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 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 20 mpg running solo (not pulling the trailer) on level ground at 55-60 mph (as you might expect, fuel economy is very speed & grade sensitive!). What we have now works well for our needs, but there are cheaper ways to get to this point.

We started in late 2010 with nearly everything Banks Engineering makes for our truck (6 Gun tuner & iQ display, air cleaner, DPF-back exhaust and inter-cooler). 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, the dramatic improvement in mileage I had hoped for. In fact, the firmware mod Ford supplied in 2011 produced about the same result and that was free.

A little about Ford’s f/w mod – While the mod probably addressed several things, the part of Ford’s f/w mod that improved fuel economy did so by simply reducing the amount of cleaning being done to the DPF (less frequent; shorter duration). Basically, if you don’t clean the DPF as much, you don’t use as much fuel. It was clear to me we weren’t going to materially affect our fuel economy until we stopped having to clean the DPF.

Then on the way back from the east coast an EGR system temperature sensor in the DPF died in the middle of Oklahoma. I couldn’t start the truck. I found a Ford dealer in Sayre, OK to do the repair on short notice, but the resulting Ford-designed repair nearly destroyed the truck. That experience left me prejudiced about the hazards of DPF and EGR systems in general. It was time to do something about the EGR system.

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. Here’s what we ended up with when all was said and done:

• Banks 6 Gun Tuner, air intake system, DPF-back exhaust, inter-cooler
• DPF-delete kit (about 30″ piece of stainless pipe)
• H&S MiniMax tuner

The Banks system doesn’t change anything in the Ford ECM; it lives between the ECM and the engine and functions by increasing or reducing the fueling commands sent to the engine from the ECM. With Banks equipment, the EGR (exhaust gas regeneration) system continues to operate and you can pass a CARB (California Air Resources Board) 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 stock ECM still goes into the regeneration cycle and any fuel saving goes right out the tail pipe. If you just install a DPF-delete kit without doing anything about the f/w to eliminate cleaning cycles, the  ECM will fail to work because at least 3 sensors are no longer operating as expected.

Since the Banks tuner doesn’t change anything within the Ford ECM to disable EGR, we needed a different tuner (ECM-simulator) that would turn off EGR. Plus we needed a DPF-delete kit (simply a piece of 4″ stainless 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 H&S 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… you can never go back.

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 choose any of the 3 power levels. In our case we just wanted the firmware installed then left in the Stock setting (0 HP gain; the Mini-Max is capable of boosting power as much as +500 HP!) where it will stay as long as we own the truck.

With the new f/w installed, the tiny Mini-Max display and cable are removed (and saved!)and the Banks is re-connected between the ECM and engine. Both tuning systems (Banks 6-Gun Tuner and display as well as the H&S Mini-Max ECM firmware) are installed and operating simultaneously, i.e. the Banks is “piggy-backed” on the Mini-Max… the Banks thinks it’s listening to the stock ECM and the Mini-Max thinks it’s controlling everything.

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. Done properly – ours was, thanks to Scott Spear at Spear’s Auto Center – I would expect another 6.4L PowerStroke diesel to produce a similar improvement in fuel economy to what we have seen. But again, their are no guarantees. Eliminating the DPF cleaning cycle and the associated 150# DPF, providing 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. The Banks tech support folks 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 significantly 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 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% – 50% less fuel. To my knowledge, that sort of data is unavailable… ???

A word of caution

Before you get too enthused about seeing your mileage jump from under 9 mpg up to over 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. Here’s a few talking-points to start considering:

• There’s no guaranty from anyone you’ll get improved fuel economy. Period. The after-market equipment suppliers won’t even talk to you about mileage. 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.
• Examine your 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 an after-market supplier in your truck’s ECM will end any warranty coverage (our warranty had already 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 our exhaust 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.

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, Scott Spear is your man!

Similar mods are available for all recent American diesel powered trucks (Dodge, GMC/Chevy, other Fords). In fact, I got launched on this path by a guy with a 2006 Dodge with a 6.5L 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.

Update: Scott isn’t currently working at his dad’s shop (Spear’s Auto Center) in Cedar Crest, NM (though the shop still does repairs on Banks systems). Now days you can find Scott at Car Crafters in Albuquerque.