Engine/Transmission (1994 - 1998) Losing boost at higher elevation?

[98rammer]

i went on a couple hour trip with a friend tonight and noticed that my boost is down. i'm only hitting 25psi on WOT acceleration (stock converter) with up to 28 pounds depending. i usually hit 35 unlocked WOT. i will check the boots tomorrow and see if my wastegate has somewhat become deplugged, but i didn't notice any extra smoke/egts today. does boost usually go down a lot at higher elevation?



Tom

 

[Joseph Donnelly]

Yes, at higher altitude, there is less air to compress. Trubos are rated in efficiency according to pressure ratio (boost psi vs. ambient psi): (boost + ambient)/ambient.

 

[98rammer]

alright. i knew that the air is thinner (spool up sucks), but i didn't think that it'd lose 8 pounds of boost.



thanks,

Tom

 

[Dkevdog]

It gets really ugly around 13,800 feet ... .....



Kev

 

[98rammer]

yeah, i stopped on a hill with a small trailer at 12000ft and floored it... . never seen so much smoke from my truck... . and i pegged the egt guage before the 2nd gear shift i've notice that-depending- my cruising egts have gone up 100 to 200 degrees higher too... . they seem to be around 800-900 where it's usually 700 at sea level. oh well.



Tom