For the longest time, performance cars were usually in the 400-500 HP range. We’re talking decades! Whether it was gentlemen’s agreements among manufacturers or something else, the last couple of decades saw car companies refraining from crossing that range even though they very well could. However, things suddenly changed not too long ago and we suddenly found ourselves amidst a horsepower race.

500 horsepower suddenly went from being a supercar power figure to a sportscar one. Some hatchbacks now make 400 HP from the factory. This horsepower race did lead to the development of some insane engines. Almost all of the engines that made big numbers used some method of forced induction. 

And if there’s something that everyone knows about engines with forced induction is that there is always room to bump up the numbers with something as simple as a tune. Yes, it’s become quite common to see people increase the power figures on engines that are monstrous right from the factory. The Chevy LT4 engine is an example of one of these big power motors and there’s a lot to learn about it, so let’s get right to it.

The Making of the LT4 Engine

Making an engine like the LT4 requires experience. Fortunately for Chevrolet that’s something they aren’t lacking. This car maker is responsible for building some of the most iconic V8 engine series ever seen in the automotive industry, including the LS family. The LT series came as its successor. Chevrolet used their experience from making the LS engines, particularly the Gen 4 LS9 to develop the LT4 engine which we’ll be taking a closer look at today. The Gen 4 LS9 was used in the C6 Corvette ZR1 and while it wasn’t lacking power, the company was looking to make something more efficient.

To give you an idea of the improvements in comparison to the LS9, it made use of a more efficient and smaller 1.7-liter Eaton R1740 TVS supercharger. This supercharger can handle up to 20,000 RPM. When paired to the 6.2-liter V8, it generates 650 HP and 650 lb-ft of torque. It does this at 9 pounds of boost. Chevrolet took many steps to ensure that the new engine could handle the additional pressure from forced induction.

These steps included stronger internals. The LT4 uses well-known Rotocast aluminum cylinder heads which are not only stronger but also better at dissipating heat. The connecting rods, on the other hand, are also quite strong but also designed to have reduced reciprocating inertia. Other upgrades come in the form of lighter titanium valves and direct fuel injection. 

The LT4 engine features a compression ratio of 10:1 which is quite high considering that it is designed to handle forced induction. Chevy has designed a lightweight piston for this motor, which features extensive use of aluminum to help reduce the reciprocating mass of the engine. 

Other areas of improvement include a stainless steel exhaust manifold which helps make sure there isn’t much flex at increased temperatures. Another benefit is that it’s a lot more resistant to corrosion. The LT4 engine found in the Corvette comes standard with a dry sump. This is the best version of the engine and as you may already know, the dry-sump allows it to maintain lubrication when being pushed to the limit. When used on a racetrack, oftentimes a car can experience high levels of g-force that could end up affecting the flow in normal conditions. This usually occurs during high-speed corners. 

Dry sump lubrication makes sure that the engine is not affected by this. Interestingly, there’s another benefit as well. Since a dry sump eliminates the need for a large oil pan, it allows for more wiggle room when it comes to positioning the engine within the car. 

What Cars Have the LT4 Engine?

The LT4 engine was used in the sportiest offerings by General Motors. Listed below are the cars it can be found in.

• 2015–2019 Chevrolet Corvette Z06 650 HP/650 lb-ft of torque

• 2016–2019 Cadillac CTS-V 640 HP/630 lb-ft of torque

• 2017–present Chevrolet Camaro ZL1 650 HP/650 lb-ft of torque

• 2022–present Cadillac CT5-V Blackwing 668 HP/659 lb-ft of torque

• 2023–present Cadillac Escalade V 668 HP/659 lb⋅ft of torque

How Much HP Can an LT4 Handle?

The LT4 engine can handle close to 1000 HP on stock internals. While that might seem like an absurd amount of power, and it is, it’s quite easily attainable with the correct modifications. It is as simple as upgrading the supercharger but should be ideally paired with minor supporting modifications. Other simple modifications can help boost performance as well.

What Are the Best Mods for the LT4 Engine?

Modding an LT4 is made somewhat easy thanks to the massive aftermarket support. This engine has been around for a hot minute, leaving enough room for various companies to come up with solid mods. Here are some of the most notable ones.

