While we build all of our exhaust systems on a jig that is an exact replica of the underside of your car, there are always minor issues that can affect fitment. Manufacturers are notoriously sloppy with the mounting points on the chassis (since they have plenty of adjustment room with rubber hangers). Also, prior repairs, corrosion, and even light damage from rocks and road debris can make the mounting points seem “off” sometimes.
When you install an exhaust system, here’s a few tips to make sure everything aligns properly:
First, you’ll want to hang the entire system loosely on the hangers. This is a good time to decide whether those old rubber hangers are going to make it through another season, or if you should replace them (we always recommend new rubber). Also, I’m a big fan of a little dab of anti-seize on exhaust system bolts – cheap insurance for later on!
Next, press your catback into position and join the parts (using jackstands is ok, but nothing beats having a friend position things properly). As you tighten the connections (a little at a time, moving around from one to another), the system should remain in the proper location. Again, you don’t want to tighten any connection all the way at once, but tighten each one gradually, moving from one fastener to another. (A good example here is the way you tighten the lugs on a wheel – when doing a 5-lug wheel, you tighten in a star pattern, so as not to bend the wheel – same concept.)
If you get all of the hardware snug (not torqued yet) and the alignment is off a bit, we’ve made the hanger rods a little longer than necessary – this is so you can fine-tune the adjustment. Loosen up the hardware. Now, using a deep socket on an extension (or a long, box-end wrench), flex the hanger a TINY amount in the opposite direction that you need the system to move. A little adjustment goes a long way, so don’t go crazy!
Once your exhaust is hanging the way it should, go back and tighten the hardware (again, a little at a time, moving from one fastener to another). Give everything a final torque (30 ft/lbs is plenty), and go for a drive. After a couple drives, go back and re-tighten everything.
Enjoy, and be safe out there!