can anybody answer this?

[procircuit406ex]

me and my buddy has been wonderin this for a while now,whats the difference in 1 cam from another?

[NY06400EX]

Try a search and see what you come up with. There's a lot of info on this topic on here already.

[zrpilot]

Originally posted by procircuit406ex
me and my buddy has been wonderin this for a while now,whats the difference in 1 cam from another?

Got a couple of weeks?!! LOL

[400exfan19]

Originally posted by zrpilot
Got a couple of weeks?!! LOL
wat r u talkin about?

[jeremy_283]

some just lift the valves higher or hold them open longer......... they all vary

[wilkin250r]

Theoretically, the intake valves open when the piston is directly at the top of the stroke, and close directly at the bottom. Well, this works fine up to about 2000 rpms. After that, the physics gets a little more complex, and you can take advantage of that.

The simple principle behind it all is, NOTHING HAPPENS INSTANTANEOUSLY. Moving air has momentum, and you can use that momentum to build power. The higher the engine rpm, the faster the air is moving, and thus the higher the momentum to utilize to your advantage.

This means, on the intake stroke, that the valves can stay open PAST the bottom, because the air momentum will continue to pack more air into the cylinder. Since this momentum is different for different rpms, you can tailor a cam around a certain rpm range.

A BIG aspect you will hear is the overlap, and scavenging. This is probably the most prevalent aspect of a cam next to lift. When the piston is on the exhaust stroke, the exhaust valves are open and the piston is traveling upwards to push the exhaust out. Once all the exhaust gasses have left the cylinder (but the valves are still open) the momentum of the exhaust gasses will actually create a vacuum within the cylinder. At this point, the intake valves open, and BOTH exhaust and intake valves are open. The momentum of the exhaust going OUT will help pull new fresh fuel/air IN. This is called scavenging, because you are using (scavenging) the energy of the exhaust gasses to help build power.

Again, these aspects are different for different rpm ranges, so you can tailor a cam for a certain rpm range. However, these aspects also have their drawbacks. Like we said, at high rpms you can leave the intake open longer, even while the piston begins traveling upwards, because the inrush momentum will continue to pack more air/fuel into the cylinder. However, at low rpms, you don't have that momentum, so if the intake is still open while the piston begins traveling upwards, you can actually begin to push air OUT the intake. The tradeoff? You get great top-end power, but you lose low-end power. It's a compromise.

[zrpilot]

Originally posted by wilkin250r
Theoretically, the intake valves open when the piston is directly at the top of the stroke, and close directly at the bottom. Well, this works fine up to about 2000 rpms. After that, the physics gets a little more complex, and you can take advantage of that.

The simple principle behind it all is, NOTHING HAPPENS INSTANTANEOUSLY. Moving air has momentum, and you can use that momentum to build power. The higher the engine rpm, the faster the air is moving, and thus the higher the momentum to utilize to your advantage.

This means, on the intake stroke, that the valves can stay open PAST the bottom, because the air momentum will continue to pack more air into the cylinder. Since this momentum is different for different rpms, you can tailor a cam around a certain rpm range.

A BIG aspect you will hear is the overlap, and scavenging. This is probably the most prevalent aspect of a cam next to lift. When the piston is on the exhaust stroke, the exhaust valves are open and the piston is traveling upwards to push the exhaust out. Once all the exhaust gasses have left the cylinder (but the valves are still open) the momentum of the exhaust gasses will actually create a vacuum within the cylinder. At this point, the intake valves open, and BOTH exhaust and intake valves are open. The momentum of the exhaust going OUT will help pull new fresh fuel/air IN. This is called scavenging, because you are using (scavenging) the energy of the exhaust gasses to help build power.

Again, these aspects are different for different rpm ranges, so you can tailor a cam for a certain rpm range. However, these aspects also have their drawbacks. Like we said, at high rpms you can leave the intake open longer, even while the piston begins traveling upwards, because the inrush momentum will continue to pack more air/fuel into the cylinder. However, at low rpms, you don't have that momentum, so if the intake is still open while the piston begins traveling upwards, you can actually begin to push air OUT the intake. The tradeoff? You get great top-end power, but you lose low-end power. It's a compromise.

Wilkin,

Very nice....:D

Thanks for that explaination of scavenging

[procircuit406ex]

Thanks alot man!