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How to Choose a Racing Alternator
1833 Downs Drive
West Chicago, IL 60185
(630) 957-4019
TECH DEPT (630) 849-7754
www.powermasterperformance.com
Choosing the correct charging system set up is just as important as having the correct engine set up.
Today, most race cars have more electrical demand than ever before. Many applications require a high
amp alternator to meet the demands. The charge wire has to be larger to handle higher amps. And the
pulley ratio has to be correct to keep the alternator charging at various speeds without over spinning the
alternator. Follow the steps on this sheet as a guide to determine the correct set up for your race car.
1. Make a list of the electrical systems components...ignition, fans, lights, cooling fans, etc.
Some components may list amp draw. (refer to manufacturer if necessary) Total the maximum
amperage requirements.
2. Select the gauge charge wire needed based on the alternator total output.
Accessory
Headlights/tail lights
Halogen bulbs
Dash Lights
Electric Fans
On Board Radio
CDI Ignition
HEI Ignition
Electric Water Pump
Electric Fuel Pump
Gauges
Example Actual
Amps Amps
10
10ea
2-4
10-50
4-10
6-36
6-10
12-25
7-15
2-6
Example Actual
Accessory
Amps Amps
Brake Blowers
8-10
Driver Cooling System
10-15
Data Recorder
2-10
Line Lock
4-8
Delay Box
8-12
Trans Brake
12-20
Throttle Stop
5-15
Nitrous Solenoid(each)
5-15
Other Accessories
Total Amp Draw
Charge Wires
Use the chart below to determine charge wire gauge.
Using too small of a gauge
will result in voltage drop.
Wire Length 5'-10' 11'-19' 20'-28'
Amps
30-70
10-8 8-6
6-4
70-100
8-6
6-4
4-2
100-150
6-4
4-2
2-0
150-200
4-2
2-0 0-1/0
Wire Size
3. Determine constant electrical load______(amps) Managed electrical load_________(amps)
4. Determine your engine idle rpm_________ Max racing rpm___________
5. Select Pulleys
! WARNING !
Max Alt RPM
18,000
Pulley Ratios and Selecting Correct Pulley Diameter
A
B
Alternator
Pulleys
p/n
181, 2.8” O.D.
182, 4.0” O.D.
183, 5.25”O.D.
Once you determine the engine versus alternator speed, insure the alternator you’ve selected will perform at
low engine rpm’s. Change pulley size if needed to maintain alternator minimum speed to give best output at
low engine rpm’s
How to Choose a Racing Alternator, Cont
Page 2
TECH DEPT (630) 849-7754
6. Now that you know your amperage requirements, it’s time to choose which alternator and
mounting bracket you’ll need. It’s vital to your overall performance that you have an alternator
big enough to maintain adequate voltage, (no lower than 13 volts on a 12V system).
Drag Race or Circle Track Alternators
Amps
50/30
50/30
50/30
50/30
60/35
80/70
95/50
95/50
95/50
100/80
100/70
Volts
12
12
16
12/16
12
12
12
16
12/16
12
16
Alt P/N
8172 jumper wire
8162 Denso
8166 Denso
8168 Denso
8102 jumper wire
8003 Delco
8132 Denso
8136 Denso
8138 Denso
8002 Delco
8006 Delco
Amps
Volts
100/60
100/60
12
16
8062 Delco
8066 Delco
100/60
100/60
100/60
100/60
105/80
105/80
105/80
105/80
120/80
12/16
12
16
12/16
12
16
12/16
12
12
8068 Delco
8072 Delco
8076 Delco
8078 Delco
8012 Delco
8016 Delco
8018 Delco
8022 Delco
8142 Denso
120/80
120/80
160/70
160/70
Alt P/N
16
12/16
12
12/16
8146 Denso
8148 Denso
8152 Denso
8158 Denso
Circle Track ONLY
Requires HI RPM’s
Amps
75/7
75/7
95/30
95/30
Volt
12
12/16
12
12/16
Alt P/N
8182 Denso
8188 Denso
8122 Denso
8128 Denso
See Catalog or Visit Web Site for Mounting Brackets and Complete Kits
CHEVY LOW MOUNT
50 AMP KIT
8-895 BBC
8-896 SBC
CHEVY SNUG MOUNT
50 AMP KIT
8-875 BBC
8-880 SBC
100 AMP KIT
8-897 BBC
8-898 SBC
100 AMP KIT
8-882 BBC
8-881 SBC
XS Volt Adj Reg
12-16 Volt System
Add #8 to end of p/n
CHEVY CIRCLE TRACK
Quick Change
50 AMP KIT
8-400
Ford 9” 3rd Member
50 AMP KIT
8-410
50 AMP KIT
8-801 SBC
100 AMP KIT
8-722 SBC
We want to Help You Select the Correct Set Up for Your Application
Please Call
Help Line (630) 849-7754
Powermaster Performance, 1833 Downs Drive, West Chicago, IL 60185 (630) 957-4019