The Upgrades for the Chevy LS3 Engine. Chevy had already firmly established their upgraded LS small-block formula by the time the LS3 arrived in 2008. The contemporary LS layout was basically a blank sheet design, but it borrowed learned aspects from the 1954 Gen I and Gen II Chevy small blocks. Despite its four-decade delay, the LS family shares a few parts with earlier Gen I and Gen II small-blocks, such as connecting rod bearings and valve lifters.
The LS3 not only comes from a long line of all-American heritage, but it is also one of the strongest and most reactive engines to modifications available. You may easily increase horsepower by a significant amount without spending a fortune with some well-chosen LS3 engine improvements. In this tutorial, we’ll go through some of the top LS3 engine improvements and also recommend a few items.
History of the Chevy LS3 Engine
The Chevy LS3 is a Gen IV LS engine that was first featured in the 2008 Corvette. Prior to the LS3, Chevrolet had already introduced the fourth generation of engine block architecture with the LS2 and LS7. In comparison to the Gen III architecture shared by the LS1 and LS6, the Gen IV architecture included a new block casting technology, increased displacement, rearranged sensor positions, and a wider cylinder bore. Otherwise, the Chevy Gen III and Gen IV engines are very similar.
The LS3 was released from the factory with 430 horsepower and 424 pound-feet of torque. That is 30 more horsepower than the previous Gen IV LS2 engine. The LS3 had a bigger cylinder bore and thus a larger displacement than the LS2. The result was a 0.2L increase over the LS2, for a total displacement of 6.2L. Higher flowing cylinder heads, a more aggressive factory camshaft, a somewhat less intense 10.7:1 compression ratio (ideal for boost), a high-flow manifold, and updated injectors are among the other noticeable changes to the LS3.
The LS3 is widely regarded in the Chevy community as one of the best examples of the LS format that Chevrolet has ever offered. The LS3 is a wonderful V8 in general, not just an excellent Chevy engine. Its simplicity and robustness are two of its distinguishing features. Unlike many exotic performance engines, an LS3-powered automobile is rarely seen in the shop for anything other than routine maintenance. Despite the fact that the LS3 engine has an ancient pushrod architecture, the Chevy aftermarket community has had decades to refine modifications. As a result, there are numerous modifications available to increase the power of your LS3.
Upgraded LS3 Engine Headers with X-Pipe
When it comes to first LS3 modifications, practically everyone agrees that improved headers and an X-pipe are your best bet. The ultimate purpose of upgrading to performance headers, like with other performance exhaust upgrades, is to remove any factory limits and reduce back pressure within the exhaust system.
Headers are a fancy term for aftermarket exhaust manifolds, and the terms are frequently used interchangeably. Because the headers are the first component of your LS3’s exhaust system, they are a critical piece of the jigsaw in terms of exhaust flow characteristics. The stock LS3 exhaust manifolds aren’t bad in and of itself, but upgrading to a set of long tube headers with high-flow catalytic converters can give significant power from a normally aspirated LS3.
While there are numerous types of headers available, primarily “shorty” and “long tube” headers, there is only one usually recommended type of improved header for the LS3. While shorty headers will undoubtedly make your engine compartment stand out when compared to stock exhaust manifolds, the horsepower yield will be substantially lower than with long tube headers.
Header diameter has a significant impact on the quantity of power generated by upgraded LS3 headers. Having said that, larger headers do not automatically correlate to higher power. The majority of the LS3 community advocates for 1-7/8″ headers. They maximize power production while still providing some flexibility for expansion if you decide to update your camshaft or add ported cylinder heads in the future.
There is a lot more to cover in terms of LS3 headers because there are so many factors to consider. As a result, we’ll be publishing a more in-depth LS3 headers guide, which will be linked here.
LS3 X-Pipe Improvement
If you want to undertake some extra exhaust changes while you’re tinkering with headers, an enhanced X-pipe should be on your list. Before we go into the intricacies, let’s first discuss the function of an X-pipe. Vehicles with more than one bank of cylinders (such as V6s, V8s, V10s, and so on) feature midpipes, which are where the exhaust gases from both banks meet. The goal of a midpipe is to balance the exhaust gas pulses from both sides of the engine. There are normally two midpipe options on LS3s: an X-pipe or an H-pipe. The LS3 community is divided about whether X-pipes or H-pipes are superior for sound and performance.
Overall, X-pipes and H-pipes function similarly to equalize gas flow. Both have large runner pipes coming from the LS3 headers. The way X-pipes and H-pipes merge is where they differ. While a 90-degree connection pipe on an H-pipe connects the two independent exhaust pipes, the two pipes curve into one other and join directly with an X-pipe. This has an immediate impact on sound and performance. LS3 fans sometimes claim that an X-pipe will produce a much more modern-sounding exhaust tone. If you want a more raspy, old-school-muscle exhaust tone, an H-pipe is the way to go.
