Best C4 Corvette Performance Mods


Looking for the most performance improvements to your C4 Corvette? Check out this article if you are looking for some cheap improvements. In this article. In this article we’ll talk about some that do cost money but will help improve your C4 Corvette performance.

These are considered upgrades that don’t take too much do. There are others like an engine swap that can do even more but those type of upgrades aren’t mentioned here.

Performance cold air intake

What is the purpose of a performance cold air intake?

A performance cold air intake allows larger amounts of cool air into the engine, resulting in improved combustion, increased horsepower and torque, better accelerator pedal sensitivity, smoother engine run, reduced detonation risk, and reduced fuel consumption.

Horsepower increase 5-20hp.

There is some debate about needing a performance intake or just creating a bigger opening in your air box and adding an K&H filter. Some reviews mention the same performance increases by just doing this.

Here are the summarized process steps:

  1. Remove the air box lid and filter from the car.
  2. Mark the area where you want to cut the air box lid to create a relief area for the filter.
  3. Use a grinder with the appropriate grinding disk to cut out the marked section.
  4. File the edges by hand to further refine and remove any sharpness.
  5. Clean the modified air box lid and consider painting it with engine enamel for a nice finish.
  6. Reassemble the air box lid and filter back into the car.
  7. A K&N air filter is recommended for better air flow
  8. Enjoy the improved performance and better airflow provided by the modified air box lid. Once again lots of debate on this.

Throttle body coolant bypass

How does a throttle body coolant bypass affect performance?

A throttle body coolant bypass reroutes the engine coolant away from the throttle body, reducing the temperature of the air flowing through the air intake. This simple mod can provide a horsepower gain of up to 5HP by allowing the engine to draw in colder air.

  1. Its a good idea to jack up the front end of the car and start draining the coolant to minimize mess during the procedure. Its not completely necessary as you should only lose a little coolant removing the lines but this is up to you.
  2. Remove the intake tube and mass airflow sensor to gain access to the coolant lines.
  3. Disconnect the coolant line going into the throttle body and remove it from the other side as well.
  4. Obtain a throttle body coolant bypass kit that includes two caps and a 90-degree angle hose. Really the bypass kit is a personal preference. Once you remove the hoses you can visually tell what angle hose you could get to to this process. Once again, up to you. The hose should be 3/4″
  5. Install the bypass kit or hose by connecting one cap to the throttle body inlet and the other cap to the coolant line leading to the intake manifold.
  6. Use the provided hose from the bypass kit to connect the throttle body outlet to the coolant line that runs into the engine block.


How do headers improve the performance of a C4 Corvette?

Aftermarket headers reduce back pressure in the exhaust system by providing each cylinder with it’s own exhaust pipe. This allows for a clean flow of exhaust gasses, eliminating power-reducing back pressure and providing a horsepower increase of 10-20 HP.

Removing the exhaust manifolds and replacing them with headers is a much bigger job than I will present here. Look for a more indepth process review in the future,

Camshaft upgrade

What does a camshaft replacement do for a C4 Corvette?

The power surge brought about by an aftermarket camshaft results from it’s ability to increase valve lift, thereby extending the valve stroke. Unlike the stock cam, which prioritizes durability, the aftermarket cam is specifically engineered to unleash raw power. With it’s greater lift, the aftermarket cam allows the valves to remain open for longer, facilitating the entry of a higher volume of oxygen-rich air.

Moreover, the duration of valve opening in these aftermarket camshafts exceeds that of a stock cam. When lift and duration are combined, a significant boost in horsepower is achieved, resulting in a remarkable increase in overall performance.

A camshaft upgrade can improve your C4 horsepower by 30+.

As you can guess, this is another major job that will be address down the road.

Adjustable fuel pressure regulator

Why is an adjustable fuel pressure regulator important?

An adjustable fuel pressure regulator ensures that the engine is not running lean on fuel, which can rob the car of horsepower. It is recommended to use a quality regulator to avoid engine damage. This modification does not provide a specific horsepower increase.

  1. Start by disconnecting the air filter and observing any signs of fuel leakage or strong fuel smell.
  2. Locate the fuel pressure regulator, which is a purple component under the plenum.
  3. Remove the plenum by unscrewing the eight bolts with a T40 torx bit, noting that two of the bolts are different.
  4. Disconnect the air and coolant lines connected to the plenum.
  5. Lift the plenum up and over, ensuring clearance for accessing the pressure regulator.
  6. Using a wrench, remove the old pressure regulator, making sure to disconnect any hoses attached to it.
  7. Install the new pressure regulator in its place, securing it with screws.
  8. Reconnect any hoses and lines that were detached, ensuring a proper fit.
  9. Reassemble the plenum by aligning it correctly and pushing it back into place.
  10. Secure the plenum by tightening the eight bolts, following the correct placement of the unique bolts.
  11. Double-check all connections and ensure everything is properly secured.


How does tuning improve the performance of a C4 Corvette?

Tuning overrides the original computer settings of the car, optimizing it for power and performance. By removing the limits imposed by manufacturers, a tune can unlock significant horsepower gains, especially when combined with other performance mods.

Details on this process are not included here.

Throttle body airfoil

What is the purpose of a Throttle Body AirFoil in a C4 Corvette?

The Throttle Body AirFoil eliminates turbulence as air enters the engine’s throttle body, allowing for a smoother flow and increased power production. By reducing turbulence, it helps optimize the airflow, resulting in a quick gain of 1 to 2 horsepower in the C4 Corvette.

I was on the fence about posting this one. Lots of discussion either way about whether this actually does anything. My guess is it’s probably not much if anything at all but it’s your call on your C4.

This is just an easy add to the front of your TPI throttle body.


These improvements are considered some the best for improving your C4 performance. Some are rather easy to do and others may need so additional help to complete. I am look to add more in depth info on each of these items in the future so say tuned.

Got a comment or concern on this post, please leave a message below. - Save 5% OFF on orders Over $50, Use Code Blaze. Ends 12/31/22.