My car hits over 17psi with, Air box mod, S2, 2.9, and GMPP catback. Keep in mind this was in 20 degree weather. I think it might just be the cold, but get it checked out just to be sure.

 

for you guys who think its the cold.
I have driven my car in -40 temperatures.
at BEST you will see 1/2 to 1lb more than summer.

you arent gonna see 3lbs of boost from a little cool weather.

 

But that's right around where you should be with the 2.9

 

Just cause its cold dont mean its gonna boost it up THAT much more...... your boost guage is probably off a little, good luck though

 

Ive driven im much colder weather and on a smaller pulley than OP and have only seen 17psi. You have an issue .

 

it's the cold. when temps started dropping here in pa i was still stock and hitting almost 13/14 psi. now i have stage two and i've hit 17 psi... and that was simply when i ran out of running room. i could probably hit more.

 

i have seen 1-3psi from cold weather..

stock pulley in the summer my car ran 10psi to redline (sure could be off slightly)
nate's 3.1 pulley 12-13 psi in the summer
now nate's 3.1 pulley 14-15 psi in winter, basiclly the aftermarket boost gauge i have isn't going to read low first than magically read high when its colder..

this is minnesota so yes we get hot summers (not as hot as some) but still will get 90+ degrees and the last few weeks we have seen single digit temps ~7degree's

i say the cold

the only other thing i have do to my car is air box mod persay...(the 04 ion intake is different that cobalts)

 

THATS WAT I WANNA GET
BUT I'M THINKING OF GETTING A 2.8 WITH 60lB INJECTORS
IS THAT OK?!

 

well i did a WOT run today and only hit 16psi...my car is weird

 

hey i ahve a 2.6 pully and 60 b injectors and a aftermarket intercooler i was going to put all this on and get a tune. do you think it would be ok? i already have intake headers high flow cat and catback exhaust.