The LML Duramax engine was introduced by GM in 2011; and equipped on the 2011, 2012, 2013, 2014, 2015 & 2016 Chevy / GMC pickup truck. With each passing year stricter emission laws are being forced onto manufactures. To comply with these mandates GM has had to install several emission components and systems to combat this. On paper and in theory these systems seem like the solution. But in practice and in the real world they are the worst thing to happen to the diesel truck industry. When these trucks are brand new everything works like it should and everyone is happy. But after 30-40k miles things take a turn for the worse. In this DPF delete guide we will explain the ins & outs of the DPF system and help you understand why doing a DPF delete is one of the best things you can do for your LML Duramax.
Emissions System Components
The 11-16 LML Duramax consists of several emission systems components. Starting at the back of the turbocharger is a short section of down pipe. Attached to the down pipe is the DOC (diesel oxidation catalyst). Behind that is the SCR (selective catalyst reduction). After that is the DPF (diesel particulate filter) from there you have the muffler and tail pipe section. The DEF (diesel exhaust fluid) tank is mounted outside the frame rail on the passenger side of the vehicle with lines routed to the exhaust so DEF can be injected into the exhaust system. All of these components can be removed with a DPF delete kit.
What is a DPF?
DPF stands for diesel particulate filter. The purpose of the DPF is to catch small unburnt particulates within its filter. These particulates are then burnt off when the truck enters its regeneration cycle. Regen is the process of heating up the DPF in an attempt to burn this particulate matter. Overtime this process becomes less and less effective. In that case the DPF becomes plugged up. When the regen process can no longer burn out this material it becomes plugged up and restricted. Fuel mileage begins to suffer substantially, back pressure increases putting more and more strain on the turbocharger, drivability suffers, horsepower and torque are also reduced.
What is SCR?
SCR stands for selective catalyst reduction. This was an additional system added to the LML in 2011. DEF (diesel exhaust fluid) gets injected into the SCR. A properly functioning SCR then turns NOX emissions into nitrogen and water. These two systems are prone to failure and often the first thing too fail.
What is DEF?
DEF (diesel exhaust fluid) is a solution of UREA and water. This fluid gets injected into the exhaust before the SCR (selective catalyst reduction). Together these systems work together to help reduce harmful emissions.
DPF delete advantages & benefits
Deleting the DPF will result in a more reliable and longer lasting engine. Keeping up with regular maintenance you can get 500k miles out of the LML Duramax. Freeing up the restriction in the exhaust alone will increase horsepower 20-30hp. Additional power is also available from DPF delete tuning. Turbo issues from excessive back pressure are eliminated. Costly repair bills and months long back-orders related to emission system components is no longer something you need to deal with. Fuel mileage gains, lower EGT’s while towing, no longer need DEF, avoid costly repairs, regen cycles are no longer needed, lower back pressure in the exhaust resulting in longer turbo life.
DPF delete downsides and disadvantages
Deleting your DPF is the best thing you can do for your truck but it does come with some potential downsides. It’s up to you to decide if the pros outweigh the cons. Most shops will not install a DPF delete kit, the liability for them isn’t worth the few hundred dollars they make from doing the install. This means you will need to do the install yourself. However, going into a shop in person and offering to pay cash with no receipt is a good work around for shops hesitant to doing the work. If you decide to trade your truck in on a new vehicle you might meet some resistance on trade in. Dealers that are familiar with diesel pickups look for deleted trucks. In most cases they will not accept a vehicle on trade if it’s not equipped with OEM components. If they do accept the trade it may reduce the resale value. If you live in a jurisdiction that requires emissions testing and they do a physical inspection you will need to reinstall the OEM components before performing this test. If they only look for a check engine light you will be find. All of the DPF delete capable tuners we sell will not a set a check engine light.
Will DPF delete void my warranty?
Technically yes, but it really depends on which dealer you talk to. Every dealership service departments knows that deleting the DPF is beneficial to the longevity and reliability of the engine. Some dealers will refuse to work on your vehicle but some will look the other way because they want the warranty work. Most issues that occur on the LML Duramax are related to the emissions system. By eliminating the emissions system entirely the need for warranty is almost non existent. By now some of these trucks are 10 years old and outside the warranty period anyway, so it’s a non issue.
What does a LML delete kit remove?
A complete delete for the LML Duramax removes the DOC, SCR, DPF, DEF & EGR.
How to delete DPF?
