Having more power is almost never a bad thing, especially in a sports car. The exception comes into play when your frame isn’t strong enough to support that power, but don’t fear. There is a way give your frame more support. When you install subframe connectors on your car, you increase the strength and rigidity of its body. While welding on the subframe connectors is prefered, there is an option for bolt-on subframe connectors. It is also possible to use bolt-on connectors and then weld them to the chassis later.
Preparing to Install Subframe Connectors
Check the structural components of the car for rust. Subframe connectors work to increase the strength of your frame, but this won’t help much if there are weak points due to rust. You should repair any rust spots before installing your subframe connectors.
Disassemble your interior. What comes out will depend heavily upon where you are making welds. You should remove any seats, carpet, stereo equipment, etc. that might get too hot and ignite due to your welding underneath it. This helps to prevent fires inside the car while you’re welding.
If you are using the bolt-on only method of installing subframe connectors, this step is not necessary at all.
Lift the car. This seems simple, but it can be tricky. Your car needs to be as level as possible to minimize body flex. If your car is uneven, it twists and flexes the body. If you then weld the subframe connectors in while the body is twisted, you weld in that distortion and make it permanent. You should use ramps or a drive-on body lifts.
Move the fuel line and the fuel tank out of the way. You do NOT want to ignite the fuel line or tank while welding. Do not shortcut this step. If you need to remove the fuel lines and tank do it.
Installing Bolt-On Subframe Connectors
Check drill clearance underneath your car. It may be necessary to move or remove parts of the exhaust in order to properly fit the drill underneath your car and install the subframe connectors. This will depend on the make and model of your vehicle.
Identify which connector goes on which side. This is easily done, as the connectors are different for either side. Make sure that you are not mixing them up. This isn’t hard as they will typically be labeled right and left and only fit on the correct side of the vehicle.
Place the subframe connectors as close as possible to the frame rail. Place a piece of wood between the subframe connector and a hydraulic jack and use the jack to hold the connector in place against the frame rail.
Install the cross brace nuts. The cross braces fits over the seat bolts and is secured by a nylock nut and washer for each seat bolt. This will help hold the connector in place while you drill the holes for the bolts.
Drill the necessary holes. With the subframe connector in place, put the drill bit in a bolt hole on the subframe connector and drill straight through the frame rail from the outside toward the center of the car. Next, go underneath your car and drill through the other side of the frame rail the same way, but this time you will be drilling from the center toward the outside of the car. Do this for all bolt holes on your subframe connectors.
Lining up the subframe connectors first and drilling through the bolt holes makes sure that the holes are aligned such that the bolts that come with the subframe connectors go straight through the frame rail. This is what fastens your subframe connectors to the car.
Be sure that you are have the subframe connectors properly aligned and that you only drill where the bolt holes are. You do not want to drill any unnecessary holes in your vehicle.
Install your bolts. Now that the holes are all cut in, you can install your bolts. Thread them through one side to the other and attach them with any washers and nuts provided. Tighten to the recommended torque listed by the manufacturer.
Welding in Subframe Connectors
Mark your welding locations. A white grease pencil works well for this. You will weld at the front and back of the subframe connectors. If you have end caps for your connectors, you will weld those on as well. It is also advised that you weld patches in regular intervals along the sides of your connectors.
Clean all welding surfaces. This can be done with a wire wheel attached to a drill. Strip all mounting points on the car and mounting plates on the connectors down to bare metal for welding.
Raise the subframe connectors into place. Just like with the bolt-on option, you will need your subframe connector to be in place along the frame rail. You can use a wooden block and a hydraulic jack to properly fit the subframe connector up against the frame rail..
If your connectors have a bolt-on option, bolt one side in to help hold the connector in place during welding.
Verify there are no gaps greater than ⅛-inch. You need the metal of the frame rail to be close enough to the metal of the subframe connector to place sturdy welds. If you notice any gaps that you could slide the thickness of a nickel, you should measure them. If you have any ⅛-inch or larger gaps, you will need to readjust your subframe connectors to close those gaps before welding.
Secure the connectors to the car using 6-inch clamps. You want to prevent the subframe connector from moving while you are welding it into place.
The connector needs to be flush with the inner rail, but don’t be concerned if the outer connector doesn’t align with the body of the car.
Weld the connectors in place at the front and back. Welding the connector will take some time.
The weld needs to run around the connector mounting plates and the car’s subframe.
If your connectors include end caps, secure the end caps and weld them in place as well.
READ ALSO: Reassembling Your Vehicle
Reattach any exhaust components. If you had to remove any parts of the exhaust to make room for the drill or welder, reattach them now.
Reinstall the fuel tank and lines. It is likely that these were removed, especially if you were welding on your frame rails. Now that all of the welding is done, it is safe to reinstall your fuel lines and fuel tank.
Reinstall all interior pieces. If you removed carpet or other interior items to protect them from welding, you should reinstall them.
Enjoy the ride. Subframe connectors improve the handling and quality of your ride, go out and enjoy the upgrade.