Gas milage for a diesel / gas engine

Thanks for that explanation. I never knew exactly how the DEF process worked.

I know the DPF system works because these new trucks don't smoke, but I sure hate to see that 'DPF Working' message appear on my dash monitor because the MPG readout heads for the basement for about 10 minutes. Despite that, these trucks still get great mileage.

One more answer to the OP’s original question:
Pulling the exact same 6000 lb. 10.5’ tall trailer, my 4.6 gas F-150 or 5.4 gas Expedition would get 8.5 mpg. Our 2012 6.7 diesel F-350 got 10.5 mpg. Everything else equal diesel will always get better fuel economy (usually stated at 15 – 30% better) because the engine will be up to 15% more efficient and the fuel contains up to 15% more btu per gallon. But that isn’t the end of the story because torque curve, engine weight, fuel cost, engine cost, mileage before trading on the replacement vehicle, etc. are important too. The diesel/gas comparisons will not be truly valid until someone comes out with a turbo, direct injected, 5.0 gas engine to compare to the on coming turbo, direct injected, 5.0 Cummins diesel engine—then we’ll have a real comparison.

On a quick read I’m not sure that the DEF DPF issue has been truly explained:
Back in the middle of last decade the EPA began to require reduced NOx levels from diesel exhaust. The first approach was EGR and engine tuning including a richer mixture. By 2008 the requirements included eliminating the black soot particles so DPF was added. The first approach to getting rid of the soot plugging up the DPF was to raise the exhaust temperature by injecting extra fuel at some place in the exhaust stream increasing the exhaust temperature in the catalytic converter to literally burn up the soot. For 2011 models the EPA required a further reduction in NOx. This level is extremely difficult to accomplish with EGR and tuning. Navistar just about went out of business trying to accomplish this method on class 8 diesel engines and had to give up. Just about every engine larger than a small car engine went to the DEF method. This method tunes the engine leaner but produces more NOx in the engine. The NOx is then broken down in one stage of the converter by injecting DEF in the presence of certain rare metals. At the same time monitoring of soot in the DPF and improved DPF design has allowed engine control to reduce the amount of fuel needed to burn off soot. Both of these changes have contributed to much better fuel mileage in the current crop of trucks than the 2008 – 2010 models.
EGR—Exhaust Gas Recirculation
DPF—Diesel Particulate Filter
DEF—Diesel Exhaust Fluid

Hey kroghville... How big/heavy was your rig?

Recent trip to Texas; Left Wisconsin @ -7degrees, arrived TX 11.2 mpg. on computer. Returned to WI. 12.4 mpg. Total Miles 4890. Approx. 2800 miles were towing. Usually average 18-20 mpg. when running around not towing. 2011 f-350 6.7 L.

Ok, I can understand Kalifornia, they're out there anyway. The link you gave for Texas refers to civil statues and refers enforcement to the EPA. It notes it is illegal and lists up to a 10k fine. Nowhere does it say who enforces it. Any law with penalties has to have an enforcement clause which defines penalties and enforcement action and who can take them.

I pull 34STAT cedar creek 5er with 05 dodge dually 5.9 any where 11.8 to 14.0 depending on road type.

avvidclif1 wrote:

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:
2012 F350 diesel SRW CC pulling a 16K 5th wheel 12.2mpg cruse control set 62mph highway when possible entire trip from California to Connecticut in the summer. MPG would increase to 12.5 if there was no DPF cleaning. Note I use no fuel additives and the Ctane is no lower than 40 at Pilot truck stops.

I thought 2012 was the 6.7 without a DPF??? Does it use DEF?

It is against the law for Ford to sell trucks without a DPF, diesel particulate filter, in the USA. If a DPF delete kit is installed by an owner they are in violation of the law and Ford with not service the truck under warranty. Ford does sell DPF delete truck in other countries that do not require DPF.

Who enforces the LAWS you keep quoting?

The state enforces the law.

Ok who in the state is checking for DPF's, who is writing tickets? Your answer is so generic it's hilarious.

And every state has different laws

I can answer for Washington. Some of the WSP are hip to DPF deletes, especially if you're in an emissions county. They will look under there and if they're missing the big canister, they will issue a fix-it ticket (typically). Of course you just gotta get stuff installed and then signed off at the WSP inspection area. However, there is a $10k federal fine for tampering with emissions.

Now you note that you're in Texas, here's your law LINK. All it would take is a cop who is hip to this and having a bad day to make your life miserable.

Also, in the good state of California, they have visual inspections for emissions equipment. They've clamped down hard on this stuff like any hardcore socialistic regime. The cops are well aware of what equipment to look for and such. So it's happening, and it will continue to spread as long as clean air is a priority in DC and in the individual states.

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:
2012 F350 diesel SRW CC pulling a 16K 5th wheel 12.2mpg cruse control set 62mph highway when possible entire trip from California to Connecticut in the summer. MPG would increase to 12.5 if there was no DPF cleaning. Note I use no fuel additives and the Ctane is no lower than 40 at Pilot truck stops.

I thought 2012 was the 6.7 without a DPF??? Does it use DEF?

It is against the law for Ford to sell trucks without a DPF, diesel particulate filter, in the USA. If a DPF delete kit is installed by an owner they are in violation of the law and Ford with not service the truck under warranty. Ford does sell DPF delete truck in other countries that do not require DPF.

Who enforces the LAWS you keep quoting?

The state enforces the law.

Ok who in the state is checking for DPF's, who is writing tickets? Your answer is so generic it's hilarious.

And every state has different laws

avvidclif1 wrote:

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:
2012 F350 diesel SRW CC pulling a 16K 5th wheel 12.2mpg cruse control set 62mph highway when possible entire trip from California to Connecticut in the summer. MPG would increase to 12.5 if there was no DPF cleaning. Note I use no fuel additives and the Ctane is no lower than 40 at Pilot truck stops.

I thought 2012 was the 6.7 without a DPF??? Does it use DEF?

It is against the law for Ford to sell trucks without a DPF, diesel particulate filter, in the USA. If a DPF delete kit is installed by an owner they are in violation of the law and Ford with not service the truck under warranty. Ford does sell DPF delete truck in other countries that do not require DPF.

Who enforces the LAWS you keep quoting?

The state enforces the law.

neal10a wrote:

avvidclif1 wrote:

neal10a wrote:
2012 F350 diesel SRW CC pulling a 16K 5th wheel 12.2mpg cruse control set 62mph highway when possible entire trip from California to Connecticut in the summer. MPG would increase to 12.5 if there was no DPF cleaning. Note I use no fuel additives and the Ctane is no lower than 40 at Pilot truck stops.

I thought 2012 was the 6.7 without a DPF??? Does it use DEF?

It is against the law for Ford to sell trucks without a DPF, diesel particulate filter, in the USA. If a DPF delete kit is installed by an owner they are in violation of the law and Ford with not service the truck under warranty. Ford does sell DPF delete truck in other countries that do not require DPF.

Who enforces the LAWS you keep quoting?