L3B GM 2.7 Turbo Performance Upgrades Guide
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Chandler is a leading content writer for 8020 Media. Outside of writing truck related GM content for Chevy Trucks he creates a lot of articles around LS engines over on TuningPro. Chandler is a gearhead with tons of hands-on experience. Furthermore, he has a masters degree in history that makes him invaluable in crafting high-quality, well-researched articles on both classic and modern Chevy trucks.
Since GM introduced their 2.7 liter turbocharged inline-four L3B engine in 2019, it has remained one of their top power plants. Producing 310-325 horsepower and 348-430 lb-ft of torque in most applications, the L3B has proven itself to be a great mix of performance and practicality. Still, for those looking to get even more power from their 2.7 turbo L3B engine, you have quite a few different options. From tuning to intakes and exhausts, there are several GM 2.7 turbo performance upgrades to increase both horsepower and torque. Read on to find the best GM 2.7 performance upgrades for the L3B engine.
GM 2.7 Turbo L3B Engine Basics
GM has produced the L3B 2.7 liter turbocharged inline-four engine since the 2019 model year. Primarily, they have used the engine inside the Chevrolet Silverado 1500/GMC Sierra 1500, Cadillac CT4 and CT4-V, and the Chevrolet Colorado/GMC Canyon. GM largely designed the engine for use in trucks, but it has proven itself well in the Cadillac sedans. There are also rumors GM is considering expanding it into even more vehicles for 2024 and beyond.
The engine uses a cast aluminum block and cylinder head with a single BorWarner dual-volute turbocharger. Dual-volute turbochargers are more responsive and efficient than traditional single-volute turbos, and produce better low-end torque. It’s similar in design to a twin-scroll turbo, but separates the volutes completely instead of just dividing them. This allows for it to work better and more smoothly. The OEM turbo runs 10-27 PSI of boost depending on the application and power output.
For the valve train, the L3B uses dual-overhead camshafts (DOHC) that have four valves per cylinder. There are 16 valves total, and the engine uses variable valve timing (VVT) to improve fuel economy and turbo spool. Compression sits comfortably at a static 10.0:1. The L3B also uses active fuel management, direct-fuel injection, and a start-stop system, to improve fuel economy and reduce emissions.
From 2019–2021, the engine produced 310 horsepower and 348 lb-ft of torque inside of GM’s half-ton pickups, and 310 horsepower and 350 lb-ft of torque inside the Cadillac CT4. There is also a 325 horsepower/380 lb-ft of torque version inside the CT4-V performance sedan. Beginning in 2022, torque jumped to 430 lb-ft of torque inside the GM pickups in a new optional high-output L3B.
Top 4 Best GM 2.7 Turbo Performance Upgrades
Our top GM 2.7 turbo performance upgrades are:
- JB4 for L3B
- Cold Air Intake
- Cat-back Exhaust
- Downpipe
Due to the L3B being a relatively new engine on the market, it does not have the most aftermarket support, yet. Still, there are a number of mods you can do to increase horsepower and torque and improve overall performance. While turbo swap kits are not yet available, you can still tune and open up both the intake and exhaust for some more power.
1) JB4 for L3B
By far, the best bang for your buck for GM 2.7 turbo performance upgrades is the JB4. Since flash tuning is not yet an option for the L3B, the next best thing is the JB4. The JB4 is quite popular in the BMW community and for the Kia Stinger, and it works very well on the L3B in all applications.
The JB4 works by plugging into the factory ECU and manipulating the electronic signals as they pass through and control the engine. This allows the JB4 to do things like crank up the boost, the fuel pressure, and the ignition/camshaft timing, increasing horsepower and torque. The JB4 is incredibly easy to install and virtually undetectable.
There are several different maps that can be run off the JB4, and it takes real time info from the engine to mitigate things like detonation and overboosting. You can also monitor your engine in real time through various gauges and datalogging, and you can make adjustments too, through the JB4 smartphone app.
For the GM trucks, the JB4 adds an incredible 85 wheel-horsepower and 120 wheel-torque without any other hardware modifications. On the Cadillac CT4 and CT4-V, the improvements are 60 wheel-horsepower and 80 wheel-torque. That’s a pretty stunning increase from just a JB4 module, making it by far the best GM 2.7 turbo performance upgrade.
