Will speak very slowly... In a high compression engine, low octane mixture will explode on its own simply from heat & pressure. Even worse, is totally uncontrolled combustion (engine designers build pistons & heads to spread flame in particular pattern. Ever seen pistons with channels cast into them that must point towards front of engine? And no, I'm not talking about valve reliefs). Only two possibilities: reduce volatility of fuel by increasing octane (1960's American premium grade was 97 octane), or shoot spark sooner before mixture has a chance to explode on its own. This is pretty common knowledge among American racing crowd. Rather than screwing around with multi valves, turbo chargers, etc, we take the simple direct route: compress ever living mess out of mixture and pump full of octane to hold it until spark hits. Go to any American track -- 12:1 compression is the norm. And station outside the gate sells 100 plus octane fuel from a special pump. Again, you and Darren can play with my 11:1 460 FOR A SHORT TIME (don't want you ruining my valve train). I defy you to run it on 93 octane timed at 10 degrees. No fair cheating with anything else in the tank. BTW: running high octane fuel in a low compression engine is counter productive. Mixture will not burn enough, leaving behind carbon that ultimately hardens and becomes part of chambers. Undesireable because carbon glows red hot, totally altering combustion characteristics, and dieseling long after electricity removed from ignition. Bill Robertson #5939 (9.5:1 compression thank you very much) >--- In DMCForum@xxxxxxxxxxxxxxx, Martin Gutkowski <webmaster@xxxx> wrote: > > Content22207 wrote: > > >2) Advancing time moves spark closer to bottom of compression stroke > >-- cuts power (but does give longer & cleaner burn. > > > Did you read the link I sent? > > Knocking is corrected by running less advance. If knocking is caused by > the fuel igniting too soon during the compression stroke, why on earth > would you be able to correct this by lighting it up even sooner?!! This > is what you're suggesting. > > http://www.sdsefi.com/techcomb.htm > > Read it. > > This is my last word. If you want further conversation on this, you can > mail Darren, but he'd put Jim to shame in an insult contest.... > > Martin Yahoo! Groups Sponsor ADVERTISEMENT <http://rd.yahoo.com/M=194081.4074964.5287182.1261774/D=egroupweb/S=170512 6215:HM/A=1754016/R=0/SIG=11pv1u2ju/*http://www.ediets.com/start.cfm?code= 30529&media=atkins> click here <http://us.adserver.yahoo.com/l?M=194081.4074964.5287182.1261774/D=egroupm ail/S=:HM/A=1754016/rand=653411334> To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service <http://docs.yahoo.com/info/terms/> .
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