1 year, a lot of research, tons of questions and finally found it, the "boost thief"

[B5Burn]

I bought this car just last year and it is tight... but since day one (a cpl thousand miles ago), it has been slowly losing boost. To the point this spring where I was hitting only about 7 psi when I could easily hit 4x that.

In my research to understand everything to possibly track down wtf was going on, I have spoken with the manufacturers of each system in my car (Greddy, TAP, SDS....), and spoken with the company who built it and tuned it. I have poured over manuals and forums.. some oldies too, because this car was built a few years ago...manipulated numbers and checked out many forms of alternative tuning concepts...

SO... last week, driving along and poof, idle will not drop below 2200 rpm. I traced every hose I could find.. every wire, little plug or thingamajiggy under the hood... I was going insane in the membrane.

FINALLY, I find it... by total fluke because I had moved on to looking for cracks in my manifold! One of the custom hoses coming off the bottom of my manifold (right in the middle, too) somehow tore right off the little pipelet. The clamp was still there with a small piece of hose attached to it. I wouldn't have spotted it without removing the intake, so it was nice to discover the open end of that plumbing. I had to move some things (thanks some fellow Audi enthusiasts) and I could barely get in there to repair... took about an hour, but there it is.

The inside edge of the hose clamp dug into the hose when the install was done, years ago... took until I GOT IT for it to go, but it has been a slow and steady decline.

Tonight I got my boost back =) a cpl pulls in and climbing each time, well over 15psi now. (I reset my ebc, so it needs to relearn the boost), 20psi here I come, woohoo!

Thank you to all of you for your patience and help with my numpty questions =)

The "Boost Thief"


VICTORY!!

[BrokeDown[20V]]

VICTORY!!

At last, good deal.

[Nor1824]

Just curious, if you would have built a pressure tester could you have found that?

[t1demont1]

Victory at last!!

[djwimbo]

Just curious, if you would have built a pressure tester could you have found that?

that depends on the type of pressure tester. If the intake manifold would've been pressurized, then probably. Most people only test from the TB to the turbo. An EVAP smoke machine could've been used as well.

... Anyways, to the OP. Congrats. I hate tracing down boost/vac leaks.

[B5Burn]

Thanks guys,

I am in the process of building a pressure tester, but the parts in the DIY I downloaded aren't as readily available to me as the guy who made the DIY. Pressure tester, VagCom, multiple performance gauges/metering equip and various other bits are pretty much mandatory to play in this game, ha-ha.

The tricky thing is with custom work, tracing factory Vac diagrams and following all the typical rules don't always yield the typical fix... I'm learning all the time though and damn this past year, I learnt A LOT! haha

B.

[onemoremile]

My pressure tester is nothing but two PVC pipe caps. One has an air fitting in it that plugs into the air compressor's hose. The pressure regulator and gauge on the compressor keep pressures down.