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Boost issue

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Dripping Springs
#1
Greetings -

I recently installed a GFB DV+ and Velossa Big Mouth. While at it, I tightened all the clamps on the Depo IC and hard pipes. I buttoned it all up, and the car was driving great, consistently hitting 26.5lbs boost on my Dizzy E30 tune. I filled up the car a few days later, and went for a spirited drive, only to find I would only hit about 23.5lbs, and on top of that, the boost would then taper off to redline, dropping as low as 12lbs. I've gotten back under the car and ensured all pipes are connected snugly and all clamps are tight.

I cannot figure out what has happened... could the DV+ not be holding the seal properly?

Supporting mods include Cobb intake, Whoosh Symposer delete, Thermal Exhaust and step colder plugs with less than 5k mi on them.

Any ideas?
 
OP
G
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Dripping Springs
Thread Starter #4
There has been an ambient temperature change, wherein, it's gotten about 15-20 degrees warmer, which should have the opposite effect (more boost for higher temps).

I did lube the piston, but seeing as that is the only other thing I haven't checked at this point, I guess it is worth taking it off... it can come back apart right, without breaking anything?

I should also do a data log and send to Jason at Dizzy... just haven't had the time or opportunity to get out and run it. Was just curious to get the collective thoughts of anything else I might have overlooked that might be causing this (vac lines all look normal and connected, etc).

Thanks again for the feedback and I welcome others to chime in -
 

Quisp

Senior Member
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#5
My first DV+ was galled up where the plunger passes through the body. It would only do 16lbs.I bought a replacement factory diverter and it took care of it. GFB warranted me a new one. Been no trouble for 30k.
 
OP
G
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Dripping Springs
Thread Starter #6
^^Very interesting. I'll take the time to pull it off over the weekend... thanks for the feedback -

Edit - just read the entire GFB DV+ thread... Hopefully I can diagnose if this is in-fact the issue -
 
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#7
Now just from what I have seen in the past is if you do not use a recirculating system it will hurt you holding boost. Especially in between shifts. Now besides that if you are making more torque it may be requesting less boost. Ecoboost engines have a torque goal so lets say the goal is 350Ft/lbs of torque. Then it will supply 10psi if that is what it will take or 20psi depending on what it needs to hit 350Ft/lbs.
 
OP
G
Messages
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Thread Starter #8
I was hitting damn near 300lbft of torque previously, but that has dropped down to about 240lbft now (estimates according to the AP3).
 

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