Synchronised Valve Timing
NEW synchronised valve timing traps the higher vacuum produced by NPS Tri-Y header in the cylinder and allows it to pull a larger intake charge into the engine
Synchronised Valve Timing is used to...
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1)
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TRAP the higher vacuum in the cylinder at the end of the exhaust stroke.
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2)
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MOVE the higher vacuum to the beginning of the intake stroke during the overlap period.
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3)
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TRAP the larger volume of air pulled into the cylinder by the higher vacuum during the intake stroke.
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4)
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PREVENT the higher vacuum from pulling the intake charge into the exhaust system during the overlap period.
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Synchronised Valve Timing synchronises 8 special valve timing events together to allow Negative Pressure Supercharging to work
Synchronised Valve Timing is a highly sophisticated valve timing process that uses a combination of 8 special valve timing events to precisely control the time the valves open and close in order to trap the higher vacuum in the cylinder, move it to the intake stroke and prevent it from being pulled into the exhaust system. The 8 special valve timing events also precisely control the time the valves open and close to trap the larger intake charge pulled into the engine by the higher vacuum and prevent the larger intake charge from being pushed back into the intake manifold or pulled into the exhaust system.
Some of the 8 special valve timing events may be similar to the valve timing used by low performance engines. This gives the false perception that the 8 special valve timing events produce the same results as the valve timing used by low performance engines. However, this overlooks the fact that the 8 special valve timing events must be SYNCHRONISED and used TOGETHER for Negative Pressure Supercharging and the NPS Tri-Y headers to work. Just like any good recipe it?s the combination that makes it work.
For example,
1) Intake valve opens 8° earlier
2) Intake valve closes 10° earlier
3) Exhaust valve opens 8° later
4) Exhaust valve closes 12° earlier
5) Exhaust duration 8° less
6) Exhaust valve lift .150" lower
7) Exhaust gas speed 100% faster
8) Overlap duration 10° less
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NOTE
These valve timing events are examples only to demonstrate the 8 special valve timing events that must be used together for the Negative Pressure Supercharging process to work. They are not the optimum valve timing events for each different size engine which is proprietary information.
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Synchronised Valve Timing becomes more complex the higher the gas speed and vacuum
The higher vacuum produced by the NPS Tri-Y header is more difficult to control and the valve timing becomes more complex the higher the gas speed above 300 ft/sec produced by conventional headers. For example, if the NPS Tri-Y header produces a faster gas speed of 450-500 ft/sec, 6 valve timing events need to work together in synch whereas, if the NPS Tri-Y header produces an even faster gas speed of 600-650 ft/sec, 8 valve timing events need to work together in synch in order for Negative Pressure Supercharging to work.
Also, synchronising the valve timing events to work at optimum becomes more critical the higher the gas speed above 300 ft/sec. This requires the 8 special valve timing events to be precisely synchronised together within 1? duration and .010" exhaust lift in order for Negative Pressure Supercharging to work. The only part of the valve timing that is not critical is the intake lift which can be as high as possible. For more details see Negative Supercharging Camshaft
For example,
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With 600 ft/sec exhaust gas velocity
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Result
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If the overlap duration is 2° more than the optimum overlap duration...
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The higher vacuum produced by the NPS Tri-Y header will pull a lot of the intake charge into the exhaust system instead of into the cylinder and substantially reduce power.
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If the exhaust valve closes more than 2° later than the optimum closing point...
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If the exhaust valve closes after TDC and the overlap duration is 2° more than the optimum overlap duration...
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The higher vacuum produced by the NPS Tri-Y header will pull most of the intake charge into the exhaust system instead of into the cylinder and the engine will lose ALL power.
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If the intake valve closes more than 2° later than the optimum closing point...
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The larger volume of air pulled into the cylinder by the higher vacuum will be pushed back into the intake manifold and substantially reduce power.
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If the exhaust valve opens earlier than the optimum opening point...
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Each one of the other 7 valve timing events must also be moved to a critical position in order for Negative Pressure Supercharging to work with the higher vacuum. For more details Opening the exhaust valve earlier
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Therefore,
Negative Pressure Supercharging and the NPS Tri-Y header do NOT work with conventional valve timing that has...
 Intake and exhaust valves open at the same time at TDC
Exhaust valve close after TDC
High exhaust valve lift
Long overlap duration
Intake valve close late after BDC
Opening the exhaust valve earlier increases the supercharging effect but requires re-synchronising the 8 special valve timing events However, it's not as simple as opening the exhaust valve earlier and the engine will produce an additional boost in power with Negative Pressure Supercharging. To trap an even higher vacuum in the cylinder and for it to pull an even greater volume of air into the engine, it requires re-synchronising the 8 special valve timing events with new valve timing events that work together with the much higher vacuum.
| Impulse Engine Technology
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Fax: +(612) 9398 5644
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Inventor of Negative Pressure Supercharging
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