991.2 S boost behavior
01-19-2020, 09:06 AM
#31
i literally just posed the following on another 991.2 boost thread...
2017 4s mt
during the summer months I was pulling the following:
in sport mode - 15-16 psi even hit 17 in a flash
in sports plus 17-18psi easily
these values were achieved due to TWO NEW factory turbos being installed (warrantee work).
more recently now that it is winter the boost has dropped to the following:
sports mode - 13 psi and I can hear the blow off valve really loud (or maybe I am hearing a leak)
sports plus - I am rapidly hitting 17psi then the blow off noises and then bouncing between 13-15 psi
is this normal behaviour given the car is now driving in the winter temps? Or should the boost be constant and independent of outdoor temps?
... is it possible I have a leak?
Rapter is online now Report Post
E
based on your post and a few other it seems your conclusion may be correct. The cold dense air is allowing the cars power/ torque target to be met and therefore less boost is needed.
do I have this right?
2017 4s mt
during the summer months I was pulling the following:
in sport mode - 15-16 psi even hit 17 in a flash
in sports plus 17-18psi easily
these values were achieved due to TWO NEW factory turbos being installed (warrantee work).
more recently now that it is winter the boost has dropped to the following:
sports mode - 13 psi and I can hear the blow off valve really loud (or maybe I am hearing a leak)
sports plus - I am rapidly hitting 17psi then the blow off noises and then bouncing between 13-15 psi
is this normal behaviour given the car is now driving in the winter temps? Or should the boost be constant and independent of outdoor temps?
... is it possible I have a leak?
Rapter is online now Report Post
E
based on your post and a few other it seems your conclusion may be correct. The cold dense air is allowing the cars power/ torque target to be met and therefore less boost is needed.
do I have this right?
I don't think you have a leak. I think the summary here is that the boost PSI varies depending on many conditions (not just temperature too). Basically the electronics are boosting the engine to hit a target and may boost more or less depending on conditions (for example, in high altitude you'll be probably seeing 16 PSI all the time). As long as your car is accelerating normally, I wouldn't worry about it.
