I pressurized my intake (PVC end cap w/air fitting + compressor) and found a pinhole in the below hose. I'll replace it regardless, but curious what impact that small hissing leak would have on my boost? Also, anyone have a part number for it?? It's probably stamped, but I'll likely destroy it taking it off.



BTW, the car is stock except for a strat DV...

 

probably not a huge impact but it will casue some issues if it gets bigger

 

That's sort of what I was thinking. I did the test because I'm a little disappointed w/the power she's producing. I've had the car for a month and it runs great, just seems a bit underpowered. Perhaps because the only 1.8T I've compared it to is my buddy's GTI. I would think the boost would come on similar to his.

I definitely need a boost gauge so I can really see what's happening...

 

but you cant really compare it to the GTI cuz its lighter than the A4 by a bit i think so the A4 will seem slugish, chip it and get an exhaust, tesp pipe, n75h and you will not be dissapointed

 

FWIW, I may have found the true culprit of the lack of performance. When I had the PVC cap in the intake boot, it extended into it well beyond the clamping area, so the issue didn't show up. After running the test, I was putting the inlet hose back on the airbox and noticed a tear in the boot right at the lip where the clamp goes (it was on the bottom so it was hard to see). It took me a while to get the boot back on with it in this state. Once completely on the airbox, the tear is not affecting anything because the lip is over the airbox flange. I'll still probably spring for a silicone inlet hose...

In short, I don't think the inlet hose was fully on the airbox. May not have been "losing boost" there, but was probably making the MAF scratch it's head... This morning, it seemed to be much more alive.

Now I'll start saving my pennies for those upgrades

 

So do you, or do you not still have a leak where you indicated in your first post w/pics???

 

Yes, I do still have the leak from the first pics...it just didn't happen to be the main root cause of my performance issue. I'm shopping for the hose now. Sorry, I think my rambling about the inlet hose may have been a bit distracting.

 

Its strange because yesterday when my wife got home i poped the hood to double check the torque on my valve cover bolts since i replaced the gasket the other day and i was hearing a slight hiss from the exact hose you are talking about right after she shut the engine off. I wiggled it around and the hissing noise got louder or changed tone when i was moving it. So i think i may have a small leak there somewhere too. Its not obvious though. I might take it off and do a isolated pressure test on it.

 

That's exactly what I experienced. When moving the hose it changed tones. The hose is tapered larger to smaller, left to right. My pinhole is in the larger part toward the "left" end. I don't know that I could have heard it with the car on though...