CHARGING SYSTEM UPGRADE WITH A TUFF STUFF ALTERNATOR
Charging system upgrade with a Tuff Stuff Alternator
From the early 1960s through 1974, Chrysler provided the buying public with a hardy, reliable, low-amp charging system that required minimal upkeep. The pre-1970 Mopars were equipped with a low-maintenance adjustable analog voltage regulator, but with the progression from a breaker-point to a breaker-less ignition, Chrysler introduced a transistorized voltage regulator, which provided better voltage spike protection than an analog regulator for the newly introduced electronic ignition module. A problem with the early Chrysler charging systems occurred when an electric fuel pump, an electric fan, an aftermarket ignition, or a slew of other electrical components started being added to the vehicle. The factory 35-amp, 46-amp, or even 60-amp alternator may not have the capacity to maintain the vehicle’s charging system effectively under all electrical load conditions. In an attempt to remedy the concern, one could swap a 1975-or-later 100-amp Chrysler alternator into the low-amp alternator’s brackets on the engine, but then the factory ammeter, bulkhead, and charging system wiring could fail with the increased amperage. In an attempt to reduce the amperage through the bulkhead, a mid-1975 (or newer) shunted ammeter could accompany the 100-amp alternator, reducing the amperage through the bulkhead. While these mods could work, was there something better? We contacted Tuff Stuff Performance Accessories of Cleveland, Ohio, and arranged to test one of their Usa-built, 130-amp, 1-wire alternators in their new Cast Plus+ finish on our test vehicle, a ’69 Dodge Dart.
Our Dart is equipped with a warmedover 340 that stirs a reverse-manual rowed Torqueflite 904 that feeds a 4.10-geared 8¾-inch rear end. At this point in its life, the Dart is almost exclusively utilized as a pump-gas, low 11-second, multi-time track champion drag car. Although, with the reconnection of the brake light switch, reinstallation of a belt and belt-driven water pump pulley, and bolting on some Dotapproved tires, the Dart could be legally driven on the street. The author has owned the Dart since the summer of 1989, and over the years, various electrical components have been added. With each addition, not only has the author’s supplementary years of experience provided a better and cleaner technique of installation, but the additional electrical demands on the charging system have also increased. Some electrical installations occurred almost 30 years ago, and while they were competent installations, the upgrade of the new Tuff Stuff alternator will provide us with an opportunity to do some modernizing of our charging system and aged electrical wiring.
As the Dart became more bracket racing oriented, a Holley electric fuel pump was added, and then a pair of Moroso fans (a pusher and a puller) was added in conjunction with a Moroso electric water pump drive. These four components increased the constant electrical demand by 32 amps (fuel pump 8 amps, water pump 9 amps, and the electric fans 15 amps) with even more amperage demand upon initial startup of each component. The factory rated 35-amp alternator couldn’t meet the charging system’s electrical demand with these additional loads. With the Dart being dedicated to drag racing, the increased electrical demand shouldn’t have been a big deal — just hook up a battery charger between rounds to maintain the battery’s charge. However, in the late rounds, many tracks in an effort to beat curfew will run the cars in a round robin affair, so charging the battery is no longer an option. It’s not uncommon for the Dart to make a series of two, three, or even four runs in a row without an opportunity to charge the battery, and due to the lack of proper charging, the ignition performance could drop off resulting in less consistent elapsed times. This situation is exacerbated when you’re going rounds and running two classes.
In the 1990s, the solution for the charging problem was to significantly enhance the factory wiring and to install a 120-amp Nippendenso alternator from a 1991 Cummins Turbo diesel in place of the factory alternator. The factory brackets were used but the belt tension adjuster bracket was flattened and flipped to allow the alternator to fit. One field wire was supplied voltage from the voltage regulator and the other field was grounded to the case. An additional charge wire was run from the alternator to the B+ terminal on the starter relay and then to the B+ terminal of the battery located in the trunk. Additionally, the ammeter terminals on the back of the instrument cluster were linked together with a jumper wire, even though a majority of the current now bypassed the ammeter due to the direct wiring of the alternator to the battery. With all of the factory and aftermarket electrical loads measured, the Dart had a 71-amp load on the charging system that the Nippendenso alternator
handled admirably for over 20 years, but now with newer Tuff Stuff technology and a more simplistic one-wire design, we began the updating of our charging system.
The Tuff Stuff alternator installation would’ve been a straightforward affair if our current alternator had been a factory alternator, and the cylinder heads were factory cast units. We would’ve slipped out the old alternator and replaced it with the Tuff Stuff alternator, but since we had the Nippendenso alternator, we had to reinstall the factory brackets before we could install the Tuff Stuff alternator. We elected to purchase all-new brackets to ease the installation process. Tuff Stuff provided instruction to run a charge wire from the B+ terminal of the alternator to the B+ terminal at the battery, or for a hidden look, run the wire to the B+ starter terminal. We elected to run a 1-gauge (American Wire Gauge) wire from the alternator to the B+ terminal of the starter taking care to route the wire clear of any moving components and the headers. The B+ terminal of the starter was the point to which the current flowed to the battery and to the newly installed electrical power junction point of the Dart. We installed a 150-amp ANL fuse between the alternator and the B+ starter terminal to isolate the alternator from the rest of the charging system in case of an alternator short.
