The Duramax engine platform mated with the Allison transmission has proven year after year to be one of the best combos in diesel performance. These trucks are the lightest of the big 3 and are easy to make into weekend warriors without draining your bank account. Each generation of Duramax has it’s pros and cons, from the LB7 to the LML, but with a few fixes, they all can be a reliable daily driver that still has loads of power when you put your foot into it. I am going to list out the best bang for your buck mods on each of the Duramax platform.

A Bit of Duramax History

It started with the LB7 back in 2001. The LB7 changed the game in diesel performance, being the first to the market common rail injection system mated with one of the nicest shifting and controlled transmissions to this day.  The 300HP Duramax and 5-speed Allison combo was now the truck to beat. Dodge and Ford had to step up their game to compete with this new platform. The LB7 is a great truck despite the injector issues they have been cursed with.  If you own an LB7, you have probably done a set of injectors, or at least know about the dreaded white smoke at idle that means you are shelling out thousands for a set. With the injectors being under the valve cover, it makes for a long job to replace a set.

In 2004 the LLY was introduced sporting a VNT turbocharger and upgraded injectors that were accessible without having to remove the valve covers. The LLY also came mated up to the 5 speed Allison 1000 transmission and had a higher HP rating than the LB7 at 305HP. In 2006, GM changed it up again with the LBZ. These trucks came out with the 6-speed Allison, a big jump in power over the LLY at 360HP. LBZ’s have a similar injector design to the LLY and have the best CP3 injection pump that is still sought after to this day.

The tap shift transmission with full manual mode made these trucks a towing machine that could still rule the track on the weekends. In 2007, with the new body style from GM, the LMM was introduced. Boasting 365HP, the LMM engine itself is very similar to the LBZ, but with the introduction of the DPF system, these trucks were cursed with bad fuel mileage from the start. With the correct modifications, these trucks can get the same mileage that previous versions were getting, but with the luxury of the new body style and loaded with features inside the cab. In 2011, GM introduced the LML trucks, the LML had a big jump in power and put these at 397HP out of the box, and with the addition of DEF Fluid and the SCR system, the mileage on these trucks went up significantly. They have the same 6-speed transmissions that were found in previous years, but with some internal upgrades to handle the extra power. The injector design and EGR changed quite a bit from the earlier trucks and made these engines a little more work to get at.

They came out with the CP4 injection pump which has also had its share of problems over the years. 2017 came along, and the L5P Duramax was brought into the world as the biggest power Duramax GM has ever produced at 445hp and 910 lb/ft out of the box. These trucks have proven to be the most powerful Duramax on the market but are still currently locked down tight when it comes to tuning options.

Before I list out modifications to cater to each truck, I will mention that none of the Duramax trucks have a fuel lift pump. They all rely solely on the injection pump to suck fuel out of the tank and crank it up to commanded rail pressure. To start, a FASS pump is the first thing I will recommend for any of the Duramax platforms.

LB7 Duramax

(2001-2004.5)

If you're building an LB7 Duramax - these are where we think you're money is best spent to get the most out of your LB7.

There's a lot of different options for tuning your LB7, however, there's nothing quite like the combination of EFI Live with Coopers Custom Tuning (CCS). Canned tuning is great and all (it's not), but custom tuning is specific to your truck, you'll make more power, run cooler (lower EGT's), and get better fuel economy. Even if you're not looking to make big power, an EFI Live is a great choice. When going with EFI Live we always recommend adding a DSP5 (Shift on the Fly) switch with the package - it's a $75 add-on that allows you to change tunes on the go. Most guys that don't purchase it with the EFI Live end up coming back to add one in. 

CCS Tuned EFI Live AutoCal 

When it comes to an LB7 - upgrading the exhaust system is a given. When it comes to 4" or 5" it really comes down to personal preference. The 4" is sufficient for most builds and will be a bit quieter than a 5" system. You'll get more of a whistle from the exhaust where the 5" is deeper and more throaty but in terms of performance, you're not going to notice a difference between a 4-inch or 5-inch exhaust system. We only run MBRP & FLO-PRO exhaust systems, we've consistently found these systems sound better, perform better, and fit better.

MBRP & FLO-PRO LB7 Exhaust Systems

MBRP GM8425 3" Downpipe

We always are asked why we only carry S&B Intakes on our website, well, it's because they're the only intake we trust. We only run S&B on our trucks, and we only sell S&B in our shop. Simple as that. 

S&B Intakes are less restrictive than stock (44.63% better on the LB7), they're fully-enclosed to protect from dirt and engine heat, and they fit better than anything else on the market. The materials used on the S&B will withstand more abuse than anything else out there, S&B Intakes will never crack, warp, or fall apart.

S&B 75-5101 LB7 Intake Kit

The more air you move, the more power you make. The OEM LB7 mouthpiece is necked down and restrict airflow to the turbo. Deviants Intake Elbow increases the size to 3-inches and will give you gains of around 25hp. 

DRP 71310 3" Intake Elbow

When it comes to bang for your buck the PPE Boost Valve is the best addition to your LB7 Duramax. It fools your wastegate into running about 10psi more boost than stock, costs $35, and installs in 5-minutes. Need I say more?

