Name: The 5 Best Duramax LBZ Mods - 5 Best 6.6L LBZ Upgrades
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The 5 Best Duramax LBZ Mods - 5 Best 6.6L LBZ Upgrades

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Skip to contentThe LBZ succeeded the LLY engine in 2006 and was short lived, being replaced by the LMM in mid-2007. Some notable changes included an upgraded CP3 fuel pump for higher rail pressure and a lower compression ratio which eliminated issues with connecting rod failure in modified LLY’s. Part of the reason for the short life of the LBZ was emissions – the LBZ engine has an EGR system but lacks all of the other exhaust emissions components.The LBZ produced 360hp and 650lb-ft. of torque. It’s lack of emissions systems and easy power gains make it common to modify. While these power levels aren’t much compared to the latest diesel engines, a handful of bolt-on upgrades can easily add over 100whp to the LBZ for a pretty low cost.This guide is going to cover the best bolt-on modifications for the Duramax LBZ. Additionally, we will talk about supporting modifications and power limits of both the engine and its Allison 1000 transmission. We are going to focus on more simple bolt-on mods since things can get really expensive once we push beyond this list.It’s easy to drop a tune and some simple upgrades on the LBZ and make 100whp+ power gains. However, there are some considerations and hurdles to doing so that you will need to consider first.The biggest hurdle on the LBZ (and all 6.6L Duramax’s) is the Allison 1000 transmission. While it gets stronger and stronger each year, the transmission in the LBZ is only good for about 400whp. Transmission tuning can help make it last a bit longer at higher power levels, but considering a stock LBZ dyno’s about 300rwhp we don’t have much room to play with before hitting the limit of the Allison transmission.The next limiting factor is the turbocharger and fueling. The stock turbo can reliably handle 500rwhp and can be pushed up around 550rwhp but getting beyond this is going to require a larger turbo. Additionally, a lift pump is always recommended since the LBZ doesn’t have on stock. But furthermore, the injectors will need upgrading when the turbo does. The stock CP3 is good for 625-650rwhp before needing an upgrade.Lastly, the most expensive flaw with the LBZ is its pistons. While the connecting rod issue with the LLY was fixed, it created an issue with the pistons cracking. The pistons are good up until about 600rwhp but it’s not unforeseen for them to crack above 500rwhp too. Ultimately, getting past 600rwhp or comfortably pushing those power levels without sacrificing reliability is going to require building out the internals.Mods for 500rwhp+:The biggest power gains on a Duramax diesel come from a tuner. Plug-and-play tuners can easily add around 100whp without need for much else. The majority of the mods discussed after this are to support a tuner and improve reliability when tuned. Running a tune on the highest performance setting without proper mods is a recipe for disaster so follow along for the other mods.Your two tuning options are getting a plug-and-play handheld tuner that simply plugs into the OBDII port and has pre-made tunes loaded into it. Or getting a custom tune from a tuning shop that is better dialed in to your specific engine.EFI Live is probably the most robust tuner available for the LBZ. One additional component to this is transmission tuning. Since the Allison transmission is pretty weak, tuning the transmission will help increase reliability and allow you to push around 400rwhp without tearing up the transmission as much as you would without tuning.A performance, or cold air, intake is the best mod to combine with a tuner. Tuners increase power mostly by increasing the boost, or psi, that the turbo the turbo is compressing the air to. Supplying the turbo with more air via an upgraded intake is a great way to reduce stress on the turbo and get solid power gains via a more efficient turbo from increased airflow.Intakes are also good for MPG, throttle response, and turbo spool. We always recommend running an intake when tuned. We also prefer open intakes where the filter is directly exposed to the engine bay since they provide greater airflow increases. More airflow = more power so open intakes are the best on the market in terms of performance.For more information on intake upgrades, checkout our detailed LBZ Intake Upgrade Guide.We are going to discuss a full exhaust system next, but a downpipe is our favorite exhaust mod on the LBZ. It bolts directly to the turbo and therefore has the biggest impact on backpressure and exhaust flow.The stock LBZ downpipe is poorly designed. It is “crushed” with bends in it that make it really skinny and therefore not great for exhaust gas flow. What this causes is backpressure to build up within the exhaust system which then creates a negative force against the turbo compressor wheel. Ultimately, it makes it harder for the turbine wheel to spin and compress air therefore increasing stress on the turbo and reducing its efficiency.Downpipe upgrades are the best exhaust mod since they have the biggest impact on backpressure reduction. Therefore, it results in a healthier turbo, better power gains, and also lower engine temps and EGT temps. Definitely a recommended mod when you are tuned and have an intake – the extra air the intake is pulling in makes exhaust gas flow even more important.Price: $219Buy Here: Boosted Performance Duramax LBZ DownpipeBoosted Performance makes our favorite LBZ downpipe upgrade on their market. Their downpipe is made of 304 stainless steel which will prevent any rusting issues. Most other downpipes in this price range are made from aluminized steel which will rust over time. Additionally, it features a nice heat shield to prevent excess engine temps.It’s a larger, non-crushed 3″ design which significantly improves exhaust flow over the factory downpipe. Furthermore, it’s a direct bolt-on part and doesn’t require any additional modifications or tuning. Overall, we think this is the best combination of price, quality, and performance available on the market.The best exhaust for a turbo car is technically no exhaust. Fortunately, the LBZ lacks a DPF filter and other exhaust emissions equipment. However, it does still have a diesel oxidation catalyst. We