For many automotive fanatics, the value of a car is determined by its ability to perform right out of the showroom. Experienced gearheads, on the other hand, know that the factory configuration is only a starting point.
While the 650 horsepower and 650 pound-feet of torque generated by the Gen V LT4 in the C7 Corvette Z06 and sixth-generation Camaro ZL1 in factory condition is plenty of grunt for most people, too much is never enough for a certain breed of horsepower seekers.
This desire for greater power also exposes one of the primary benefits of factory-installed forced induction systems: the ability to expand.
LT4 Supercharger Engine
The LT4 is an engine produced by General Motors for use in ultra-high-performance vehicles. Part of GM’s 5th-generation Small Block engine family, the engine displaces 6.2 liters, has eight cylinders in a “V” layout, and features a purpose-built supercharger.
The engine originally debuted in the Corvette C7 Z06 before going on to power the third-generation, 2016-2019 Cadillac CTS-V as well as the sixth-gen Camaro ZL1, followed by the Cadillac CT5-V Blackwing.
LT4 Engine is the most powerful production engine ever offered in a General Motors vehicle. The LT4 engine builds on the design strengths of the previous LS9 supercharged engine used in the sixth-generation Corvette ZR1 and leverages the technologies introduced on the seventh-generation Corvette Stingray, including direct injection, cylinder deactivation and continuously variable valve timing, to take Corvette performance to an all-new plateau.
Here are few simple modifications to improve performance of LT4 supercharger engine
Replace LT4 supercharger lid
This Billet LT4 Supercharger Lid replaces the factory supercharger lid on GM LT4 Superchargers for a quick and clean install. The goal of this modification is improved airflow design of the lid which increases up to 25HP.
One of the most popular LT4 supercharger lid manufactures is a US based company, MPI. Wauconda, IL based supercharger lid manufacturer offers lids in custom finish options as well as vehicle matching colors. Lid design entails minimal interference on the underside, thus allowing more air to go in the same direction. It also utilizes the stock gasket and fasteners which makes the install especially easy.
Power gains resulted in +11 RWHP and +14 RWTQ on a Hole Shot Mustang Dyno on an otherwise stock motor and stock tune in a 2017 Corvette Z06. The boost is available quicker and is more consistent through the power band. Finally, the additional whine of the blower is intoxicating!
Here is a closer look at MPI’s LT4 supercharger lid in action!
Replace Air Filter / Install Cold Air Induction
Air filters are one of the easiest and quickest parts to swap out for an aftermarket component. There are plenty of companies claiming their design will increase horsepower, torque, and improve acceleration. With little research you can find aftermarket filter from reputable company and on-budget. Many other companies make full blown cold air induction bolt on modifications that enhance power, make the blower a little louder and let everything breathe better!
For supercharged engines, one very common and cheap modification is changing the pulleys on the supercharger. A variety of aftermarket minded companies offer high end pulley swap packages that can produce well over 700HP and 700 lb-ft of torque at the flywheel over a stock LT4 engine with proper tuning. Common packages include a dry sump torsional vibration damper, 15% overdrive balancer pulley, pulley hardware, belts, larger idler kits and with this boost of the supercharger increases by anywhere from 2.5 to 5.0 PSI, thus adding horsepower and torque to the performance of the engine. The nice thing about this modification is it does not impact drivability.
A performance exhaust is one of the most popular modifications for enthusiasts. Just like a performance intake, a performance exhaust is designed to flow better than a stock setup. Aftermarket exhausts are usually louder than stock but may also save a few pounds. Depending on your vehicle application, additional exhaust components such as long tube headers and higher flow mid-pipes with or without catalytic converters can add substantial horsepower gains to all modern GM powerplants such as the LT4 engine.
With these few affordable modifications, your LT4 engine can generate more horsepower, more torque and stunning blower whine with MPI’s LT4 supercharger lid.
Last but not least and perhaps most important is the tune on your LT4 engine. Finding a reputable shop that is well versed in modern GM applications should have ability to remotely or dyno/street tune your vehicle’s computer to optimize all inputs (air/fuel, timing, boost, etc.) to get your LT4 running the best it can (and safely). It is critical to find a tuner with experience and a large sample size track record with happy customers. There are good tuners and bad tuners. It’s worth the $500-800 to have a GM tuning guru optimize your vehicle. You can tune a stock LT4 engine and get meaningful results, but if the right tuner ties together the benefits of the modifications above, you have a far more enjoyable vehicle to drive.
In this article, we reference performance enhancements that are affordable, ease of installation is high and they do not impact internals of the engine or drivability of the car. Once people go more aggressive with modifications such as modified heads, custom grind camshafts, etc., these mods, if not carefully done, can change the reliability and drivability of your LT4 engine.
If you seek performance gains, economically and want to retain stock drivability at modest RPM’s, the modifications in this short article can help get you to the finish line faster with minimal hassle.