PPE Boost Increase Valve

These modifications added together are budget friendly but give you a good reliable LB7 that's a blast to drive on the street but isn’t going to blow apart when you put your foot down.

LLY

(2004.5-2005)

If you're driving or building an LLY Duramax - these are our go-to recommendations. If you've read the LB7 section you're going to see some duplicates, this is because these components work so well on the engine.

There's a lot of different options for tuning your 2001-2010 Duramax, however, there's nothing quite like the combination of EFI Live with Coopers Custom Tuning (CCS). Canned tuning is great and all (it's not), but custom tuning is specific to your truck, you'll make more power, run cooler (lower EGT's), and get better fuel economy. Even if you're not looking to make big power, an EFI Live is a great choice. When going with EFI Live we always recommend adding a DSP5 (Shift on the Fly) switch with the package - it's a $75 add-on that allows you to change tunes on the go. Most guys that don't purchase it with the EFI Live end up coming back to add one in. 

When it comes to an LLY - upgrading the exhaust system is a given. When it comes to 4" or 5" it really comes down to personal preference. The 4" is sufficient for most builds and will be a bit quieter than a 5" system. You'll get more of a whistle from the exhaust where the 5" is deeper and more throaty but in terms of performance, you're not going to notice a difference between a 4-inch or 5-inch exhaust system. We only run MBRP & FLO-PRO exhaust systems, we've consistently found these systems sound better, perform better, and fit better.

MBRP & FLO-PRO LLY Exhaust Systems

MBRP GM8424 3" Downpipe 

FLO-PRO FLO-10100 3" Downpipe 

We always are asked why we only carry S&B Intakes on our website, well, it's because they're the only intake we trust. We only run S&B on our trucks, and we only sell S&B in our shop. Simple as that.

S&B Intakes are less restrictive than stock (43% better on the LLY), they're fully-enclosed to protect from dirt and engine heat, and they fit better than anything else on the market. The materials used on the S&B will withstand more abuse than anything else out there, S&B Intakes will never crack, warp, or fall apart.

The S&B Turbo Inlet will increase your airflow by over 78% when compared to stock. This not only improves power but it will increase your throttle response, lower your EGT's, and look much better in your engine bay.

S&B 75-5102 LB7 Intake Kit

 
S&B 76-1006B LLY Turbo Elbow

Dirty Diesel Customs A007 EGR Upgrade Kit

Dirty Diesel Customs A020 EGR Upgrade Kit

Like we've said before, the Duramax trucks do not have a fuel lift pump from the factory. They rely on the injection pump to suck fuel from the tank, we highly recommend a FASS Lift Pump as one of the first upgrades you do on your Duramax. The FASS system will pump fuel to the injection pump and remove any air or water in your fuel. This means your pumps working less, and receiving cleaner fuel. This alone will extend the life of your injection pump, injectors, and the rest of your fuel system. We recommend a 165GPH pump as it's a good platform to build from, you won't damage your truck by putting too big of a lift pump on it.

FASS Lift Pumps From

Same as the LB7, these will be great modifications to make your LLY. They'll make it a blast to drive while keeping it reliable and safe.

LBZ/LMM

(2006-2010)

For the most part, the LBZ & LMM parts are interchangeable so we'll categorize them together.

There's a lot of different options for tuning your 2001-2010 Duramax, however, there's nothing quite like the combination of EFI Live with Coopers Custom Tuning (CCS). Canned tuning is great and all (it's not), but custom tuning is specific to your truck, you'll make more power, run cooler (lower EGT's), and get better fuel economy. Even if you're not looking to make big power, an EFI Live is a great choice. When going with EFI Live we always recommend adding a DSP5 (Shift on the Fly) switch with the package - it's a $75 add-on that allows you to change tunes on the go. Most guys that don't purchase it with the EFI Live end up coming back to add one in. 

EFI Live w/ CCS Tuning

When it comes to an LBZ or LMM - upgrading the exhaust system is a given. When it comes to 4" or 5" it really comes down to personal preference. The 4" is sufficient for most builds and will be a bit quieter than a 5" system. You'll get more of a whistle from the exhaust where the 5" is deeper and more throaty but in terms of performance, you're not going to notice a difference between a 4-inch or 5-inch exhaust system. We only run MBRP & FLO-PRO exhaust systems, we've consistently found these systems sound better, perform better, and fit better.

The LBZ & LMM kits will fit both trucks without any issues. The manufacturers will break them up into different categories (like you'll see on our website). However, the 2001-2010 Duramax Trucks all use the same exhaust system and mounts.

LBZ Exhaust Systems

LMM Exhaust Systems

MBRP GM8424 3" Downpipe 

FLO-PRO FLO-10100 3" Downpipe

We always are asked why we only carry S&B Intakes on our website, well, it's because they're the only intake we trust. We only run S&B on our trucks, and we only sell S&B in our shop. Simple as that.

S&B Intakes are less restrictive than stock (50% better on the LBZ/LMM), they're fully-enclosed to protect from dirt and engine heat, and they fit better than anything else on the market. The materials used on the S&B will withstand more abuse than anything else out there, S&B Intakes will never crack, warp, or fall apart.

