Camshaft tuning is an important part of supercharger tuning. Camshafts orchestrate the valve opening and closing events in the engine and determine whether what comes out of our motor is beautiful high power music, or a mess of dysphonics. The use of the correct supercharger optimized cam shaft can go a long way towards Supercharger Porting And Rebuilding and present considerable power gains for the money invested.
To understand camshaft timing and camshaft selection we need to understand first:
Relativity: Changing once the valves open or close (intake or exhaust) changes the the valve timing with regards to:
The piston position within the cylinder. According to where pistons is incorporated in the stroke, and where our company is within the combustion cycle, then opening the valves will exploit the stress difference between the cylinder as well as the intake and exhaust manifolds.As an example it could sound right that the ideal time and energy to open the intake valve is should there be peak vacuum inside the cylinder in order that when the valve opens, the maximum level of clean air may be ingested. Similarly, it makes sense to not open the exhaust valve until peak cylinder pressures have already been achieved in the combustion chamber and also the combustion is finished and all the ability is extracted.
The high and low pressure pulses produced by the design and runner lengths of the intake and exhaust manifolds.It could make sense to open up the intake valve just like the reflected pressure waves within the intake manifold reach the intake valve as being a high-pressure portion of the wave, thus opening the valve at this high-pressure point provides a ‘ram air’ effect through volumetric efficiency resonance tuning increasing air ingestion which increases power.Similarly on the exhaust side, it makes sense to start the exhaust valve, just like the reflected low pressure (vacuum) part of the exhaust wave (reflected back through the collector) reaches the back of the exhaust valve.
At this time in time there is certainly both peak pressure in the cylinder, and vacuum inside the exhaust which results in a higher pressure differential along with a faster evacuating exhaust gas. With respect to the ignition timing event, for instance a shorter duration or advanced exhaust cam, opens the exhaust valve sooner with regards to when the mixture was originally ignited, because of this although by advancing the exhaust cam we might have matched our header design and opened the valve using the lowest possible exhaust back pressure for optimum efficiency, at the same time, we now have reduced the amount of time the mixture is combusted and perhaps opened the valve before reaching our peak cylinder pressures and thrown away some horsepower.
The intake valves with respect to the exhaust valves: and normally, this is described in terms of lobe separation angles (the offset in degrees between the center of the exhaust cam and between the core of the intake cam), or with regards to how many degrees of overlap (the quantity of degrees that both intake and exhaust valves are open simultaneously).
Considering that the combustion in the cylinder occurs in a greater pressure than atmospheric pressure, and also since exhaust valves are generally smaller than intake valves (for this same high-pressure reason) then exhaust gas velocity is significantly higher than intake gas velocity. So, in certain engines it really is good for open the intake valve earlier than usual over the last part of the exhaust stroke, this is known as overlap.
During overlap – at the very end in the exhaust stroke – the volume of pressure left within the cylinder is low so it is easy to breathe in new air under atmospheric pressure, at the same time, our prime velocity from the exhaust gasses exiting help draw in a lot more outdoors from your intake side inside an effect just like ‘syphoning’ where the fluid (within our case air) flows as being a continuous stream drawing in new intake air following the old exhaust gas leaves.
Another a part of phenomenon that relates to timing intake valves with regards to exhaust valves is the period of time where both valves are absolutely closed, which is your power stroke. Here is the area of the combustion cycle in which the mixture could be compressed and combusted. If either (or both) intake or exhaust valves are open you are going to not be able to ebrtxr compress nor combust the mixture, and also the absolute duration of time (in degrees of rotation) that your mixture is combusted and permitted to reach peak cylinder pressures is affected by camshaft selection and cam timing. One important thing to notice is that the valve angle offers quite a bit to do with exhaust scavenging, obviously you will definitely get maximum scavanging if the exhaust and intake valves had ‘line of sight’ i.e. when the valves were separated by an angle of 180*.
In that case, the exhaust air can directly pull in new air. Conversely, you would probably hold the least possible scavenging should you have had valves which were at a narrow angle (zero degrees in the extreme) in between each other, in order that the air would essentially must make a U consider come in with the intake and acquire pulled out your exhaust.