Low boost?

[GreenF350]

I think I have a little bit different of a boost problem. I still seem to be able to get roughly the same peak numbers as before, but lately it seems like I have a little more smoke and usually at steady 70mph cruise I was getting about 3-5 psi with the new turbo and yesterday I noticed that I had between 1 and 2 psi on the same road and same speed. I drive it every day, so I am positive that it really is a few psi lower. Any ideas? I would think a boost leak would get worse at higher pressures. Pre turbo exhaust leak? Can higher outside temperature cause lower boost? It's been hotter and I didn't notice it, but I don't stare at my boost gauge all the time either. The truck still runs and drive fine other than that. Thanks for any ideas.
-Aaron

[IHsMoKeR]

Is this on stock tune? Also when you really romp on it does the gauge bounce around and you dont hit as much boost as you used to?

[GreenF350]

No, it is on my 120 tune, but it does it on all of them. The gauge is steady even when I hammer on it, the only thing I really notice is lower cruise numbers and more smoke when I stab it. There may be a bit of peak boost lost, but 2 to 3 psi max.
-Aaron

[larz18]

your saying you only get 2-3 psi at full out full throttle?
sounds like a boost leak somewhere. Where you picking up you boost sensor?
pre-turbo exhaust leak is possible, easy to check, im sure you can see soot back there if you look up under, it would have to be a pretty major leak.

i would check your hose connections at the intakes below the cross pipe mine would always blow off until i rigged up something new.

[GreenF350]

No, the 2-3 psi is at cruise speed. Only 1 or 2 psi lower, but it seemed like there was more smoke too. I took it out last night after a good shakedown of all the connections and still got my max boost numbers. It was MUCH cooler outside coming home and it looked like I got the 1 psi or so back. Will 20 degrees difference in outside temp make a noticeable difference? Been seeing around 100 degrees mid day on my way home, seems normal when temps are back down around 80 degrees. I guess I was just worrying about my truck too much. Thanks though.
-Aaron

[larz18]

ya that sounds pretty normal to me then, just my thoughts.
could also be the boost gauge fluctuations to. i think they are only good for +- 1-2 psi depending on what gauge you have. plus the timing will change the boost so the engine could be adjusting timing for temp and altitude. But ya all sounds normal.