Collection: 2019-2021 Cummins 6.7L

6.7L Cummins — Tuning, EGR, Exhaust & Fuel

Calibrated tuning, EGR upgrade kits, exhaust, and fuel hardware for the 2019–2021 Ram 6.7L Cummins. The 6.7L came with the 68RFE (2500/3500) or heavy-duty Aisin AS69RC (3500 HO / cab & chassis); tuning and transmission hardware differ between the two. Every part here is matched to your truck and ordered the way you'd build it.

What you need to tune the 6.7L Cummins

A supported device (EZ Lynk Auto Agent, HP Tuners MPVI4, EFI Live, MM3) plus a Dieselr-calibrated tune file — GDP and Chaos Custom Tuning calibrations are also available. EZ Lynk requires no send-in.

68RFE vs Aisin

These trucks run the 68RFE (2500/3500) or the heavy-duty Aisin AS69RC (3500 HO / cab & chassis). Tuning and transmission hardware differ; Dieselr provides transmission-specific TCM files for both.

Exhaust & off-road hardware

Downpipe-back and turbo-back exhaust in aluminized and stainless, plus Cat & DPF race pipes for off-road and competition use. Larger-diameter exhaust lowers EGT and frees airflow as power climbs. EGR upgrade kits include block-off plates, coolant bypass, gaskets, and EGT provision. Off-road and competition use only; pair with a matching calibration so the engine runs correctly.

Fuel

FASS, S&S Diesel, Dynomite Diesel, and Dieselr fuel hardware support higher fueling as power climbs.

Compatibility

Organized by confirmed fitment for the 2019–2021 Ram 6.7L Cummins.

FAQ

What do I need to tune a 6.7L Cummins?
A supported device plus a Dieselr-calibrated tune file. Add off-road EGR and exhaust hardware if your build moves past the factory emissions configuration.

Do I need a tune with an EGR upgrade kit?
Yes — the calibration prevents fault codes and derate after the hardware change.

68RFE or Aisin — which do I need?
Match your transmission: 2500 trucks use the 68RFE; many 3500 HO and cab & chassis trucks use the Aisin. Dieselr offers tuning and parts for both.

What fuel upgrade do I need?
Stock-to-mild builds run the factory system; higher power calls for added fuel supply and supporting hardware.

Are EGR upgrade kits and race pipes street legal?
These products are intended for off-road and competition use only. It is the buyer's responsibility to comply with all applicable federal, state, provincial, and local emissions laws.