In terms of performance, both will add a handful of more ponies, but nothing spectacular. In general, an X-pipe will add 5-10 horsepower, while an H-pipe will add a few less.
Camshaft Upgrades for the LS3 Engine
Upgrading the stock cam is one of the most straightforward performance-enhancing changes you can do to an LS3. The LS3 is an excellent candidate for hotter cams because it already has a formula that allows for more aggressive cam timing. The factory LS3 camshaft is without a doubt one of the most restrictive features of the LS3 engine. In general, there is always a cost to running a more aggressive cam profile. Chevy chose a very mild 204/211.551/.525 117 cam from the factory to protect fuel economy and daily drivability. Having said that, the LS3 can handle considerably more aggressive cams. The question is, how bold do you want to be?
In terms of cam profiles, generally speaking, the wilder the cam, the less performance you’ll get down low. There is a direct tradeoff between low-end performance and more power at the top. There is, however, a strong middle ground that can increase performance across the whole rev range. A larger cam does not always imply better overall performance. While a large LS3 camshaft improves top-end horsepower, it makes your Corvette or Camaro a headache to drive on the street.
Considerations for LS3 Engine Cam Upgrade
Unfortunately, improved LS3 cams aren’t a simple bolt-on update. Before you throw the biggest cam you can find into your LS3, there are a few things you should think about. When performing an LS3 cam upgrade, there are two key issues to consider. They are, in essence, valve spring rates and piston-valve clearance.
In terms of the former, the issue is self-explanatory. The factory valve springs were not built to handle the additional stress and duration induced by larger camshaft lobes, and hence are insufficient for aftermarket cam alternatives. The solution is to replace the factory springs with performance springs designed to tolerate the higher forces. Without improved springs, you may experience serious problems such as valve float and coil bind.
The second, and possibly more serious, issue is piston-valve clearance. The amount of space between the valves and the pistons decreases as the cam profile size increases. This causes serious issues on the LS3 engine with aggressive cams, as the gap between them might become non-existent. The pistons can then make contact with the valves, and we all know how that goes. That’s not good. The only way to solve this issue is to replace your LS3 pistons with ones that feature valve reliefs, which will give you a little more clearance.
Typical LS3 Engine Cam Profiles
Cam profile possibilities for the LS3 include (224/232.624/.590 111), (231/239.617/.624 111), and (235/244.647/.612 111) cams. Those are listed in descending order of aggression, from least to most aggressive.
If you’re looking for a large increase in usable power for street use, a milder 224 cam might be your best alternative. While not the most aggressive option available, the 224 cam increases the factory cam duration by 20 degrees, which makes a substantial improvement in power. It is predicted that an LS3 224 cam switch will add 50 horsepower across the full rpm range.
A 231 profile is the next step up from the 224 cam. This is where the power truly begins to accumulate. A 231 cam is one of the most talked about cam choices in the LS3 world, with a much longer duration than the factory cam. The 231 profile is on the verge of requiring pistons with valve reliefs, as the piston-valve clearance is only.041 in-Hg. That’s where things start to become dicey. That being said, the cam modification can produce power in the neighborhood of 70 horsepower.
Finally, a 235 grind is the most severe cam profile on our list. While an improved 235 cam may increase power across the rev range, it will degrade idle quality. That directly correlates to on-street performance, which will undoubtedly be impacted. For a 235 LS3 cam, you’ll also require valve relief pistons.
LS3 Cylinder Head Ported
It goes without saying that the LS community loves porting cylinder heads. While this is true, the LS3, or any other LS motor for that matter, does not have poor flowing cylinder heads. In fact, for a factory engine, the LS3 boasts some extremely amazing flow statistics. In factory trim, the LS3 heads produced roughly 312cfm at.600-in. 223cfm at.700-in lift and 223cfm at.700-in. The exhaust should be lifted. Flow numbers can be greatly enhanced with a quality hand or CNC port job on either original or aftermarket heads, resulting in increased power.
If you’re unfamiliar with how ported heads function, we’ll explain it in layman’s terms. The primary purpose of porting LS3 heads is to restructure and smooth the cylinder heads’ interior channel. The cylinder head casting process isn’t suited for high-performance applications in general. The operation usually leaves behind debris or blockages within the heads. Turbulence within the passageways can result, limiting the volume of air that enters the combustion chamber. By porting LS3 heads, you remove these intrinsic flaws, increasing flow and power.
There are several methods for incorporating ported heads into your LS3 design. The first option is to send your LS3 head to a machining shop that specializes in hand/CNC porting. Alternatively, there are numerous aftermarket manufacturers of high-quality ported LS3 heads that generally start with LS3 crate engine top ends. One of the most popular options is the GM Performance Parts ported LS3 head package.
