Boost spike when TCC kicks in at WOT

[BuickMike]

Like the title says, I get a boost spike when the TCC locks at WOT. I have boost set at 23psi and it jumps to 29-30 when the TCC locks. Within a couple seconds I start to get a little knock even though AFR is steady. Just too much boost for the timing. My setup is below, however I am running a Mease DP with a Turbonetics Racegate and a manual boost controller plumbed like in the pic below. What can I try to fix this? I have never ported the wastegate hole on the turbo, do I start there? Do I try a lighter spring? Maybe loosen the tention on the spring?

 

[BuickMike]

I guess I can start by removing the top port off of the wastegate and see where boost is at with spring pressure. I can always adjust it lower or put in a lower spring and see what happens. Maybe this will also help with my surging a little too.

 

[we4Mateo]

Locking the tc does that! I usually only pick up 2-3 psi though but my wastegate hole is ported. That may be the key for you too.

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[we4Mateo]

Oh, and don't trust afr when you see knock if sustained. It'll trick you.

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[BuickMike]

I will port it when I get a chance and see how it helps. I only got 1 .5 degree of knock, but obviously it is coming from too much timing at that level of boost. Not that I want to run 30psi LOL. I can handle 25psi in 3rd at 11.0:1 AFR and 19-20 timing no problem, so if I can set it to 22 and let it creep to 25 with the TCC locked I'll be fine with that.

 

[BuickMike]

So spring pressure was fine. Today I pulled the downpipe to ceramic coat it and noticed that the wastegate hole on the turbo was way off. I can open that bad boy up quite a bit on one side. On top of that, the hole on the turbo outlet is a bit small on the downpipe so I'll open that up while I'm at it.

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