Choosing The Right Alternator And Starter For Bracket Racing

Starters and alternators aren’t the parts that most racers will put on the top of their list as the reason they won a race, but that doesn’t take away from how important they are. You can’t win a round of racing if your vehicle won’t start, so that’s why you want to use high-quality starters and alternators.

The 427 cubic-inch LS engine that the students at SAM Tech built for our Project Number Cruncher Firebird has a healthy 13:1 compression ratio. We plan on racing this car a lot in the future, so a starter that can stand up to some abuse is a must-have item if we want to go rounds. We worked with the team at Powermaster Performance and determined one of its Powermaster XS Torque starters would get the job done.

Number Cruncher’s 780 horsepower LS engine needed a powerful starter to kick it over, and a stout alternator to make sure the FuelTecu ECU would function properly.

The engine is being controlled by a FuelTech ECU, so our electrical requirements are going to be higher than your average bracket car. Since there could be situations where the car won’t see a battery charger every round, an alternator that could keep our battery charged was on our list of things to get. The car is still using a 12-volt electrical system, so Powermaster suggested we use one of its larger 12-volt alternators.

Getting Things Started

Your racecar might be full of custom parts designed for your specific application, and that should also apply to the starter you’re using. Just because you have a small-block Chevy under the hood doesn’t mean any small-block Chevy starter is going to fit — that’s why it’s important to make sure you select a starter that will work with your overall engine package.

Chris Donaldson from Powermaster explains the factors that play into starter selection for a racecar.

“When it comes to fitment, there’s nothing stock about a racecar. You need to think about the area between headers, oils pan, and even suspension components to make sure the starter is going to fit. Many of our XS starters feature a billet aluminum mounting block that can be adjusted a full 360-degrees to get the starter in the right position.”

You need to use a starter that will fit your application physically. It's also important to make sure you've got the mesh correct between the starter and the engine's flexplate or flywheel.

A starter is quite literally in a hot spot of action under the hood of your vehicle — it sits in a location where it’s surrounded by things that generate heat. All of that thermal activity is natural for the engine, but it can have a negative effect on the solenoid inside the starter. A starter that doesn’t use a high-quality solenoid will struggle with the demands of starting a big displacement, or high-compression engine after exposure to a lot of heat. This is why it’s so important to use a starter designed for high-performance engines.

When it comes to torque, you need to be sure that your starter is capable of handling the compression of your engine. – Chris Donaldson

Now, if you’re using an EFI system like we are for Project Number Cruncher you need to also think about the starter’s ability to produce enough cranking speed. The ECU needs to see a certain RPM level to recognize it’s time to start the engine. If your starter can’t spin the engine to that level, the ECU won’t give the command to start. This can really become a problem if your engine has a large displacement, or high compression ratio and the starter isn’t strong enough to roll the engine over at the right RPM level for the ECU.

The starter you select must be strong enough to turn over the engine you're using. A starter designed for a racing application will also be more durable than an OEM-style starter.

The amount of torque a starter can generate is very important. You don’t want to use price as the main factor when you’re shopping for a starter, but rather the need to have enough rip to start your engine numerous times, so you might have to spend a little more to get the right part for your application.

“When it comes to torque, you need to be sure that your starter is capable of handling the compression of your engine. A 10:1 engine is going to be easier to crank over than a 14:1 engine, and if you’re running a blower, there’s even more demand placed on the starter. If anything, go overkill on the torque output of your starter and the engine will crank every time,” Donaldson says.

Don’t overlook the wiring that runs to your starter. If your wires can’t carry the load to your starter it won’t function properly and could be damaged.

Starters are tough, but that doesn’t mean you can abuse them without any consequences. If you want your starter to function flawlessly for an extended amount of time, you’ll want to do a few things to keep it happy. Basic items like checking the wiring to the starter for proper grounding, and shimming it correctly can extend the starter’s life exponentially.

“When you install the starter, be sure to check the pinion gear engagement to the ring gear as well as the gear mesh. These are both easy to check and adjust to make sure you’re getting the best fitment. Next would be the use of a high-quality cable capable of providing the extreme current demands of the starter – on both the battery terminal and starter wire. Poor wiring causes a lot of starter issues that could have easily been prevented,” Donaldson explains.

Keeping Things Charged

A good alternator will keep your battery charged for longer periods of time.

The typical alternator you pick up at the local auto parts store really isn’t designed to deal with the rigors of drag racing. These alternators are meant to be used on engines that only spin to a certain RPM level, so just because they fit doesn’t mean you should use them. The last thing you want to deal with on raceday is a battery that won’t stay charged because the alternator can’t keep up due to quality issues.

“Before deciding on an alternator, check with the manufacturer on its ability to charge at an idle. Like ignition coils, many alternators are promoted on their peak current output because that’s the highest number, however, charging at low RPM is very important – even for a drag car. You warm up in the pits, drive it to the staging lanes, and cruise back from the top end – all at lower RPM. Make sure to understand the lower RPM output as well as the peak output,” Donaldson states.

You need to ensure that you have an alternator that exceeds the demands of the electrical system. – Chris Donaldson, Powermaster

You also want to make sure you get an alternator that’s compatible with your electrical system. Most racecars run off a 12-, 14-, or 16-volt system depending on the application, and you need an alternator that will keep that voltage system happy. Powermaster does offer alternators that have adjustable voltage output, that way if you purchase one of these alternators you won’t have to change it if you move to a higher voltage electrical system.

The voltage output of an alternator needs to be high enough to charge your battery, but that power has to get there, and that’s where the wiring comes in. So, if you want to get the most out of your alternator and avoid any issues you’d better make sure the wiring is acceptable.

You want to make sure the alternator you select can charge well at idle and low RPM. Think about it: how much time do you spend with the car idling in the staging lanes and driving through the pits? That's the time you want the alternator doing its best work.

“You can have the highest output alternator available, but if you skimp on taking the time and using the right cables to connect the alternator, it won’t make a difference. Going overkill on alternator wiring isn’t going to hurt a thing, but always use a multi-strand, copper cable to connect the alternator and battery positive terminal. Also, it is recommended to run a ground cable from the alternator housing to the engine or chassis ground,” Donaldson says.

Now, your average bracket car isn’t going to have a lot of electronics onboard that are drawing power from the battery. Most racers will have things like a fuel pump, fan, delay box, and maybe a data recorder to go along with the engine’s ignition system. A more complex car will have additional items, but an EFI car takes things to a whole new level.

Spending the money on a high-quality alternator made for a racing application will save you a lot of headaches on race day.

It’s simple: the more electronics you have, the more current you’ll need to keep everything running, and that’s where having the right alternator comes into play.

“If you originally had a racecar with a single electric fan and a high output ignition, the current requirements might only be 30-40 amps. Yet, once you add a high volume electric fuel pump with eight injectors and an ECU, they’re going to draw more, placing more demand on the charging system. If the alternator and battery can’t keep up with the demands of the components, their output is going to suffer, resulting in poor performance on the track. You need to ensure that you have an alternator that exceeds the demands of the electrical system,” Donaldson explains.

The last thing any racer wants to deal with at the track is an electrical problem, especially if it happens right after they get called to the staging lanes and their car won’t start. If you use a starter and alternator that’s designed for drag racing it will help you avoid this nightmare scenario and provide you with some peace of mind each time you hit the ignition button.

Article Sources

About the author

Brian Wagner

Spending his childhood at different race tracks around Ohio with his family’s 1967 Nova, Brian developed a true love for drag racing. When Brian is not writing, you can find him at the track as a crew chief, doing freelance photography, or beating on his nitrous-fed 2000 Trans Am.
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