The Synapse Synchronic Wastegate is a fundamentally different approach to wastegating. This line of modular wastegates will be the first to eliminate the use of a diaphragm. Since there will be no diaphragm/membrane, it is more responsive to changes in boost pressure. It is also be the first pneumatically actuated wastegate that will have built in boost pressure adjustment at the actuator level without bleeding of pressure, which will produce mathematically rock solid boost levels. Another first the Synapse Synchronic Wastegate has is the ability for the serious tuner to use different combinations of valve size and spring rates in order to match to the specific engine’s performance profile.
Materials
- Investment-cast stainless steel 304 for exhaust valve housing
- 6061-T6 Aluminum for actuator housing
- High temp engineered axial contact polymer seals
- Self-lubricating Carbon Kevlar valve seal
The current philosophy is to use exotic materials, and voila your wastegate is now better. Or perhaps use exotic materials to band-aid problems like sticking valves. The Synapse Engineering approach is to have a fundamentally sound design first, and then select the appropriate materials. We don’t want to take a bad design and simply improve it with better manufacturing and better materials. We truly want to bring you prototypical innovation, by design.
The use of 304SS for the valve housing will allow for a good mix of Nickel and Chromium content for thermal insulation, resistance to creep deformation, corrosion and high temperatures. We decided against the use of 254MA or 347SS for the casting due to the high Nickel and low Chromium content. Yes, these materials have higher strength at elevated temperatures, but they aren’t being used as stressed structural members, thereby eliminating the need for strength. 347SS and 254MA’s melting points are close to that of 304SS, which is what matters. More importantly, these materials are very high in Nickel, and the higher the Nickel, the greater the factor for thermal expansion, meaning that the parts will grow at extreme temperatures. For the one-piece valve and valve seat we are testing a high Chromium, low Nickel 400 series stainless steel that can be treated for hardness. The Chromium stabilizes the steel at high operating temperatures, maintaining the critical tolerances in extreme service. It is no wonder that legacy designs have valve sticking problems, since Nitronic SS is a high Nickel SS with a high coefficient of thermal expansion. So as temperatures elevate, the parts grow and bind with each other. Our material selection seeks to eliminate this problem. In addition, the valve stem seal used in the Synchronic wastegate will neither gall nor bind with steel at any temperature. In fact, it has a higher melting temperature than the seal, and self lubricates.
Features
- Interchangeable valve sizes and seats
- Upgradeable wastegate with interchangeable actuator bodies
- Miniature actuator for tight installations
- Flanges and hardware will be included
- First wastegate with built in boost control
- On-board anti-lag functionality
- Precision valve actuation using Synchronic actuator geometry
- Self-Centering Piston actuator
- No valve guide
- Minimum of 8 different boost settings built into each Synchronic wastegate
- Adjustable spring pre-load
- Variable and tunable spring rates at the same boost level
- First wastegate with a valve that can spin
In the legacy wastegate design a flexible diaphragm/membrane is used to control the wastegate valve. This diaphragm is also pushed down by a spring. The main problem with the design is that the diaphragm is usually made from a rubber/polymer. As temperature increases the diaphragm becomes more flexible and the durometer changes. This means that it takes more psi to make that diaphragm move that valve. So as pressure increases in the actuator, the diaphragm has to stretch before actually controlling the valve. What we have seen is that the legacy wastegate, opens late, and then once open, opens up too much. Resulting in peaky horsepower that drops once the wastegate is open too wide and venting too much exhaust gas instead of driving the turbine. You cannot even vary the spring rate with a diaphragm wastegate since you are married to the durometer of the diaphragm. The Synchronic design utilizes a piston that reacts far more quickly to changes in boost pressure. It also allows the tuner to fine tune wastegate response by allowing you to use different spring rates for the same boost level and even adjust for spring preload, or target boost pressure. Spring rates cannot be varied on the legacy diaphragmatic wastegate, because you will only force the diaphragm to stretch more as spring rate increases.
Lastly, since there is nothing holding the Synchronic piston down, it can actually rotate in place, in service, over time. What this means is that the entire valve and valve stem will be exposed to the “hot” side and cold side of the wastegate. So that over time, you don’t build up a hot spot on the valve or valve stem, generate a localized stress point and then eventually, failure.