Years ago, when the battery was moved to the trunk, we added 0-gauge wire that ran from the B+ starter terminal to the master cutoff switch located in the trunk. From the master cutoff switch, a short 0-gauge wire ran to the B+ terminal of the battery. Also, from the B+ starter terminal, we ran a pair of 10-gauge wires to our newly installed junction point. The junction point powered up previously installed components (auxiliary fuse box, B+ starter relay, and backup starter relay) as well as a newly added ammeter bypass wire.
We finally addressed the Achilles’ heel of a classic Mopar’s charging system: the ammeter. With a jumper wire, we had connected the terminals of the ammeter together, but as we found during our preparation to test the Tuff Stuff alternator, damage to the bulkhead connector had already occurred. At some point in the last 49 years, the connector terminals became corroded causing an overheating condition, which melted our bulkhead connector at pins J and P. To fix this ammeter problem permanently, we removed the male terminals J and P from the bulkhead connector. We ran a 14-gauge fusible link 10-gauge wire from the junction point in the engine bay to the instrument cluster. We removed the two wires from the ammeter terminals and bolted the fused 10-gauge wire and the two ammeter wires together. Tying these three wires together provided current flow to the various factory components that utilized the ammeter wires under the dash. This modification greatly increased the quality of the charging system, the ammeter is completely disconnected from the charging system, and the terminals at the bulkhead will no longer cause a problem. In the future, we could add a voltmeter in place of the ammeter, and all that would be required is tapping into one of the original ammeter wires for the B+ and provide a ground for the voltmeter to be operational.
With all of our prep work completed, we installed the Tuff Stuff 1-wire alternator into the factory brackets. With some spacing adjustments due to the aftermarket heads, the alternator fit perfectly. We attached the 12-volt charging wire from the 150-amp ANL fuse to the B+ terminal on the back of the alternator. With everything secured, we turned the ignition key, and the engine roared to life. The charging system voltage was measured at idle at the B+ terminal on the alternator, and it was instantaneously above 14.5 volts (maximum reading of 14.65 volts). There was no need to blip the throttle to get the alternator to charge. At
2,000 rpm, the voltage remained above 14.5 volts (maximum of 14.67 volts). We checked the voltage drop between the alternator and the B+ starter terminal, the voltage drop between the B+ starter terminal and the battery, and the voltage drop between the B+ starter terminal and our newly installed junction point, and we found less than .1-volt drop throughout the charging system.
The Tuff Stuff alternator installed with ease, fit properly, and provided a steady voltage and ample current to meet our drag racing late-round requirements. If the vehicle has a master cutoff switch like our Dart does, there needs to be a way to drop the field when the master cutoff switch is pushed to the “off” position. We cover this in the accompanying photos. Follow the steps to finish the installation, and if there isn’t a master cutoff switch on your vehicle, just install the Tuff Stuff alternator, run a B+ wire to the battery, and enjoy the trouble-free charging system on your Mopar.
Tuff Stuff alternators are available in a wide range of finishes including chrome plated, polished aluminum, black chrome, stealth black, as cast, or the new Cast Plus+. The alternators are available in 1-wire or OEM plug-in style in 60-amp, 100-amp, or 130-amp outputs. All Tuff Stuff alternators are built in the USA and have a one-year limited warranty. We selected a 1-wire, 130-amp alternator in the Cast Plus+ finish for our ’69 Dart.
Tuff Stuff doesn’t want the alternator rpm to exceed 18,000 rpm. At the dragstrip, the Dart’s 340 runs through the traps between 6,600 and 6,800 rpm. An underdrive crankshaft pulley was added in the 1990s to minimize the alternator rpm at high engine rpm. The ratio between the Tuff Stuff alternator pulley and the crankshaft pulley is 1.7:1, so we’re well below their rpm limits. For information about the pulley ratios and other data, click on their Instructions and Dimensions tab on their website.
The B+ starter relay terminal had become a source for battery voltage for the many components that had been added to the Dart. While this has worked for almost 30 years, with the upgrade to the Tuff Stuff alternator, we planned to reengineer our existing wiring to a more manageable design.
In the 1990s, due to the high electrical demands on our Dart’s charging system, we installed a 120-amp Nippendenso alternator. To install this alternator, we had to modify the mounting brackets, but we were able to retain the factory field winding control with a factory replacement voltage regulator. We ran a charge wire from the alternator straight to the trunk-mounted battery.