Dropping boost..

[paradox616]

hey, so ive just rebuilt my 7m, its going good, feeling smooth and its responsive

my mods are,

BC valve springs
3" cat back exhaust
FMIC with hard pipes
electronic closed loop boost controller
engine balanced

anyway my boost drops with higher rpm under WOT, the stock dump elbow looks restrictive and im using a stock cat as well

planning to ditch the stock dump and get a custom one made up.

watch the blue digital gauge at the bottom, my missus was filming so she kinda took it off frame after a few seconds but you can cleary see it drop to 5psi. round 5500rpm

with the boost controller disconnected boost does not spike, hits 5.8 smack on and sits there, not sure if it drops round 5000rpm

im really just seeking confirmation that the exhaust is causing this drop in boost, as it did the same thing with 2 diffrent MBC's.

no fuel smell, no black clouds out the exhaust, does not feel like its running rich or like there is a boost leak. absolutely no error codes either.

http://s29.photobucket.com/albums/c295/paradox616/?action=view&current=run01.flv

 

[jdub]

Weak wastegate actuator spring.

 

[paradox616]

Weak wastegate actuator spring.

would testing it with a air compressor really do me any good? as i know it opens but i kinda need it to stay open..

id really like to know where to get a replacement actuator that wont cost me a arm and a leg.

 

[enjoi.this]

Testing with a compressor and regulator turned down to 4 psi then work your way up to see when it opens. and want you mean is you want the wastegate to stay closed.

 

[WhtMa71]

Pretty common..You could try shimming the WG with a couple of washers and see if it helps.

 

[paradox616]

Pretty common..You could try shimming the WG with a couple of washers and see if it helps.

are any washers supposed to be there as per stock?

shimming it would give it a little more tension, sounds like something to try, i plan on fitting a GT35R but we all know they're not cheap and i need to get a new ecu fitted before i think about putting a turbo that big on. ill try a pressure test as well.

Testing with a compressor and regulator turned down to 4 psi then work your way up to see when it opens. and want you mean is you want the wastegate to stay closed.

yeah i mean i want it to stay closed, typo

 

[paradox616]

quick question, are any washers supposed to separate the waste gate and the actuator plate?

i found 1 washer in there maybe the previous owner did it?

 

[Angry7M]

quick question, are any washers supposed to separate the waste gate and the actuator plate?

i found 1 washer in there maybe the previous owner did it?

The washers should seperate the wastegate actuator plate from the turbo housing.

Make sure you have the same amount of washers on both sides (stating the obvious).

 

[paradox616]

The washers should seperate the wastegate actuator plate from the turbo housing.

Make sure you have the same amount of washers on both sides (stating the obvious).

i thought i might put 8 washers 1 side and 4 the other...

my question was are there supposed to be any from factory or direct contact from the actuator plate to the turbo compressor housing?, i know how to shim the waste gate as well.

 

[WhtMa71]

None come there stock.

 

[paradox616]

they're was no preload on the actuator and had around 2-3mm of play in it, i assume this is not normal, i used 3x 1mm washers to preload up the actuator, hopefully this will give me a positive result, i'm going to test run it soon.

 

[paradox616]

they're was no preload on the actuator and had around 2-3mm of play in it, i assume this is not normal, i used 3x 1mm washers to preload up the actuator, hopefully this will give me a positive result, i'm going to test run it soon.

holds more boost until round 5000rpm where it drops back to 5.8psi goes a HELL of alot harder too. ill fit a new dump pipe and check the result.. and hopefully get it dyno tuned with a new ecu as well soon