40psi is, in fact-- way too much. You are risking catastrophic turbo failure.
The proper way to limit boost is with something a little more precise on the wastegate. Either with a 1)ball-and-spring boost controller from
www.boostcontroller.com, or 2) with an electronic wastegate conversion using a Hobbs switch and solenoid valve to control the WG.
The former is cheaper, the latter is better.
In lieu of the 1. 6/TST combo, maybe you should consider the M4/no fueling box combo.
The TST/1. 6 combo will make a little more power than the M4s with no fueling box, but the injectors without the fueling box will burn more efficiently and with lower EGT at a given HP point-- say 400hp.
Bob Wagner has test the #9 combo plus Mach 4s with a Dodgezilla extensively-- you should call him or PM him about it. (
www.wagnerandassociates.com)
One other nice thing is that stepping up to the larger Mach 4 injectors is a lot cheaper than adding a $550 fueling box.
The 1. 6s are GREAT injectors... but for a big 150hp injector, the Mach 4s are pretty clean- even in altitude. You might want to try SW #7 or SW #5 with them though, as Mach 4s with SW #9 will smoke pretty easily in high elevation-- it's just too much fuel too soon. I know because I tested them in Cheyenne WY (6100ft) extensively.
True, the TST gives you a little more flexibility wrt switching off a box. But I'd see no problem towing with a Smarty and Mach 4s with a Dodgezilla, given the somewhat light load (5K, right?).
I'm personally hoping to add a TST to my ecm/M4 combo in the near future. I need a wee bit more fuel
