around 7 tonight i took my cobalt out for some runs since it was 22 degreess. i hit I 65 and did about 5 3rd gear pulls.. each time my car pinged 14.5 psi nearly 15. i never felt so much power. mods i have are./. cx heat exhanger (front mount),air box mod. hks muffler dragger muffler. i highly recommend this muffler my car sounds amazing. deep..non raspy...very loud. but why would i hit so much boost?? im usually around 11-12 isnt 10 factory??? if so 5 psi above factory is pretty sweet.

its because ur so cool.

 

factory is 12.5. it hit so high because its cold out. wonderful thing huh? nothing to worry about though.

 

Its because of the cold air......when it gets warm out...you'll be back to 12.5psi. But it is nice isnt it.

 

lol cold air will give you at most 1 more psi when going from like 80F to 20F. Id say either your boost guage isnt reading properly or your cat is on its way out.

 

i dont see how it being colder would create higher psi. more power...yes, but atmospheric would still be 14.7psia

im gonna guess ur cat is clogging up

 

yeah 12.5psi is stock. but its just cause its cold out. same thing is happening to me. its about 30* and i'm hitting 13.5ishpsi

 

no the PSI will increase because the colder air is denser, meaning you can compress more air molecules per revolution of the supercharger, but once they get compressed they heat up and expand, increasing the PSI. But by no means should he see 5 extra PSI.

 

i dont know why, but your car DOES in fact make more boost when its colder. and wayy more of an increase than 1 psi if you went from 80 to 20 degrees out. when i was stock i had the same jump. when it was 90 out i may hit just over 11 psi at like 70 i hit the full 12.5 and around 50 degrees i would see like 13.5

 

unless this is tested with a computer, that stock innacurate guage does not count. And this is such a typical css.net response. He has no idea what hes talking about, but hes damn sure of it. And yes there is something to worry about, his car isnt properly tuned for a higher PSI. Theres a reason that any good tuner will have a summer tune and a winter tune, and its for this very reason. Your car runs alot leaner in the cold weather.

 

You guys all need smaller pullies. Worrying about who makes the most boost on a stock pulley is like fighting a retarded kid. Even if you win, you still suck.

 

a stock SS/SC with a stock tune should bypass anything over 12.5 psi right?

 

Any good tuner knows not to have a setup that only runs in certain weather ranges. Fueling and airflow tables should be correct no matter what temperature or air pressure. ECM's have been designed to operate under variable conditions for years. If you have lean issues in cold weather you're doing something wrong. We range from 35 degrees celcius in the summer to -40 degrees celcius here in the winter and my fueling is rock solid on any day of the year. Only issues were coming to close to maxxing 42# injectors when it was that cold for my comfort.

 

Correct, but heat soak and stuff like that still allows a little more than 12.5, it also depends on the specific car. Some are really sensitive, others aren't.

 

They're missing out on all the fun!

BTW, pulls like a beast on spray.

 

GUYS... stop doing these long highway pulls in the cold! How many times do I have to say it?



Meh, not my car to blow up anyway.

 

My car loves highway pulls.

 

Even when it's 17 degrees outside?

 

That all depends on the capability of the ECU to react. The factory tune is incredibly rich, to allow for the cold weather, it won't lean out enough to bother anything, just run better. Down here in the 100 Degree weather, we get 10:0 A/F on stock and stage tunes. Cooler weather brings them much more in line, but it also allows more timing due to IAT adder tables and such.

On many setups, the amount you can compensate for weather changes is minimal, and an optimum power tune in the summer will be dangerous in the winter, and a winter tune will lose power in warmer weather.

Glad to hear that. Its fun, isn't it

 

I know

I never sprayed it before it blew originally, so I didn't know the full potential.

 

12.5 stock, u'll get maybe 1 with the cold but thats it..somethings up ur not gonna get another 2.5 just from the cold

 

i see what your saying. but if the IAT1 charge is cooler, then the IAT2 charge will also be cooler. i figured it would be proportionately cooler so that the pressure is still 12psi

 

my car made 14.1 psi on the stock pulley on my old setup.

 

My car is beastly in this cold....I wish it ran like this during the summer. When I had my car dyno'd in early-mid oct. it was 40 out and my A/F was 10:0......stock, talk about pig rich. Its nice, the cold has leaned it out just enough, nothing but great power now.

 

Were you tuned or have the stock limiter . A stock pulley will show more psi when spun to 7K or 7200 rpm right?

 

it shouldnt really. the blower spinning faster will create more airflow, but the engine revving faster will also use more air faster...so psi should be the same. this is why you dont have 2x as much boost at 6krpm as you do at 3krpm, even tho the blowers spinning 2x as fast