Boost?

[Huntinducks82]

I was riding down the highway earlier and notice that when i was going down hill with the cruise set between 60 and 65 that my truck would pick up about 3 to 4 psi of boost. I want to know if this is normal cause its the first time i have notice and if so why is it doing it.;

 

[McRat]

Interesting. Perhaps it was closing the vanes to increase engine braking. Closing the vanes INCREASES boost on our chargers.

 

[Killerbee]

x2. Programmed in to add resistance to the exhaust tract...braking.

 

[Huntinducks82]

Yeah that what i figured it was for some kind or engine brake. I looked at my tune but not sure where to make the adjustment to get rid of it but i guess i will figue it out. Also while cruising 60 to 65 on flat ground i do not build any boost at all. Do you all think this is good or bad for fuel milage.

 

[Killerbee]

No boost is required at part throttle empty hiway cruise. I think most folks find some fuel savings here, but that is on earlier delco PCM's.