Best Hyundai Genesis 3.8 Mods

For those looking to gain horsepower and torque, the best Hyundai Genesis 3.8 mods are a tune, upgraded cold air intake, headers and or test pipes, and a cat-back exhaust. The 3.8 liter Lambda II RS V6 engine already makes a healthy 286-348 horsepower and 264-295 lb-ft of torque, but it is definitely capable of more. While there is only so much room to make improvements while staying naturally aspirated, I’ve found that the 3.8 V6 is a solid power plant that is capable of some serious grunt when needed. Let’s learn about how to really make Hyundai’s 3.8 V6 really fly with the best Hyundai Genesis 3.8 mods guide. 

Hyundai 3.8 Genesis Mods Basics

Before I get into the best Hyundai Genesis 3.8 mods, let’s first talk a little about the motor to familiarize ourselves. Hyundai has released two main variants of the engine: the Lambda II MPI and Lambda II GDI. The difference between the two is in the fueling and compression ratio. The MPI uses multi-point fuel injection (10.4:1 compression) and the GDI uses gasoline direct injection (11.5:1). GDI is more efficient, allows for better performance and fuel economy, and can use higher compression vs MPI. 

Hyundai has been using the 3.8 Lambda II RS since the 2009 model year. They began installing the GDI version in 2012 models and it has now completely replaced the MPI. Depending on the version, year, make and model the Lambda II RS outputs 286-348 horsepower and 264-295 lb-ft of torque. That’s pretty powerful for a naturally aspirated V6, and the Genesis 3.8 gets rave reviews from enthusiasts. Of the two, I would definitely prefer the newer, more efficient, and more powerful GDI version. 

As you can see from an article in DSPORT Magazine, just a few mods can go a really long way on the 3.8 Genesis coupe. They concentrate on the intake and exhaust to increase airflow in and out of the engine. This is the best way to start your 3.8 Genesis build and make some great power. 

How to modify the Genesis V6

When looking for the best Hyundai Genesis 3.8 mods, there are three main areas you will be concentrating on: ECU tuning, the intake, and the exhaust. Modifying and upgrading these aspects of the Lambda II are by far the best ways to increase horsepower and torque. 

For the intake, your goal is going to be to increase the volume and velocity of airflow into the engine. Generally, the best way to do this is to install a cold air intake. A cold air intake simply refers to an intake with a filter that is located as far away from the engine as possible, usually close to the fender wall or wheel-well. This helps to avoid the hot air from the engine bay and suck in colder and more oxygen-rich air. More oxygen means greater combustion and thus more power. 

Additionally, upgrading the intake will also decrease restriction in the system, which allows for bigger and better airflow. This allows the air to reach your engine quicker and with less turbulence, again helping to increase combustion. 

For the exhaust, your goal is to increase the flow of exhaust gasses exiting the engine by decreasing back pressure and restriction. Faster exhaust flow means your engine can replace the spent gasses with clean air quicker. This allows for better exhaust scavenging and performance. Headers replace the exhaust manifold and potentially downpipes, and test pipes replace the secondary catalytic converters. Both the headers and secondary cats are the most restrictive part of the system, making them the best candidates for upgrades. 

Finally, we have ECU tuning. ECU tuning is when a “tuner” modifies the computer programming for your engine to optimize performance parameters. ECU tuning the Genesis 3.8 is a great way to gain power without doing any bolt-ons. 

Best Hyundai Genesis 3.8 Mods

Our Best Hyundai Genesis 3.8 mods are:

• Tune
• Intake
• Headers and/or Test Pipes
• Cat-back Exhaust

1) Hyundai 3.8 Tuning

For those starting on their Genesis 3.8 build, I would suggest starting with ECU tuning as your first mod. ECU tuning allows you to pick up horsepower and torque relatively safely, cost effectively, and without having to do any major installs. For most modern engines, not just the Lambda II RS, ECU tuning is almost always the best bang for your buck in terms of performance. With tuning, you can expect to pick up around 20-30 wheel-horsepower without any other mods on the 3.8 V6. 

With 3.8 Genesis tuning, your tuner will typically adjust parameters related to the air-to-fuel ratio (AFR), ignition timing, throttle mapping, and the torque management system. By running more aggressive ignition timing, throttle mapping, and AFRs, your engine will make more horsepower throughout the entire power band and feel much more responsive. Adjusting the torque management will stop your ECU from cutting power when it feels any slippage. This helps make the ride more smooth and aids launches and aggressive cornering at the track. 

Best Genesis 3.8 Tuners

There are many tuning options out there for the Genesis 3.8 V6. Some of the most popular E-tuners are BTRcc, SFR, and PowerAxel. These companies allow you to send your ECU to them for tuning, or you can purchase a new one. You can also find local tuning companies that will put your car on a dyno to do in-person tuning. Make sure you go with someone reputable, as your tune is only as safe as your tuner.

