It's cold! Boost is low!

[JasonCzerak]

temps just dipped below 35-ish finally. And I had this problem last year. Why the heck can't I boost over 32-psi when it's cold out? The EZ is fooling the map first, then the juice. I figured it was just a buggy Attitude box.



Is air density really that big of a difference at 35 vs 40 to lose 10psi of boost?



Or do I really have something broke fueling box wise.

 

[JCleary]

If you're taking the reading from the MAP sensor, keep in mind that you're reading the "Manifold Absolute Pressure" which is different than boost psi.



If you have a mechanical boost gauge you may find that your boost gauge says 40, and the Attitude will say 34. The boost is relative to atmospheric pressure, and the MAP signal is not.



Another thing to consider is the additional cooling you get through your intercooler in cold temps. That will lower boost considerably. Especially if you're running a stock turbo out of its efficiency range.

 

[Prairie Dog]

Wouldn't we get more boost if the air is cooler and more dense?



Scotty

 

[JCleary]

Wouldn't we get more boost if the air is cooler and more dense?



Scotty

That would make sense, but perhaps it's harder to compress dense air, resulting in lower MAP readings?



Just a guess...

 

[SP Diesel]

My guess is that Edge's boost fooling is having issues once the temps get down and the wastegate is opening prematurely. We have our electronic wastegate controller coming out soon that could solve this issue for you.

 

[JasonCzerak]

If you're taking the reading from the MAP sensor, keep in mind that you're reading the "Manifold Absolute Pressure" which is different than boost psi.



If you have a mechanical boost gauge you may find that your boost gauge says 40, and the Attitude will say 34. The boost is relative to atmospheric pressure, and the MAP signal is not.



Another thing to consider is the additional cooling you get through your intercooler in cold temps. That will lower boost considerably. Especially if you're running a stock turbo out of its efficiency range.

if that were true then when the attitude say 38, I"m doing 48? and when it's maxed out at 40psi I"m prolly closer to 55?



I think idea is off. the MAP that the attitude is reading is pressure period. the other MAP is on the air filter.



Also, performance is down. truck feels slower once I can't get above 32psi. But once the temps are around 40, it's like a switch, 40+psi and more power.



Same thing if I sit and idle around for 30 minutes and the motor heats up, intake temps get to 80-100 degrees as read by the attitude, the first run though the gears, I can smack 40psi and that's it, no more 40psi anymore



I've had my boxes in at edge once for this and they can't reproduce it. I think it's the box more and more. But I've been wrong before.

 

[JasonCzerak]

Ya know, other then the obvious performance issues felt when this occurs, could the ECM realize that at 32-degrees there is more O2 in the air there for open the waste gate earlier, and the edge unit doesn't realize this?

 

[cerberusiam]

Wouldn't we get more boost if the air is cooler and more dense?



Scotty

Denser air gives BETTER air at less boost so we don't need as much boost pressure to get the same amount of oxygen for the burn cycle. Once you get so far past stoichiometric the combustion heat drops which starts dropping the boost and rpm's.



As SP says, it sounds like the boost fooling is working too good and not compensating for the denser air and adding more fuel.

 

[JasonCzerak]

I suppose the only way is to dyno it in the cold and warm

[

Just that the butt dyno feels like the numbers are lower.

 

[RMalone]

Could the edge be defueling based on its cold engine protections??

I know it is supposed to be reading coolant temps so the idea doesn't make sense if you can idle for a few minutes and get full boost then lose it after one run. The fact that you can idle in the cold and make things warmer doesn't make sense to me either, my coolant temps steadily decline when ideling in cold weather. One way or another your boost fooling is getting fooled or something is defueling because it senses "too cold" of temps. Let us know how it works out.

 

[JasonCzerak]

Could the edge be defueling based on its cold engine protections??

I know it is supposed to be reading coolant temps so the idea doesn't make sense if you can idle for a few minutes and get full boost then lose it after one run. The fact that you can idle in the cold and make things warmer doesn't make sense to me either, my coolant temps steadily decline when ideling in cold weather. One way or another your boost fooling is getting fooled or something is defueling because it senses "too cold" of temps. Let us know how it works out.

the high got to about 37 and the truck was smoother, less ridgid. I got a chance to hit 39 psi (heavy traffic) once. I don't get it. I need to get another box in this truck to see if it really is the ez juice combo