LS2 throttle body
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LS2 Throttle Body Guide

Chandler Stark

Meet Chandler

Chandler is an automotive expert with over a decade of experience working on and modifying cars. A couple of his favorites were his heavily modded 2016 Subaru WRX and his current 2020 VW Golf GTI. He’s also a big fan of American Muscle and automotive history. Chandler’s passion and knowledge of the automotive industry help him deliver high-quality, insightful content to TuningPro readers.

Since its release in 2005, the GM/Chevy 6.0 LS2 V8 engine has been a popular power plant for performance builds. GM/Chevy put it in cars like the early C6 Corvette, Pontiac GT/G8, Trailblazer SS, the SSR, and CTS-V. Previously, we’ve looked at guides for the 6.0 L engine including the Top 5 LS2 Mods, an LS2 Supercharger Guide, an LS2 Headers Guide, and an LS2 Intake Manifold Upgrade Guide. Today, we’re looking at LS2 throttle body upgrades. We’ll go over the best throttle bodies available and analyze them by cost, performance, and craftsmanship. Let’s get started.

LS2 throttle body
Credit: Weapon X Motorsports

Stock LS2 Throttle Body Basics

First, let’s start by discussing what throttle bodies do. They sit between the intake and the intake manifold and regulate the amount of air passing through. To regulate the flow, there is a blade in the middle of them, which opens or closes depending on how much air is needed. The stock throttle body from 2005-early-2008 came from 2005 – early-2008 with a silver blade for the throttle body. From mid-2008 on, the blade changed to a gold blade.

The GM/Chevy 6.0 engine uses a “drive-by-wire” (DBW) setup, opposed to a “drive-by-cable” (DBC) setup, which we’ll get into later. The stock unit has a diameter of 90 mm, which is pretty big as far as stock sizes go. The engine has a unique throttle body as far as the LS series of engines goes. It is different from the LS1 tb because it has a four-bolt design instead of three-bolt, and it is different from all LS3+ series engines because it is DBW instead of DBC.

Why upgrade to a bigger GM/Chevy 6.0 throttle body?

The purpose of getting a larger diameter is to increase the amount of air going into an engine. A larger diameter means more air can make it into the intake manifold and eventually into the engine. The only way to make more power is to increase airflow, which throttle bodies succeed at.

For most builds, the stock unit is more than adequate. It really only becomes necessary to upgrade to a larger one if you are making a lot of horsepower and the stocker is becoming a restriction. Typically, this happens when you are upgrading the intake manifold to something larger, or adding forced induction, like a supercharger.

Putting a larger throttle body on a naturally aspirated build making less than 600 horsepower won’t add very much in gains, but it will prevent a bottleneck from occurring if you push it harder in the future. You still might see 5-8 horsepower, but it won’t be a huge difference. In addition, putting too big of a throttle body for your power level can cause your engine to lose low-end torque and struggle and low loads.

What are ported throttle bodies for GM/Chevy 6.0?

One option many people take is porting their stock throttle body instead of getting a bigger one. Porting involves smoothing and shaping the inside of the unit to promote air flow and velocity. While it does not make the diameter bigger, it allows air to travel through quicker with less resistance and turbulence. In many cases, a ported throttle body will do the equivalent of jumping up 1-3mm in size.

Drive-by-Wire to Drive-by-Cable Conversion for GM/Chevy 6.0

While it is possible to convert the LS2 from DBW to DBC, it’s very tedious and not usually worth it. If you have a very high horsepower LS2 build and are using it in competition, then you might look into it, if not it’s a pretty prohibitive process. Alternatively, if you are using an LS2 as a swap engine, it might be worth it to invest in a DBC system from the beginning.

For a conversion, you’ll need a new wiring harness, DBC throttle body, E40 PCM, new accelerator pedal, and an ECU tune. The ECU tune is so the engine can properly function once the new DBC has been installed. One of the biggest issues can be a faulty idle, so an ECU tune is necessary.

Throttle Body Sizing

As we stated, the stock throttle body diameter is 90 mm. For most applications, this is plenty, however, there are important times when a new throttle body is needed. Most often, a new throttle body is needed when putting a new intake manifold on the LS2 due to forced induction.

Most aftermarket intake manifolds use a larger-than-stock 92 mm or 102 mm throttle body. In addition, you can fit a larger throttle body to the stock intake manifold and pick up horsepower, too, though its minimal. If you are using an LS2 for an engine swap, you might want to start with a larger throttle body if you are planning on getting a larger-than-stock intake manifold or want to run boost.

Gold vs Silver Blade Options

As we mentioned earlier, the LS2 throttle body came with two different blade options, first a silver from 2005-2008, and a gold from mid-2008 on. Performance-wise, there really isn’t much of a difference between the two. However, the gold blades actuate in the opposite direction of the silver blades.

Unfortunately, this means that silver and gold blade units are not interchangeable with each other. If you need a replacement, make sure you get the correct blade or your car will struggle to operate.

Throttle Body Upgrade Benefits

  • +5-15 horsepower
  • +5-10 lb-ft of torque
  • Improved air flow and velocity
  • Smoother power band
  • Improved throttle response

There are several benefits to upgrading from the stock throttle body. Most significantly, you will see a bump of 5-15 horsepower, depending on the build. If the stock throttle body is a restriction, you will see larger gains. Builds under 600 horsepower will probably see ~5 horsepower in gains, while bigger builds can see as much as 15 horsepower if the stock throttle body is a big bottleneck.

On applications where the throttle body is a restriction, you will see improved air flow and velocity into the engine. This will allow your engine to breathe easier and work more efficiently, which leads to a smoother overall power band. You won’t see as many dips in power because any restrictions will be lifted. You’ll also see improved throttle response because of the increased flow.

Top Throttle Body Upgrades

Here are the top 3 LS2 Throttle Body upgrade options that we recommend:

  • Ported Stock Throttle Body
  • Nick Williams 103 mm
  • LS Racing 92 mm/102 mm/108 mm

Throttle Body Upgrades are Beneficial for Some Builds and Unnecessary On Others

While upgrading the LS2 throttle body might not be the most common mod, it can definitely be beneficial when used on the right builds. The stock unit is 90 mm, which is fine for naturally aspirated and moderate builds, but if you really start cranking up the boost you’ll want something bigger. Alternatively, a ported stock unit can provide solid gains, too.

Our recommendations run porting the stock unit all the way up to giant 108 mm options. As we’ve said, if you’re naturally aspirated or below 600 horsepower, stick with porting, if you’re running boost it becomes another story. The 92 mm options will be good for low boost, while the 102 and 108 mm recommendations are for 20+ PSI builds.

What experience do you have with upgraded LS2 throttle bodies?

Let us know in the comments below!

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