T3-T4 Turbo Cover The new, easy fit design can fit a T3-T4 or T5-T6 turbine. The turbo cover keeps the turbine spooled up, reducing turbo lag. The dual layer construction increases performance and durability, reduces under hood temperatures, improves horsepower and performance by maintaining temperatures inside the turbo. Kit includes grommets and wiring for easy installation. Made in the USA.