I'm not quite sure what your saying here but basically if you use a fuel without octane enhancers it ignites faster.The faster it ignites, the farther from top dead center it happens. At some point you're trying to drive the piston down while it's still coming up. That's not good. Adding higher compression or higher intake temps as with a turbo contributes to faster ignition. In that case you need to tone down the fuel with octane enhancers. Newer engine management systems like obII will compensate and retard spark but a turbo DeLorean will have problems with low octane fuel. Older cars designed with leaded gas in mind relied on the lead to lubricate the valves. Running them on unleaded for any length of time requires hardened valve seats or there will be eventual problems. The DeLorean is too new to have that problem. I may have mis-understood what you said here but I think your wrong in saying the only consequence is poor performance. You absolutely can damage an engine running too low an octane and an old vehicle without hardened valve seats will have problems before long if run on a diet of unleaded fuel. Bruce Benson >Gasoline only enters the engine >through the intake and valves (or FI system), sits on the >piston until >it explodes and then is gone; higher density (higher >octane) the >better performance as well as fuel economy youâ?Tll >have-no damage >either way higher or lower. If you have a poorly built or >designed >engine that's going to start knocking anyway, >manufactures will tell >you to use higher octane only- to prolong the inevitable >knock >otherwise, they will tell you to use higher octane so >youâ?Tll get the >performance (especially on turbo engines). Now if you >were to run >leaded fuel in an unleaded car then you'll have valve seat >problems, >if you run unleaded in a leaded car-you'll just have noisy >valves, no >damage. Also- Higher octane DOES clean some of >your engine-it is a >proven fact that the added detergents clean & keep >clean parts of the >engine. -----Dani B. #5003 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/