“Who has the best diesel tuning?” is a question that is asked over and over on various internet pages. Diesel tuning to enhance performance is nothing new. In fact, it is usually one of the first upgrades made to a truck right after it is purchased. But tuning can come in various forms, and knowing what will work best for your truck means understanding what you need from your truck and talking to people who understand the tuning process.

I wanted — scratch that — I needed to add transmission tuning to Project WorkHorse and since that requires the use of a custom tuner, I knew I needed some help. I checked out a few diesel forums and social media pages and learned that Calibrated Power is highly regarded as “one of the good ones.” So, to get some answers that would educate me and ultimately not lead you down the wrong path as I write this article, I spoke to Chris Ehmke at Calibrated to see what he would recommend for Project WorkHorse.

(Editor’s Note: Although I am working on a Ram with a Cummins engine, Calibrated Power has tunes for GM and Ford trucks as well.)

According to Chris, “I’d say the Ram is a great foundation for diesel tuning. These trucks do have some ‘flaws’ in factory form, but nothing that can’t be addressed. Our main goal is to make these trucks more drivable and responsive, and improve upon the truck’s overall operation.”

Switch On The Fly Diesel Tuning For More Options

During our conversation, Chris mentioned that Calibrated has several options for almost every truck on the road, ranging from tunes for those who tow lightly, tow heavy loads, or want a performance tune. Since WorkHorse is an all-purpose tow rig, he recommended Calibrated Power’s emissions-intact Switch On The Fly tuning. This is an adjustable tune that offers the ability to change between five tuning levels while driving. This adjustability gives you the option of utilizing any one of the five custom tunes available (Stock, Street, Performance, Light Tow, or Heavy Tow). But what does “tuning” actually do for your truck?

“As far as engine tuning, we change/recalibrate the engine’s timing operation, fueling, vane position/boost thresholds, and torque management,” Chris states. “Our engine tuning is going to change the truck’s power delivery. Most of the time guys think only about peak power, but the bigger improvement is usable power (broadening the engine’s torque curve). In doing this, the general outcome will offer improved fuel efficiency, a smoother engine operation, and of course a better response.”

When it comes to tuning the transmission, Chris went on to say, “transmission tuning will help improve the shifting characteristics of how the transmission shifts from gear to gear (less hesitation). Next, the shift schedule is changed to allow the engine to operate in its operating range. Lastly, it improves line pressure for improved clutch coupling. This has alot of benefits to a stock truck looking for an improved operation. However, as a lot of guys look into upgrading their tires, the transmission tune holds that much more value. With the bigger tire, they can support an improved shift schedule around the bigger tire.”

While diesel tuning is available for just the engine or transmission, the Switch On The Fly tuning adjusts parameters for both. This will definitely help WorkHorse since it has a heavy trailer hooked to it quite often.  “We generally recommend doing both together,” says Chris. “The engine tuning gives us the ability to improve the truck’s responsiveness and improve the usable power the engine has to offer.  At the same time, we are able to offer an improved operation to the transmission in the form of the transmission’s shift schedule and line pressure to improve clutch coupling.  A big complaint owners of these trucks have is the ‘clunkiness’ with the 68s.  So pairing the engine and trans calibration together gives us the ability to tune some of that out.”

Sport Tune

• Additional 100 horsepower and 180 lb-ft of torque
• Fastest possible acceleration
• Firm shifting

Street Tune

• Additional 80 horsepower and 144 lb-ft of torque
• Retains factory turbo-braking feature

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To upload the tuning to a 2019 and newer Ram, you will need to purchase a separate "bypass connector (left). This wiring is needed to allow you to upload the tuning as the newer trucks have a Gateway Security module that needs to be bypassed. The small plug connector is plugged into the green junction box under the dash on the left side of the cab. The other OBD-II connector is piggybacked with the EFILive upload device.

Light Tow

• Horsepower and torque increase of 40 horsepower and 72 lb-ft of torque
• A balance between Daily Driving and Towing
• Custom “SMART EGT Control” will automatically manage your EGTs
• Air-fuel ratio limits built into calibration to limit soot production
• Designed to tow less than 8,000 pounds
• Factory turbo brake retains complete functionality
• Revised pedal sensitivity

Heavy Tow

• Horsepower and torque increase of 20 horsepower and  36 lb-ft of torque
• Safe for towing heavy
• Increase power, not EGTs
• Air-fuel ratio limits built into calibration to limit soot production
• Designed to tow 8,000 pounds up to GVW
• Factory turbo brake retains complete functionality
• Revised pedal sensitivity

Optimized Stock

• Slight revisions to factory calibration
• No significant increase in peak power

Initially, I was mostly concerned with transmission tuning. Sure, the 68RFE in my truck worked “okay”, but I was not a fan of how sluggish it felt every time it shifted. Before this, I upgraded the valve body which helped with the sluggish feel. But I knew that the addition of tuning could make the transmission even more reliable. I say that because line pressure is a big issue with the latest electronic transmissions, and with the upgraded valve body and the addition of tuning, as Chris stated, line pressure can be increased to ensure better clamping of the clutches in all gears. This means the frictions and steels will not slip and can offer longer life.

Transmission tuning alters certain parameters of the Transmission Control Module’s (TCM) calibration that control the way a transmission shifts. According to Chris, “from the factory, your truck’s transmission calibration leaves a lot to be desired. Pretty much everything in modern diesel pickups is decided by the computer, and this holds true for transmissions too — from determining line pressure through the gears to deciding when the torque converter locks up.  The factory calibration simply isn’t configured for optimal performance or driving experience, meaning there’s untapped potential just sitting in your truck right now, even if it’s bone stock.”

Better Diesel Tuning With A Mouse Click

So, with the required switch-on-the-fly diesel tuning chosen, Chris emailed me the files I needed so I could upload them to my EFILive Flashscan and then into the truck. If you do not have an EFILive device of your own, don’t worry. Calibrated Power can put the necessary tuning on a device and mail it to you. All you will need to do is attach the device to your OBD-II port and upload the tune.

Just like when I swapped the valve body, the transmission will once again need a relearn process. If you have access to a computer or scanner that can accomplish this, great. I do not, so just like when I changed out the valve body, I drove the truck “gently” for about 100 miles (in each of the tunes) to ensure all the parameters were as needed. By gently, I mean at less than 30 percent throttle application and did not tow anything. While my Ram is capable of a relearn without a computer, not all trucks are.

After the learning process was complete, I definitely noticed a change in the shift pattern. I noticed the truck was winding higher into the RPM range between each shift. I reached out to Chris to find out why this was happening.

“Calibrated has two shift programs, an extreme, and a mild shift, he relays. The Extreme shift is intended for trucks with bigger tires. For a standard tire-size truck, I strongly recommend the mild transmission tune. Both transmission tunes will have line pressures added, but the shift scheduling will be different amongst the different transmission files for the different tire size/gear ratios these trucks may see.”

Diesel Tuning Complete

That said, Chris sent me the mild-shift tune for me to load into WorkHorse. I immediately noticed firmer shifts and each time I drove the truck, I could feel the shift quality getting even better. Again, it will take roughly 100 miles of easy, in-town driving to help the transmission relearn. With the tuning installed, I asked Chris about the need for the Tow/Haul mode to be activated. “After the tuning is complete I still strongly encourage the use of Tow/Haul when towing.  This will work in conjunction with our tuning.”

Project WorkHorse is quickly becoming the ultimate towing machine I had hoped for, and now with a solid bevy of switch-on-the-fly tuning options at the touch of a five-position knob, There is no worrying about what I haul or tow, as I know the Ram will do it with ease.