A key component of any alternator, and especially the high performance/ racing alternator, is the voltage regulator. For seven years Powermaster has been offering the racing community a custom designed one wire voltage regulator with specific features, including a high voltage output of 14.9V. This circuit has crossed the finish line first thousands of times since. This regulator will continue to be available on our 12V alternators.
This year a newly designed voltage system will be available with Powermaster racing alternators. This new racing alternator is called the XS VOLT The XS VOLT alternator still operates as a one-wire, meaning that the only connection necessary is the charge wire (or battery output). It has all the circuitry necessary to automatically sense when the alternator is spinning, and therefore energize itself. But other terminals and connections are included for additional features. These secondary features include adjustable voltage and a power saving mode that could generate some major benefits.
First of all, the voltage adjustment allows the racer to change the set point of the voltage system while the unit is running. The set point is the level that the unit sees as the goal, the perfect level of the electrical system. On the XS VOLT, turning a small potentiometer on the back of the alternator can move this set point. The range is 13.5V - 18.5V, allowing one alternator to be used with 12V and 16V batteries -and anything in between. Charging sensitive gel batteries at low voltages or using the hybrid 14V batteries are not a problem for the XS VOLT. This means that one XS VOLT alternator will work with your car no matter what battery you choose.
The power saving mode of this alternator is a new idea to racing. This alternator actually has two operating levels. Keep in mind that the horsepower draw of an alternator is directly proportional to the amperage being drawn from it. Therefore, changing from the high level to the low level at the right time can conserve valuable horsepower.
By grounding one terminal on the XS VOLT alternator, the set point is temporarily dropped 1.25V from the set point. With it set at 14.9V and this pin grounded, the set point becomes 13.65V. This immediately reduces the horsepower drag of the alternator to a minimum level, saving as much as two horsepower (depending on the amp load of the vehicle, the size of the battery, and the size of the alternator).
This mode is easy to use, as the signal to the regulator is simply a connection to ground. This can be accomplished through a throttle position switch, a dash mounted switch, or some other means of signaling the alternator that all available horsepower needs to be at the wheels right now. At times when extra horsepower is available (such as braking or other deceleration moves), the alternator can safely take horsepower and charge the battery at a fast rate.
The XS VOLT features an indicator light drive. This is a terminal that will illuminate a bulb when the alternator is spinning, and yet the alternator is not charging. This can be used as a simple charging system monitor as it is used in a passenger car.
The power output curve of racing alternators is typically changed to maximize the unit's efficiency. This involves changing the winding and the rotor coil. A huge MOSFET transistor and heat sink insure that the XS VOLT can handle this increased load with capacity to spare. Of course, all forms of racing stress components to the edge of failure. Parts are subjected to a variety of harsh environments, and the XS VOLT is engineered for this. The XS VOLT is short circuit protected. It also features loss of ground protection. The entire circuit is sealed in epoxy, keeping the water and grit out while isolating vibration.
Some components can make use of a tachometer/ frequency output, which is provided on the XS Volt. In some street applications, this terminal drives an electric choke. In other applications, this terminal drives a tachometer. Given the number of poles in the alternator, the alternator's exact RPM could be monitored in some applications using this output.
The majority of the high performance Powermaster racing alternators, and also select high amperage alternators are available as XS VOLT systems.
Increasing the amperage output of an alternator from stock requires a lot of changes. Every major component requires attention, and a very important one is the voltage regulator. This is the focus of the XS VOLT high amp systems for this year. The XS VOLT alternator operates as a one-wire alternator, meaning the only connection necessary is the charge wire (or battery output). It has all the circuitry necessary to automatically sense when the alternator is spinning, and therefore energize itself. But other terminals and connections are included for additional features. These secondary features include adjustable voltage, a dual voltage level mode, an indicator light drive, and a stator signal output, all making the XS VOLT very versatile. The XS VOLT alternator will be compatible with most OE computer systems (where applicable).
