So I noticed I was only getting about half boost at the track this weekend and have traced it down to where the F-Hose connects to the aluminum intake (see below) - when I try to pressurize the system it comes directly out of that hole connected to F hose.

Since I just had the diverters out I am guessing one of the check valves is bad? Any other ideas? Thinking #45 and #21 in the diagram
Thanks

 

Could be bad DVs but I would bet its a bad #16 check valve. Try taking off the hose that connects right before the inlet side of the driver side turbo, that's where a bad #16 would dump out I think. When mine when it pushed air back up the intake tract and so it seemed like it was coming out by the F hose but it wasn't.

 

I can feel the air coming out of the intake in the picture so it is something in the diverter valve region....that's why I thought it was 45 or 21. I don't have secondary air anymore so I wonder if 16 is still even in the car.

 

a cracked #16 wouldn't limit boost to "half". larger leak/hose etc, is my guess. plus, you'd hear it "whistle" as air escaped while pressure testing.

 

Yea the air is coming through the intake that hooks up to the F hose...its all coming out from there...

 

which again suggests it's lower by the y pipe or direct from the turbos, and not atop the plenum where the 16 is. i have no direct experience with the forge or any aftermarket hose but i'd be looking there. i'd say check the inlets at the turbos, but i'm supposing you already have?

this is ( presumably ) a *large* leak. "minor" leaks ( as you know ) don't cut boost by half or result in "limp mode". i'll bet ya, it's a hose.. what else could it be? last major boost loss i had was a c-clip failed. trace the hose(s) from the inlets to the y-pipe(?).

all i got. GL.

 

Thanks - maybe I am not being clear - the "leak" is clearly coming from the inlet where the F pipe meets the aluminum intake housing...not anywhere else. So I was curious if this is the result of a stuck open check valve around the DV's since that is where the air is coming in

 

you were clear. my issues were always related to "lower" along the intake path, hence my bias toward that region. what do you mean when you say you just had the dv's "out"?

whatever was last messed with.. (?)

 

gotcha. I just had my injectors cleaned so everything was out. I will double check the flow on the check valve tomorrow see if it's upside down or something stupid like that. if not i am stumped

 

got it. that then leads even more credence to the supposition that "last thing messed with" will lead you to your leak, as opposed to a "failed" part. again, GL w it.

 

Yup - checked this morning - going to throw some 710n DVs in and see if those are the culprit and work from there.

 

my previous car had the older oem's, then i "upgraded" to the 710n's. with this car, when i got it, it already had evoms installed, i have never again had a dv issue. they seem to be indestructible and have never "honked" once lol. again, gl with it!