Over time, soot will build up in the DPF, triggering active regeneration, which then leaves fine ash particles behind. The buildup of ash over time noticeably limits the DPF's life span.
LIFE WITH OR WITHOUT THE DPF
Owners of new diesel-powered trucks basically have two choices. For example, they can choose to work with the new emissions equipment on their truck by installing a DPF-back exhaust, which does not break federal emissions laws as long as the DPF system is still intact and the truck is still able to enter active regeneration mode. However, running a high-horsepower tuner in conjunction with the DPF will cause the filter to plug up more often. The second option, which is removing the entire DPF system and using computer software to stop your truck from going into active regeneration, does violate federal emissions laws. Obviously, this option allows you to run high-horsepower tuners without plugging up the DPF.
The DPF Element on an '08 Super Duty with the DPF (left) and catalyst (right) closest to the downpipe.
THE CHALLENGE
The challenge behind getting rid of the DPF system on new diesels is in their electronics. The aftermarket has had to develop delete systems that trick the truck's ECU into believing the DPF system is still intact. Most delete systems come with mounting holes for both back pressure sensors to plug back into, but a tuning module is required to delete the DPF and override the system's regeneration mode electronically.
CHEVYS
Deleting the DPF on a Duramax has proven to be the easiest of the Big Three, and can be accomplished using EFILive, PPE, or Quadzilla tuners. Jason Carrier of Extreme Diesel and Exhaust in Chico, California, is quite familiar with the new Chevys and has seen DPF delete-kit-equipped ones increase their mileage as much as 4 mpg. According to Carrier, stock '07-'08 Duramax-powered trucks get 14 mpg on average, but with a DPF delete pipe kit and an aftermarket engine calibration, they see 18 mpg or better. Ditching your Duramax's DPF and getting more power and fuel economy from a tuner may cost you more than a grand, but it will return you to the diesel days where big power and fuel economy went hand in hand.
DODGES
It is important to most truck owners that aftermarket and performance add-ons don't produce a check engine light after installment. This brings us to the Cummins, which has proven to be the hardest to fine-tune. In addition to buying a delete pipe kit, the Cummins requires a tuning box to disable the truck from throwing a code. Currently, Bay Area Diesel Performance (BADP) offers a processor box that seems to work. Its tuning box was developed in-house specifically for the new 6.7L Cummins to eliminate the truck's ECU from initiating any performance-ailing codes. Keven Kroeger of K2 Diesel Performance is one of BADP's distributors and has seen this processor work firsthand. He claims customers who purchase a DPF delete pipe kit and BADP box typically increase their mileage from 14 to 20 mpg.