aren’t going to get into the topic of deleting the DOC, but we will get into larger exhaust systems.A 4″ or 5″ downpipe-back exhaust is the second best way to reduce exhaust backpressure. Since it sits after the DOC and downpipe it isn’t as important of a mod, but it still can help lower EGTs and engine temps even further thru less exhaust backpressure. Ultimately, this mod is more so dependent on whether or not you want a louder exhaust note. They’re pretty affordable and definitely worthwhile if you are okay with a louder exhaust note.The LBZ doesn’t have a factory lift pump. Lift pumps essentially help transfer fuel to the high pressure CP3 pump. What this does is reduce stress on the CP3 pump and the fuel injectors. Since increased power requires more fuel tuning an LBZ without a lift pump can cause the CP3 to fail more quickly and can also cause issues with fuel starvation if the pump can’t supply the engine with the fuel that it needs.Ultimately, this is a supporting mod and one that isn’t going to really add any power. However, it will allow you to supply more fuel to the injectors without the need for an upgraded fuel pump or larger injectors. With a lift pump the CP3 doesn’t need to be upgraded until 600+rwhp.Another great mod is an intake Y-pipe, or Y-bridge alongside an upgraded up-pipe/intercooler piping. These will help with improved intake air flow from the turbo to the intercooler and to the engine. However, this upgrade really isn’t necessary unless you are trying to push beyond the limits of the Allison 1000 and get it built. While it will help improve airflow and therefore help the engine “breath” better you’re going to be looking at close to $1,000 for this upgrade.Since the Allison is the first limit we hit when modding the LBZ, it is the first major “supporting” upgrade that needs to be made. A built transmission is going to run you $5,000 to $8,000 so it’s a big leap to make. If you aren’t trying to push the LBZ too far then sticking with a tuner, intake, downpipe, and lift pump are really all you need to get some extra enjoyment out of this engine.The LBZ engine is easy to modify and can hold power pretty well. Simple bolt on modifications like a tuner, intake, and downpipe can get this engine to up around 400rwhp. However, pushing past these power levels is where it gets expensive.Limiting power factors are the Allison 1000 transmission that can only hold about 400-425rwhp (when tuned). The pistons are known to crack above 600rwhp. The stock turbo is good for 500-550rwhp and alongside a turbo upgrade will require larger injectors. And then pushing to 600rwhp and past is where you will need forged internals and a built motor to keep going.So while the LBZ can handle some serious horsepower builds it costs a lot of money to get there. For this reason our favorite upgrades are sticking to the simple bolt-ons like a tuner and transmission tuning, a cold air intake, exhaust downpipe, and a lift pump. Some other optional upgrades are a downpipe-back exhaust system and a intake Y-bridge and upgraded intercooler piping. Outside of these mods you are going to be pushing to an echelon that we aren’t covering in this guide.Ultimately, a few thousand bucks in mods and tuning and can give you a reliable 400rwhp Duramax LBZ. What mods are you currently running and how has your experience been with upgrading the LBZ?General Motors designed the 3.0L Duramax for use in their full-size half-ton trucks and SUVs. It was created as an alternative to the 6.6L Duramax&nbsp;which is far too big for the half-ton 1500 trucks. The engine was a collaboration between GM and Opel and was introduced as an option in the 2019 Chevrolet Silverado 1500…GM replaced the Duramax LMM in 2011 with the LML in part due to emissions requirements. One of the new features of the LML was the addition of he SCR system in conjunction with DEF fluid, which GM claims reduced emissions levels by over 50 percent. However many early model LML’s experienced SCR and DEF…LBZ Duramax Cold Air Intake Upgrade Basics If you had the 8.1 Vortec engine in your truck instead of a Duramax, I’d probably be telling you an intake is a waste of money. However, for turbo-diesel engines it’s one of the first mods we recommend for people just getting started. Outside of an upgraded LBZ…The LBZ Duramax is, still today, the favorite Duramax of diesel enthusiasts. Produced from 2006 to 2007, the shortest production Duramax, the LBZ produced 360hp and 650lb-ft. of torque. To support the power increase over the LLY model, the block was improved, the rods were forged, and the engine was overall built to withstand more…Hitting Chevy and GMC trucks starting in 2004, the LLY Duramax is the 2nd version of the 6.6L V8 Duramax. In order to meet stricter emissions regulations, the LLY replaced the LB7 engine and was the first Duramax to use EGR emissions technology. In addition to EGR, the LLY switched over to variable-vane turbocharger (VVT)…The Duramax LB7 was the first engine released under the new 6.6L Duramax platform. The LB7 was considered a strong and stout engine for the time, producing 235hp and 500lb-ft. of torque which was upgraded to 300hp and 520lb-ft. of torque in 2004. However, the LB7 produces about half the power as the diesels of…Wow, only 400 HP for my Allison Transmission?? Then from the factory it should already be shredded, it not and doing just fine..ReplyChevytrucks.org is a website dedicated to modern, classic, and vintage Chevrolet Trucks. The site focuses on maintenance, do-it-yourself, and performance modification guides amongst general Chevy Truck articles. We are a team of automotive enthusiasts with deep knowledge of GM vehicles.

Skip to contentThe LBZ succeeded the LLY engine in 2006 and was short lived, being replaced by the LMM in mid-2007. Some notable changes included an upgraded CP3 fuel pump for higher rail pressure and a lower compression ratio which eliminated issues with connecting rod failure in modified LLY’s. Part of the reason for the short life of the LBZ was emissions – the LBZ engine has an EGR system but lacks all of the other exhaust emissions components.The LBZ produced 360hp and 650lb-ft. of torque. It’s lack of emissions systems and easy power gains make it common to modify. While these power...

The 5 Best Duramax LBZ Mods - 5 Best 6.6L LBZ Upgrades

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