Common Problems: Gaining Power Legally

Published in the September 2017 Issue August 2018 Feature Dave Friedli

As a 6.4L Power Stroke owner, my ears tend to perk up when new products are released for my particular Ford. So when I first heard about Bully Dog’s new bolt-on Performance DPF that could give my 2008 F350 up to 17 percent higher flow than stock, I was more than interested. The larger and better-flowing filter equals higher horsepower and torque and the best part is it’s also legal! Being able to unleash my truck’s true potential while remaining emissions-compliant is very important to me. 

Fighting the EPA is a battle you won’t win and there are plenty of aftermarket companies who have learned this the hard way. That’s why I have a lot of respect for a company like Bully Dog who is actively working towards solutions and doing it the right way instead of just looking for shortcuts or workarounds. This is a look at the future and I’m just thrilled Bully Dog started with 6.4L Power Strokes because that means I’m ahead of everyone else. 

First Impressions

Any trepidation I might have had after going online and ordering the Performance DPF for $1,799 quickly went away when it first arrived. It looked more like art instead of just another part to be installed under my truck. 

Constructed in North America from 409 and 304 stainless steel, the DPF shined beautifully in the box with its mirror-like finish. Just seeing it assured me I had made the right call when placing my order since it was clearly built for long-term durability while being resistant to weather and corrosion.

Removal Process

When it arrived we stopped everything that was going on at B&D Welding & Fab Inc. and immediately got started. Thanks to an understanding boss, I gathered a few guys in the shop and only a couple of tools and climbed under the truck to remove the existing filter assembly. 

It seemed pretty straightforward as there was only the filter, a gasket and a few bolts. I made quick work of removing the nuts surrounding the filter. I was thinking that was all there was to it so we next went after the exhaust clamp that held the back half of the system. We were able to remove it with some extra effort and after we had the clamp removed and wrestled the exhaust rubber mounts from the pins, in our minds we thought we were ready to drop it. Wrong. 

We spent the next little while working on trying to separate the filter from the front half of the exhaust. It didn’t matter what we tried; nothing seemed to work as we just couldn't figure out how to remove the assembly. At this point I decided it was time to get a fresh set of eyes to look at it and after a little while we discovered that the very top bolt had two nuts on it and once we got that off and unclamped a couple of sensor wires, it was finally off. We tried to remove one of the exhaust sensors from the filter with “try” being the key word as again we tried everything we could think of to remove it. Finally we realized it wasn’t coming off so we just sent someone to a nearby parts store to get a new one. 


We applied anti-seize to the new threads and added the exhaust sensor to the new filter. I climbed back under the truck and with some help we installed the new bolts and gasket on the filter. Getting the old exhaust clamp back into place turned out to be a big job as well, but we finally did get it. Here is a time-saving tip: I would recommend just buying a new exhaust clamp instead of trying to use the old one because it will be a lot less work for you overall.  

We were able to get this new filter installed and get my truck back on the road that same day. It was a pretty straightforward job that most do-it-yourself types should be able to handle with a little patience as well as applying the tips from what I learned.


The stainless V-band clamp that came with it allows full access to your filter for cleaning, which means this Performance DPF will be the last DPF you ever buy. Plus, with slower soot accumulations and faster-igniting particulate matter, I’m now experiencing fewer regens while keeping consistent power between those regens. All I ever hear is how the EPA is robbing trucks of this or that so it’s good that I can respond back to my friends that I’ve been able to take back any lost efficiency while legally adding performance to my 6.4L.

Bully Dog truly is a pioneer who is blazing it own trail in the diesel industry and currently offering a solution that no other aftermarket company has been able to offer to this point. It feels good to be riding around in an emissions-compliant Power Stroke while still experiencing horsepower and torque gains over what I had before with my stock truck. After adding the Performance DPF to my Ford, I’d highly recommend other 6.4L owners to do the same.

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