Well the weather and alt will effect the boost levels. But even in winter I have never seen it drop to stock levels. I only drop 20 PSI but I also am not driving it near as hard either.

You should still see more than 17 PSI reguardless. Even in the dead cold I still pop over 20 PSI if I can get traction.

 

That sounds about right for me as well. Lower boost numbers but same hp/tq numbers on my dash.

Right...

I haven't seen it that low.. right now in teen temps I see 15-17 psi

I know but I don't want to risk my 5yr/100k drivetrain warrenty.

You have the GM stage 1 or aftermarket tune?

 

I have only the GM Tubo Upgrade kit.

Note I still can see 23 PSI on a cold day but it just seems to spool up slower.

The car will vary a little boost wise but it also adjust pretty well with the computer. GM did a pretty good job on this car and it works well in many conditions that a turbo in the past would have issues with.

 

Anybody got an answer for this guy cuz I got the same issue. My 2010 ss 5sp wit the gms1 will not boost past 18psi. It's not the weather or the barometric pressure I assure you. This is my second hhr ss. My first one was an 09 ss auto with gms1 and it would boost AT LEAST 20 psi all year long( even in sub-freezing temps).Both cars were driven in the same city at the same elevation....do not blame this issue on the weather cuz that's not it!

 

Batman is absolutely correct. I have expanded upon the properties of air vs energy in some past posts, which have been reiterated here...

Boost pressure is related to how much air enthalphy can be dissipated (amount of heat energy present in a given volume of air). On cool mornings, air molecules are already condensing and your air/fuel mixture is optimized, so you will not see a positive gain on the gauge, but you will feel it in pressure on your backside against the seat.

Additionally, air pressure (sea level) is another factor. Also, humidity adds to air density, and the more humidity, the more air enthalpy (again enthalpy is heat energy, which is what intercoolers circumvent). So never assume that the gauge will always be at a constant. Pegging the pedal under the same physical circumstances, but with varying atmospheric circumstances, I have personally seen "boost compensation" between 16PSI and 23PSI. I can almost "feel" what the gauge will read even before taking the car out for a Sunday morning ride.

If you keep the intersecting lines of a psychometric chart in the back of your mind when you're nailing the throttle and looking at the boost gauge, you'll be more apt to understand the discreet nature of boost pressures. (you don't have to memorize the chart, just understand it).


Vertical axis = Dry bulb temp
Horiz axis = moisture content per kg of dry air
Sweep radius = Relative humidity

Note when temps are higher (vertical toward the right) intersecting with high moisture content (horizontal toward the top) and the relative humidity sweep is high a direct effect will result on the enthalpy scale. In this case, air molecules are hotter, contain more moisture and are less dense, which has a negative effect on pressure.

 

Its been awhile since my turbo days and things may have changed quite a bit but with my old Talon the first thing I would check for if I was having boost issues would be for a boost leak. Also just out of curiosity, what kind of boost control does the SS use?

Its a long shot and probably not the issue but it could also be a problem with the gauge.

 

87Silver...that's not it. I can't even break the tires loose in first gear with the 2010 5sp and with the 09 auto it was had not to. I don't normally look at the boost gauge but since it felt as if there was a BIG lack of power that's where I went to gauge the performance, and also to help explain to others the lack of power I'm experiencing. Once again this is my second hhr ss and I understand how my environment affects boost numbers on this vehicle.

 

I have no idea how the boost is controlled mechanically. How would you go about testing for a boost leak if the car you are testing requires a load to put on the engine before boost is created?dyno?

 

Its fairly simple if you can get your hands on an air compressor. You essentially build a cover for the turbo inlet and then pressurize the system with the air compressor checking to make sure it holds the boost and if not trying to track down where the leak is coming from. On my old Talon I'd run right around 20 psi and the tiniest hole would cause the boost to fall 3-4 psi.

Check this link out on how to make one. They are cheap and easy.
http://forums.evolutionm.net/evo-how...er-5-02-a.html

 

I had a boost leak, at the Ic conection of the hot side, I could hear the whistle over the exhaust easy, over 12lbs or so.