LS2 Throttle Body Guide
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, and an LS2 Headers Guide. Today, we’re looking at LS2 throttle body upgrades.
While a tb upgrade might not be as common as some other mods, on the right builds it can provide solid power gains and seriously increase airflow into the engine. There are a lot of kits available, but unfortunately the vast majority of them are absolute junk.
Our guide is here to help you navigate through any throttle body questions or upgrades and cut through the junk. We’ll go over the best throttle bodies available and analyze them by cost, performance, and craftsmanship. Let’s get started.
*Keep in mind, the LS2 was available in a pretty wide range of vehicles. This guide is meant to cover blowers for as many LS2 equipped vehicles as possible. However, still make sure you confirm fitment with your specific vehicle model before making any purchases.
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 bigger GM/Chevy 6.0 throttle bodies?
The purpose of getting a larger diameter is to increase the amount of air going into an engine. 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.
GM/Chevy 6.0 Drive-by-Wire Setup
We used the terms “drive-by-wire” (DBW) and “drive-by-cable” (DBC) earlier, but what do those terms mean and why is DBC considered to be superior by many people? The difference is in how the throttle blade is actuated during use.
On a DBW setup, the throttle blade is controlled by a series of sensors that relay the accelerator pedal position to the throttle body, telling it how much to open. It’s called drive-by-wire because the signal is sent electronically, through a series of wires. On a DBC setup, the throttle blade is controlled by a direct cable that links the throttle body to the accelerator pedal. The throttle blade opens or closes depending on its control from the cable, hence the term drive-by-cable.
Many people consider the DBC configuration to be superior because there is a faster response from the accelerator pedal to the throttle body. This means the car will be slightly more responsive at first touch, though it doesn’t have an effect on horsepower/torque. The fact that GM/Chevy decided to switch up to the DBC halfway through production should be an indicator of its superiority for this application.
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.
LS2 Throttle Body Sizing
As we stated, the stock LS2 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 for GM/Chevy 6.0
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 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.
LS2 Throttle Body Upgrade Benefits
The top benefits of a larger or ported LS2 throttle body are:
- +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 LS2 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 LS2 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 LS2 Throttle Body Upgrades
Here are the top 3 LS2 Throttle Body upgrade options:
- Ported Stock Throttle Body
- Nick Williams 103 mm
- LS Racing 92 mm/102 mm/108 mm
1) Ported Stock LS2 Throttle Bodies
Price: Mamo Motorsports: $300.00 – $700.00; Weapon X Motorsports: $499.00
Mamo Motorsports Ported Stock LS2 Throttle Body
Weapon X Motorsports Ported Stock LS2 Throttle Body
Our first recommendation for an upgrade is the Mamo Motorsports and Weapon X Motorsports ported stock throttle bodies. These are both 90 mm stock options that have received porting treatment to optimize flow. These are direct bolt-on fits for the LS2 manifold and do not require any tuning or modifications.
Both of these options are the silver-blade and will fit 2005 – early-2008 LS2 engines. The Mamo Motorsports option is $300 if you send in your core and have them port it, or $700 if they use their own core.
In addition, you can also look into local porting services from local motorsports businesses. It will likely be cheaper and quicker to have it done locally, and you can potentially work with that shop on your LS2 build.
For basically any build that is naturally aspirated and making less than 600-700 horsepower, a ported unit will be the best option. It will fit the stock intake manifold the best and will more than likely not be a bottleneck. Many boosted applications utilize ported throttle bodies without any restriction. It’s really only necessary to go bigger if you’re running a lot of boost.
2) Nick Williams 103mm LS2 Throttle Body
Nick Williams 103mm LS2 Throttle Body
Our next recommendation is for those looking at upgrading their units for boosted applications. Nick Williams throttle bodies are known for quality, and their 103 mm DBW unit is very well reviewed. Most of their applications are for DBC systems, and this is one of the few DBW options they offer.
The diameter is 103 mm, 13 mm larger than stock, and is CNC machined from billet aluminum. It utilizes the 6-pin connector associated with the later model wiring harnesses (gold blade). Tuning is required with this throttle body and it will not fit the stock intake manifold or air intake.
If you are looking at getting a bigger diameter tb to run lots of boost, the Nick Williams 103 mm is by far the best choice. It is very well reviewed and has been put on many forced induction LS builds.
3) LS Racing 92mm, 102mm, and 108mm LS2 Throttle Bodies
Price: $349.00 – $849.00
92 mm LS2 Throttle Body LS Racing
102 mm LS2 Throttle Body LS Racing
108 mm LS2 Throttle Body LS Racing
Our next recommendation is from LS Racing. LS Racing offers three different options, ranging from 92 mm, to 102 mm, to the ultra large 108 mm. They are all the gold blade setup and will not work with early silver blade engines. It uses the late model 6-pin wiring harness.
All of the LS Racing options are CNC machined billet and meant for boosted applications. The 92 mm throttle body will fit the stock unit, with a spacer, and will provide mild gains when used on the stock manifold. The 108 mm throttle bodies are meant for high boost applications for high horsepower builds. The 92 mm is less than half the price of the much larger 108 mm option.
If you’re looking at a high boost application then LS racing has your biggest diameter option. The 92 mm and 102 mm options are also nice for non-stock intake manifolds, and provide solid bumps in performance. Still, we’d only suggest upgrading if you’re running forced induction.
LS2 Throttle Body Upgrade Summary
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!