RE: Re: Re: Re: Re: Superchips Dyno Results

From: Bob Mankin (bob@coralfarms.com)
Date: Thu May 29 2003 - 11:14:45 EDT


> -----Original Message-----
> From: owner-dakota-truck@bent.twistedbits.net
> [mailto:owner-dakota-truck@bent.twistedbits.net]On Behalf Of
> scsilverdak
> Sent: Thursday, May 29, 2003 7:14 AM
> To: dakota-truck@dakota-truck.net
> Subject: DML: Re: Re: Re: Re: Superchips Dyno Results
>
>
> AND as far as the octane rating debate,
> most chips and power adding devices such as Superchargers, and Nitrous
> require a slightly higher octane rating of fuel to slow the
> rate of fuel
> burn to ward off detonation.........pinging is mild detonation or
> pre-ignition of the fuel before it's supposed to.
>
> Ron-
>

FYI, pre-ignition and detonation are two different things. Detonation is an
uncontrolled burn of the air/fuel mix that is timed correctly but burns
improperly, usually with an "explosion" at some point in the burn event
which is the ping or knock you hear.

Pre-ignition, OTOH, is burning of the air/fuel before it is supposed to burn
or earlier in the ignition cycle. This event is not always audible.
Detonation is, generally speaking, associated with high cylinder pressures
and pre-ignition is generally associated with high cylinder temperatures and
not so much pressure.

Detonation will pop a head gasket. Pre-ignition can lead to extremely high
cylinder temps and just melt stuff. Sometimes when you see someone who has
knock the ring lands off a piston, what they probably had was detonation,
which led to pre-ignition, which overheated the piston, thereby causing it
to break up. It's common for folks to lump this all in the "detonation"
catagory.

Of the two events you can see which is more destructive.

Bob



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