boost pressure issue, more then 1,3bar are not achievable

[Zenki]

Did you try adjust to more spring load on the HKS actuator ?

=> The setting at the boost controller where at the max. full set and gain
The way you adjust the set and the gain to the max, it is almost leak away all the pressure to the actuator,
if you tried disconnecting actuator vacuum hose still cannot get more boost than 1.3 bar, it is either actuator spring not strong enough or you have too much exhause pressure inside the exhause housing.

Hi, yes the HKS actuator was loaded as much as possible, 1,3 bar max. peak boost

[unex]

remove actuator, close wg door with some wire tight or something, and run:
a. it will overboost.
b. you missed something, that mentioned earlier.
c. your turbo is dead.

where are no other choices

[louiswun]

hummm......did you check any external object inside intercooler pipe ?
like work glove ? one of my mate did left a working glove inside the hot side pipe and his car not willing to boost.

[Zenki]

I use a similar recirculated bov like this:



Today I got the idea to take it out, and guess what it was my problem

So at some boost it starts to open a little bit it is recirculated so the air stays in the system

Thanks for all your comments

[louiswun]

I use a similar recirculated bov like this:



Today I got the idea to take it out, and guess what it was my problem

So at some boost it starts to open a little bit it is recirculated so the air stays in the system

Thanks for all your comments

Which side in the photo, it will see pressure (except the vacuum hose) ?
And did you feed the pressure to the vacuum hose port while pressure testing ?

[Zenki]

I use a similar recirculated bov like this:


Today I got the idea to take it out, and guess what it was my problem

So at some boost it starts to open a little bit it is recirculated so the air stays in the system

Thanks for all your comments

Which side in the photo, it will see pressure (except the vacuum hose) ?
And did you feed the pressure to the vacuum hose port while pressure testing ?

[louiswun]

This photo show how I pressure test the BOV (or dump valve)
https://www.facebook.com/photo.php?fbid ... =960%2C540

The direction of the dump valve will seal better if you put it in reverse. Actually, the flow direction in your photo will not seal properly.
I did many pressure test on these dump valve, included the plastic one from Bosch,

viewtopic.php?f=12&t=2545
This is exactly how I describe the bosch DV to someone :
I have test many BOV, Blitz, HKS, Greddy, RB20/25 stock bov...etc, all piston facing to the pressure side and the piston opening movement same as air release direction,
most of them leaking, leaking from the adjustable screw, leaking from the piston sealing surface, or the mounting surface. especially when over 1.5 bar. Can't hold the pressure, testing was done on a both end sealed intercooler pipe at 1 to 2 bar fully submerged.
And yes, high pressure acting on the back of the piston, this is exactlly the same as plastic bosch dump valve on Audi and VW, and the boost pressure help sealing the piston, more boost pressure , more sealing force, and it still works fine to blow off at high boost.
And this is the only BOV that have zero bubble when testing under the water, ( a good genuine HKS SQV still have zero bubble in the water but it blow off when positive pressure is droping, still positive pressure but not vaccume, I have also see an old genuine HKS SQV leaking seriously on all small bolts surrounding the valve body)
You won't belief, a small plastic bosch dump valve can hold pressure tight at 2.5 bar, when high pressure acting on the back of the piston, but it still leak when high pressure acting on the front of the piston.

[louiswun]

Genuine HKS SQV Gen 1 leaking on the sealing face
https://www.facebook.com/video.php?v=10 ... 988&type=3

Genuine HKS SQV Gen 2 leaking everywhere
https://www.facebook.com/video.php?v=10 ... 988&type=3

Genuine HKS SQV Gen 2 not actually leaking, but not react fast enough to holding pressure when pressure spike
https://www.facebook.com/video.php?v=10 ... 988&type=3

This is not Bosch dump valve but same design
Install the dump valve the way pressure against the back, no leaking.
https://www.youtube.com/watch?v=SXZAKV8 ... BMkzyVy1CA

[Zenki]

@ louiswun

You have done many test, thanks for sharing it

I will test my bosch one reverse

[culater]

u changed turbine housing? did you match the turbine impeller to it? could be flowing around it seen it before.