First of all, the voltage adjustment allows the user to change the set point of the voltage system while the unit is running. The set point is the level that the unit sees as the goal, the perfect level of the electrical system. On the XS VOLT, turning a small potentiometer on the back of the alternator can move this set point. The range is 13.5V - 18.5V, allowing one alternator to be used with 12V and 16V batteries -and anything in between. Charging sensitive gel batteries at low voltages or using the hybrid 14V batteries are not a problem for the XS VOLT. This means that one XS VOLT alternator will work with your car no matter what battery you choose.
The dual voltage level mode of this alternator is a new idea to the performance marketplace. This alternator actually has two operating levels. This can be used to conserve horsepower, or to create a voltage boost mode for competition car audio. By flipping a switch, the voltage could go from a drive-able level to the competition level. This mode is easy to use, as the signal to the regulator is simply a connection to the ground. This can be accomplished through a dash mounted switch, or some other means.
The XS VOLT also has an indicator light drive. This is a terminal that will illuminate a bulb when the alternator is spinning, but not charging. This can be used as a simple charging system monitor.
High amp alternators are made by changing the power output curve and fine tuning the pulley ratio. This involves changing the windings and the rotor coil. All of the changes in a high amp alternator increase the heat and load. A huge MOSFET transistor and heat sink insure that the XS VOLT can handle this increased load with capacity to spare. Made to take abuse, the XS VOLT is short circuit protected and has loss of ground protection. The entire circuit is sealed in epoxy, keeping water and grit out while isolating vibration.
Some components can make use of a stator output, and this is provided on the XS VOLT. In some street applications this terminal drives an electric choke. In other applications, this terminal drives a tachometer.
The majority of the high performance Powermaster racing alternators, and also select high amperage alternators are available as XS VOLT systems.
There are several choices when it comes to buying a performance starter. Powermaster has a wide range of choices to fit just about any application. Narrowing the choices down to exactly the right unit can be accomplished in three steps:
Torque Requirements:
The torque output of a starter is the most important consideration. The starter must be able to spin the engine, and do it without overheating internally. Since there is no such thing as having too much torque -even on a street vehicle - a 200 ft.lb. starter will work for everyone. Speaking in general terms, a over 12:1 compression or higher engine should use a 200 ft.lb. starter. Engines up to 12:1 should use at least a 180 ft.lb. starter. 160 ft.lb. starters are good for engines up to 10.5:1.
One thing to keep in mind is that the torque characteristics of a starter are a function of its design. High voltage batteries or low internal resistance batteries will affect the kilowatt output of the starter by changing the output speed but not the torque. Therefore, buy enough torque to begin with.
Fit:
Of course for a starter to work, it must fit the application. Consider headers, oil pans, and the mounting points on the engine. What size ring gear do you have (for Chevy applications)? Does your Chevy block accommodate a straight mount starter, or is the only pattern drilled in the engine block for a diagonal or offset pattern starter? In racing, did the oil pan manufacturer lock you into a particular shape of starter? In your Ford application, is your ring gear 3/8” from the engine plate - indicating a typical manual transmission starter - or is it closer to a 3/4” -requiring a typical auto transmission unit? How tight are the headers around the starter? These are just some of the questions that will help you determine the right starter for your application.
Weight:
Lastly, depending on the form of racing, the overall weight of the starter is a consideration.
Torque is the ability to overcome rotational resistance. High compression, large displacements, tight rings, blowers, and other factors all offer rotational resistance - and it takes torque to overcome this. Unfortunately, starters are rated in kilowatts. This is a measure of its torque and speed combined. The torque output is really unknown.
Starters, like engines, have different powerbands. Some have a maximum power point at a relatively high RPM with little torque. Whereas others produce more torque and yet lower RPM. In the performance environment, torque is the most important consideration, generally because a performance engine offers more rotational resistance than stock. As a result, kilowatt ratings can be confusing because two starters with the same kilowatt rating can have very different torque characteristics.
The engine will demand a certain amount of torque for cranking. When the torque demands cause a starter to exceed its maximum power point, the extra input energy is wasted as internal heat. Asking a starter to produce more torque than it is comfortable with results in low electrical to mechanical efficiency and drastically increased internal heat. This is what causes premature starter failure. The key is to use a starter that has a power peak at a high torque point. Then, in the event that the cranking conditions offers high resistance, the starter will have the torque characteristics to handle it without overheating.