2) 3.8 Hyundai Intake Upgrades

After tuning, the next best Hyundai Genesis 3.8 mod is an upgraded intake. As mentioned earlier, upgraded intakes help increase the volume and velocity of airflow entering the engine. If you look at the OEM 3.8 Genesis intake, you’ll probably notice that it is already a cold air intake due to the filter placement. The gains you’ll see from an aftermarket 3.8 Genesis cold air intake will be decreased restriction through more efficient and lighter tubing. 

In addition to a CAI, you’ll probably also see recommendations for SRIs or short ram intakes. These are basically the opposite of a CAI, because they place the filter as close to the throttle body as possible. The theory is this allows for the least restriction possible from filter to throttle body. However, it also leads to vastly increased intake temperatures, which will make your engine feel more sluggish when it gets hot enough.

For that reason, we generally recommend a CAI for the 3.8 Genesis over a SRI, but both are popular. Additionally, the stock airbox has shown a tendency to dip in torque around 4,500 rpm. An aftermarket CAI usually fixes this, but a SRI will usually not. 

If you combine your intake with tuning, you’ll see even more gains together than if you just put them on individually. Your tuner can take advantage of the extra airflow to increase performance, making your car much faster. 

Best Hyundai Intakes

Like tuners, there are a ton of 3.8 Genesis intakes on the market. Some of the most popular are from AEM, Injen, and K&N. Looking at them, I’ve found the AEM intakes place the filter as low as possible compared with others. This will allow them to have the coldest intake temperatures, and thus have the best performance. With a solid upgraded intake, I would expect performance gains in the 5-10 horsepower/torque range on the 3.8 Genesis. 

3) Genesis 3.8 Headers and Test Pipes Upgrades

Now that I’ve shown you how to upgrade the intake and tuning on the 3.8 V6, the next of our best Hyundai Genesis 3.8 mods are headers and test pipes, AKA the exhaust. Looking at the Lambda II RS, one of the biggest restrictions is the exhaust system. This is due to multiple reasons, mainly small diameter tubing as well as catalytic converters. 

The Genesis 3.8 exhaust consists of four main parts: the exhaust manifold, downpipes, secondary cats, and cat-back. The exhaust manifold, also known as headers, is the portion of the exhaust that connects directly to the cylinder heads. Connected to the exhaust manifold are a left and right downpipe, with each having their own primary catalytic converter. After the downpipes are secondary cats, and then the cat-back comes last. 

When replacing the headers you have two options. Option one is to go with short-tube headers which only replace up to the downpipes. Or you can go with long-tube headers which also replace the downpipes, with optional replacement high-flow cats. If you are staying naturally aspirated and under 400 horsepower, you’ll want 2.25-inch to 2.5-inch diameter at a maximum. If your diameter is too large you’ll lose low-end torque and make the car feel sluggish down-low. 

Replacing the secondary cats with what are known as test pipes are the other main exhaust upgrade for performance. Test pipes completely remove the cats and replace them with hollow tubing. This really decreases restriction and allows the exhaust to open up and flow exceptionally well. With both headers and test pipes, I would expect gains in the 10-25 wheel-horsepower and torque range. 

Best Hyundai Headers and Test Pipes

There are tons of different headers available for the 3.8 Genesis. Some of the most popular are from J2 DNA Engineering, CP-E, and ARK Performance. Keep in mind, not all headers have the same diameter, and you’ll want 2.25-inch for the best performance and power band. For test pipes, the most popular are from ARK Performance and J2 DNA Engineering, and they both perform the same. 

4) Genesis Cat-back Exhaust Upgrades

For the final of our best Hyundai Genesis 3.8 mods we’re looking at cat-backs. The cat-back is the portion of the exhaust that connects to the secondary cats or test pipes. Upgrading the cat-back is not so much about gaining power as it is about changing the exhaust tone. The stock Hyundai cat-back and mufflers already sound like hot garbage, and it becomes much worse if you upgrade the headers and/or test pipes. 

I would only expect to gain maybe 1-5 horsepower and torque from a cat-back upgrade, so you’ll want to look for what looks and sounds the best to you. As usual, there are a ton of different 3.8 Genesis cat-back options. Some of the most popular are 7ism Exhaust, Ark Grip, GReddy TiC, Injen SES, and Magnaflow. 

Top Hyundai 3.8 Mods Summary

Hyundai’s Lambda II RS 3.8 V6 engine is one of the most popular modern engines, and it is capable of some pretty solid performance. Overall, the best Hyundai Genesis 3.8 mods are a tune, upgraded cold air intake, headers and or test pipes, and a cat-back exhaust. With these mods, you can expect to add more than 40 wheel-horsepower and torque and really broaden the power band. 

Genesis 3.8 mods are a great way to take advantage of the powerful Lambda II RS and really let it perform. Hyundai deliberately detuned the engine from the factory for emissions and fuel economy reasons, and it definitely hurt performance. You can get some back with mods, and a great place to start are an intake, tuning, or exhaust upgrades.

Top Hyundai 3.8 Mods FAQ