Battery Shuffle: Improving Weight Transfer with a Battery Relocation Kit

It’s Moving Day for the Optima RedTop battery in our subject vehicle, a 1998 Camaro. The average weight of a RedTop battery is around 36 pounds. Moving that poundage to the rear will improve weight transfer, helping the car launch harder and run quicker ETs. The ideal battery location is on the passenger side of the vehicle, either over or behind the rear axle. The additional weight helps preload the passenger side rear tire to counter the “torque twist” effect that tends to lift the tire when the car launches.

The Camaro has an ideal battery box location just behind the rear axle and gas tank. There is nothing under the floor to damage when drilling holes—a nice plus. Curtis from AutoDynamics centered the hold-down over the battery and tapped each hold-down stud with a mallet to mark drilling locations in the bottom of the box. He will drill a 13/32-inch hole through the box and the trunk floor at each location.

After assembling the cables and terminals and mounting them on the battery, Curtis determined the cable exit locations and marked them with a white paint marker. He will drill 3/4-inch holes at those points and insert grommets in the holes to protect the cables from abrasion.

Curtis decided to route the battery cables out the side of the trunk and along the rear inner wheelwell. He marked the exit locations, drilled two more 3/4-inch holes, and inserted two more grommets.

Curtis drilled a 3/4-inch hole through the battery box and trunk floor for the vent tube. The tube will allow any sulfuric acid fumes that build up in the box to escape. The vent tube should be positioned so the fumes do not collect under the car and possibly get into the cabin and ruin your day, not to mention your life. Curtis used the hold-down studs to keep the battery box in place when he drilled the vent tube hole.

This is how the battery hold-down should be assembled. We strongly recommend adding the optional washers under the lock nuts on the battery box floor. They’re cheap insurance against stressing and cracking the plastic.

Depending on how your vehicle’s trunk floor is shaped, you might have an excess of stud thread protruding above the hold-down. You can cut the studs or use the two large fender washers included with the Battery Relocation Kit to secure the hold-down as shown.

Here’s what things look like underneath the battery box location. Make sure an ample amount of hold-down stud thread is visible below the lock nut as shown.

One Optima RedTop battery, safe and secure in its new home. There probably should be a little more clearance between the positive cable and the hold-down washer to prevent the washer from abrading or cutting into the cable jacket.

Curtis grounded the negative battery cable to the body with a self-tapping screw. Note how he scraped away the paint so the cable will make contact with bare metal. That’s the proper way to do all of your ground connections.

Curtis routed the positive battery cable across the passenger side inner wheelwell and the down alongside the subframe rail and rocker panel. The Summit Racing Battery Relocation Kit comes with six insulated clamps to secure the cable to the car. If you need more clamps for your particular vehicle, Summit Racing insulated clamps are available in handy 10-packs.

The positive cable from the battery ends at the positive lug on the starter solenoid. Some electrical tape and convoluted tubing protect the cable from damage. The red cable at the upper right is the OE positive battery cable. It runs from the positive lug to the old battery tray, where it splices into the power lead that runs to the Camaro’s main electrical junction box.

Curtis reused the OE negative battery cable as a redundant ground strap. He connected one end to the chassis as shown here, and the other end to the engine block.

The last item of business is installing the foam rubber seal in the channel of the battery box lid. The seal is self-adhesive—just route it along the channel and cut off any excess.

The finished product. The lid is secured to the box with two 1/4-inch bolts that thread into nutserts at each end of the box.