[Guide] 1997-2004 C5 Corvette Bolt-On Mods to Make More Power

To Remain or Not To Remain Factory Equipped? That Is the Question…

Every Corvette owner knows that driving their car can be incredibly fun.  Hard acceleration, high top-end speed and unbelievable cornering makes driving a Corvette an experience that no driver will soon forget.  Even mashing the gas pedal to the floor in a base model, bone-stock Corvette can be a hair-raising adventure – at first.  

However, like anything else, even the most extreme driving machines can become familiar.  What we once accepted as exhilarating performance becomes almost commonplace, and it leaves the driver yearning for more.

From a factory standpoint, Corvettes have gotten more and more powerful with each successive generation.  

In the early nineties, Chevrolet introduced the LT1, which boasted a respectable 300 horsepower, in 1997, the LT1 was replaced with the LS1, and bumped the horsepower up to 345.  By 2005, with the introduction of the LS2, even the base model Corvettes were pushing north of 400 horsepower.  

Corvettes are definitely getting faster – but more speed also translates into more expensive.

However, just as the newest models drive the price up, they also cause the price of the older models to go down. Where just five years ago a fifth-generation – or C5 – Corvette – cost more than $25k on the used car market, today you can find them for nearly half that price.  

The tradeoff, friends, is that the older models just can’t produce the power, acceleration or handling that the newer cars do.  

Or can they?

Over the past 20 years, the aftermarket auto parts industry has become a staple of the sports car industry.  While “souping-up” a weekend cruiser has been a thing since just about the introduction of the automobile, the available hardware that can be purchased today can safely and correctly transform your car from “mild to wild.”

Today we’re going to list some of the most common modifications that can be made to your fifth-generation Corvette to help give it that “something extra” under the hood.  (Note – While all of the items listed in this article are proven to increase horsepower, performance or handling, we recommend that you consult with your local Corvette mechanic before proceeding with modifying your engine.)

1) The Cold-Air Intake System

Simply put, a cold air intake (CAI) is an aftermarket assembly of parts used to bring relatively cool air into the car’s intake manifold.  The theory behind the CAI is that cooler air is denser, which means it contains more oxygen per volume unit than warmer air.

While there are multiple manufacturers out there that offer a cold air intake system for the fifth-generation Corvette, we’ve found that most of them offer similar horsepower gains – about 18 horsepower @ 5,500 rpm.  While the increase in horsepower may not be appreciable during normal driving conditions, hard acceleration (when drag racing, for example) should show some minor gains just by installing this simple bolt on modification.

Our Recommendation?

While there are a number of good cold-air intake systems out there, the preferred among Corvette owners is the Vararam Cold Air Intake.  However, Corvette owners also acknowledge that the Vararam units tend to not be a perfect fit – which can lead to a frustrating installation.

From our experience, BBK Cold-Air Intakes are a comparable alternative, at a better price point, and they are more of a direct bolt-on solution.  These units can be purchased from a number of automotive retailers, and claim a 13 horsepower increase upon installation.

Price: $320-350.00

2) Reprogramming the ECU

For drivers who know their car intimately, re-programming – or “tuning” – your C5 Corvette can help improve on everything from shifting to acceleration, to engine performance and operation.  While tuning may not directly unlock hidden horsepower, it can still dramatically affect how the car operates, accelerates and drives.

Tuners vary dramatically in price and features, so when researching a tuner for your vehicle, it is important to spend some time learning what each has to offer.  For example, a Hypertech Maxpro Programmer will enable you to adjust rev and top speed limiters, improve engine cooling, tweak automatic shift points and firmness, recalibrate speedometers to correct for gear and tire size changes, and adjust engine idle speeds.

It is important to note, however, that there are dramatic differences between a programmer and a true tuner.  While a programmer will enable you to optimize the performance of your car by adjusting factory settings (in essence, writing a custom tune once the factory variables are changed), a true tuner re-programs the ECU with a scripted tune that comes with the programming device.  While the distinction is subtle, it is worth noting because of the dramatic differences in price.

Also, when considering a programmer/tuner for your car, please take time to research the unit you are considering purchasing.  Most tuners on the market today are very reputable, but the reality is that you are re-programming your car’s operating system, so you want to buy from a company that has a strong, solid reputation.

Our Recommendation?

It is important to understand that using a tuner means modifying your car’s factory programming.  As such, we spent a fair amount of time evaluating the available tuners not only for their ability to enhance the performance of the car, but also to preserve the factory program in the event that you ever wanted to return your car to its original settings.

