Owners manual

ManualsBrandsPypes Performance Exhaust ManualsAutomotiveSJJ25S Cat Back Exhaust System Fits Wrangler (JL)

SJJ25R / SJJ25S

2018 Jeep Wrangler JL 2DR & 4DR HGC

Stainless Steel Catback System

After you have inventoried the parts begin by placing your Jeep on a lift or 4 jack stands so you can work safely

under your vehicle.

Unbolt the factory muffler using the 15mm socket and remove the muffler from the vehicle. To aid in the removal

presoak the bolt and nut as well as the rubber bushings.

Next using a 13mm socket loosen the ball socket clamp at the end of the factory down pipe and remove the fac-

tory mid-pipe. Save all the rubber hanger bushing they will be reused. (Removal of the skid plate is recommend-

ed for this step.)

Now it’s time to start the installation of your new cat back. Begin by installing the tailpipe into the two factory

rubber hangers located above the sway bar followed by the muffler using two HVC21 band clamps.

Next install the new MJJ23 mid-pipe using the HVC21U ball socket clamp. On 4 door models no modification is

needed to the mid-pipe. For 2 door models you will need to cut the mid-pipe to length. Do this by seating the ball

socket portion into the factory down pipe then hold it against the nipple of the muffler. Mark the mid-pipe allowing

enough engagement into the muffler. A general rule is plus 1 ¾” from the end of the muffler nipple.

Now that you have the major components loosely installed align the system (the bends in the mid-pipe will run Now that you have the major components loosely installed align the system (the bends in the mid-pipe will run

parallel to the ground) and tighten all clamps. Make sure the ball socket is seated and the U- clamp captures

both parts equally. This is critical to creating a good seal. Air tools are highly recommended for this part.

Now start your vehicle and check for leaks. It’s not uncommon to see condensation coming from the relief cuts in

the pipe for the first few hundred miles. Double check all clamps and hardware for tightness after the first week

of operation and adjust accordingly.

SJJ25S

SJJ25R

1 TJJ23 Tailpipe

1 MVR200S or MVS11 Mufﬂer

1 MJJ23 Midpipe

2 HVC21 Clamp

2 HVC21U Clamp