How To Install a C8 Corvette Catback Exhaust and/or Swap In a High-Wing Spoiler on a Z51
Installing a C8 Corvette catback exhaust and/or a high-wing spoiler only requires simple handtools, but you need a friend and some patience.
The days I spent behind the wheel of the C8 Corvette were all-time. It’s nothing short of remarkable. But like any vehicle, there are compromises. And, in my humblest opinion, the C8 Corvette is a little quiet unless you have the accelerator mashed all the way to the floor. (Tunnels and bridges also help.) Luckily, swapping out the OEM catback system, aka The Suitcase, is a super easy job almost anyone can do at home with jack stands, simple hand tools, a good buddy, and a wee bit of patience.
We recently spent the day at CorvetteForum vendor American Heritage Performance documenting the install of a Fabspeed C8 Corvette catback exhaust as well as an OEM high-wing spoiler so we could share a few tips with you. Full video above (and HERE). Or, if you prefer to read, here’s a quick write-up.
PREP: DISCONNECT THE BATTERY
Not everyone will do this, but any time you’re fiddling with electronics on modern cars, it’s a good idea to disconnect the negative battery terminal.
- The C8’s battery is located in the front trunk (aka frunk) compartment.
- To access it, simply remove two side pieces of plastic molding at the top edges of the front.
- Then lift up the larger center plastic cover and disconnect your negative battery terminal.
PART 1: REMOVE THE REAR BUMPER COVER
- Take off your rear wheels, which will give you clearer access to the rear wheel well liners.
- Next, you’ll need to undo several T-15 TORX SCREWS that run above the bumper cover along the rear-edge of the trunk. There are also a few 7MM BOLTS around the edges and underneath.
- Don’t forget to remove the plastic mud-flaps/splash guards in the wheel wells because…
- Under those and behind the wheel well liners, you’ll find more bolts. Behind the driver’s side liner, you’ll find TWO 7MM bolts and ONE 10mm bolt. It’s the same on the passenger side, but the 10mm bolt is hard to get because it’s tucked in behind the EVAP cannister. You’ll need an assortment of extensions and swivels to reach it. (This is the hardest part of the process.)
- With the bumper loose, grab your buddy, lift the bumper up and rearward, BUT not too far because…
- You have to disconnect THREE electrical connectors from the bumper cover.
- Set the bumper down on something soft.
At this point, you can either install your catback exhaust install OR do a spoiler swap. Skip to PART 6 if you want to do the high-wing spoiler.
PART 2: REMOVE THE ENGINE BAY ACCESS PANEL & DISCONNECT THE CATBACK
- To unbolt the OEM catback from the headers, you’ll first need to access the engine bay from the trunk.
- First, remove the fabric TRUNK LINER. (If you have a coupe, you’ll also need to remove the latches that secure the TARGA top.)
- With the trunk liner removed, there are another 20-plus T-15 TORX screws around the edges of a plastic cover. (FYI, this is also the cover you need to remove to change your engine’s AIR FILTER.)
- Unbolt the suitcase. There are TWO bolts on the driver’s side pipe, and THREE on the passenger side.
PART 3: REMOVE THE OEM “SUITCASE” MUFFLER
Two things to keep in mind about this part. First, you need to disconnect FOUR plugs going to the electric motors on the suitcase. Two of these are part of the ACTIVE VALVE EXHAUST system, while the other TWO are part of the, ACTIVE FUEL MANAGEMENT system. The AFM motors are hard to reach, but there’s a hack (see below). Second, there are FOUR hangers holding the suitcase in place. Two in the rear and two on the sides. Here’s how to approach the process:
- Disconnect the TWO plugs for the Active Valve Exhaust motors (they’re on the sides and easy to reach).
- Losen all FOUR 10MM bolts on the rear hangers ALMOST all of the way, dropping the suitcase couple of inches while making sure it’s still secure.
- Reach in and disconnect the TWO Active Fuel Management plugs.
- With you and a friend supporting the suitcase, slide both rubber isolators off the two SIDE hangers.
- Then finish undoing the four bolts holding the rear hangers in place.
- Pull the suitcase down and away and set it down on the ground.
PART 4: PREP YOUR CATBACK EXHAUST FOR INSTALLATION
This will vary by manufacturer, so be sure to check your specific instructions. In the case of this Fabspeed catback system, it arrived in three pieces: the actual X-Pipe and two active valve mufflers with dual carbon fiber tips.
- Move both ACTIVE FUEL MANAGEMENT motors over to the X-PIPE. They don’t actually do anything in this system, but installing them prevents a check-engine light.
- Transfer the ACTIVE VALVE motors onto both mufflers along with the rear hangers as well as the rubber isolators from the side hangers.
PART 5: INSTALL YOUR NEW C8 CORVETTE CATBACK EXHAUST
Again, this may vary based on your catback. For the Fabspeed, here’s what we did:
- Install the X-Pipe. Make sure you have someone to support the pipe as you bolt it to the header piping.
- Don’t forget to reconnect the plugs for your active fuel system management motors. (NOTE: you may have to remove a clip on the passenger side for that wire to reach.)
- Install both mufflers by sliding the rubber isolators onto the SIDE hangers
- Bolt the rear hangers into position while connecting the X-pipe to the mufflers with the supplied CLAMPS.
- Don’t forget to plug in the ACTIVE VALVE EXHAUST motors on each side.
- It’s a good idea to keep everything a little loose still so you can make minor adjustments.
PART 6: HIGH-WING SPOILER INSTALL
If you’re not doing anything with your spoiler, go ahead and skip to PART 7 and reinstall your rear bumper cover. But in our case, American Heritage Performance also swapped an OEM high-wing spoiler onto this Z51 Performance Package C8 Coupe. Again, this is a relatively simple job, but it’s a good idea to have a friend. TAKE YOUR TIME to avoid scratching your rear bumper cover.
- With the bumper on the ground, there are only six 10MM BOLTS holding the Z51 spoiler in place: TWO PAIRS on the outer edges and TWO SINGLES in the middle.
- The great news is that the high-wing spoiler uses the exact same bolt pattern. The bad news is that you also have to slowly remove the factory ADHESIVE at the Z51 spoiler’s four main touchpoints. (This is the hardest part. TAKE YOUR TIME.)
- With the Z51 spoiler removed, make sure to clean off any leftover adhesive. (Yes, the bolt pattern is the same, but the touchpoints are different sizes.)
- Now you can install the high-wing spoiler (which doesn’t come with additional adhesive).
- However, because the spoilers bolt STUDS are longer, you should take out the TAIL LIGHTS to get better installation access. This is also easy. There are a push-pin connector and SIX 7MM bolts holding those in place.
- Bolt the high-wing spoiler into place and check fitment.
- Reinstall your taillights.
PART 7: REINSTALL YOUR C8 CORVETTE BUMPER AND CHECK FITMENT
Part 7 is effectively doing the reverse of everything you did in part one while making sure the quad tips don’t have any clearance issues. Along those lines, don’t forget to:
- Reconnect the THREE electrical plugs for all of the rear bumper cover electronics.
- Tighten all of the catback’s clamps and bolts once you approve fitment.
- Tighten all of the bolts and T-15 TORX screws.
- Reinstall your engine access panel and rear trunk liner.
- Reconnect your battery.
PART 8: GLORIOUS ENGINE GROWLS
Enjoy your new C8 Corvette catback exhaust and/or high-wing spoiler! (Sample audio in the above video!) Thanks again to Kohle and Matt and American Heritage Performance as well as CorvetteForum member Tony Milello for allowing us to film.
Have you done any wrenching on your C8, let us know HERE in the forums!
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