Supercharger Lid Upgrade

There are aftermarket billet supercharger lids that replace the stock one on the LT4 engine. The lid is easy to replace and it works by allowing more airflow. This additional airflow can increase the power by up to 25 HP. The most popular lid upgrades use the stock gasket and fasteners which makes the installation straightforward. You will also be treated to a louder whine from the supercharger with this modification.

Replacement Air Filter 

Another fairly easy modification is swapping the air filter. These are readily available and do improve airflow marginally. They do not bring about a big change in performance, however a decent aftermarket air filter will help the engine breathe better and make the supercharger a little more audible.

Pulley Change

If you are looking for a noticeable power gain without spending a lot, swapping the pulley should be on top of your list. There are several aftermarket pulleys available and they can increase power and torque to 700 HP and 700 lb-ft when paired with a tune. What’s nice is that while there’s a significant increase in performance it doesn’t come at the cost of driveability.

High Flow Exhaust

Another common upgrade for the LT4 engine is a performance exhaust. Like the air filter, it helps the engine breathe better. When paired with an air filter, the engine will have improved airflow overall. 

This modification will also bring about a weight reduction as aftermarket units almost always weigh less than stock units. Additionally, if the exhaust is catless or a system that’s a larger diameter, it can result in a tangible bump in performance.

ECU Tune

As with most modern engines, there’s always power to be gained with a performance tune. The LT4 engine packs a supercharger which makes it easier to increase power with a tune. A good tune will deliver a noticeable improvement especially when paired with any of the aforementioned modifications. However, it is important to keep in mind that it will almost certainly void the car’s warranty.

LT4 Engine Common Problems

The LT4 engine was the most powerful engine General motors made when it was launched. As with most higher performance engines, some complications were to be expected. Here are some of the more common issues you could be facing with this motor. 

Limp Mode

One problem that upset LT4 engine owners of the Corvette Z06 had to do with its performance on the racetrack. There were multiple complaints that the car would force itself into the limp mode after being driven aggressively for as little as 15 minutes. Some reports also suggested that this happened after spirited driving on the road as well.

While the limp mode got activated for a good reason (to protect the engine from overheating) it wasn’t something owners were expecting from a car that was designed to be driven hard. General Motors offered a tuning device that would stop the engine from going into its limp mode, but it would come at the cost of the engine warranty.

Valve Spring Issue

A couple of years ago, General Motors revealed that they were carrying out a recall to fix the valve spring issue on some of its V8 engines, and the LT4 was part of this list. According to GM, the problem would illuminate the service engine light and cause the engine to misfire and produce a strange noise. The manufacturer has said that this issue occurs because of faulty valve springs.

Is the LT4 a Good Engine?

As you may be able to tell, the LT4 engine has a lot more advantages than disadvantages. That said, the two problems mentioned above can be a real pain in the rear. 

The best thing to do is to make sure that the potential problems were addressed early on. That, or get a car that doesn’t suffer from these issues at all. With that covered, the LT4 engine is amazing. Yes, it holds the title of being the Chevy’s most powerful engine, but it’s still incredibly potent. If money is no object, you could take things a step further and acquire the LT5 which is the LT4 engine’s successor and another incredibly powerful machine.

How Much Does an LT4 Engine Cost?

While we are on the subject of money, it has to be said that the LT4 engine does not come cheap. A brand-new LT4 costs around $15,000, while a dry sump-equipped unit will cost closer to $16,000. If you acquire this engine from GM Performance, they will also sell you a six-speed gearbox. 

Like the engine, this potent gearbox does cost quite a bit being priced close to $5,000. The engine is also available with several automatic transmissions. General Motors offers a 2-year/50,000 mile warranty. That being said, you can expect the price of the engine to drop considerably if you acquire a used one.

Get the Right Parts for Your LT4 Engine

As with any other high performance machine, the key to keeping an LT4 engine on the road is proper maintenance. Here at Newparts.com we carry a wide range of engine oils, filters and other maintenance items for various Chevrolet vehicles. 

To find what you need, simply head over to our store section, select your vehicle using our car selector tool and search for the parts. The results will only include products that are a guaranteed fit for your make and model.