Boost Vs Cold Weather
 

Hi, I'm new to this forum (found it last night). I own a 2006 3500 duallie and just installed the MBRP dual's, AFE Intake, 6 Gun Banks tuner with the Power PDA. The problem is when the temperature is about 30 - 35 degrees I boost up to 39lbs on level 7 but when it gets really cold 25 degrees and below I can only get about 25lbs and will not go over. I have replaced the fuel filter and added fuel supplements to prevent gelling but nothing changes. Any suggestions would be appreciated.

Welcome to the DTR. you will have a few repiles here soon. one or two things that come to mind, and I am not up on banks at all is the truck up to full temp before you try and make boost or go to the mat with the throttle? I am going to say yes it is. another thing watch the EGTs see iif they are getting hot or you have your Defuel limits set too low in the pda for EGTs I am sure the banks has some type of defuel limits in there. If they are set wrong the Truck will defuel and you wont make boost. one test that may help you out set the banks on stock and you should make around 32 psi. and it is also a possible that with the air being so good it hit a high boost defuel before you see the number on the pda and defuel that way also. this may not be it but gives you a place to start, Just keep in mind no fuel no boost. it could also be a fuel sys problem. Good luck and let us know what you find. and glad to see someone here also has a real truck DRW LOL

stang, thanks for the help. My truck runs fine as long as the weather outside is 30+ degrees. The problem is when it's really cold out that I can't make enough boost even if the truck is a optimum temp's. My mechanic told me that it's definately a fuel issue, too much cold air and not enough fuel. I was thinking of upgrading to the dual fuel filters to have better fuel pressure. Any help would greatly be appreciated. DRW all the way!!!!

Your turbo is designed to move a certain amount of air, not sure what it is but it is something like 0.46 kg/min (1.01lbs/min), air density is directly affected by temperature. So in order too move the same mass of air, the turbo will not create as much boost in order to supply that air. Its the old P1V1/T1 = P2V2/T2. So dont worry about it, its not a fuel thing, its a thermodynamics thing.

I know but in cold weather the truck should run better. From 39lbs down to 25lbs is a very noticeable. It should run better but for some reason it will not go over the 25-26lbs in cold weather. I called Banks and was left with "This has never happened before".

WELCOME TO DTR!

Check all your inner cooler connections.

Thanks, will do.

Your boost should be the same in cold weather vs Hot. I would check out your banks system first. Unhook the banks and see if truck runs normal.
I run a TST and at -12 (coldest it has got so far this year) I was pulling 39 psi on hills like the truck normaly does.

Just a thought, but doesnt the banks products hold off until the temp is up to 180F or something. Maybe the truck isnt getting warm to lack of a winter front?

I agree RAMRODD, it should be the same no matter what.

BlueDually, even when the temp on the engine is 180 plus it still won't boost over 25-26lbs. This is just my luck with one of these weird issues. The minute the day warms up I am right back to 39lbs.

Thanks for all the help fella's, keep it coming.

Aren't you gonna get wildly varying readings in cold weather if you are monitoring the MAP or have a analog gage in the air horn?

Temp's will be in the 50's tomorrow afternoon and I am going to experiment early morning boost readings compared to the warmer afternoon temp's and see what happens.

Seem's like it's a cold weather issue, early this morning I would not go over 26lbs of boost and this afternoon with the temp's in the low 50's I was getting 36-39lbs. What now?

I have the same isuue in a sense but im pretty sure its because the turbo can't compress the cold air as well. Some one above had a pretty scientific explanation which is along the same lines I was thinking. The turbo is pulling the same amount of air thru the intake no matter what temp it is outside. Warm air however is more dense and easier to compress than cold air and makes more boost pressure. In the summer I run 42 lbs of boost and the most I run under 35 degrees is 37 lbs. Ive also noticed that in hot weather I of course run higher EGTs but they also run higher in cold weather due to lower boost. 50 to 60 degrees seems to be where the truck makes the most power - 40 lbs + of boost and EGTs stay under 1300. Sounds like your truck is Ok unless your Banks kit for some reason is defueling due to colder temps?

Actually, warm air is less dense than cool air.

I have noticed no significant difference in boost pressure whether the ambient is 20*F or 110*F.

The impeller takes whatever air molecules are fed into it and centrifugally compresses them according to whatever drive pressure is acting upon the turbine and by the restriction created by the remainder of the intake tract, and limited of course by the turbo's wastegate and it's non-adiabatic pressure map... at some point, every turbo will heat up the air beyond it's ability to compress it.

Boost quality is just as important as boost quantity.