View Full Version : How-To Do A Proper Boost Leak Test on A6/4 - 2.7T

06-22-2014, 07:06 PM
Ok, I have come across the normal boost leak test. Also not my 1st turbocharged car. Is it my 1st Audi with hoses to so many valves, tanks and twin turbo's... so yes I know how to boost leak test have on many cars.

Now the APB 2.7T engine in my car is only holding about 5/7psi. With more output from air compressor I have get to 11-12psi. Haven't timed leak down. It's florida, it sucks to be outside. What I have been doing is removing Y-pipe a capping off 1 crab claw. And use the other for my pressure input.

Now a few people talk of the n249 valve. They say to pinch it of. Which one of 3 lines? When? Also been told to ignore wastegate control lines. I'm guessing this is why I'm doing.

Am I seeing if the n249 is my boost leak?

Also I hear air by passenger cam tensioner and either under intake manifold by driver diverter. Now the leak by DV. I don't know what's going on. I have checked anything I know it could be. Re torqued intake manifold bolts same.

My tune is NVR Stage 2++ told to be 20-21psi hold taper to 15psi. Taper seems off. My logs show about 18-19 maybe and holds 15psi like it should.

Also I just got my ebay SMIC, 3" Tiptronic Downpipes from XSpower, Torque Converter Replaced and boost gauge. TCU upgraded. SAI removed. Block off plates installed and air hoses are blocked off. Also no rear o2.

My car has no CEL at all. I have removed everything from the ecu file I custom make out of the NVR Stage 2++

Boost Gauge is from Ebay, looks like a digital (with sending unit) APR style replica which maxs -15 to 30psi and a 21psi warning light...

Now at idle cold I get -8 to -9. On deceleration in 2nd gear max -11

Here is Measuring Blocks 032, 015 and 016 SCREEN SHOT

Alittle about my car and setup

I run BKR7E's at .028, stock airbox with pipercross filter and forged (none leaking) DV.

Any ideas or info someone please. I can post my last log. Also DazDlinger has pointed out in my logs I have a boost leak and a not so good tune with timing pull at 4k or so. Anyone. Help???
All I have is a husky 2 gallon 110psi max air compressor with regulator.

Please let me know whats up with how to properly test the system, and what the pdf about blocking off the N249 hose is all about and which ones.