The Throttle Body Guide for Chevy LS3. The Chevy LS3 is the third engine released using Gen IV architecture, and it debuted in the 2008 Corvette C6. The LS3 engine replaced the preceding LS2 engine, becoming the new powerplant for post-2008 base model Corvettes. With the new engine came some noticeable design changes that improved the LS3’s performance over the LS2. A bigger cylinder size, smoother flowing heads, and a more aggressive camshaft are among the most notable upgrades. Furthermore, and most importantly for this essay, the throttle body design was adjusted dramatically.
While a change in throttle body design isn’t as significant as the LS3’s increased displacement, it does bring the topic of throttle bodies into the LS3 discourse, and there’s a lot to discuss. There have been a variety of throttle body variations throughout the LS range. They’ve ranged from 78mm cable-driven three-bolt designs to 90mm electronically controlled four-bolt designs. While none of them are inherently harmful, there are several that are better suited to a specific application.
The world of LS3 throttle bodies is vast, and there are numerous factors to consider. Size, bolt pattern, intake compatibility, and drive by cable vs drive by wire are all important factors to consider before pulling the trigger. In this article, we’ll go over the fundamentals of LS3 throttle bodies and suggest you in the direction of ones that might work for you.
LS3 Throttle Body Stock
Depending on the model year of the LS3-equipped car, GM used a couple of different throttle body layouts during the LS3’s production cycle. Starting with the LS2, GM switched from a three-bolt to a four-bolt configuration. That merely implies that the newer Gen IV LS engines secure the throttle body to the intake with four bolts rather than three, as was usual on older models.
The LS3 also included a new internal blade, which is the mechanism that allows air into the manifold. The LS2 previously used a 90mm silver throttle body blade. For the LS3, this was replaced with a gold 90mm throttle blade. It’s also worth noting that early 2008 LS3s used the same silver blade throttle body as the LS2. The LS3 received the gold blade update by mid-2008. The blade direction was reversed as part of the update. A stock LS2 throttle blade’s top should revolve towards the manifold opening. In the case of a gold blade LS3 throttle body, the opposite is true.
The LS3 TB has a different port form in addition to a different blade color and rotation direction. The LS3 throttle body is designed to work with a different E38 PCM than the LS2’s E40 PCM. That means the two aren’t interchangeable in terms of stock wiring and programming. Finally, 2009 and later LS3 engines have the same gold plate throttle body as the LS7.
Drive-by-Wire vs. Drive-by-Cable Chevy 6.2L
Throughout the LS engine lineup, GM has used both drive-by-wire and drive-by-cable throttle bodies. Surprisingly, the LS1, which debuted in 1997 as the first engine in Chevy’s contemporary line of small-blocks, initially had an electronic throttle. However, in 1998, it was converted to a drive-by-cable configuration.
The 90mm gold blade LS3 throttle body is drive-by-wire from the factory, which means it is electronically controlled by the LS3’s PCM. Drive-by-wire systems take accelerator pedal readings using an auxiliary throttle position sensor and an idle air control valve. The throttle body blade is then actuated to the required position using a servo motor. The wiring harness of the LS3 connects the accelerator pedal and the throttle body servo motor. LS3 drive-by-wire systems are configurable via PCM tuning and can be tailored to your driving style.
Despite the fact that it is an aftermarket addition, many LS owners like the analog feel of a drive-by-cable throttle body. Unlike drive-by-wire systems, which use several sensors and are operated electrically, a drive-by-cable system is entirely mechanical. A drive-by-cable arrangement connects the throttle body and accelerator pedal via a cable linkage. A wire pulls the throttle blade open when you put your foot down. This simpler architecture gives quick response, which a drive-by-wire system cannot. This is due to the fact that pedal inputs must first pass via the electrical system.
Conversion of an LS3 to a Drive-by-Cable Engine
Because most LS owners prefer the traditional drive-by-cable type of throttle body, there are a plethora of aftermarket conversion alternatives available. For LS3 swaps into earlier vehicles, the drive-by-wire to drive-by-cable conversion is extremely prevalent. While an LS3 drive-by-cable conversion increases throttle response significantly, there are a few steps required to get the conversion operational.
The first step is to replace the OEM LS3 crankshaft reluctor wheel with an older, Gen III 24x wheel. The crank reluctor wheel’s function is to provide crankshaft position data to the PCM. Older Gen III LS engines utilize 24x wheels, however Gen IV LS engines use 58x wheels, which are more precise. Your LS3 will require the older wheel for a drive-by-cable upgrade.
You’ll also need to install an earlier E40 LS1 PCM in addition to the older reluctor wheel. Because the earlier reluctor wheel is incompatible with the LS3’s OEM PCM, an LS1 PCM is required. You must also figure out how to get the throttle cable from the accelerator pedal to the throttle body. There are numerous aftermarket manufacturers who sell brackets for this purpose.
