5 L5P Duramax Tuning Tips

Steve Gadd

Steve Gadd

Outdoor photo of a black 2020 L5P Duramax diesel pickup truck.

Thinking about putting some more power to the wheels of your L5P Duramax?

There’s nothing more satisfying than the first drive after installing tuning on your vehicle; the immediate change in power delivery and driveability is something that will surely put a grin on any driver’s face.

There are a number of different tuning platforms available on the market right now but you can divide them into two categories: custom tuning and box tuners. For this article we’ll focus on the former, given that we specialize in custom tuning.

Motor Ops and other custom tuning companies deliver their L5P calibrations on HP Tuners platform. This platform allows tuners, such as ourselves, to deliver calibrations that provide industry-leading power gains and perfected driveability without sacrificing reliability.

Once you’ve decided you’re ready to tune your truck and maybe add some other aftermarket goodies onto it, here are 5 tips that will make sure your L5P Duramax tuning experience is nice and smooth.

1. Do NOT install your aftermarket parts onto the truck until after it has been tuned

We see this happen on a daily basis. Sometimes the parts show up before all the tuning hardware gets delivered and the customer gets excited to get those new shiny parts on so they dig in and get them installed only to find out that the truck doesn’t drive well without the tuning installed.

In some cases this can even leave your truck undriveable until the tuning hardware arrives. When this happens it could mean that all the time you would have to remove the aftermarket parts installed, reinstall the OEM parts, install the tuning, and then reinstall the aftermarket parts. That seems incredibly counter productive, doesn’t it? Pump the brakes, wait for the tuning hardware to arrive and install the tuning first.


2. Install the tune when your custom tuning company is open

If this is your first tuning experience, it’d be most ideal to perform the tuning process when the company you bought your tune from is open so that they can assist you in installing the hardware, if needed.

That might , but The L5P tuning process is more in-depth than tuning any other previous Duramax models.

On older Duramax models (LB7, LLY, LBZ, LMM, and LML), tuning hardware has been able to unlock the ECM and TCM through the OBDII port during a programming sequence. That’s not the case on L5Ps, though, which is why you need to get an HP Tuners Modified ECM in order to get true custom tuning support.

Have a question about your tune? Don’t hesitate to reach out to us for help.

3. Read through the instructions thoroughly

Reading instructions might not sound like much fun, but what if doing so was the difference between your truck running properly or not running at all?

That’s the reality, so make sure to follow the instructions provided and the whole process will move forward seamlessly.

4. Let your transmission go through a re-learn procedure

As soon as you’ve completed your tuning, you’re going to want to go out and give the truck a beat down, right? I mean, you just paid to have peak performance and reliability so why shouldn’t you be able to go throw the throttle down?

Wrong, that kind of thinking could put your transmission in jeopardy of premature failure.

We recommend going out and allowing your truck to shift through the gears with various throttle inputs. Start at 10% throttle, then 25% throttle, then 35% throttle, then 50% throttle, and make your way all the way up to 100% gradually.

What you’re doing is giving the transmission a chance to learn the new torque curve so that it can anticipate what is coming at it, preventing against premature failure.

5. Use the correct tune for your truck

This might seem to go without saying, but we hear from a lot of people who tow their trucks in the race tune.

Don’t do that to your truck, it won’t appreciate it , and neither will your bank account when you need  to do a rebuilt transmission after towing your boat in the race tune 3 or 4 times.

The tow tune is designed for towing, our Sport Economy Tune is designed for unloaded daily driving, and our Max Effort (Race) Tune is designed for performance situations when you need to put someone in the rear view mirror.

Typically guys who decide they’re going to tow in the race tune are doing it because they feel like they need the extra power and they like having the immediate torque right at their fingertips. It’s important to understand that while you may be a careful tower operating in the Race tune, the quick access to large torque values can put a beating on a torque converter that has a heavy load behind it.

Just because your EGTs (exhaust gas temperatures) are staying below 1,400 degrees Fahrenheit doesn’t mean that the truck is still within safe operation. When towing, you need to be conscious of the transmission fluid temperature, engine coolant temperature, engine oil temperatures, exhaust gas temperatures, and torque converter slip RPM.

If you’re going to regularly tow in a tune above 500 RWHP / +1000 ft lbs of torque on any stock transmission, you should get comfortable with the idea of rebuilding your transmission in the near future, understand what the safe operating temperatures are for all the listed PIDs above, and understand how heat rejection (the cooling system) operates on your truck.

(Also, if you need more than 500 RWHP / 1,000 ft. lbs of torque to tow a load, you might need to reconsider the vehicle and chassis you have selected to tow with.)

Looking for tuning? Head on over to our L5P Duramax store to have a look at our industry-leading tunes.

Steve Gadd

Steve Gadd

Steve is the owner and general manager of Motor Ops and has been involved in the diesel pickup truck tuning space for over 10 years.

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