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 engines 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 dont 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 arent being used as
stressed structural members, thereby eliminating the need for
strength. 347SS and 254MAs 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
dont build up a hot spot on the valve or valve stem, generate a
localized stress point and then eventually, failure.
