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Discussion Starter · #1 ·
I have a new to me 2016 F350 which has been deleted, running a bully dog tuner with stock Canadian tunes.

When I run on the "no-power" setting which i normally do, i am seeing boost up to 36-37 psi. Is this normal?? I have the boost defuel setting set at 31 psi because 36-37 seems to high.
 

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That seems high to me, I’m seeing a max of around 25psi on my 2014 with a “performance” tune. Also, are you watching the gauge and this is a sustained boost level or is it hitting that when you first mash it and then dropping back?
 

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Discussion Starter · #4 ·
That seems high to me, I’m seeing a max of around 25psi on my 2014 with a “performance” tune. Also, are you watching the gauge and this is a sustained boost level or is it hitting that when you first mash it and then dropping back?
Thanks for the info....however it's my belief that the 2014 and 2016 do not have the same turbos.....and therefore is not a fair comparison.

It appears as though it spikes to 37 and then levels off....
 

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Thanks for the info....however it's my belief that the 2014 and 2016 do not have the same turbos.....and therefore is not a fair comparison.

It appears as though it spikes to 37 and then levels off....
That’s not really how it works. They have different turbos but the pressures will still be in the same neighborhood if operating correctly. Changing a turbo doesn’t necessarily mean a different boost pressure and that’s what you are reading on the gauge, it’s a pressure meter, not a flow meter.
 

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Discussion Starter · #6 ·
That’s not really how it works. They have different turbos but the pressures will still be in the same neighborhood if operating correctly. Changing a turbo doesn’t necessarily mean a different boost pressure and that’s what you are reading on the gauge, it’s a pressure meter, not a flow meter.
Macd... thanks for the explanation, I fully understand how pressure and flow relate to each other. My original question was to try and gain some insight into what other people are seeing who are actually running the same Gen 2 6.7 Powerstroke under similar conditions.

However I think I figured out the issue..... I took out the MAP sensor, cleaned it ( it was plugged with soot ). Took the truck for a drive and watched boost pressure closely ( BullyDog numerical value not "tattle-tale" gauge on dash).

Initially it still built upwards of 37psi when WOT from a roll, ( truck warmed up and on flat straight road ) .

After a short drive however it now tops out a 32psi....which is what I was expecting. Driving to work this morning it also topped out at 32psi.

Seems like the GT37 VGT turbo and PCM must have some "learning" that is happening after cleaning a MAP.

Compared with a co-workers 2013 6.7 with the previous GT32 model turbo on the way to work ( also deleted and running a H&S tuner ) , his maximum boost under same conditions was 23psi.

He stated that originally his tune made 31psi, however H&S contacted him and suggested he update his tunes and now he see's 23psi as maximum. ( H&S explained to him that anything higher on the GT32 turbo and things begin to fail )
 

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That’s not really how it works. They have different turbos but the pressures will still be in the same neighborhood if operating correctly. Changing a turbo doesn’t necessarily mean a different boost pressure and that’s what you are reading on the gauge, it’s a pressure meter, not a flow meter.
Negatory, sir...

Stock for stock, a 2011-14 turbo with the small dual stage compressor wheel will MAX around 20 PSI if you are pushing it. 15-current turbo will push around 25-26 psi.

Now tuned for tuned, let's say a 150 HP "hot" tune for each, expect 28-30 (won't live long pushing this hard) on a 11-14 turbo. You'll see 33-35 psi easy out of a 15+ turbo, and it ought to live some time.

A VGT turbo, especially on a non-stock tune, will "spike" in pressure due to the veins in the exhaust side of the turbo closing in order to spool up faster to match commanded fuel. The turbo ESPECIALLY when tuned (not as smoothed out of a file as compared to stock) may overshoot the commanded airflow, creating an overboost situation. The veins adjust to match actual airflow to commanded airflow after the spike in commanded fuel has settled, and all will be kosher.

Some other factors to look into may be the MAF being dirty (not really likely), or carbon fouling in the intake manifold.
 
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