Performance car upgrades often include introducing a bigger turbo or an exhaust with a larger downpipe diameter. The engine is almost always part of the equation when you want to get more HP and torque from it. One component that doesn’t get enough rep for being a crucial performance upgrade is the camshaft.
Automotive camshafts help regulate the opening and closing of the valve. While this may be a simple task, setting the right interval at which the valves open can be tricky. Car camshafts do that in both an efficient and optimal way so that there’s always the right air-fuel ratio in the cylinders. Upgrading these metal rods with lobes on them can make all the difference.
What to Consider with a Performance Camshaft
Lift
One of the most confusing and important factors to keep in mind when shopping for a performance camshaft is cam lift. There are two types of it, cam lobe lift and valve lift and you need to consider both with aftermarket performance camshafts. Different rocker arms will change different lifts thus affecting the performance of your engine differently.
Duration
Camshaft duration refers to the amount of time a valve is going to stay open. The longer a valve stays open the more fuel or air is going to enter. But that isn’t always going to bring you better performance as too much of it can go the opposite way. Make sure to consider both intake and exhaust duration in this case as they equally matter when it comes to car camshafts.
Lobe Separation
What’s measured in degrees is a cam’s lobe separation. This greatly affects when the valves open and thus a narrow love separation angle means that as one valve starts to close the second one opens before the first one is closed. The shape of the cam’s lobe affects its separation angle and the wider it is, the later that second valve opens.
Profile
There are 3 different cam profiles and the best one for low-end improvement is a cam profile between 257° and 260°. With it, you can improve fuel economy and power responsiveness.
A cam profile between 270° and 285° gives smooth tick-over which makes for a camshaft for vehicles that are used both on the road and on the track over the weekends. Fuel economy may not be the best but it’s still within releasable limits.
Actual performance camshafts have a profile between 290° and 320° as they have the best operation over 3000 RPM with clunky tick-over. Although this doesn’t make it for a road-legal car, it makes for a fantastic track car.
ICA
Also known as installed centreline angle, ICA is a measurement that refers to the relative position between the cam’s timing and crankshaft position. This position tells you a lot about the max lift of the cam’s intake lobes. Simply put, this should be taken care of by someone with a degree as your average car enthusiast is going to have a hard time figuring out the right centreline angle according to the placement of the camshaft.
Timing
If your vehicle is a Honda, BMW or Toyota you’ll also need to keep in consideration its variable valve timing technology at play. Honda uses VTEC, BMW has VANOS and Toyota has VVT-i. Each one has a unique process through which it determines which lobe to use so that the valve stays open for longer. If your new camshaft doesn’t support that you will lose a significant amount of HP especially higher up in the rev range.
Overlap
Valve overlap is what’s known as the relative timing of intake and exhaust valves. Each cylinder has either one intake and one exhaust valve or a pair of both. There is an overlap when the intake valve opens before the exhaust valve does. If you increase valve overlap in a high-revving engine it increases the amount of air and fuel introduced into each chamber. However, it can also be detrimental when it comes to low-end torque if you overdo it.
Types of Camshafts
Roller
Roller car camshafts are those that operate with the help of smooth roller wheels that come in contact with the lobes. Their smooth surface is what can help make for a smooth-running engine and a car that you want to produce lots of torque. Roller cams are also not noisy and don’t require adjustment from time to time.
Flat Tappet
When it comes to pure performance, especially in the higher end of your vehicle’s rev range a flat-tappet camshaft is what you should consider. That’s because these types of automotive camshafts have slightly convex lifters which make the lobe slide across it far quicker and therefore you can get to higher RPM a lot quicker. Again, this makes for a noisier engine that you need to tend to more than most, but it delivers well on a performance level.
Hydraulic vs Solid
Your roller or flat-tappet camshaft can have either hydraulic or solid lifters. The benefit of hydraulic lifters is that they have smooth operation and make for quieter vehicles with less maintenance required from the user. On the other hand, you have solid lifters which have a more straightforward design that makes them more suitable for true track cars. They are not as simple when it comes to maintenance though.
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