Advantages of 6.2L LS3 Ported Heads
- Significantly increased intake and exhaust flow rates
- improved fuel atomization and fuel economy
- Significant power gains of roughly 20-30 horsepower, as well as corresponding torque gains
LS3 CNC Ported Cylinder Heads by GM Performance Parts
As previously said, there are several options when it comes to ported LS3 heads. The GM Performance Parts ported LS3 head is the go-to option since who wouldn’t trust GM with their own product? The GMPP CNC Cylinder Head has 276cc intake runners and 92cc exhaust ports to provide significantly more flow to the “as-cast” LS3 cylinder head. Overall, the CNC ported heads will produce around 15% more flow than the original heads. WeaponXMotorsports.com measured a 30 horsepower gain over their benchmark LS3 setup.
Engine Tuning for the LS3
We’ve reviewed some of the best bolt-on modifications for your LS3 in this article. While the modifications can result in greater power figures on their own, they won’t completely come to life until you add an LS3 tune to the mix. An engine tune’s goal is to allow your LS3’s PCM to identify the installed parts. A tune will modify engine parameters such as the air/fuel ratio, ignition timing, and idle settings.
In general, there are two primary paths you can pursue when it comes to tweaking your LS3. The first alternative is to install an off-the-shelf tune that is compatible with the adjustments you have made. This is definitely the best solution for most normally aspirated LS3s. A number of well-known tuning businesses have created off-the-shelf tuning solutions that cover a wide range of common LS3 upgrades. Typically, off-the-shelf LS3 tunes are installed with a programming device that fits into your vehicle’s OBD port. The SCT X4 programmer, which comes preloaded with downloadable tunes, is by far the most popular alternative for LS3-equipped vehicles.
The other, more expensive, tuning option is to have a nearby tuning shop dyno tune your LS3-equipped vehicle. In that instance, your car will be placed on a dyno, and an expert with considerable tuning experience will make on-the-fly adjustments to your vehicle’s tune based on the modifications you have installed. A dyno tune will improve performance more than a “canned” tune because it is tailored to your individual design. That being said, it will be substantially more expensive.
Advantages of LS3 Engine Tuning
- Support for existing modifications has been improved.
- Engine characteristics can be completely customized.
- Simple installation for off-the-shelf tunes
- Massive power increases ranging from 30-100 horsepower depending on other changes
The Most Popular LS3 Engine Tune
When it comes to LS3 off-the-shelf tunes, most LS3 aficionados swear by only one name: DynoSteve. Since 1996, Steve and the RDP crew have been supplying GM parts and services. They have a solid reputation in the LS community for supplying outstanding songs and unrivaled customer service. Steve provides remote tuning. That means all you have to do is buy an SCT X4 tuner and call him. Furthermore, if you buy the tuner and performance parts from him, he will free of charge update your tune for new parts. Steve offers tunes for a variety of bolt-on modifications such as headers, intakes, ported heads, throttle bodies, and many more. DynoSteve is your best bet if you have a mildly modified LS3-powered Chevy.
DynoSteve SCT X4 GM Tuner Package Includes Lifetime Custom Tunes
Summary of the Best Chevy LS3 Engine Mods
The LS3 is a modern classic as one of the top engines in the Gen IV Chevy series. The 6.2L, 430 horsepower V8 offers all of the characteristics that you expect from a Chevy small block. Because of its simplicity and robustness, the LS3 is an excellent engine to alter because it can withstand a considerable deal of abuse.
Exhaust changes are always an excellent place to start for most normally aspirated engines, including the LS3. A good pair of performance headers can drastically reduce LS3 backpressure while also increasing horsepower. An modified X or H-pipe can also change the tone of your LS-powered Chevy’s exhaust, making it stand out from the crowd.
Another fan favorite in the LS community is a bigger LS3 camshaft, as the stock LS3 cam is one of the key components holding the LS3 back from the factory. Larger cams have the ability to significantly improve horsepower, but you must be cautious with stock valve springs and piston-valve clearance when using more aggressive LS3 cam alternatives.
While the factory LS3 cylinder head has amazing flow figures, ported heads can increase performance by tens of horsepower. Imperfections in the OEM LS3 cylinder head can be removed to increase airflow into and out of the combustion chamber. This is closely related to greater power figures.
Finally, none of the LS3 engine upgrades outlined above would be effective without a proper tune to support them. Tuning is an important part of the LS3 modification process. To fully benefit from enhanced flow, adjusted valve timing, and so on, you must tune the engine. For the most frequent bolt-ons, there are a plethora of great LS3 off-the-shelf tunes available.