crossbow said:Yup..and thats happened to some 6 owners. Destroyed cats at relatively low mileage.
Regardless, the 3/6/8 all dump excess fuel at upper rpms. The 6's A/F ratio at 6500 rpm is about 9.7:1.
It actually drops below 10 at 5500 rpm. I bet the MPS 6 is doing the exact same thing, and dropping boost, which explains the sudden drop in power after 5500.
Direct fuel injection allows leaner operation, I read an article about the MSP6 running stoich ratios under boost!!
It's possible it was a preproduction tune and could be different in final cars but the potential is there