18 psi too much

[wv-t]

Had my car at the renowned garage in central North Carolina, and they did everything they could to turn my boost down but couldn't get it below 18 psi. The adustable puck under the turbo is turned all the way to the end. And TT reburned my chip to lower the boost, too. But I am still getting too much detonation on my Scanmaster using 93 octane. My question is do I buy a new adjustable wastegate actuator, or is it possible to replace the wastegate itself? I never see just a wastegate for sale. To tell you the truth I have only had my turbo shield off one time and that was five years ago.

Thanks TB community in advance for any advice.

 

[blacknight80]

Do you have an adjustable boost controller?

 

[deezdad]

What did the renowned shop recommend?

 

[turbojd]

You might have a Heavy duty wastegate actuator on there , which will allow higher boost levels then the stock wastegate actuator.

 

[zapp240]

What did the renowned shop recommend?

^^^^^^

yes, what did they suggest?

Also, presuming everything is stock, as per your sig, what are you reading your boost with? i hope not the factory boost gauge. they are notoriously inaccurate. if you pull the actuator rod off altogether, do you build boost? you shouldn't. if you are the puck may be hung up.

 

[Pronto]

Add alky and enjoy the 18 psi.

 

[1986 Buick GX1]

To add to what others have mentioned,

Disconnect wastegate rod to check puck and lever movement.

Disconnect boost hose from wastegate actuator, apply pressure or vacuum to make sure the wastegate actuator diaphragm is intact.

It might be possible the previous owner put an HD actuator on it (18- 30 psi).

Has the boost always been that high?
What changed from when the boost was "normal"?

 

[pmesfun]

You can drill out the restrictor in the Y connector. I was able to get boost in the 15s on a HD actuator.

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[rag231]

what turbo are you running?

 

[ITSAV6]

How much KR are you getting? Was timing pulled with the chip adjustments? Instead of ruining the Y straight out pull the hoe off the wastegate solenoid and plug the line and see where the boost goes to. If it still goes to 18 pull the Y out and take note where the orfice is and hook the orfice toward the solenoid line so there's no restriction to the wastegate actuator.

 

[Steveb87Gn]

Not an expert but i believe the Y vac connector can be reversed, causing high boost. Think i read that somewhere.

 

[pmesfun]

That wouldn't change anything, restrictor would be the wastegate side, no difference

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[Steveb87Gn]

Gotcha

 

[turbo89]

That wouldn't change anything, restrictor would be the wastegate side, no difference

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not true .. there would be a difference of inverting the side that feeds the gate

 

[pmesfun]

Ok so you would get higher boost?

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[turbo89]

Ok so you would get higher boost?

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opposite would lower

 

[1986 Buick GX1]

opposite would lower

^^^ this. The orifice slows down the boost to whatever it goes to.
When the orifice is toward the actuator the actuator reacts slower and the engine sees more boost.
When the orifice is toward the solenoid the actuator reacts quicker so the engine sees less boost.

I think I have that right.

 

[pmesfun]

Makes sense. I just drilled mine out since I have an adjustable wastegate. With it in stock configuration I couldn't get boost under 31 psi.[emoji1]

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[turbo89]

Makes sense. I just drilled mine out since I have an adjustable wastegate. With it in stock configuration I couldn't get boost under 31 psi.[emoji1]

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surprised it didn't unload the head gaskets

 

[wv-t]

Thanks everyone. Renowned shop owner RC and Xavier and Sydwinder told me it was 18 on their $2500 boost gauge. I know the stock gauge is for laughs. Shop also told me to have TT reburn my chip, which he was nice enough to do. Shop adjusted puck all the way and 18 was low as it would go. Still getting knock up to 4 or 5 unless I use Sunoco 260, which is expensive. Don't really want alky. So I might be interested in drilling that wye connector. But where to drill the hole and what diameter hole? Is that my best option? I want it done right.