[DML] Re: delorean fuel

["stainlessilusion" <5n-@xxxxxxx>]

I'm just curious to know how it ignites faster to the extent that it
will ignite while the piston is still on its way up. If there is
preignition then the engine has overheated valve or plug problems. If
the engine is trying to ignite fuel while the piston is still on its
way up-the engine won't run at all or kickback. -----Dani B.

--- In dmcnews@xxxxxxxxxxxxxxx, "Bruce Benson" <delornut@xxxx> wrote:
> 
> 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








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