Not all cams are created equal. Pick the wrong camshaft and you can actually lose power instead of gaining it. This is one of the most common questions we get at Meksta, and the answer is never simple, but it can be broken down into a handful of key factors.
A cam swap can deliver:
- More torque
- Better power at higher rpm
- Higher peak power
- Smoother idle
- Better fuel efficiency
But it is not as simple as bolting in a new cam and going faster. The result depends on your specific engine, your goals and how the vehicle will be used.
Intended use: the most important question
How will the car be used? The answer paints a clear picture of the engine's operating range. A serious street car still needs a strong midrange to pull through the gears, while a drag car can live with a narrower powerband high up in the rev range. On a daily driver, idle quality and throttle response from low rpm matter a great deal.
In other words, the application dictates the "size" of the cam, meaning how aggressive the profile needs to be.
Power goals
Just like the intended use, the power target helps pin down the cam specifications. It lets us narrow the options for the specific application.
Here is an interesting detail: a 2-liter turbo engine making 300 hp and a 3-liter turbo engine making 1,700 hp have very different needs, but a 300 hp 2-liter naturally aspirated engine and that 1,700 hp engine can actually run quite similar cam profiles.
Rev range and power curve
We ask this question to determine the cam's duration. Shorter duration suits lower rpm, longer duration suits higher rpm.
Do you need a narrow operating range with high torque, say for a jet boat, or a wider torque band for smoother power delivery in a class with limited traction? This also affects the choice of lifters and valve springs.
Turbo or naturally aspirated?
If the engine runs a turbo (or supercharger), we need to know. Turbo sizing affects the powerband and the torque curve. Matching the cam profiles to the turbo's characteristics is essential for good results.
Fuel type
Fuel matters more than most people think. Going from gasoline to methanol, for example, physically increases the amount of fuel in the intake charge. In some cases the cam timing needs adjusting to compensate. The fuel type also helps us judge the engine's total power potential.
The rest of the engine spec
Stroke, cylinder head work, intake and exhaust: the whole package matters. A long-stroke engine can have a limiting piston speed that caps the usable rpm. And a completely stock engine, from air filter to muffler, can actually lose performance from a cam that is too aggressive.
Gearbox and gearing
A heavy car with tall gearing may need slightly shorter duration and a tighter lobe separation angle to maximize torque. A light car with close-ratio gears can instead exploit a narrower powerband with more peak power at the expense of the midrange.
The gearbox also affects the valvetrain. A sequential box with hard shifts puts higher demands on the valve springs to handle the sudden unloading.
The bottom line
There is no universal answer. The right camshaft depends on the whole package: use, power goals, rev range, boost, fuel, engine specification and gearbox. Once we at Meksta have that information, we can help you choose the camshaft and matching valvetrain parts that give the best result for your particular build.
Contact Meksta and we will help you find the right cam.
Also read about flat tappets vs roller lifters, hydraulic vs mechanical lifters, compression and cam choice and the complete valvetrain.