Originally posted by DemonSVT:
Please explain that statement in detail since it makes absolutely no sense considering today's technology and engine design. (Brad touched on this briefly already!)
Maybe if you are stuck in the 70's with low tech pushrod V8's and no engine managements system but otherwise it is very outdated and wasting a great deal of power potential.

10:1 engines running 87 octane are common place. 11:1 engines running 91 are common place.

Heck Brad even ran his ~11-11.2:1 hybrid on 87-89 octane fuel with no detonation problems and still making decent power.

You really need to jump forward several decades in your thinking or at least stop "recommending" others to jump back to that out dated thinking.



Just because you cannot audibly HEAR detonation with your ear doesn't mean it's not there. He can run whatever compression ratio he wants, but I know that 11 to 1 compression with 12.7 to A/F ratio and optimal timing will have a high tendency to pre-detonate (granted- a little less so since the heads are aluminum). If the car has an ECM with a knock sensor, this wont happen, but power will be compromised since ECM must retard the timing when it senses knocking. I also know that I got 140,000 miles out of my old 5.0 EFI Mustang with 9.8 to 1 before I sold it, and none of my friends could get even 50,000 miles out of their high compression engines that they were running on the street. Don't get me wrong, I believe EFI and engine management along with efficient engine design has gotten very good these days, but if it were safe to run higher compression in these new rigs, then the factory would surely make them high compression from the factory since high compression improves emissions, economy, and power all at the same time, all without burning extra gas. Think about WHY Ford doesn't make high compression come stock. Pure and simple, to make it compatible with 87-92 oct (depending on CR they set it at) so the engine will give good service life and make it through warrantee

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