S&B 75-5080 LBZ Intake Kit

S&B 75-5091 LMM Intake Kit

SDP-1032 Billet Y-Bridge & Intercooler Kit

DDC A020 Passenger Side Up-Pipe

The Suncoast Diesel TransGo JR Shift Kit will clean up your Allison and make it shift better than new. It will give you firmer, smoother, and crispier shifts. It makes a massive difference in the drivability of your truck and at only $145.96 it's money well spent.

Suncoast Diesel TransGo JR Shift Kit

These few things can turn your LBZ or LMM into an absolute beast. On top of the massive gains in driveability, the upgraded turbocharger that started in 2006 and EFI Live will give you an exhaust brake while towing. It's personally one of my favorite options on the LBZ/LMM trucks. 

LML

(2011-2016)

The EZ-Lynk system is the future of tuning on the Duramax trucks. It allows you to be in direct contact with your tuner at any given time and uses cloud technology for tuning your truck. This means you don't have to visit a shop to get new tunes, just message your tuner from the app and they can send the tunes directly to your truck. Everything is controlled wirelessly from your mobile device and you can get custom tunes for your LML from Proven, or CCS.

Proven Diesel LML EZ-Lynk Tuning

CCS LML EZ-Lynk Tuning

There's a lot of different options for tuning your 2001-2010 Duramax, however, there's nothing quite like the combination of EFI Live with Coopers Custom Tuning (CCS). Canned tuning is great and all (it's not), but custom tuning is specific to your truck, you'll make more power, run cooler (lower EGT's), and get better fuel economy. Even if you're not looking to make big power, an EFI Live is a great choice. When going with EFI Live we always recommend adding a DSP5 (Shift on the Fly) switch with the package - it's a $75 add-on that allows you to change tunes on the go. Most guys that don't purchase it with the EFI Live end up coming back to add one in. 

EFI Live w/ CCS Tuning

When it comes to an LBZ or LMM - upgrading the exhaust system is a given. When it comes to 4" or 5" it really comes down to personal preference. The 4" is sufficient for most builds and will be a bit quieter than a 5" system. You'll get more of a whistle from the exhaust where the 5" is deeper and more throaty but in terms of performance, you're not going to notice a difference between a 4-inch or 5-inch exhaust system. We only run MBRP,P1, & FLO-PRO exhaust systems, we've consistently found these systems sound better, perform better, and fit better.

The LML has a split year in 2015 for their exhaust systems. The 2011-2015 trucks will have a V-Band Flange where the downpipe meets the turbocharger, while the 2015.5-2016 trucks will have a 3-Bolt Flange. Other than a different downpipe, the rest of the exhaust system is identical. 

MBRP, P1, & FLO-PRO LML Exhaust Systems

2011-2015 MBRP GM8427 3" Downpipe

2011-2015 FLO~PRO FLO-10102 3" Downpipe 

2015.5.-2016 MBRP GM8428 2015.5-16 3" Downpipe

We always are asked why we only carry S&B Intakes on our website, well, it's because they're the only intake we trust. We only run S&B on our trucks, and we only sell S&B in our shop. Simple as that.

S&B Intakes are less restrictive than stock (29% better on the LML), they're fully-enclosed to protect from dirt and engine heat, and they fit better than anything else on the market. The materials used on the S&B will withstand more abuse than anything else out there, S&B Intakes will never crack, warp, or fall apart.

S&B 75-5075-1 LML Intake Kit

SDP-1067 Y-Bridge, Intake, & Intercooler Kit

DDC A020 Passenger Side Up-Pipe

The LML already has great power, but with DEF issues that it’s cursed with, these mods will bring it to life and help your pocketbook in the long run.

L5P

2017+

The Banks Derringer and S&B Intake are all you need to add extra fun and extra mileage to these beasts. With the ECM’s being locked down hard by GM, reflashing these ECM’s has proven to be very tough and very expensive. It can be done, but with these trucks already making big power out of the box, we install a couple of extra pieces and these trucks will walk all over anything on the road.

Banks Power L5P Derringer Tuner

We always are asked why we only carry S&B Intakes on our website, well, it's because they're the only intake we trust. We only run S&B on our trucks, and we only sell S&B in our shop. Simple as that.

S&B Intakes are less restrictive than stock (43.86% better on the L5P), they're fully-enclosed to protect from dirt and engine heat, and they fit better than anything else on the market. The materials used on the S&B will withstand more abuse than anything else out there, S&B Intakes will never crack, warp, or fall apart.

S&B 75-5103 L5P Intake Kit 

Conclusion

This isn’t by any means everything that can and should be done to each truck, but I wanted to give an idea to you of where would be the best place to spend your money when starting out to modify your Duramax.  Maybe you just bought your truck, or maybe you’ve had it for years and have always been wanting to get a bit more out of it.

These are the products we recommend in-house and put on our own personal trucks to keep them lasting long and have fun driving them at the same time. If you want some clarification or have any questions at all, feel free to contact us directly or drop a comment below. We are always more than happy to help.