Boost Creep issues

[5280GN]

I installed a new Gbody parts downpipe and now I'm having trouble turning the boost down. I extended the wastegate arm pretty far and am still having the same issue. It pulls to 20psi, flutters and then goes to 23-24psi. Should I just port the wastegate hole to 1" and see if that solves the problem? thanks.

 

[earlbrown]

Yes.

 

[TurboBuRick]

External gate?

 

[5280GN]

Internal wastegate

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[ikle]

You have to remember the bigger the waste gate hole the more spring pressure needed to control boost. I ported mine to .950 and radius the inner part of the hole towards the header and it seems to control the boost rather well. I believe if you guide the exhaust gases towards the waste gate hole the less porting needed to control boost. If look inside the stock casting of the exhaust housing the exhaust gases have to make a pretty abrupt turn in order to exist the waste gate hole. I could be wrong but that is what I do and it's been working for me so far. Hope this helps, Kyle.

 

[5280GN]

Thanks for the reply,Kyle. I ported the turbo yesterday to just under an inch. The most room was toward the firewall but I also chamfered the hole and allowed a smoother flow for the exhaust gas. Worked great and controlled my boost steadily at the track today.