An engine doesn’t just achieve the status the LS has without doing something right. While it developed quite the reputation right from the beginning, it reason why it’s so popular is the fact that this platform got better and better as it evolved. The keyword here is evolution. General Motors knew what they were doing and made sure to keep the engine competitive and relevant by constantly working on fresh iterations.
One iteration or version of the engine that will certainly be remembered for the years to come is the supercharged LS9. That’s because the LS9 engine didn’t just make an impact with incredible performance numbers, but was also specced incredibly well. General Motors didn’t spare any expenses when diving into this engine and that’s evident by just looking at just how well it was kitted out.
We take a closer look at the LS9 and discuss everything that made it special, while also touching upon the few things that weren’t so great.
How Much HP Does an LS9 Have?
The LS9 had the most HP of any engine made by General Motors. Before we dive into the technicalities and share details on the LS9 engine, you must get an idea of just how capable it is. The supercharged LS9 engine was solely reserved for use in one vehicle, the 2009–2013 Chevrolet Corvette ZR1. The ZR1 wasn’t just the sportiest version of the Corvette, but this vehicle was also the most powerful car General Motors ever made until then.
The LS9 engine made 638 HP at 6,500 RPM and 604 lb-ft of torque at 3,800 RPM. These huge power numbers in the lightweight Corvette body meant it was capable of hitting 60 MPH in just 3.4 seconds. The acceleration didn’t slow down after that as 100 MPH came up in 7 seconds. The LS9 engine also propelled the Chevrolet Corvette ZR1 to a quarter-mile in 11.3 seconds.
LS9 Engine Specifications
When compared just based on its capacity of 6.2-liter, the LS9 engine isn’t that different from other LS engines. However, it’s once you start looking deeper that you begin noticing changes. To begin with, the aluminum block it uses is a stronger version of the unit found in the LS3. It was built stronger simply because it had to withstand the additional stress of the supercharger.
As one would expect, the aluminum block does help keep the weight in check. This engine is about 100 lbs lighter than most of its equivalents. General Motors made two improvements to reduce vibration on the LS9 – they used cast-iron cylinder sleeves and a deep-skirt design. Other improvements came in the form of polymer-coated forged pistons and titanium connecting rods. The compression ratio wasn’t the highest, but it was well-suited for this application.
The LS9 block also made use of heads that featured a significant amount of air flow. This was essential given the engine’s supercharged nature. Speaking of the supercharger, it was a sixth-gen, 2.3-liter Roots-style unit. This supercharger used a 4-lobe design and maxes out at 15,000 RPM. The LS9 also made use of an intercooler that ensured the engine was reaching a cool air supply and this is what helped it generate the immense performance.
General Motors were also aware that owners of the LS9 would certainly be pushing it to its limits, which is why they made sure to ensure the engine also had sufficient oil flow. Along with increased oil capacity, the engine also had a factory-fitted dry sump system. This was race car technology and a massive boon when a vehicle is being pushed hard in the corners. This system added to the cost and complexity of this engine, but that didn’t stop General Motors.
Is the LS9 a Good Engine?
Yes, the LS9 is a really good engine. It might seem like another big American V8 that owes its power figure to its high capacity. However, that isn’t the case. Yes, it’s a big engine, but it also has an output of around 100 HP per liter which is quite impressive and surprisingly efficient.
The most powerful General Motors engine at the time was specially developed for the Corvette ZR1. The American carmaker didn’t just surprise the domestic market but left quite the mark internationally as well. The ZR1 managed to change the way the world looked at American sportscars. That’s not all, the engine was rather smooth at low speeds. Being the torque-laden V8 it was, tractability was to be expected.
The supercharger was also tuned quite well and allowed the ZR1 to have a docile nature while also having aggression when required. The supercharger also linearly delivered its power across the rev band, which meant it had quite a broad performance range. While General Motors were considering using a 7-liter block during the development stage, they felt it wouldn’t work well with the supercharger. The “sized-down“ 6.2 liter was a good fit as it allowed them to achieve the wall thickness required.
What Replaced the LS9?
The General Motors LS9 engine was replaced by the LT4 in 2014. Like the LS9, the LT4 was also a 6.2-liter supercharged engine. Aside from that though, it was unique and had a Gen 5 engine. While the power and torque weren’t all that different at 625 HP and 635 lb-ft, the biggest changes came in the form of efficiency.
The LT4 made use of a more efficient and smaller-sized supercharger. It used an improved version of the dry-sump system along with a titanium intake valve. General Motors also had to make sure the engine was more fuel-efficient than before, and they managed to do so by reworking the fueling system and another onboard tech like direct injection and variable valve timing.
Can the LS9 Engine Be Modified?
The LS9 engine makes tons of power in stock form, but enthusiasts are always looking for it no matter what. Luckily, the LS9 responds quite well to modifications and minor ones can deliver a noticeable increase. Interestingly, the LS9 engine can be tuned to gain around 40 HP without any modifications. A few hours on the dyno and a good tuner can increase performance with just a few tweaks.
Other simple upgrades like an aftermarket intake and less-restrictive exhaust will allow the engine to breathe better and in turn produce more power. The next stage would be to upgrade the supercharger and at this point, you are looking at a 100+ HP gain. One limiting factor at this stage is the fuel pump as it simply can’t fulfill the additional demand.
While this should be enough for most, there’s a lot more that can be done to take things to the next level. With upgrades to the cylinder head, camshaft and block, the LS9 engine can easily cross the 1000 HP mark. One has to realize that a performance gain of that sort will possibly come at the cost of aspects like low-speed performance and reliability.
LS9 Common Problems
The LS9 engine has proven to be phenomenal when it comes to reliability. Its lower compression and redline mark have proven to keep it together while it generates loads of power thanks to its supercharger.
Valve Guide Wear
The valve guide problem is certainly a bigger issue on the LS7 engine, but it has also been reported by LS9 owners. While the valve guide issue led to engine failure on the LS7, the consequence isn’t as bad on the LS9. This is because the LS7 suffered from bad exhaust guide wear. The LS9, meanwhile, has intake valve guide wear and that hasn’t proven to be as problematic. That said, they still require to be replaced as soon as possible.
Bad Supercharger Isolator
While this problem isn’t as common as valve guide wear, it’s not unheard of. There have been a few reports of supercharger isolator failure. Owners will notice a vibration from the supercharger. While some shops will recommend swapping in a brand-new unit, some recommend getting a replacement isolator which is most probably the cause.
Keep All 8 Cylinders Firing!
Here at Newparts.com, we offer a wide range of genuine, OEM and aftermarket replacement parts for the entire range of LS engines. So whether you have a truck or a sporty Corvette, you can head to our Shop and checkout with parts at the best prices within a matter of minutes. While components like the supercharger and dry-sump system are quite complex, the engine is fairly straightforward especially in terms of upkeep.