Several other factors effect starter performance dramatically. Voltage is very important. Cabling and quality disconnect switches are important because under heavy load, voltage will be lost or "dropped" in undersized or hot cables, or hot switches. The internal resistance of the battery itself results in decreased voltage to the starter. Therefore, low internal resistance batteries like typical 1000CCA - or better yet - spiral cell AGM batteries such as Optima and others should be used. High voltage batteries like the new 16 Volt Powermaster battery is a perfect choice for any racing application.
When you purchase a Powermaster starter you will get a dyno sheet that shows you the exact performance of your starter. The sheet itself will explain how to interpret the data, but you can be assured that Powermaster starters are built to a consistent, statistically controlled standards, and that they are dynamically tested throughout their entire power range.
For most people, the only alternator rating they are familiar with is the amperage rating. Alternators are spoken of as a 65 amp or 100 amp alternator. When replacing the alternator on the family car, this is probably the only information that is necessary. After all, all one needs is an alternator that matches the original.
When building a custom car from the ground up however, a deeper understanding of the power curve of an alternator is required. Usually a custom pulley or so-called "power pulley" set is used with a performance alternator. A mismatched pulley ratio and alternator will spell trouble, especially at idle speeds where alternator performance is critical. To avoid this, it is important to understand the alternator's capability at slow speeds.
An alternator's output is dependent on speed, but this can be deceiving because this output is not linear. Instead, it follows a curve. Each alternator has a unique curve, and at idle small changes in the alternator's speed can make a big difference in its output capacity.
Because of the preceding, pulley ratios are very important, especially when using high amperage alternators. The pulley that are supplied with the alternator are matched to the winding and power curve. It is important that any dress up pulley sets do not deviate from this ratio. Typically, a street driven car should have a pulley ratio of at least 3:1. If the vehicle has an automatic transmission with a low idle and the vehicle spends a lot of time cruising, then a higher pulley ratio - perhaps 3.5:1 - should be used. Alternators can take high speeds up to 20,000 RPMs for short periods, so overdriving the unit is not a problem.
The output of high amp alternators can drop off substantially under 2400 rotor RPMs. Therefore, Powermaster does not recommend power pulleys with high amp alternators.
Powermaster uses a state-of-the-art computer alternator dyno to measure the performance of each alternator we manufacture. Output curves, engine idle speeds, and alternator pulley ratios are carefully considered to assure good drivability at idle and slow cruising speeds.
The alternator rotor RPM is not necessarily the same as engine RPM. To calculate the actual alternator RPM, determine the ratio between the two pulley diameters.
Ratio = Crankshaft Pulley Diameter/ Alternator Pulley Diameter
Now that we know the ratio, we can now determine the rotor speed:
Rotor RPM = Pulley Ratio x Engine Speed
(example; 2.1 x 870 = 1827 Rotor RPM)
Generally, the alternator should be 1:1 with the motor for circle track racing. For drag racing, the alternator should be overdriven by a ratio of 1.75:1 or more. This will allow charging on the return slip and in staging. For street use, we recommend 3:1.
Ignition - The window of performance for most electronic ignitions is 12 to 16 volts, with performance advantages at the higher voltage. A fully charged battery is only 12.6V, and it goes down hill from there. With a Powermaster alternator, your system voltage goes to a constant 14.9V. This assure peak performance.
Fuel pumps and other electrical devices need 12 volts at all times for maximum performance.
Consistency - Using a battery charger instead of an alternator is a variable. Running a Powermaster alternator will keep the battery fully charged and predictable.
Convenience - Sizing the alternator (amps) to the load will eliminate the need for the battery charger.
One wire alternators should NOT be "switched" , or isolated from the battery. This causes severe internal spikes in the alternator, which could cause damage. We do not recommend switching alternators on/ off while the engine is running. However, if your application requires this, we can custom build alternators that are safely switchable.