The Big Question: Should You Delete Your 6.7 Cummins?
Deleting a 6.7L Cummins (2007-2018) delivers major performance gains but comes with real legal risks. Here’s what you need to weigh before deciding:
✅ The Benefits (Why People Delete)
✔ +30-50 HP & Torque (Removes DPF/EGR restrictions)✔ +2-4 MPG Gain (No more fuel-wasting regens)✔ Longer Engine Life (No soot recirculation = cleaner oil)✔ Eliminates $5,000 Repairs (DPF replacements, EGR cooler failures)
❌ The Risks (Why Some Regret It)
✔ EPA Fines Up to $4,500 (If caught with tampered emissions)✔ Failed Inspections (In emissions-testing states)✔ Resale Value Impact (Some buyers avoid deleted trucks)✔ Warranty Void (If still under factory coverage)
Performance Gains: What a Delete Really Does
1. Horsepower & Torque Increase
Stock 6.7 Cummins: ~350 HP / 660 lb-ft
Deleted + Tuned: 400-450 HP / 800+ lb-ft
Biggest Gains: Turbo spools faster, no exhaust backpressure
2. Fuel Economy Improvement
Before Delete: 14-16 MPG (with regens)
After Delete: 16-20 MPG (no wasted fuel burning soot)
3. Engine Longevity
EGR delete stops:
Carbon-clogged intake manifolds
Coolant leaks from failed EGR coolers
DPF delete prevents:
Turbo damage from backpressure
Cracked pistons from high EGTs
Legal Risks: Can You Get Fined?
Federal Law (EPA)
Tampering with emissions = $4,500+ fine per violation
Shops that perform deletes risk $37,500+ fines
Enforcement increasing (especially in CA, TX, NY)
State Emissions Testing
Strict States (Fail if deleted): CA, CO, NY, PA, etc.
No-Test States (Safer): FL, OH, MI, most of the South
Resale & Warranty Issues
Dealers may refuse CPO warranty
Private buyers often pay less (unless it’s a performance market)
Alternatives to Full Deletes
If the legal risks worry you, consider:
1. DPF Cleaning (
300−
300−600)
Extends DPF life but doesn’t fix underlying issues
2. EGR "Soft" Delete (Tune-Only)
Keeps hardware intact but disables function via tuning
3. Partial Deletes (Mock DPF Shells)
Maintains stock appearance but improves flow
🚛 Final Verdict: Who Should Delete?
Worth It If You:
Live in a no-emissions-test state
Tow heavy and need reliability
Own an out-of-warranty truck
Accept the resale/fine risks
Not Worth It If You:
Live in CA or strict emissions states
Have factory warranty remaining
Plan to sell to dealerships
Can’t afford potential fines
⚠️ Thinking About Deleting? Do This First:
Check local laws (Google “[Your State] diesel emissions testing”)
Get quotes for repairs (Sometimes fixing emissions parts is cheaper)
Research tuners (Some hide delete capability better than others)
FAQ
❓ Can you undo a delete later?Yes, but reinstalling DPF/EGR costs $2,000+ in parts.
❓ What’s the #1 delete mistake?Using cheap tuners that throw obvious CELs during inspections.
❓ Are there “legal” deletes?No – any tampering violates EPA rules, but enforcement varies.
