When the map sensor wire popped off if toy got some detonation it could cause the rings to flutter and cause a lot of blowby.

 

Why did you go with the 1.15a/r? Don't most people just go with the .82a/r? What would the difference be and is it more helpful to go bigger on that side? Did you have any boost creep problems with the 6466?

 

It's a twin scroll setup, so in order to get the same flow on the top end you have to run a larger a/r. The A/R is just an area ratio. T3 .82 and T4 .82 have the same numbers, but the ID is huge on the T4 setup. Add a divider in the middle and it's as small as a .63 a/r (faster spool, but restrictive up top) turn this housing into a 1.15 and it's like a .82 a/r down low and larger up top where you need more flow area.

 

Thanks for the info.