Gaz20VT

Active Member
Aug 5, 2011
122
15
Hi all,

Time to ask for the help of the collective wisdom of SCN once more! I've spent hours searching but not found an answer.

I've had my virtually standard 2003 LCR for a few weeks now, and have noticed an increasing hiss noise when on light throttle, which sounds like a metallic air filling noise.

The car runs smoothly with no codes logged but I'm not sure it feels like 210bhp.

I've done a boost leak test by removing and blocking off the turbo outlet pipe, and the throttle body pipe, and pressurising the system through the N75 pipe into the charge pipe, and didn't find anything major - the diverter valve hose was creeping a bit but tightening the clamp solved it.

During the boost leak test to approx. 10psi, the recirc valve was lifting and venting pressure quite early, but then I wasn't applying pressure to the control side of the valve through the pipe nipple.

The car has a 2014-dated 710P valve fitted. The N249 is fitted, and the one-way valve works properly. The resistance of the N249 is within spec'.

Are these cars generally noisy on boost, or have I got a leak somewhere?
 
OK thanks Andy, so does anyone have a recommendation of where to get a smoke test done in Essex (Basildon area)? Sounds like I have a leak, then....
 
So to follow this up, I replaced the DV, and the whoosh/hiss noise on boost has reduced, and the fuel economy has increased slightly, but I still have what I think is excessive hiss on part throttle, a bit like Darth Vader is under the bonnet. It sounds like a "filling" noise, rather than a hole in something.

I can't find any leaks, using the DIY boost leak tester, anyone got any suggestions of things to check next?

Is this just normal noise from the steel LCR charge air pipe?
 
probably a boost leak somewhere, follow all your intercooler pipes around and see if you can find a split in a pipe.

if you have one of those Vape thingys you can blow smoke into your TiP and see if any appears elsewhere, id say take the Maf off 1st tho, as to not contaminate it with vape oil.