Truck repairs and changes

1 November 2012

Hey, dude... what did you have to do to get your mileage to improve so much?

If reading technical details about our truck (repairs, mods, whatever) is b-o-r-i-n-g and if hearing again my obsessive rhetoric about fuel mileage makes your eyes glaze over, you'll want to skip this post.

To anyone left, if you've read through the our year-and-a-half of whining and up & down emotions with each mod or repair, you know we've spent a lot of $$$ to get to 13 mpg when pulling our 15,000# Montana over fairly level ground. What's more, we're now getting about 17 mpg running solo on level ground at 55-60 mph. What we have now works well for our needs, but there are cheaper ways to get to this point.

We started with nearly everything Banks makes for our truck (air cleaner, DPF-back exhaust, inter-cooler, and their 6-Gun Tuner). It helped improve fuel economy by 15-20% and it was all CARB-approved mods (it could pass a pollution inspection in California). It was not, however, a dramatic improvement in mileage. In fact, the firmware mod Ford supplied in 2011 produced about the same result.

Then the EGR system temperature sensor in the DPF died. The resulting Ford-approved repair by the dealer in Sayre, OK nearly destroyed the truck and left me prejudiced about the hazards of DPF and EGR systems in general.

Thanks to having access to a mechanic that has dealt with all this before, I learned about a way to keep the Banks tuner, remove the DPF and its attendant cleaning cycle, and have access to the power-boosting settings that our Banks tuner offered. As I see it, it's not till you defeat the EGR system that you get meaningful improvement in fuel economy.

But before you get too enthused about seeing your mileage jump from 9 mpg up to 13 mpg while pulling a 15,000 lb. load on level ground, there are a few things you need to inform yourself about. There are more issues than just fuel consumption, but here's a few talking-points to start considering:

• There's no guaranty from anyone you'll get improved fuel economy, Period. They won't even talk to you about it. DPF-delete plus a compatible tuner is strictly an off-road system.
• You're left with a truck that will never pass a pollution inspection, so understand what your state requires.
• Understand your own feelings about driving a truck that may cause more pollution. Your personal cost of fuel isn't the only issue.
• Installing the necessary non-Ford firmware from S&C in our Ford's ECM would have  ended any warranty coverage; our warranty had expired July 2012.
• I'm told some (most?) dealers won't work on a truck with these mods even if the repair is unrelated to the mod. That may be urban myth, but you should ask your local dealer if you think you may need their help at some point, like to repair the transmission or change the oil.
• Diesels have smelly exhaust, but ours seems stronger than when the truck was stock.

So do your homework to understand the ramifications, both legal and practical. Installing a DPF-delete kit in the exhaust and loading 3rd party firmware in the Ford engine control module (ECM) is a slippery slope. There are traps, trade-offs and the potential for damage to your wallet and your truck.

This is the hardware we ended up with

In our case we already had a Banks 6-Gun Tuner and all the other Banks hardware. But our Banks doesn't change anything in the Ford ECM... it lives between the ECM and the engine. So with Banks equipment, the EGR (exhaust gas regeneration) system continues to operate and you can pass a CARB inspection in California (CARB has approved the Banks 6-Gun and a sticker with the permit number is supplied by Banks). No matter what Banks has done to improve mileage, the ECM still goes into the regeneration cycle and the mileage goes right out the tail pipe. If you just install a DPF-delete kit, which is nothing but a piece of tubing that fits where the DPF used to be, the  ECM will fail to work because certain sensors are no longer installed.

Since the Banks tuner doesn't change anything in the Ford ECM to disable EGR, we needed a different tuner that would turn off EGR plus a DPF-delete kit (a piece of " or 5" exhaust tubing). With that tuner installed first, then the Banks tuner can be "piggy-backed" on it and continue to modify fuel flow as it always has. Scott steered us toward the S&C Mini-Max tuner as it's been proven in this application. The Mini-Max replaces the stock Ford ECM firmware with something similar except it has no EGR functions. At this point your warranty is dead and you've got an off-road vehicle.

The Mini-Max must be installed in a specific way prior to re-connecting the Banks 6-Gun tuner. Normally the Mini-Max display and cable is used to install new firmware in the Ford ECM and then left in place so you can see truck/engine operating parameters as well as set any of the 3 power levels. In our case we just wanted the firmware installed then left in the Stock setting (0 HP gain). With that done the Mini-Max display and cable can be removed and the Banks re-connected between the ECM and engine. Both tuning systems (Banks 6-Gun Tuner and display as well as the S&C Mini-Max ECM firmware but not its display) are installed and operating simultaneously, i.e. the Banks is "piggy-backed" on the Mini-Max.

In our installation, none of the Mini-Max hardware is used after the replacement firmware is installed. The 6-Gun display continues to operate the Banks tuner, completely oblivious to the presence of the modified ECM firmware. S&C has created some impressive tunes for their system (as high as +500 HP over stock on a 6.4L Ford), but only one is available without their display. So for our installation the S&C will be left set to Stock for as long as we have the truck.

The tech doing the mod really needs to have been down this road before- it's complicated! Doing something out of sequence can leave you with a dead truck. If it's done properly - ours was, thanks to Scott Spear at Spear's Auto Center - I would expect your 6.4L PowerStroke diesel to produce a similar improvement in fuel economy to what we have seen. But again, their are no guarantees. The exhaust cleaning cycle, elimination of about 150# of metal, cooler inlet air (that's what the inter-cooler does for us), and less-restricted intake and exhaust are all involved in making the engine more efficient.

We've never felt a need for more power from our 2008 Ford F-350. It has plenty of torque just as it comes from the factory. Yes, we still have the option to dial up an extra 50-185 HP, but what for? If it reduces our fuel economy, we're not interested. Banks will tell you, though, that the best economy may not come from the lowest power setting. Yet I continue to avoid those higher settings because my greater concern has always been that more power may cause transmission or differential damage.

On the down side, the exhaust odor while idling is stronger than when the DPF was installed and we've found we're getting a little diesel exhaust inside the Montana while we're pulling. I guess the latter explains why some some owners install vertical exhaust stacks on their pickups. Plus we're at risk of being cited and fined for having tampered with the EPA-approved exhaust system.

I'd love to see numbers which compare emissions caused by the stock system (including the ash blown out during cleaning) vs. a system that defeats pollution controls while using 40% less fuel. To my knowledge, that sort of data is unavailable... ???

If you decide to attack the fuel economy issues with your truck, get a good diesel tech to help you and to do the work, or at the very least guide you. That ain't me, but if you're near central New Mexico (Cedar Crest, NM), Scott Spear is your man!

One more thing: our truck is a 2008 Ford F-350 with the 6.4L PowerStroke diesel with 4-wheel drive, long bed, dual rear wheels, 4.10 differential, stock tires, tow package. It's big and it's heavy. I would expect what I've described above to be applicable to any similarly equipped Ford F-350 PowerStroke, but if you have anything different - e.g. single rear wheels, 2-wheel drive, whatever - the results will surely be different. Maybe better, maybe worse, but certainly different.

Similar mods are available for all recent American trucks (Dodge, GMC/Chevy, other Fords). In fact, I got launched on this path by a guy with a 2006 Dodge with a  Cummins diesel. Do your homework for your truck. I'm just highlighting one way to peel this onion called fuel economy. I will never recommend anyone else do what we've done.

There are a few forums where you can get info from other owners... Google is your friend. Lots to be found out there. Just remember that along with all the good info is a lot of stuff that's flat wrong! It's your job to separate the wheat from the chaff.