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Turbosmart Iwg75 & Over Boosting


Serangan
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  • Member For: 7y 9m 6d
  • Gender: Male
  • Location: Central Coast NSW
Hi Guys, I need of a bit of help here.

First up, car is tune for this actuator.

Actuator is a Turbo Smart IWG75 with a 12 pound spring.

Was running at 15 psi of boost for a few months, then it's started boost cutting at 20+ psi. In an attempt to find out what is wrong, I tried bypassing the stock electronic boost controller and expected to see roughly 12psi of boost but I didn't, it kept boosting till the gauge hit 20psi and then the ecu cut in and went into a limp mode.

Skipping forward. Today I took the turbo out to see what if the waste gate actuator is at fault.

Turns out I can't move it by hand, not sure if this is normal or not?

When I connect a hand pump to it, it moves.

Following this I connected it to a bike pump and set the pressure to 5psi, actuator moved.

Tried again at 12psi moved further but wasn't fully extended.

Kept upping the pressure up by 2psi until it reached the max extent, turned out to max out at 22psi.

Is this normal? Shouldn't it be fully extended by 12psi?

Thanks



A search led me here, good old grave dig.
I've tested my 7psi spring as you did with your 12psi Spring.
I have 1.5 turns of preload which is about the 2mm.
When I pump air into the actuator the rod doesn't start moving till 7psi then isn't fully extended till 14psi.
Is the rated spring meant to be the end psi result or is it meant to be the beginning of when the flap starts to open ?
Trying to fix my overboosting issue on BA. Hence landing here via search.8f5d5b90ebb98ffc10e31aacab0066e2.jpg
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  • ...JD TUNING ADELAIDE...
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  • Member For: 14y 3m 24d
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Spring rated pressure is "cracking" pressure only, not full extend pressure 

 

the Turbosmart IWG is a tricky beast on the XR turbo and ALOT of tuners dislike them as they can be a bitch 

 

I had good success using and tuning them but I had to tweak my installation methods to get desired outcomes on customer cars 

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  • Member For: 7y 9m 6d
  • Gender: Male
  • Location: Central Coast NSW

Hey thanks for clearing up the "cracking" pressure.
If the 7psi Spring had the flap fully opened at 14psi would it mean if I fitted the 5psi Spring the flap would be full open at 10psi ? I'm trying to get this boost down to a stable level. Car came with 4-5" dump pipe into what looks like a very well made 3.5" exhaust. Standard port wastegate still.

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  • ...JD TUNING ADELAIDE...
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  • Member For: 14y 3m 24d
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Well that's your issue mate, port size is to small you need the 38mm port and flap job done and while you're at it fit a genuine 8psi Garrett actuator !!

Edited by JETURBO
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  • Member For: 7y 9m 6d
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  • Location: Central Coast NSW

Looks like I best be doing the port job. Have been reading lots of posts on here about that.
Being I already have the iwg75 , wouldn't the 5psi Spring be ok to use with the ported housing? Just thinking of way not to have to buy another actuator.

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Rull of thumb on internal wastegates is to not go higher than double the spring pressure. 

 

So 5psi - max should be 10

10 - max would be 20psi

And so on....

 

Ofcourse that doesnt mean you cant and nearly everyone does but that's what garrett etc recommend.

 

Are you sure you dont have the preload too tight?

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  • Member For: 7y 9m 6d
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  • Location: Central Coast NSW

I'm confident I have the preload correct. Made rod just neatly slip over the lever of the flap, then pulled the rod off and shortened rod by 1.5 turns. Flap cracks open at exactly 7psi too.
I'm not looking for big power. Just be happy with low boost that won't skyrocket when full throttle is given.
Looks like the port job as mentioned above is a must do thing to give me any hope of getting boost down.

 

Am thinking with the port job and fit the 5psi Spring I should have low stable boost.

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  • less WHY; more WOT
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  • Member For: 14y 5m 14d
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  • Location: Melbourne

If you can get the actuator set so that you don't run high boost, you don't need a port/flap job. Port/flap job is done to control boost better... but low boost (read: stock level plus only a small amount) can easily be controlled in comparison to the higher boost capability of the stock turbo.

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