Diesel Exhaust System Upgrade — DPF-Back & Turbo-Back Exhaust
How to install a performance exhaust on a diesel truck. Covers DPF-back systems, 4" vs 5" pipes, muffler delete, stack kits, and what to expect for sound and performance gains.
Tools Needed
Find Materials Near You
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Instructions
Understand Your Options
DPF-back: starts after the DPF filter and is 100% street legal. Best for emissions-compliant trucks. Turbo-back: runs from the turbo outlet all the way back — requires deleting the DPF and DEF system (not street legal in most states). Single exit vs. dual exit vs. stack (vertical exhaust behind the cab). 4" pipe is standard for most diesels; 5" is for high-power builds. Straight-pipe (muffler delete) gives max sound; resonator-back is quieter.
Soak All Exhaust Hardware in Penetrating Oil
Spray every exhaust clamp, bolt, and flange joint with PB Blaster or Kroil the night before. Exhaust hardware rusts onto itself — without penetrating oil, you will break bolts. Heat the joints with a torch if bolts won't budge. Replace any broken studs before installing the new system.
Remove the Old Exhaust
Lift the truck and support it safely. Start at the back (tailpipe) and work forward. Remove exhaust hangers from their rubber mounts — use a flathead screwdriver as a lever. Disconnect the exhaust from the DPF outlet flange (or turbo outlet for turbo-back). Have a helper hold sections as you unbolt them — exhaust systems are heavier than they look.
Install New Mid-Pipe & Hangers
Start from the front connection point and work rearward. Loosely hang all sections first using the supplied clamps and hangers before tightening anything. This lets you align everything before locking in position. Make sure all rubber exhaust hangers are properly seated — missing one hanger causes the system to crack from vibration.
Tighten Clamps & Check Clearances
Once everything is aligned, tighten clamps from front to back. V-band clamps: 25–35 ft-lbs. Lap-joint clamps: 40–50 ft-lbs. Check that the exhaust clears the frame, driveshaft, fuel tank, and spare tire by at least 1". Exhaust heat will damage anything plastic or rubber it touches. Wrap any close-clearance areas with exhaust heat wrap.
Start the Truck & Check for Leaks
Run the truck and listen for exhaust leaks — they sound like a ticking or hissing. Feel carefully around all joints (don't touch — use your hand near, not on the pipe) for escaping exhaust. Tighten any leaking clamps. Exhaust leaks before the turbo reduce power significantly; leaks after are mainly a sound/fume issue.
Break-In Period
The new exhaust will smoke and smell for the first 20–30 minutes as factory oils and coatings burn off — this is normal. Don't be alarmed. Take it for a 30-minute drive to fully heat-cycle the system. Re-check all clamps after the first heat cycle.