3) Short-Throw Shifter

A short-throw shifter is a popular and affordable modification that can be completed without much difficulty.  While they don’t provide an actual change in vehicle power or performance, they do serve two beneficial purposes:

First, they shorten the distance that the gear lever needs to travel between gears by reducing the angle that the shaft travels.  The theory is that reducing shift times by introducing shorter shifts will improve drive performance because less time is wasted on the shifting movement.  However, this performance improvement is negligible to most drivers.

The second (and more noticeable) benefit of a short throw shifter kit is in the way it transforms the driving experience.  A shorter shifter throw instantly gives the driver (and the car) a far sportier shifting experience.   Even while Corvettes don’t have a long shift throw, there are aftermarket kits to improve the factory shifter, which is commonly known to be heavy and difficult to get in gear at times.

4) Aftermarket Exhaust Systems

There has always been a fair amount of debate about the actual power gains achieved by adding an aftermarket exhaust system to your factory vehicle.  While most would agree that it does result in a net power gain, the reality is that, like the horsepower increase referenced in the cold air intake (above), most of your power pick-up occurs at higher engine RPM’s.  

Still, there are a couple of definite benefits to adding an aftermarket exhaust system to your C5 Corvette.

First, an aftermarket exhaust will be less restrictive than the factory option.  Less restrictive means better exhaust flow.  On an LS1 engine, better exhaust flow means less back pressure which translates into more horsepower.

That said, how you modify the exhaust (where you start – manifold or X pipe, size of pipes, etc.,) will influence the power gains on the car.

Second, a more appreciable – and immediately noticeable – gain will be the resonant sound of the aftermarket exhaust system.  Like anything else, exhaust systems come in a variety of options, and the sound of the exhaust system – most especially the mufflers and resonators – can take the exhaust note of your Corvette from “mild to wild!”

5) Rear End Gears

While this conversion can be a little more intensive than some of the bolt-on options we’ve listed up to this point, the net gains of changing out the rear end gears on your C5 Corvette can be significant.  If you are looking to launch your Corvette off the line, or if you are looking for more aggressive low-end acceleration, aftermarket gears with a more aggressive ratio is a definite mod to consider.

All base C5 Corvettes came equipped with either a 2.73 gear ratio (on automatics) or a 3.42 (on all manuals.)  Consumers also had the option of ordering a more aggressive 3.10 ratio when purchasing an automatic Corvette.

So how aggressive do you want to go?  Understanding how a gear ratios are calculated can help you determine the gears you want to consider installing on your Corvette.

An automobile uses gear ratios in both the transmission and the drive axle to multiply power.  The two ratios multiplied together equal the final drive ratio.  For many performance cars, 3.73 and 4.10 are common gear choices.  The rear-end gear ratio refers to the relationship between the ring gear and the pinion gear. By dividing the ring gear tooth count by the pinion gear tooth count, the axle-ratio is determined.  For example, a ring gear with 41 teeth and a pinion gear with 10 teeth has a gear ratio of 4.10:1 (41/10=4.10).

When considering gears for your rear end, you should also consider the size of the tires on your Corvette.  Tire diameter will have also have an effect on the vehicle’s final drive ratio.  As tire diameter changes, so will the engine rpm at a given speed, so it is imperative to consider your options carefully, decide exactly how you intend to use your car, and make sure you select a gear ratio that best suits your needs.

NOTE: For anyone considering a rear-end swap, we’ve found a useful tutorial online that was originally posted by the team at www.superchevy.com.  You can view this article by clicking HERE. http://www.superchevy.com/how-to/18978/

6) Turbo Charger

If serious acceleration is your primary goal, then the next two bolt-on recommendations are definitely worth considering.  Either used individually, or in conjunction with one another, introducing a turbo charger and/or a supercharger (see No. 7, below) can help you achieve levels of rear wheel horsepower that far exceeds anything we’ve suggested so far.

A turbocharger, (or simply, a “turbo”) is a turbine-driven forced induction device that increases an engine’s efficiency and power out by forcing extra air into the combustion chamber.  The improved to engine power output is due to the fact that the compressor can force more air – and proportionately more fuel – into the combustion chamber.

While the principals between a turbocharger and a supercharger are fundamentally the same, a turbocharger is powered by a turbine driven by the engine’s exhaust gas whereas a supercharger is a mechanically driven device.  Turbochargers tend to be more efficient than a supercharger, but they also require longer lead times to generate the needed boost to increase horsepower.

