What can cause only secondary to leak??
 

:scratch:

I have a boost leak only when secondary is supposed to kick-in. No issue on primary.
Pressure slowly drops when I floor, hearing the leak and when I release the throttle I can hear a nice big swoooosh.

The problem came up right after I played little hard but that's the purpose of this d**n car isn't it?

I'm not plugged to the pair of solenoids anymore as I have a pair of hallmanns manual bc, checked them of course.

I checked my ACC and rod is moving when starting the car and shuting it down.

CRV seems OK and even tested with the stock BOV instead. Replaced the hose.

Now I haven't checked thoroughly the connection between ypipe and secondary but it doesn't seem to be loose...

Any idea ???

If you are getting full boost on the primary, you probably don't have a leak. I would start with replacing all the check valves with new viton ones.

The only place that comes to mind where boost can leak during parallel operation compared to primary is the CRV.

Hi guys thanks for the thoughts!

All my check valves have been replaced by vitton ones and hose job done during a recent rebuild.
The only vacuum hoses not replaced were the very ones that connect to the ACV and CRV, I need to replace those as they might be too loose.

Autosportracetech is a gold mine, I've already been through extensively...

I am now considering going non sequential to simplify all this mess!

Which leads to another question: do I need to remap going non seq? I have a Knightsport 4beat ECU that I can't remap...

Adam, the point is that I can hear a leak noise and a swooosh when I release the throttle

the swoosh sound is your stock blow of valve. normal operation

:pfanndina

Thanks for that brilliant comment :icon_tup:

This was the giveaway clue that you don't have a boost problem at all. The rest of us missed that point.

Yeah i assume the noise description is mistaken. I meant the kind of weird noise you hear when their is a leak that make a seal vibrating for instance

The point is:

If you can achieve full boost on the primary, that means you don't have a boost leak. You have a problem with actuating the secondary turbo.

There are several things that can cause this. Bad (or installed backwards) check valves frequently cause this problem. The swoosh upon throttle release is normal.

I've had the same problem with my FD.

I'm currently stripping the engine to the block to do many maintenance things and also to install my solenoid rack from aezknight. I've found the 2 following issues:

Found out that the preivous owner superglued a broken nipple from the pressure tank back on it and it seems to broke of under boost and that the flapper-door in the manifold had the C-clip missing, therefore the actuator rod was hanging around...