airflow Research Aluminum angle plug Heads, Roller Hydraulic cam and lifters, aluminum intake, 670 Holley Avenger, Headers, MSD Ignition, and a few other upgrades.
1986 Vette , 6spd Richmond, Airflow Research Aluminum angle plug Heads, Roller Hydraulic cam and lifters, aluminum intake, 670 Holley Avenger, Headers, MSD Ignition, and a few other upgrades.
Thread Starter
Heel & Toe
Joined: Aug 2015
Posts: 17
Likes: 0
Found this (below). Doing a bit of math looks like at any given moment most common items, msd, lights, ac, electric fan, etc, (if all ran at the same time looks like im drawing about 165 amps plus a 20% cushion that's 198 amps. a 200 amp alternator sound about right?
Amp Draw of Some Common Accessories
Accessory: Amp Draw:
Air Conditioner 20-21
Audio Power Amplifiers 10-70
Back-up Lamps 3-4
Cigarette Lighter 10-12
CD/Tuner with amp 7-14
CD/Player/Tuner without amp 2.5-5
Clock 0.3
Dome Light 1-2
Electric Cooling Fans 6-15
Head Lamp Dimmer 2
Head Lamp (Low Beam) 8-10
Head Lamp (High Beam) 13-15
Heater Defroster 6-15
Horn 10-20
Ignition 1.5-4
Ignition (Racing) 8-36
Instrument Panel 0.7-1.5
Lamp, Gauges 1.5-3.5
Lamps, License Plate 1.5-2
Lamps, Parking 1.5-2
Lamps, Side Marker 1.3-3
Lamps, Tail 5-7
Nitrous Oxide Solenoid 5-8
Power Windows Defroster 1-30
Power Seats 25-50
Power Windows 20-30
Power Antenna 6-10
Pumps, Electric Fuel 3-8
Starter Solenoid 10-12
Voltage Regulators (1 Wire) 0.3-0.5
Amp Draw of Some Common Accessories
Accessory: Amp Draw:
Air Conditioner 20-21
Audio Power Amplifiers 10-70
Back-up Lamps 3-4
Cigarette Lighter 10-12
CD/Tuner with amp 7-14
CD/Player/Tuner without amp 2.5-5
Clock 0.3
Dome Light 1-2
Electric Cooling Fans 6-15
Head Lamp Dimmer 2
Head Lamp (Low Beam) 8-10
Head Lamp (High Beam) 13-15
Heater Defroster 6-15
Horn 10-20
Ignition 1.5-4
Ignition (Racing) 8-36
Instrument Panel 0.7-1.5
Lamp, Gauges 1.5-3.5
Lamps, License Plate 1.5-2
Lamps, Parking 1.5-2
Lamps, Side Marker 1.3-3
Lamps, Tail 5-7
Nitrous Oxide Solenoid 5-8
Power Windows Defroster 1-30
Power Seats 25-50
Power Windows 20-30
Power Antenna 6-10
Pumps, Electric Fuel 3-8
Starter Solenoid 10-12
Voltage Regulators (1 Wire) 0.3-0.5
Team Owner
Joined: Sep 2003
Posts: 25,331
Likes: 2,722
At some point it might be safe to assume what is there was handling the chore I'd think. What is there presently?
If you know that the battery is good, the cables are good and the required connections are clean and solid I'd have a load test done on the system with every component still in the car by someone with a good "carbon-pile" tester. That test will evaluate the entire charging and cranking system very effectively.
Regardless of what you buy you can't be assured the system is capable. You mention "1-wire" in your accessory list. Does it currently have a 1-wire alternator?
I'd rush to buy NOTHING but first evaluate what is there.
Do you know if it's been updated to maybe a CS-144? The original would have been a CS-130 @ 105AMP.
FIRST ID WHAT IS THERE AND IS IT MAYBE WIRED APPROPRIATELY FOR THE ACCESORIES !!!!! What gauge is the charge wire?
If you know that the battery is good, the cables are good and the required connections are clean and solid I'd have a load test done on the system with every component still in the car by someone with a good "carbon-pile" tester. That test will evaluate the entire charging and cranking system very effectively.
Regardless of what you buy you can't be assured the system is capable. You mention "1-wire" in your accessory list. Does it currently have a 1-wire alternator?
I'd rush to buy NOTHING but first evaluate what is there.
Do you know if it's been updated to maybe a CS-144? The original would have been a CS-130 @ 105AMP.
FIRST ID WHAT IS THERE AND IS IT MAYBE WIRED APPROPRIATELY FOR THE ACCESORIES !!!!! What gauge is the charge wire?
Last edited by WVZR-1; Aug 23, 2015 at 05:00 PM.
Burning Brakes
Joined: Jun 2005
Posts: 1,188
Likes: 13
From: Wallingford Vermont
First, your dash dimming sound more like a (common) dash grounding issue. Your stock CS130 (105 amp) alternator should keep up with the stock demands.
That being said the CS130 alternators are kinda overtaxed from the longevity standpoint. If you're looking to upgrade most swap up to the CS144 (120+ amp) used in the '92 - '96 Corvette (and many others). The CS130 didn't handle high RPMs too well either, that might become an issue for you. It's kinda hit or miss on some of the "high performance" alternators; QC and low RPM performance being their issues.
Search CS144 and you find lots of info on the swap; it's quite easy. Should also look around for dash dimming threads too.
That being said the CS130 alternators are kinda overtaxed from the longevity standpoint. If you're looking to upgrade most swap up to the CS144 (120+ amp) used in the '92 - '96 Corvette (and many others). The CS130 didn't handle high RPMs too well either, that might become an issue for you. It's kinda hit or miss on some of the "high performance" alternators; QC and low RPM performance being their issues.
Search CS144 and you find lots of info on the swap; it's quite easy. Should also look around for dash dimming threads too.