JB4 Purchase Links:
2) GM 2.7 Turbo Cold Air Intake Upgrades
Next up on our list of GM 2.7 turbo performance upgrades is a cold air intake. To be fair, the factory intake is technically a “cold air intake” due to the placement of the filter. Aftermarket intakes essentially are beneficial for their improvement to airflow. Still, it’s one of the most popular mods for the L3B engine, and has shown some decent performance increases.
The purpose of an upgraded air intake is to decrease the amount of restriction present in the factory intake system. This usually involves using larger diameter tubing, lighter weight and more efficient materials, and a cone-style filter instead of panel-style. All of these allow for superior flow over stock, allowing for more air to reach the engine faster, increasing combustion and adding power. Additionally, upgraded intakes generally look much sleeker than the OEM units and help liven up the engine bay.
For the GM 2.7 turbo, there are many different cold air intake options. One of the most popular is the aFe Power Momentum GT intake for Silverado/Sierra 1500. As you can see from the dyno plot above, the aFe Power intake adds as much as 25 horsepower and 30 lb-ft of torque on an otherwise stock Sierra 1500. This is from a 12% increase in flow from the intake, and it’s a pretty significant improvement.
Other intakes for the L3B are the S&B intake for Silverado/Sierra 1500 and the S&B intake for Colorado/Canyon. These are set to be released in the Fall of 2023, and look to be solid offerings. S&B is a huge name in the truck intake community, and their L3B offering seems poised to perform very well.
3) Cat-back Exhaust for L3B
For our third GM 2.7 turbo performance upgrade, we’re looking at cat-back exhausts. Now, a cat-back won’t add nearly the performance of a JB4 or an intake, but they are one of the top aesthetic mods for the L3B engine. Horsepower and torque increases are probably limited to about 5 horsepower at the most, and most of the benefit comes from the increase in sound.
Typically, cat-backs will have 3 inch exhaust piping with high-flow mufflers, which allows for a big improvement in volume. They will usually bolt-up directly to the factory exhaust, and are often made from a high-quality steel like 304 stainless. Depending on your preference, there are single-exit, dual-exit, side-exit, or rear-exit options. Generally, a single-exit exhaust will sound louder than dual-exits, but a lot of it depends on the muffler.
For the L3B, there are many different cat-back options. One of the most popular for dual-rear-exit cat-backs is the aFe Power Vulcan Dual Exit Cat-back. It comes with either silver or black tips, and uses 304 stainless. For single and side-exit exhausts, both the aFePower Vulcan Side Exit Cat-back and Borla S-type Side Exit Cat-back are great options.
4) Downpipe for GM 2.7 Turbo
For our final GM 2.7 turbo performance upgrade, we suggest looking into a downpipe. The downpipe is the part of the exhaust system that connects directly to the exhaust housing on the turbocharger. It takes the excess exhaust gasses away from the engine and routes them into the cat-back. It’s probably the most restrictive part of the OEM exhaust system, and one of the most important parts to upgrade for serious power increases.
Unfortunately, there are not many available downpipes for the L3B engine. Some of this has to do with the fact that the OEM downpipe contains a catalytic converter emissions system. Removing the cat is only an option for non-street vehicles, as it is a mandatory emissions system.
Currently, the only available downpipe is the aFe Power Twisted downpipe for the ‘19-’20 Silverado/Sierra 1500. It’s good for 10-15 horsepower/torque by itself, or even more with tuning. It’s highly recommended you tune (or use the JB4) when adding a downpipe, as without it you are prone to running lean and potentially overboosting.
Top GM 2.7 Turbo Performance Upgrades FAQ
Yes! There are tons of excellent performance upgrades available for the L3B GM 2.7 turbo engine. The best mod is the JB4 for the L3B, which can add as much as 80 wheel-horsepower and 120 wheel-torque by itself. You can also upgrade the intake and exhaust for even more horsepower and torque gains.
Yes! There are tons of excellent performance upgrades available for the L3B GM 2.7 turbo engine. The best mod is the JB4 for the L3B, which can add as much as 80 wheel-horsepower and 120 wheel-torque by itself. You can also upgrade the intake and exhaust for even more horsepower and torque gains.
Yes! There are tons of excellent performance upgrades available for the L3B GM 2.7 turbo engine. The best mod is the JB4 for the L3B, which can add as much as 80 wheel-horsepower and 120 wheel-torque by itself. You can also upgrade the intake and exhaust for even more horsepower and torque gains.
