Questions about h&s mini maxx

The-Fett · Oct 1, 2014

I am driving the truck up from San Antonio to Gillett Wyoming. About the truck 2011 ccsb king ranch fx4 dpf off h&s box tunes and a 5 in exhaust. I noticed while passing someone in Gillett on the performance tune I'm only building 23 lbs of boost with rail pressure from 29 to 27.5 ksi. Where as in San Antonio I would build 26 psi boost with rail pressure at a steady 28 to 27.5 ksi range.

What would cause the drop in boost? As I understand going up in elevation causes you to build more boost. what would cause 1000 ksi/psi change?

Truck has new fuel/air filters. oil was changed about 2500 miles ago running 5w40 amsoil. I also use power service if that matters

drunk on diesel · Oct 1, 2014

just a different spot on the map

The-Fett · Oct 2, 2014

Map as in the tune?

kampy · Oct 2, 2014

The altitude causes the loss in boost, the air is less dense. I think your understand it backwards.
Every turbo engine I've had boosts 2-3 psi more in Illinois @800 ft than it does here in NM @5500 ft, its even worse over 9000 ft in CO

drunk on diesel · Oct 2, 2014

he's saying he's seeing less boost but more rail pressure

the rail pressure just boils down to how the tune is mapped out. I wouldn't worry about it

bigrpowr · Oct 3, 2014

drunk on diesel said:
he's saying he's seeing less boost but more rail pressure

the rail pressure just boils down to how the tune is mapped out. I wouldn't worry about it

exactly . these pumps are so TPS driven its crazy. they will not make full rail unless you are completely WOT . I would not worry about anything being seen here.

The-Fett · Oct 7, 2014

That is what I was worried about at the time this was at wot in Gillett Wyoming. It's back to normal now so I'm not as concerned it still does bug me though.