Boost Pressure vs. Outside Air Temperature

[zippyshoe]

Something that I have noticed with my current setup is that my boost pressure as displayed by my boost gauge appears to vary between the summer months and winter months by about 2-3 psi (without any change to the boost controller setting). My boost pressure appears to be 2-3 psi higher in the winter months than in the summer months. My boost gauge is connected to the intake manifold, my Hallman manual boost controller is using the nipple on the turbo compressor housing as its boost reference, and I am (unfortunately) still using the factory intercooler. My theory is that the pressure drop through the intercooler is varying with the outside air temperature with the pressure drop being greatest during the summer months. However, its my understanding that pressure drop is due to the restriction to airflow that the intercooler introduces. But I wouldn't think that the amount of restriction would vary with the outside air temperature. I was wondering if anyone else has experienced this variation with their setup? Thanks for any feedback.

 

[aero_sallee]

Something that I have noticed with my current setup is that my boost pressure as displayed by my boost gauge appears to vary between the summer months and winter months by about 2-3 psi (without any change to the boost controller setting). My boost pressure appears to be 2-3 psi higher in the winter months than in the summer months. My boost gauge is connected to the intake manifold, my Hallman manual boost controller is using the nipple on the turbo compressor housing as its boost reference, and I am (unfortunately) still using the factory intercooler. My theory is that the pressure drop through the intercooler is varying with the outside air temperature with the pressure drop being greatest during the summer months. However, its my understanding that pressure drop is due to the restriction to airflow that the intercooler introduces. But I wouldn't think that the amount of restriction would vary with the outside air temperature. I was wondering if anyone else has experienced this variation with their setup? Thanks for any feedback.

I have definitely noticed that before. I think its a combination of quite a few factors. Higher temps mean less dense air, the turbo has to work harder to compress. The compressed air is also less dense meaning the engine will ingest less per cycle, meaning less exhaust gas to spool the turbo.

I'm sure other people have some more input too.