Detonation in a turbo is a serious problem. It takes only a few seconds to do major damage. I would do a leakdown to see if the engine is ok.
Higher octane fuel can help to prevent some detonation, bnut not all. If you have crazy high temps with bad timing, even 110 leaded will detonate.
GTC Motorsports, PCA Club Racing National Scrutineer
'92 Euro Cup #96ZNS498058 (PCA GTC1 #19)
Past '91 C2 Turbo (PCA D Class #38), '04 Cayenne S, '74 914-6 3.2 (236rwhp), '02 986S M030, '71 914-4 2.1, '76 914-4 2.0