Just got a C4 Corvette?
Or been had it, but finally got inspired to work on it?
Whichever it may be, the fact is you have a beautiful piece of machinery. One that deserves to be revived and modified to do what it does best…GO FAST!
So if you want to hold your own at a stoplight, you’re in luck! Many performance modifications can be done to your corvette c4, and they are listed here.
We’ve come up with this list of mods through our experience in building quick C4 corvettes for the track (breathless racing team). And also through working with numerous C4 owners who aimed to upgrade their car’s performance.
And while some of these mods can cost you an arm and a leg, some you can do for cheap—even free!
That’s right, there are some cheap and free modifications you can do to your C4 immediately to raise your horsepower. We’re talking 20, 30, and even 40 horses. BTW, many of the mods I speak of are fairly simple to install. Most have step-by-step instructions on youtube (I’ll provide a few links to the videos in this article).
Just imagine the folks underestimating your C4 because of its age… having to catch their jaw a few minutes later…Because your C4 is either holding its own against their newer cars or simply leaving them in the dust.
So if you want the speed, pride, and recognition that comes with modifying your Corvette C4, then carefully examine the following article. I will show you the most popular mods along with their cost, difficulty, time to complete, and potential HP gain.
Weight reducing mods
The lighter you make your car, the faster it will be––no secret there. That’s why track cars only carry the minimum parts (no additional seats, spare tires, stereo systems, etc.) Unnecessary parts weigh the car down, requiring more power to move it. Therefore, to make your C4 faster, we can apply this concept of ditching unnecessary weight…these are your free mods.
1) Remove the Frisbee
Installed initially to dampen out vibrations when the AC cycled on/off, it was later found that it caused the belt to chirp. So eventually, GM omitted this element from the water pump pulley. Basically, it’s an optional 10-pound piece that weighs your car down.
Some people report that removing the frisbee can add 10HP to your C4, but this claim isn’t proven. However, what is proven is that your C4 is 10 pounds lighter, making it a little easier for the car to accelerate and achieve top speed quicker.
2) Eliminate the muffler
Some Corvette C4 owners claim that their car could use a bit more roar––so they remove the 25-pound muffler. As the name suggests, the muffler’s purpose is to reduce the sound emitted by the engine’s pistons and valves. Once removed, you’ll get powerful and intimidating sound waves that’ll make anyone think twice about challenging you. And of course, you’ll get a lighter, speedier car.
3) Air smog pump eliminator
Continuing on our list of C4 corvette mods, we have another delete modification. This time, the air pump/smog pump. Originally placed in the car to reduce tailpipe emissions by blowing clean air into the exhaust, the smog pump adds no horsepower. Therefore, many C4 owners take it out.
4) Spare tire removal
Got roadside assistance? If so, then removing those extra 30 pounds that is the spare tire might be a viable option for you. Along with the tire goes the tire carrier, which is another 10-15 pounds. In total, those 40-50 lbs can increase your HP.
That’s it for the free weight-reducing mods. Now, let’s look at some cheap mods that pack a big punch, making your C4 Corvette horsepower increase a notable one.
Cheap C4 Corvette Mods That Pack A Punch.
5) Performance Cold Air Intake
Easy to install and relatively cheap… it’s no wonder this Corvette C4 mod is a go-to for most owners who are starting to modify their cars. Just imagine a boost of 5-15 HP for only about $250 bucks! Hard to beat that!
An air intake works by allowing larger amounts of cool air to make its way into the engine. Since cooler air is oxygen dense, your car gets improved combustion and thus better performance.
Car manufacturers make stock air filters with longevity and quietness in mind, sacrificing power in the process. The stock air filter is filtration-focused, and as a result, it restricts the amount of air it lets in. On the other hand, an aftermarket filter is performance-focused, allowing more air in––while filtering just enough.
The same goes for the shape and design of the stock air ducts. They are sound reduction and aesthetics-focused. Their location in the engine bay can lead to much heat absorption from nearby components, letting heated oxygen-poor air into the filter instead of the optimal cool air.
An aftermarket intake is shaped and strategically placed in the engine bay to absorb as little of the surrounding heat as possible––all while collecting as much cool air as it can.
All in all, the advantages of this simple C4 Corvette performance mod are:
- More Horsepower and torque… Via allowing more air into the engine.
- Unlocking the flow of cooler denser air. Instead of the hot air in the engine compartment.
- Increased accelerator pedal sensitivity
- Smooth and soft engine run
- Reduced detonation risk
- Reduced fuel consumption
An aftermarket quality air intake should:
- Be composed of heat resistant materials
- Take air from the coldest places
- Have an optimal filter location
- Have smooth tubing
We recommend our very own Corvette C4 Vortex Air Intake System. Through continual trial and error, and the testing of multiple other air intakes, we have put together one that combines the pros of all other intakes, but without the cons.
- C4 Corvette Horsepower increase: 5-20
- Approximate cost range: $175-$400
- Install time: 1-2 hrs
6) Throttle Body Coolant Bypass
To reduce the chance of the throttle body icing over in extremely cold weather, GM chose to run the engine coolant through the throttle body.
