This is another WORKS original product imitated by others.
The shaft seals on an OEM stock throttle body can only withstand a limited amount of pressure before they fail; especially as they get older and contaminated. The WORKS seals are the absolute best on the market! Other aftermarket seals hold less psi or fit poorly due to their housing design.
If you plan on tuning your EVO and running higher boost, these seals can give way leading to more expensive problems and troubleshooting frustrations. Some enthusiasts have experienced a 2.5psi+ pressure loss!
Thankfully WORKS has addressed this issue by developing special high pressure shaft seals for our Aperture throttle bodies. Designed to fit exactly like the stock throttle shaft seals, these stronger units have been tested to 38psi when installed properly thanks, in part, to the CAD designed, OEM-style metal casing surrounding the uniquely designed WORKS internal rubber seal.
These are a must if your shaft seals are over 3 years old, have more than 30k miles, or you plan on running a bigger turbo or higher boost. Reasonably priced, the WORKS High Pressure Aperture Shaft Seal kit is an inexpensive way to prevent engine problems on all EVOs.