LS3 Throttle Body Ported
Swapping the stock TB for a ported one is one of the most popular LS3 throttle body mods. While ported throttle bodies do not always enhance horsepower, they can significantly improve LS3 throttle responsiveness. Because ported LS3 throttle bodies reduce internal turbulence from incoming air, flow and velocity increase.
There are numerous myths surrounding ported LS3 throttle bodies and the porting process in general. The porting technique does not significantly expand the internal diameter of the throttle body. Porting, on the other hand, is intended to smooth out any defects generated by the initial casting process. There is frequently debris left behind from the casting process that might obstruct airflow and velocity. To remove these defects and enhance flow, throttle body porting can be done by hand or by a CNC machine.
While a ported throttle body may not be the finest LS3 alteration to begin with, the benefits of enhanced throttle responsiveness scale with other performance changes. A ported LS3 throttle body will truly come alive when combined with other LS improvements such as a performance intake, cams, and ported heads.
Recommendation for a Ported Throttle Body
LS3 90mm Ported Throttle Body WEAPON-X
$174.00 with Core, $399.00 without Core
While the process of porting an LS3 throttle body isn’t difficult, you should still have it done by an experienced specialist with a lot of experience. In terms of quality ported LS3 throttle body options, WeaponXMotorsport’s 90mm gold blade ported LS3 throttle body is hard to beat. WeaponX has been providing quality components to the LS community for years and offers a terrific blend of knowledge and experience to the table. Their ported throttle body reflects this.
According to the Weapon-X crew, their ported LS3 throttle body is one of the highest flowing alternatives on the market. It also offers unrivaled dependability. They have tested their product on their in-house flow bench to back up their claim. Overall, you’re unlikely to find a better product at a lower price.
Chevrolet 6.2L Throttle Body Dimensions
When it comes to upgrading the standard LS3 throttle body, there are normally two options. One of them, upgrading to a ported LS3 throttle body, has already been discussed. The alternative option is to upgrade to a larger-diameter throttle body. As previously mentioned, the factory 6.2L LS3 throttle body has a 90mm diameter blade.
The idea behind upgrading to a larger throttle body is simple. The throttle body introduces air into the intake manifold, and more air usually means more power. A bigger diameter throttle body aperture allows more air to enter the system. The real performance improvements from a larger throttle body, on the other hand, are hotly contested in the LS3 forums. The debate stems from the fact that there are numerous 1,000whp+ Vettes on the market with 90mm throttle bodies. Even when forcible induction is used.
Upgraded 102mm Throttle Body
Having said that, there are justifications for using a larger 102mm throttle body in conjunction with a turbo or positive displacement blower. Increased airflow is always advantageous with forced induction, as turbos and superchargers rely on a large volume of air to produce power. While an upgraded intake manifold is more likely to improve FI performance, a larger throttle body can limit performance if the rest of the system is properly adjusted.
Running a 102mm LS3 throttle body with a PD blower results in more internal pressure, which results in more horsepower. By upgrading from a stock 90mm throttle body to a larger 102mm throttle body, some Corvetteforum.com users have observed an increase of roughly 2 psi, equal to around 50 additional horsepower. As previously stated, with forced induction and a stock throttle body, it is feasible to get totally ridiculous performance. The throttle body, on the other hand, may be a limiting factor if the system has been optimized in every other way.
Suggestion for 102mm Chevy 6.2L Throttle Body
Throttle Body BBK Performance LS3 6.2L 102mm
If you’re looking for a larger LS3 throttle body, you have a lot of possibilities. The 102mm gold blade LS3 throttle body from BBK Performance, on the other hand, stands out. BBK is a Daytona Beach-based American corporation. Since 1988, they have been selling quality components to the Ford, Chevrolet, Dodge, and Jeep communities.
Their LS3 102m m throttle body is CNC machined from 356 aluminum and comes standard with an OEM quality throttle gear, double sealed bearings, and o-ringed throttle shafts. The BBK throttle body is superb in terms of quality and dependability. The throttle body retains an OEM four-bolt connection for use with stock LS3 bolts. If you need more airflow for your LS3 forced induction, the BBK-Performance throttle body will do the trick.
Summary of the Chevy LS3 Throttle Body Guide
The 6.2L Chevy LS3 engine is one of the most famous in the world. Its Chevy Gen IV small-block architecture, larger displacement, and highly robust components give it an excellent foundation for performance enhancements. While the stock LS3 throttle body is not defective, there are some nice mods available to improve airflow or increase forced induction performance.
The drive-by-cable conversion is a popular upgrade, especially when replacing an LS3 into an older vehicle. While certain additional components, such as a 24x reluctor wheel and an LS1 PCM, are required, the conversion can greatly enhance throttle responsiveness. If you don’t want to go that route, you could always replace the factory 90mm throttle body with a ported one. A ported LS3 throttle body improves throttle responsiveness by reducing internal air turbulence.
Another frequent TB alteration is to install an LS3 throttle body with a larger bore. While there isn’t a significant performance advantage to doing so with a naturally aspirated LS3, the benefits for a peak-efficiency blower-equipped LS3 are significant.