That said, a introducing a turbocharger to a C5 Corvette can produce horsepower gains that can more than double the factory output of your LS engine.  Take time to do your homework and research the type of turbo you plan to install to ensure that the components in your engine are adequately designed/bolstered to handle the added power.

7) Supercharger

Much like the turbo charger option (number 6) above, a supercharger is designed to increase the pressure or density of air being supplied to the engine.  This increase in air pressure during the engine’s air intake cycle provides more oxygen to the engine, which allows the engine to burn more fuel and increase engine efficiency and output.  

Superchargers are powered mechanically by means of a belt or gear drive connected to the engine’s crankshaft.  

As with a turbocharger, a supercharger can produce significant performance gains in your Corvette’s engine.  While a fairly expensive addition to your car, the output of a C5 Corvette equipped with a supercharger can easily exceed 650-700 horsepower.  Moreover, consumers have equipped their Corvettes with both a turbocharger and a supercharger.  This combination – known as a “twin turbo” setup, allows the mechanically driven supercharger and the exhaust-gas-driven turbocharger to work together to maximize output across the entire power band.

8) Performance Seats

While our recommendations up to this point have centered on maximizing engine performance and output, there are other bolt-ons that are equally valuable to the performance-minded driver.
While high levels of acceleration and handling are vital to better lap times and overall performance on the track and open road, the driver’s ability to remain focused while driving is vital.  Performance seats are specifically designed to better secure the driver (or driver and passenger) in place during all driving conditions.

Performance seats offer greater body support via use or larger seat bolsters, firm cushions and reinforced sub-structures.  This translates into greater steering and pedal control.

Like everything else, finding the right seat to fit your driving needs is crucial.  Consider that performance seats may not offer the same degree of comfort as your Corvette’s factory seats.  However, one of the major criticisms of many C5 owners is that the factory seats simply do not provide enough support during more aggressive driving conditions.  It is therefore important to understand how you plan on using your vehicle before deciding which seats best suit your needs.

9) Higher Temp Brake Pads & Vented Rotors

While acceleration and handling may be one of the most important considerations when purchasing a Corvette, being able to slow down and/or stop quickly are also vitally important.  While the factory brake system on the C5 Corvette is well equipped for the majority of their owners, heavy duty braking systems – which include high-temperature brake pads, vented rotors and more robust brake calipers – will ensure that your car stops quickly in even the most aggressive driving situations.

The key advantage of high-temp brake pads and vented rotors is the braking systems ability to dissipate heat quickly and to stop even when heated.  As braking systems heat, conventional brake pads can produce a layer of gas that forms between the surface of the pad and the brake rotor.  This gas layer is known as “brake fade” and can result in decreased brake responsiveness in environments where the brakes are used frequently.  

By introducing vented rotors and high-temp brake pads, much of this brake fade is reduced/eliminated and provide driver with greater confidence that they’ll be able to stop their vehicle quickly.  The tradeoff of using higher-temp brake pads is that the brakes may actually perform poorly when wet or cold, and they will often produce a squealing noise because of the harder, more dense material used on the pads.

When considering a performance brake system for your C5 Corvette, consider replacing the pads, rotors and calipers as a set.  While the upfront cost of this modification will be considerable, it will also ensure that you are maximizing your stopping power.

10) Wider Wheels and Tires

This final bolt-on modification is one that many Corvette owners might easily overlook.  After all, the factory wheels and tires on the C5 Corvette are already pretty wide.  However, increasing the car’s overall surface area contact with the road can result in appreciable gains in performance – both during acceleration and braking.

Wider tires offer a number of advantage during vehicle operation including improved road-handling, greater turn-in precision, and quicker deceleration.  

At the same time, larger wheels can result in increased weight, which can counteract performance and efficiency.  As part of the process of “upsizing” your wheels and tires, it is important to consider all the variables that go into that decision.  Where wider tires might offer you more grip, the weight of the wider rim and rubber tread might actually increase your Corvette’s overall vehicle weight.  Consider all the variables – including wheel size and material type, the type and durability of the tire itself (stiffness of sidewall, overall wheel rating), how well the wheel displaces water and the total contact surface area/grip of the tire.  Understanding these items will help you make an informed decision and will ensure that your wider tires provide you with a higher level of performance than the ones that came from the factory.