The problem is that many people don’t need this setup because they live in warmer weather, or perhaps they don’t drive their C4 during the winter. In these cases, all the stock set up does is heat up the air intake, wasting away precious power-producing cold air.
The throttle body coolant bypass kit saves the day and your HP!
It does this by rerouting the engine coolant away from the throttle body, reducing the temp of the air flowing through the air intake. This simple 20 dollar corvette C4 mod is said to give you a horsepower gain of up to 5HP. It’s not much, but every little bit counts!
This mod is easy to install, but before you do, consider that if you live in an area where the temps reach freezing, your throttle body will ice over.
- C4 Corvette Horsepower increase: 1-5hp
- Approximate cost range: $20-$30
- Install time: 30-60 min
7) Throttle Body AirFoil
A quick 1 to 2 horsepower gain is what you’ll get from installing this cheap corvette C4 mod. The Throttle Body AirFoil works by eliminating turbulence as air enters your engine’s throttle body, allowing it to produce more power.
Installation is pretty easy, taking no more than an hour:
- C4 Corvette Horsepower increase: 1-2hp
- Approximate cost range: $25-$35
- Install time: 1-2 hrs
Remember, the engine that’s most efficient in terms of power is the one that can get air in and out of its cylinders the easiest. We have already improved the intake of air into the engine with the cold air intake. However, now we tackle the expulsion of air and gasses out of the engine––to keep a nice, clean flow.
A good set of aftermarket headers work by reducing back pressure in the exhaust system.
Unlike a common manifold, an aftermarket header provides each cylinder with its own exhaust pipe. Also, in an aftermarket header, each pipe is the same size, that’s not the case in the stock manifold. This assures that the exhaust gasses from each cylinder exits at the same rate––eliminating power reducing back pressure.
You can gain from 10 to 20 hp with this relatively simple install. The header’s price can range from $600 to $1500. Installation prices, if you don’t want to do it yourself, can cost you from $400 to $700.
- C4 Corvette Horsepower increase: 10-20hp
- Approximate cost range: $600-$1500
- Install time: 8-10 hrs
How would you like 30 or more horsepower to your C4 Corvette? That is what a camshaft replacement can do for you!
An aftermarket camshaft achieves this surge in power by getting more valve lift, which increases the length of the valve stroke. You see, unlike the stock cam, which is made for longevity, the aftermarket cam is designed with raw power in mind. Since the valves open longer in an aftermarket cam because of the greater lift, more oxygen-rich air gets in.
Furthermore, the duration in which these aftermarket camshafts stay open is greater than that of a stock cam. So combined, lift plus duration, leads to a pretty grand increase in horsepower.
A camshaft can run you from about $300 to $550, depending on the brand and aggressiveness.
- C4 Corvette Horsepower increase: 30+
- Approximate cost range: $300-$550
- Install time: 7 to 15 hrs | $2k for installation approx.
10) Adjustable fuel pressure regulator
With your engine’s newly increased capacity due to turbo upgrades or other performance mods, you’re going to want an aftermarket fuel pressure regulator. This will ensure that the engine isn’t running lean on fuel, thus, robbing you of horsepower.
When choosing a fuel pressure regulator, you want to make sure you get a quality one. Getting a faulty regulator can cause damage to your engine. We recommend our very own fuel pressure regulator, which has been track tested and proven to increase performance.
- C4 Corvette Horsepower increase: –
- Approximate cost range: $120-$250
- Install: $110-$150 for installation approx.
How to make my C4 Corvette faster you ask…Tune it!
The idea of increasing your car’s horsepower significantly without adding any parts sounds like make belief to many people. But with a tuner, that is exactly what’s happening.
As mentioned multiple times before, manufacturers put harsh limits on your car’s power potential because they prioritize longevity and fuel economy over all else. Programming the car’s computer so that it holds back engine output is how they achieve this. This way, the car gets higher gas efficiency, and hopefully, an extended lifetime.
But as speed seekers, this is not what we want! We want to unleash the beast!
A tune basically works by overriding the original computer settings set by the manufacturers, then optimizing for power and performance. This is especially important when you have already performed other mods to your car. Without the tune after the installment of aftermarket mods, you pretty much left most of the potential HP gains on the table.
It’s hard to pinpoint exactly how much horsepower a tune will give you. With no performance mods installed, you should expect a 15-20 hp gain. However, with performance mods installed, you can expect hp gains of 30, 40, 50, and much much more. Make sure you go to a skilled tuner.
- C4 Corvette Horsepower increase: stock 10-15 hp | Modified C4 Corvette 40+ hp
- Approximate cost range: $250-$1500
There you have it, those are your top Corvette C4 Performance Mods. And while there are mods that can give you much more power right off the bat like a supercharger kit…
…the mods in this article are a good starting point.
If you perform the C4 corvette performance mods mentioned you will most definitely notice big horsepower increases.