what can cause boost to spike?

[blackgn231]

I blew my head gaskets and noticed my boost would jump up to the 20's but it was set to 18 it would come back down to 18 but am worried this may have caused the blown HG's. What can cause this? I have a adjustable arm on the waste-gate, Would a leak in one of the hoses do it? Did replace the boost control sensor so just not sure anyone ?

 

[TurboBob]

what kind of boost controller and wastegate?

 

[blackgn231]

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