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Detonation

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Hi.

I need a second opinion on this subject.

Had my my car on the dyno about 3 times and we were experiencing detonation every session. Engine in question is old school Audi 5 cylinder with Emtron KV8 ECU.

Wastegate spring was 2bar which was very difficult to control. knock was occurring at 20psi. Static compression ratio 10.2:1, piston has 6cc positive dome.

We tried the following fuels: 98 pump fuel with boostane, Power plus 108Ron(96MON), VP QM25(100MON). I spoke to the supplier of pistons and he said they don't have any issues with the pistons cause many customers are using them with 29 psi boost on pump fuel and some run E85 with no issues either. (US based) .The supplier also advised that the engine should not detonate with VP QM25.

My question thus is, are we experiencing false knock? What measures can i apply to eliminate the possibility of false knock?

On the other hand, how can we definitively prove that the engine does generate knock.

hope you guys can help.

Regards

Paxton

Bit of a long shot, but what spark plugs are you using - if they're stock try a set a couple of grades colder/harder, just to double check it isn't auto-ignition from a hot plug tip.

Hi Gord . Spark plugs are NGK BCPR7ES

How big was the turbo on the engine? Back pressure could be causing detonation big time...

Garrett GTX 42.

7 heat range seems pretty wild for 2 bar boost. I would go a couple of steps colder, probably worth trying a platimum or iridium in that heat range.

How are you currently detecting knock? If you are only relying on knock sensor through ECU then listen to engine using Detcans or Plex etc to confirm what you are seeing.

Also, when you retard ignition timing does it have any impact on knock?