With the L5P being the newest Duramax engine on the scene, it's also one of the best performing right out of the box, making 400hp and 850 ft-lbs of torque when tested on our dyno. This iteration of the Duramax engine was designed in all the right ways, with a thicker crankshaft, a more advanced turbo, and pistons that can handle more load and heat than we've ever seen in a stock Duramax engine. Not only do we get improved performance, but we also get an engine that can handle way more power than it left the factory with. Which means that with bolt-on upgrades alone, you can raise horsepower way beyond stock without having to do any upgrades to the engine's internals. We've seen L5Ps pushing up to 900 HP on the stock internals. Even trucks still equipped with emissions systems can gain about 300 HP and 500 ft-lbs of torque with just a few bolt-on upgrades.
1. Custom Tuning
If you want to bump up the horsepower right off the bat, then custom tuning is a great place to start. The L5P already has a lot of power from the factory. However, there is much more power to be had from the stock engine through tuning alone. When first researching tuning options for L5P's rookie diesel owners, you may be tempted to go with a box tuner. These devices manipulate the ECM to increase the amount of fuel added per injection. While this can result in more power, it does so at the cost of efficiency. What you really want for your L5P is custom tuning. Custom tuning is designed to bring every element of the combustion cycle to peak efficiency. Custom tuning (offered by DuramaxTuner.com) can bring the horsepower of a stock truck with a full emissions system equipped up to 595hp and 1180 ft-lbs torque. Making this a great way to get the maximum power out of an engine. Including engines with performance upgrades already installed. If your truck has a few bolt-on upgrades, a bigger turbo, or an aftermarket intake, custom tuning is the best way to get the most power from your upgraded components.
If you use your truck to haul heavy loads regularly, there are also tunes designed specifically for you. They will allow you to get the maximum torque and power from the engine while keeping it safe from high exhaust gas temperatures generated under heavy load. They can also improve fuel economy by providing more power, which allows the transmission to stay in higher gears and the engine to run at lower RPM. Less reciprocating mass will always improve fuel efficiency. This is a great performance upgrade for your tow rig.
For many, this is great to hear. If you're looking to take the L5P to its absolute limits. While some choose to delete their truck, most of us won't actually need to. You can still have a responsive truck that's fun to drive without the added cost of deleting.
2. Transmission
The transmission is how you get all that power from the engine to the ground. If your transmission isn't shifting where you'd like it to, you could be giving up a lot of that power. Transmission tuning is the best way to fix that. By adjusting the shift scheduling and torque converter lock-up scheduling, the transmission can more effectively take advantage of the engine's wider power band. Giving the transmission access to more top-end power.
This is especially useful when the engine already has a tune or other modifications installed that alter the stock power band. Any time the engine's power band or drive-output ratios change, such as when installing larger-than-stock tires, attention should be given to tuning the Transmission Control Module (TCM). That said, any planned modifications to the truck should be completed before the TCM upgrade.
In addition to improving performance, transmission tuning can enhance your transmission's durability. By electronically increasing line pressure, you can increase the clutch packs' holding strength, improving your transmission's durability during lugging or high-output scenarios.
3. Turbo
Upgrading the stock turbo is one of the best ways to get peak performance out of an L5P. You’ll only be able to get around 600hp out of the stock motor with tuning. The turbo is your limiting factor.
The stock turbo is capable of moving 60-62 pounds per minute (ppm). Typical power figures show that for every 1ppm, we can expect to get 10hp. We can calculate that the stock turbo is good for up to 600hp, maybe 620hp on the best day, with a proper tune. If you want to see horsepower figures above 600, you will need to upgrade from stock. With an upgraded turbocharger, you can expect to get anywhere from 70ppm to 80ppm, allowing maximum horsepower to reach the 700hp-800hp range. These horsepower figures are only achievable with a tune; however, upgrading your turbo on a stock tune will net you only an additional 20-25hp over stock. So tuning should also be a priority when deciding to upgrade turbos.
4. Intake
When it comes to intakes on the market for the L5P, there are many options. From cold air intakes to turbo intake horns, knowing when and where to start is important for getting the most bang for your buck. Upgrading parts of your intake makes for a great supporting modification alongside other upgrades you may want to do to your truck.
If you are thinking about getting a tune or upgrading your turbo, then installing an aftermarket intake on top of either is a great idea. This will give you the most power for your money and help you maximize the performance you get from your tune or turbo upgrade. Getting your truck tuned is definitely necessary to get actual performance out of an aftermarket intake. Without a tune, you may see a slight increase in performance and better fuel efficiency. But you won't be able to use it to its full potential without tuning.
If upgrading your stock turbo is in your plans, an upgraded intake horn is also necessary. The stock plastic intake horn the L5P comes with will choke any upgraded turbo. The upgraded intakes on the market all feature larger 3.5 in tubing and a less restrictive opening. Providing more air volume and smoother flow to the turbo inlet. This less restrictive opening does come with a price, though, and that is the turbo surge. Since most aftermarket intake horns either don't include anti-surge features or have very poor supplements for the stock solution. Turbo surge, which will shorten the turbo's life, is almost certain to occur. Therefore, an aftermarket anti-surge ring is also something you won't want to go without if you are planning on upgrading the turbo along with the turbo intake horn. The upgraded surge ring simulates the stock anti-surge ring built into the stock intake horn but is redesigned to provide a larger opening to match the upgraded turbo’s larger compressor inlet. This will prevent any restriction while providing better anti-surge performance than aftermarket intakes alone.
Cold air intakes are another possible upgrade to your L5P’s intake system. Aftermarket cold air intakes, such as those offered by WCFab, all feature enclosed air boxes that still use the factory ram-air intake. All cold air intakes keep intake air cooler, resulting in higher air density and more air entering the engine. Cooler intake air temps, combined with improved designs for better flow and less-restrictive filters, all add up to producing more power with better efficiency. Some cold air intakes even claim to reduce soot output, which will allow more time in between regen cycles. Just by adding a cold air intake, you can expect a slight bump in power of around 10-12 HP; however, as with any case, adding a tune on top of the cold air intake will get you the most performance out of it. On a tuned truck that's only sporting a cold air intake, you can expect to see an extra 30-40hp on top of what the tune could normally add.
Summary
With these simple modifications, much more performance can be extracted from the L5P platform. Tuning is arguably one of the best ways to see a large increase in power right off the bat or get you the most power from a heavily modified engine. If peak performance is what you want from your L5P, the turbo and intake are both limiting factors that need to be upgraded. As well as the transmission, which is another very important part of getting all that power you’ve made to the ground. All of these mods should be done together to get the best version of your L5P. Overall planning should be done to maximize the efficiency of the parts you choose to add and get the biggest power increase for your money. This list was made so you know which potential upgrades for your L5P are worthwhile and how they can best be used together.
