Even if you use synthetic oil, you STILL have to let your turbo cool down. The turbo spins at about 100k rpm when at full speed. When you run it hard, the manifold and turbine housing actually start to glow cherry red. If you shut down the car, you can bet that any oil will choke in a heart beat.
Synthetic oil does not break down to heat as easy as dyno oil does, but that does not mean that it will not break down.
The SRT-4 comes with synthetic oil from the factory, and we have the same cool down schedual as listed above.
On my toyota supra, i always used synthetic oil. WHen the seals wore out on my turbos , i swapped them. I noticed a little bit of choking in the old ones even though i let the car cool down.
3" Turbo Back Prototype, Greddy EGT, HKS SSBOV, GReddy-e01 Boost controller, Blitz Turbo Timer.