Venom Pistons... The pistons that work like porting....
There is an enormous amount of design criteria that influences ultimate power and longevity characteristics of a piston design. Venom is the industry leader and innovator in custom performance piston design. Until Venom brought high performance piston design principles to the off road industry, all that was offered were stock configuration pistons with large domes put in the middle to raise compression.
Venom Performance Pistons are all 100% custom designs exclusive to Venom. All Venom pistons are manufactured by the
#1 manufacturer of performance pistons; CP Pistons. Venom has a long time relationship working with the engineers at CP to provide custom high output endurance racing pistons. If you don’t choose a Venom piston for your machine, without question you should choose one of the pistons from CP's lineup. Venom is also a master distributor of the entire lineup of CP pistons.
Compression Ratio is important in engine building, but ultimate performance is built from much more than just a static compression rating. In fact , it is possible to not only make different levels of power with the same compression ratio, it is also possible to optimize a pump gas compression piston that will outperform most race gas compression pistons that do not take advantage of all possible technical advantages.
Venom Piston Principles... these are all variables that can be used to extract maximum power and longevity.
Tight Squish Clearance:
This is one of the most neglected of all design criteria in aftermarket performance pistons. Squish clearance is the area between the flat periphery of the top of the piston, and the flat area on the bottom surface of the cylinder head when the piston is at the top of its stroke. Even with the same compression ratio, a piston with a tighter squish clearance will make more power than a piston with more clearance.
Fuel\air mix from the squish area is pushed into the center of the chamber as the piston approaches the top of its stroke. There are two reasons forceful air motion makes more power. The fast swirling of this mixture aids in spreading the flame front quickly through the combustion chamber for a more complete, faster, and more powerful burn of the fuel\ air charge. The second advantage is that any charge trapped in the squish area does not add to the main burn of the combustion chamber. Tighter squish allows for more of the charge to be pushed into the combustion chamber and adds pressure to the main burn.
As an added bonus, tight squish also makes an engine less susceptible to detonation.
All Venom pistons are designed with the most optimum squish clearance.
As long as a pistons design and materials are up to the task, lighter weight is always desirable. Added weight on the end of your rod\crank assembly is never a good thing. Added weight is more stress on crank related components, and is also harder to accelerate.
All Venom pistons are designed as light as possible without sacrificing strength. Tight squish tolerances are a perfect way to get high compression without adding weight to a piston.
Unobstructed Combustion Chamber:
Within each desired compression ratio, it is always an advantage to have the least amount of piston obstruction in the form of tall dome sticking up in the middle of the combustion chamber.
A tall dome does 3 negative things:
It obstructs efficient flame front travel when the air\fuel charge is lit by the spark plug, slowing down the main burn event.
It obstructs "overlap flow". There is a period of cam timing at the end of the exhaust stroke\beginning of the intake stroke, where both the intake valves and exhaust valves are open. This is known as the overlap phase. At this time a well designed exhaust system will provide a significant amount of vacuum throughout the exhaust valves. This vacuum not only pulls hard to extract remaining burn charge, but while the intake valves are open it will also begin to pull fresh fuel\air mix from the intake port even before the piston begins its downward intake\vacuum stroke.
Designing a piston with tight squish clearance is a perfect way to increase compression without adding a big obstructing dome into the center of the piston\combustion chamber.
All Venom pistons are designed with the most unobstructed combustion chamber possible within each compression ratio.
Ring Friction \Tension
Piston ring drag is a huge power loss in an engine. Ring sets that are thinner, and designed with less radial tension, will "free up" power due to less friction and drag. Ring sets that are nitrided have super long wearing characteristics. For ultimate reduction of ring friction, some pistons are designed with a single compression ring. Power gains from single compression rings are most noticeable as the operating machine RPM increases.
All Venom pistons have thin\ low tension \ nitrided ring sets.
Radial Ring Gas Ports
Piston rings would not be able to seal against combustion chamber blow by with only their lateral tension. Rings use the pressure of combustion to push the ring from behind, against the cylinder wall, to make an effective seal. Radial gas porting is a way to assist in quick and efficient transfer of combustion pressure to the back side of the compression ring.
All Venom pistons use lateral gas porting.
Forced Pin Oilers
Wrist pins deal with a tremendous amount of pressure and friction. Oiling via the "Spray and Pray" method, hoping oil flung from the crank will somehow find its way to the wrist pin, is just wishful thinking on a performance engine.
Forced pin oiling channels, cut from the oil control ring groove to the wrist pin boss, use centrifugal force to push much needed lubrication to the wrist pin bore. Less friction means more power and longer life.
All Venom pistons have dual forced pin oilers.
Advanced Critical Clearances
The shape of a cold piston is neither round nor cylindrical. The shape of a cold piston has to be designed such that the disproportionate heat load from the top to the bottom turns the piston fit to perfect when the piston is fully up to operating temperature. A tighter\better fitting piston creates a better platform for ring seal, and is much more efficient at transferring the heat load from piston to cylinder walls and cooling system.
Venom is constantly collecting data and refining piston profiles and tolerances for maximum life and power.