new turbo buggy, detonation and/or loud valves at wot?

[huelsdonk]

Hello, i have recently acquired a turbo charged 20??cc air cooled manx with bosch k-jetronic CIS fuel injection and a 009 distributor and it is pretty amazing. My last vw was a stock 66 type 3 fastback which i loved but it is long gone.
So i have this new buggy and it runs real well and the afr meter says its dialed in pretty well but it either is detonating or rattling the valves at wide open throttle at about 4 to 5000rpm and i need some input on how to figure out what it doing and how to solve it. Im not a dummy, i hope, i just havent ever had a sweet ass turbo VW to maintain. [/img]

[TinCanFab]

Do you have a boost gauge? What psi does it read? Is your fuel old and or premium grade? What is your timing advancing to under boost? (or maybe timing is locked and not advancing at all?). What is your fuel pressure under boost? A lot can cause detonation with a turbo engine....

When you pop the valve covers off, can you tell if you at least have dual valve springs? Valve float can be aggravated by intake boost pressure. Basically, as I understand it the valve can be held open with weak valve springs that can't overcome the force of intake air.

Can you slowly drive up to the high rpm's without generating full boost to determine whether its boost related, or happens all the time? With my draw through setup, I only saw boost under hard acceleration. Can you tell us what you know about the engine? Specs, compression, turbo etc?
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