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Discussion Starter #1
I have a question regarding turbo boost, gear, and RPM. You can see my mods in my sig...

When I do a wide open run with my truck my boost runs up to about 28psi, which I know is normal for my setup. Now say I'm cruising down the highway at 60mph in 5th gear with the TC locked and I lay into the pedal (about 80%) my boost will shoot up to 32psi. Why doesn't the turbo spool up to the full 32psi when I do a wide open run?

I guess what I really want to know is what exactly controls how much boost the turbo makes? Give me some food for thought.
 

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The Silent Service
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First, what tune are you running and how are you monitoring boost?

As for a reason, are you able to hold 32psi on the highway, or does it drop back off?
There seems to be something in the programming that will decrease the boost around that level, back it off a few psi and hold it. Its holding up the aftermarket turbo guys a bit on the '05-'07 trucks.
 

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Discussion Starter #3 (Edited)
First, what tune are you running and how are you monitoring boost?

As for a reason, are you able to hold 32psi on the highway, or does it drop back off?
There seems to be something in the programming that will decrease the boost around that level, back it off a few psi and hold it. Its holding up the aftermarket turbo guys a bit on the '05-'07 trucks.
Hey Ben!

I am running Vivian's Looney Wild. I am monitoring boost via an Edge Insight CTS.

I am only able to hold 32psi in 5th gear with the TC locked. If I go WOT and downshift the boost goes down to about 28, but I can hold the boost.

I will shoot Vivan an email and ask her if theirs something in the programming that is limiting the boost at WOT. I also feel that I'm getting a bit too much smoke at WOT and if I was putting out 32psi at WOT I would probably see less smoke.
 

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Discussion Starter #4
I just heard back from Vivian. Here's what she said:

"Boost is determine by the computer taking into account load, wind, speed, mass air, temperature and probably a few other things. What you are experiencing is completely normal as that is how it works. For instance, when you are cruising on the highway at 60mph in 5th gear with the converter lock and hit the pedal, the truck will feel it has a bigger load and will increase your boost pressure in coordination. Technically, more load/more fuel/more boost.

You may see less smoke with more boost pressure but I don’t like to force the turbo or anything else for that matter. I like for the truck to do its thing. It should not be smoking at wot since the smoke should disappear when the turbo kicks in. Some trucks tend to smoke more than others but if you are seeing too much smoke at wot, that is an indication that we need to check why. It could be a bad sensor, etc.

I can change a couple of parameters to see if we can’t get rid of some of the smoke."

I am awaiting the new tue and will give it a try and let you guys know what happens.


Sent from my Autoguide iPhone app
 

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VGT Duty Cycle.


I have a question regarding turbo boost, gear, and RPM. You can see my mods in my sig...

When I do a wide open run with my truck my boost runs up to about 28psi, which I know is normal for my setup. Now say I'm cruising down the highway at 60mph in 5th gear with the TC locked and I lay into the pedal (about 80%) my boost will shoot up to 32psi. Why doesn't the turbo spool up to the full 32psi when I do a wide open run?

I guess what I really want to know is what exactly controls how much boost the turbo makes? Give me some food for thought.
 
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