A high-performance starter is designed to turn over an engine with alot of cubic inches or tons of compression, but it can’t do its job if it doesn’t have enough power. The biggest culprit of a starter struggling due to a lack of power is incorrect wiring.

The math to slove this problem is pretty easy: if you’re moving to a bigger engine and bigger starter, you need to reconfigure the wiring to the starter. Adequate power is key, so if you’re experiencing starter troubles with a new car you just purchased, or with a bigger engine package, the wiring should be the first thing you check.

We sat down with Don Meziere of Meziere Enterprises to go over some best practices in the area of starter wiring. Meziere starts out by explaining why you’ll experience issues with the wrong size wire running to your starter.

“Bigger displacement requires you to rethink things, just like with fuel delivery, valvetrain parts, and so on. The starter got bigger and the output grew, so the wire must get bigger too. It’s really easy to find information online about what your percentage loss will be over a given length of wire. You want to keep that loss below 5-percent, and closer to 3-percent if possible. That’s the biggest deficiency we see is the engines keep getting bigger, but the wire size on the starter has remained the same.”

Eyeball inspection of the mechanical components will usually reveal any trouble. However, electrical issues for a starter can be more difficult to find because they’re not as obvious as a chipped tooth on the pinion or a broken solenoid. These electrical problems are hidden and can’t easily be seen, so you have to do a lot of testing to track them down.

“There are several symptoms that can show up if you don’t take care of the electrical side. One of the biggest ones we see is weak starting. This can be due to several smaller problems that add up to one bigger one. It’s not one thing that’s bad, it’s several choking points causing it. The more current restrictions you have in the electrical system, the more likely you’re going to have issues,” Meziere explains.

Common Weaknesses On The Activation Side

Most high-performance starters use two wires: the larger main wire, and the smaller activation wire. The activation wire is attached to the switch that engages the starter — it’s the signal side of the ignition process. The activation side builds the coil inside the solenoid and pulls it; when the solenoid is pulled far enough, the bus bar in the back solenoid will move and pass power to the starter motor itself.

Where racers can get into trouble is when they’re using an activation wire that’s too small; that being the case, the coil in the solenoid will not produce the required “pull.” It will cause degrading of the solenoid and the switches in your electrical system. You also need to be sure that any switch in that circuit has the proper electrical rating that exceeds what your starter will demand.

“The demand of the solenoid that creates the initial inrush current that engages the starter can be as much as 40-amps,” Meziere says. “Your typical cube relay isn’t going to be able to handle that. If you don’t have a relay, you’re about to ask every switch in the circuit to withstand a 40-amp jolt, and most switches aren’t designed for that. It’s common for a race car to have a 14- or 16-gauge activation wire for a starter, but that’s too small…you need at least 10-gauge wire to take on that 40-amp inrush.”

You’ll want to pay attention to how you wire the activation side of your starter. You’re going to need more than a standard cube relay to handle and distribute the load required to activate a starter, and in most cases, a circuit that doesn’t have any relay is creating a recipe for disaster.

This wiring scheme is how Meziere suggests customers wire their starter to avoid any issues.

“The standard type of wiring scheme we recommend uses a Ford-type relay to carry just the activation side. It’s not going to carry the main cable amperage, just the 40-amp signal. You give it a good 12-volt supply from a bus bar and run a 10-gauge wire all the way to the activation post of the starter. That’s the best way to have that side of the system healthy,” Meziere states.

The Ford-type relay should only be used for the activation wire of the starter. Meziere recommends that you send power to the starter directly from the battery, like what you see in a street car — this will eliminate a weak point because you can’t expect a switch that’s only rated for 75-amps to take on the 200-300 amp demands of the starter.

According to Meziere, jumper wires are another thing that gets racers in trouble when it comes to the activation side of a starter.

“If your car has a jumper wire, that’s not something that will work at peak performance. Typically, when there’s a jumper wire, you have some other switch controlling the main cable and activation wire together,” Don explains. ‘The jumper activates everything at the starter. If your switch is rated high enough, that’s fine, but most vehicles won’t be set up correctly. Most are using this wiring scheme because it cuts off the 12-volt power from the starter so you don’t have a live wire out there creating a possible arc. Unfortunately, it’s not the correct way and can cause a lot of problems.”

Common Weaknesses On The Main Wire

Your main starter wire is what provides the juice to turn everything over, so it needs to be very robust. Many racers think the wire they’re using is large enough, but it might not bring the amount of juice needed to keep a starter happy.

“A lot of cars, and especially dragsters, will slip 4-gauge wire through the framerail to the battery. It might look cleaner but it can’t properly carry the amperage. The drop will be way over 5-percent loss, so your starter isn’t going to see the voltage you think it sees. It’s hard on the starter, causes slow cranking, and can cause the connections to be exposed to more heat causing reduced life,” Meziere says.

The positive wire size is critical, but the other side of that is how you ground the starter itself. There are a few different ways you can ground the starter, but the best course of action is to use a dedicated ground.

“There are alot of cars out there that are made of chromoly, and chromoly is known for being a bad material for grounding current. If you have a car that you’re relying on the chassis to carry the ground back to the battery, you may actually pick up a good bit of conductivity by running a dedicated ground. So, running a dedicated ground is going to save you a lot of headaches,” Meziere states.

Now, there are other ways you can make sure your main wire is in tip-top shape. The first and easiest is to check all of your connections — you want to look at all the crimps to ensure they have plenty of engagement, all of the wire is making contact with the connector, and to use solder whenever possible. Corrosion is your enemy and you want to clean off any that’s found. Also, make sure you’re using adequate relays in the system. The wrong relays will degrade over time and eventually fail.

You should take the time to wire your starter the right way and use materials that are robust enough to carry the electrical load you’re sending to the starter. The last thing you want to deal with is a race car that won’t start in your pit or the staging lanes, causing you to miss a round of racing.