On the way to work this AM, the outside temp was 22 degrees and with the wind chill factor, it much much colder. On the "back road" before my work's parking lot, is a huge straight-a-way and usually the time that I get there, there is no one on the road. So, I do 3 passing gear test, 1 below 60 mph, and the other 2 between 60 and 65 mph

test 1 15 lb psi
test 2 19.5 lb. psi
test 3 20.4 lb. psi

I think the reason the boost was higher in test 2 & 3 is that it was done above 60 mph and it must have something to do with the curve, at those rpm's. Of course I have no scientific data to back this up, just my logic........
I realize that with the colder weather, boost does come down quite a bit. But I have to say even with the cold temps this AM, I think these numbers, especially test 2 & 3 are quite good. I have had the BSR (HAHN) Tune for over 7000 miles and have not had 1 problem with it. It just performs and keeps going.
I know alot of members are going with the GM tune and for warranty reasons, and there is nothing wrong with that at all, but with some members paying the install prices that are being paid, you could have had a BSR tune and made the change in 42 seconds. And go back to stock at any time.
I am still happy I purchased this tune, it is way to much fun to drive, and looking forward to some minor add ons for the future........

 

boost is basically controlled by the ECU , BUT weather will effect this. turbos LOVE cold air, usually boosting quicker and sometimes higher, hot air has reverse effect unless you FOOL the sensors

 

I have nowhere the knownledge that alot of you on here have about turbo's, but I do know that when it is hot as in this past summer, I have never had any problems seeing 23, 24, 25 lbs psi of boost in my SS. Even before I put the BSR tune in, I was at 19, 20, sometimes 21 lbs of boost, the BSR (Hahn) tune made it more consistent and of course increased the boost, along with the increase on power was quite and still is impressive. just take at look at my Dashhawk 0-60 times, going from a best stock 6.75 sec to a best (so far) 5.6 sec with the tune.
my SS has always ran great, it just runs that much better with the tune

 

I tested at 40 mph, then kicked it and got 19.5 lbs of boost. It was just a short blast for 3-4 secs. Roads are full of dry salt on the pavement and wheel spin was ridiculous with the winters tires on. I really enjoyed the power of the Stage 1 though.

 

the way i understand it, engines love cold air, due to it being more dense, thus more power can be made. with our ECM trying to "learn down" as it's been termed around here, and trying to regulate power levels, in cold temps you should see lower boost out of these cars, because the denser air is capable of making more power without the boost, so less boost is required to make the same power levels, whereas hotter weather has the opposite effect. more boost required because the intake air is hotter ie less dense, thus capable of making less power, so more boost is used to compensate and make the power levels the ECM wants.

granted this is only really true for any car that tries to "learn down", and you should see different results on turbo cars that do not "learn down". in which case it should be like rodhotter stated. actually, come to think of it, on unregulating cars, boost should be the same, you'll just experience more power in cooler temps.