Is a 6.7 Cummins Delete Worth the Cost? Performance vs. Legal Risks

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:

1. Check local laws (Google “[Your State] diesel emissions testing”)

2. Get quotes for repairs (Sometimes fixing emissions parts is cheaper)

3. 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.