Did not see the original post 2 years past but thought this might be of interest as this is being looked at again, for what it is worth:
We went from the 14G to the 16G to the 16G super for our Mitsu 2.6L Starion motor. The step from 14G to 16G was good fro overall power at mid range and top end, but the 16G super was a much more significant step up in terms of turbo response than I expected; the lag was definitely less and the low end response definitely better with the super 16G over the 16G. When we went to a true 8.2 CR (thanks JVL) from the stock pistons that were supposed to make 8.1 but were actually 7.2 CR, the bottom end of the motor really came alive and the torque is strong from a bit under 2K to about 6k, and it jumps right from low end grunt into the turbo boost. With the larger motor (vs. a 2.0L for instance) , I would not expect the RPM's to be up to 7k, and it's not needed anyway; the larger displacement presumably heps the turbo get going at a lower RPM. We run about 15 psi boost tops. The boost holds to up the upper RPM end, and I think we are getting limited in the throttle body, not by the boost.
I am sure we make in the 250-300 HP range (not WHP). I don't know your displacement or anything, and I assume cams can/will make a difference. The Starion cams are stock intercooled 2.6L cams; I am not sure I have the cam specs but can look if anyone likes.
Never, ever have had the wastegate hang up on these Mitsu turbos, and that is with about 200-300 stages and lots of time at max boost. I have had the wastegate shaft shift a bit on one unit and it would hang a bit open from time to time. I put some lube around the shaft from time to time. The presure dashpot we us are the stock intercooled Starion ones, and we have had no issues with them at all. We always put some good NAPA antisieze on the studs and never have issues removing things.
We run the stock Starion intercooler; they are known to be a good piece. Have not had one blow yet nor any hoses. We use a metal tube set for the Starion with aircraft hose connecting pieces a few inches long, and that help the reliability of the hoses.
One thing that helped more than I expected was going from 2-1/4" exhaust to 2.5" exhaust. It helps some all over, but seemd to helped the top the most. (It may have helped the lag but am not sure as we made more than one change at once.) We were careful to keep all the kinks out and it really made a difference. Again, I don't know your dispalcement so 2.5" exhasut may be larger than needed for, say, a 2.0L.
Regards,
Mark B.
