Detonation=death. It always seems that turbo mopars can run 800+ hp on a stock block with zero issues but N/A they get pounded to death. I'm no expert and I haven't stayed at a Holiday Inn Express in ages, but I think this is because a turbo motor only runs 20 odd deg of timing for one and they don't as a rule spin the wee out of it for two. My money is on the timing.

I have a friend that does some pretty cool R+D for the Big 3 and he had pressure transducers installed in the combustion chamber of an EFI'd Brand X engine. You would be astounded at how much detonation goes on that you can't "hear" but with this technology you can "see" it as pressure spikes. With the engine on the dyno, you could add or subtract timing on the fly and it would start to show up several degrees retarded from "stock". It was considered acceptable in a stock engine because it didn't adversely affect reliability but now with increased emissions restrictions, any uncontrolled combustion is a problem.

From a performance standpoint, when you add more displacement along with compression that pressure spike increases exponentially. You still don't hear it and it isn't enough to show up on your plugs either but it is hammering your bottom end to death just the same.

Kevin