This is the age-old problem with cam swaps because, as mentioned earlier, what a cam gives in one area of the rev range, it usually takes away from another. But on the whole, engines tend to be either single cam and two valves per cylinder, or twin cams with four valves per cylinder. Some engines can have three or five valves per cylinder, too. To complicate things a little, some engines – most commonly from Honda – have a single cam operating all 16 valves, and there are engines (a few older Ford and Fiat units in particular), with twin cams but only eight valves. The LS engines, along with many older engines, also have the camshaft mounted in the block, but the vast majority of engines now have the camshafts at the very top of the engines, mounted in the head. These engines are getting much rarer, but are still produced today, most notably the awesome LS engines seen in Corvettes, VXR8s, and so on. Many older engines have two valves per cylinder and a single cam operating them all. So twin cams on straight engines, and quad cams on V and flat engines. The vast majority of modern engines have four valves per cylinder, and these generally have separate cams for the inlet and exhaust valves. It doesn’t hugely affect performance, but different engines have different positions for cams, as well as different amounts of them. This means that there’s almost always room for improvement, but with mild engine specs, especially on turbocharged engines, these standard cams can often be the best overall choice. From the factory, a car’s cams are generally very mild, and are usually made in such a way for economy, reliability, and, most of all, driveability. The thing with camshafts is they generally remove performance from somewhere in the rev range to add it in another, and once you add forced induction to the mix things can get even more complex.ĭon’t think for one second that the wilder cam you go for the faster your car will be, even if it produces higher peak power numbers, as this is often not the case. Whatever you do, don’t just rush into changing cams straight away, as a cam swap is not always a good thing! You need to be sure it will improve your car before you do so, as we have seen some swaps that have dropped huge amounts of power. However, a mistake can have disastrous consequences, not just for performance, but for reliability too. As you can imagine, with the right changes a camshaft swap can seriously improve performance. The amount, length of time, and point at which the cams open the valves all play a big part in dictating how much power and torque an engine develops, where in the rev range it does this, and if the engine will even run at all. It’s their job to open and close the inlet and exhaust valves the right amount at the right moment. This feature should give you a better understanding of performance cams, and what is good for your engine.Īt the most basic level, camshafts are cylindrical rods of metal in piston engines with lobes protruding from them. Your car may have one, or as many as four, but no matter the number they are a vital part of your engine’s performance.Ĭamshafts are a hugely complex subject that verge on top-level physics if you delve deeply into it, but even at a basic level they are probably the most misunderstood subject in UK tuning, leading to very common and pretty major mistakes when choosing cams for your engine. Unless you own a rotary powered car, you can be assured camshafts affect you.
WILL BIGGER CAMS MAKE TURBO SPOOL FASTER UPGRADE
What are performance camshafts? And should you upgrade yours? Find this out and more in our guide to performance cams…