Jerome writes: In delving further in to the morass of biodiesel and new engines ... I have looked into "DPF delete kits," and wanted to get your thoughts on them ... these kits seem mostly for off road use as they hurt emissions, but by running biodiesel I would not be doing that. Do you think this kit would solve the issue of running the biodiesel in a new truck like my F-250 2008? Are their claims for higher mileage and power anything to believe, or just hollow claims? I appreciate your time.
Regarding your specific comments and questions--just to keep things nice and organized--we'll step through them one-by-one as we did in the previous response. But first, as a general comment, we don't have any direct experience with the company "DPF Delete Kits." We did however spend time investigating their website, the claims they make and the products that they offer.
... these kits seem mostly for off road use as they hurt emissions, but by running biodiesel I would not be doing that.
First off, these kits are absolutely intended for off-road use only, and installing them for use with on-highway diesels is illegal. Note that you must sign a liability waiver before they will even ship the parts. Secondly, running biodiesel (BD) only, in lieu of diesel fuel, will not mitigate the emissions that are captured by the DPF and other exhaust components. While BD does significantly reduce most harmful diesel engine emissions, it does not eliminate them, not by a long shot. The exhaust stack catalysts and filters still play a predominant role in clean diesel emissions. Here's a short list of regulated emissions average change by using pure B100 (no diesel fuel dilution) versus diesel fuel:
Unburned hydrocarbons ......... -67%
Particulates (soot) .................. -47%
Carbon monoxide ................... -48%
Oxides of Nitrogen .................. +10%
Source: National Biodiesel Board
Alarmingly, oxides of nitrogen actually go up by 10 percent (this is caused by the complicated relationship among cylinder temperature, cylinder pressure, fuel delivery timing and the presence of nitrogen in the atmosphere). These are just some of the reasons why the EPA put such harsh restrictions on diesel emissions and why it's illegal to remove the emissions components.
Do you think this kit would solve the issue of running the biodiesel in a new truck like my F250 2008?
As you can see, burning BD without the DPF will still emit substantial soot, and further, by removing the oxidation catalyst (with their CAT/DPF delete kit), the suppression of CO and NOx will be eliminated. Beyond that, removing/altering any emissions components would likely void the manufacturers warranty on the exhaust stack (from the manifolds to the pipe tip cooler) and could impact the EGR and turbo (which are driven by exhaust gases) warranties as well.
Are their claims for higher mileage and power anything to believe, or just hollow claims?
Well, as good of a job as the catalytic converters and the DPF do on scrubbing emissions, they do introduce the penalty of back-pressure. Back-pressure (you probably know this, but just in case) is caused by the restriction of the flow of exhaust gases as they exit the combustion chamber and travel through the exhaust stack and out the tail pipe. Culprits are: bends in the pipe, catalytic converters, traps and mufflers. The higher the back-pressure, the harder the engine has to work to force out spent gases, and thus the more fuel it consumes and the less power it can deliver to the wheels. It stands to reason that removing the DPF and OxyCat would reduce backpressure and improve fuel efficiency and engine power.
When we did our test drive and review of the 2008 Ford Super Duty Diesel, we averaged between 14 and 16 mpg. According to their website, the folks at DPF Delete Kits guarantee a 4-7 mpg increase. Doing the math from our observed mileage, that's a range of 26 to 47 percent. Honestly, that seems incredibly optimistic to us. We'd be more inclined to believe something on the order of 10 to 15 percent. Yes, the emissions scrubbers do inhibit exhaust gas flow, but realize that the exhaust stack on these big trucks is already 4 or so inches in diameter, so free-flow is pretty much designed into the system. We think their claims are based on more than reduced back-pressure. The kit does include a flash device to reprogram the truck's onboard computer for fuel delivery, shift points, rev limits etc. That is probably what the performance and mpg promise is really based upon.
Hope this helps,
Christine and Scott