The vast majority of our customers install DPF delete kits themselves. With basic hand tools and couple hours of time you can remove/install exhaust and install a DPF delete tuner. If you have access to an automotive style lift it will cut the time in half. All of the DPF delete kits we sell include everything needed for a complete installation. So you're not going to need to take any special trips to the hardware store. YouTube also has a ton of resources with step by step instructions for your specific vehicle.
Is DEF fluid required?
Doing a DPF delete and installing a DPF delete tuner will deactivate the DEF system. You will no longer need to use UREA or DEF fluid. You can remove the tank completely or unplug the wiring harness and leave it installed. You may need to cap off the lines to prevent residual fluid from leaking.
Will doing a DPF delete set a check engine light?
No. With the correct DPF delete capable tuner installed you will not have any check engine light or diagnostic trouble codes set. If you have any previous codes set from emissions related issues those will also be cleared after installing a DPF delete tuner.
Is a DPF delete worth it?
We might be just a bit biased, but its 100% the best thing you can do for your truck. It’s the first thing you should do once the truck rolls off the showroom floor. The fuel mileage gains alone can pay for itself after 15k miles.
DPF delete fuel MPG gains?
One of the biggest benefits to doing a DPF delete on your LML Duramax is the fuel mileage gains. Every situation is different depending on how plugged up your current DPF is but must people are getting approx. 13-14 mpg when they decide to address the DPF. After deleting the DPF expect to see a combined 18-20 mpg, more or less depending on tire size & driving habits. We ran some numbers on how long it would take to get a return on your investment. With fuel prices currently around $5/gallon and improving fuel mileage from 13mpg to 18mpg you would save approx. $41 per 30 gallons or 540 miles of driving. After 15,000 miles you would have saved $1148.
What parts do I need?
To remove the DPF on your LML Duramax at minimum you need a DPF delete capable tuner and DPF delete pipe. A DPF delete pipe is approx. $300-$400. If you decide on a full exhaust system you will need to spend $500-$1,000 depending on if its aluminized steel or stainless steel. A DPF delete capable tuner is going to run you $800-$1,500. So for the complete setup, depending on which direction you decide to go its going to cost you anywhere from $1,200 to $2,500.
Best DPF Delete Tuner
Tuning is required when the DPF is deleted. There are several sensors in the exhaust system that will be removed during this process. The regeneration cycle also needs to be turned off. To prevent a limp home mode, check engine light and any DTC’s (diagnostic trouble codes) from setting you will need a DPF delete tuner. The best DPF delete tuner for the LML Duramax depends on the features you're looking for. Do you have additional aftermarket modification that need to tuned properly for? In that case we recommend the EFI Live AutoCal. Do you want to monitor your trucks parameters while driving? The H&S Mini Maxx would be our pick if you want a screen with gauges. Would you like to use your phone or tablet to change power levels and view gauges? The EZ Lynk Auto Agent can take care of that. There are a few other tuning options on the market but we have decided to only offer the best of the best. You really can’t go wrong with any of these three options.
Best EGR Delete
Over the years we have come across every manufacture of EGR delete kits on the market. Nowadays the only thing left is made in China junk. We couldn’t stand the idea of sourcing parts from China so we found a source in the US that can manufacture a higher quality made in America part. We offer the best EGR delete kit available for the LML Duramax.
Best DPF & CAT Delete Pipe
There are several options available on the market for a DPF & CAT delete pipe. The majority of other companies are selling made in China junk. Fitment is terrible, craftsmanship of materials is poor, etc. etc. The best DPF & Cat delete pipe for the LML Duramax is our stainless T-409 kit. The 11-15 LML Duramax uses a v-band clamp attachment for the down pipe. 2015 was a split year. If you have a 2015 truck be sure to check how the downpipes is attached. 2015.5-2016 uses a 3 bolt flange attachment for the down pipe.
Best DPF Delete Exhaust
It sounds like a broken record but what’s available on the market is limited. Other companies just want to sell what makes them the most money, ie. Made in China. We offer 4” and 5” DPF delete exhaust systems. These kits are made by two big name manufactures located in Canada. For only a few bucks more you can get a quality exhaust that isn’t imported from overseas. Install the best DPF delete exhaust we have to offer for your LML Duramax.
To sum it up
By this point you can surely see where we stand. It simply comes down to this; If you plan on keeping your truck for the long term the best thing you can do is install a DPF delete kit on your LML Duramax. If you’ve made it this far and decide to got that route here’s a discount code: “ dpfdeleteguideLML ”