Do You Need an EGR Delete After a DPF Delete?
The Short Answer
You don’t have to delete your EGR just because you deleted your DPF, but on most modern diesels the two are tied together. If you delete the DPF and leave the EGR active, the EGR will still dump soot-laden exhaust back into the intake — and that soot will now have no DPF to catch it later. Most people doing a full delete do both at the same time.
What the EGR System Does
Exhaust gas recirculation (EGR) routes a portion of exhaust back into the intake to lower combustion temperature and reduce NOx emissions. It works, but it has side effects:
- Soot and carbon buildup in the intake manifold and on the valves
- Reduced intake air density — less oxygen, slightly less power
- Higher intake temps — which can raise EGT under load
How EGR and DPF Interact
The EGR and DPF are two halves of the same emissions strategy. The EGR cuts NOx by lowering combustion temperature; the DPF catches the particulate (soot) that results. They work together, which means:
- If you delete the DPF but keep the EGR, the EGR keeps pushing soot into the intake with nothing to filter it downstream.
- If you delete the EGR but keep the DPF, you’ll still have to deal with DPF regeneration cycles.
This is why "full delete" — DPF, CAT, and EGR together — is the standard approach on competition and off-road builds.
Do You Need to Delete EGR After DPF?
Here’s the practical answer:
- If you’re going off-road / competition full delete → Delete both. Leaving EGR active on a deleted truck reintroduces the exact soot problem the delete was meant to solve.
- If you only deleted the DPF for flow → You can technically leave EGR, but you’re leaving the messiest part of the emissions system in place.
- If the truck is street-driven → Don’t delete anything. It’s illegal and you’ll fail inspection.
Pros and Cons of EGR Delete
| Pros | Cons |
|---|---|
| Cleaner intake — no more soot buildup | Illegal for on-road use |
| Cooler, denser intake charge | Requires EGR block-off plates and tuning |
| No more EGR cooler failures | Will trigger check-engine light without a tune |
| Simpler engine bay | Higher NOx (irrelevant off-road) |
What a Complete Delete Requires
A full delete isn’t just a pipe. You’ll need the full parts list — we’ve laid it all out in our DPF delete parts checklist. At minimum:
- DPF/CAT delete pipe (platform-specific)
- EGR block-off plates or a full EGR delete kit
- A tuner that suppresses DTCs and adjusts fueling
Start with the right delete pipe for your truck: Ram 4″ delete pipe, Ford 4″ delete pipe, L5P downpipe, or the L5P race pipe.
FAQ
Will deleting EGR trigger a check engine light?
Yes — without tuning to suppress the EGR-related DTCs, the light will come on. A proper tune is mandatory.
Do I need EGR block-off plates?
Yes. Unplugging the EGR isn’t enough; you need to physically block the passages or the exhaust can still leak into the intake.
Does EGR delete add horsepower?
Modestly. The bigger wins are a cleaner intake, lower intake temps, and removing a common failure point (the EGR cooler).
Is EGR delete legal?
No for on-road vehicles. EGR and DPF deletes are off-road and competition-only modifications.
Important: DPF, CAT, and EGR delete products are for off-road and closed-course competition use only. Removing emissions equipment violates the U.S. Clean Air Act for on-road vehicles. Always check your local and state laws before modifying your truck.