[Diy_efi] More power from a blown head gasket

[Mike]

At 11:29 AM 12/20/02 -0500, you wrote:
>Mike wrote:
>>Thats where your raped ape got its extra power, from
>>water in the chambers - enough to perhaps increase CR
>>(effectively) and reduce pinging for the short period of
>>time,
>
>That did occur to me.  However, my spark plugs weren't 
>green from the coolant.  And I was spewing a lot of 
>coolant from the oerflow.  My coolant hoses were 
>definitely pressurized by the combustion.  I think that 
>the major flow was out of the combustion chamber, not 
>into.

Well, there are a heap of assumptions in that observation.
Was the coolant there long enough and onto the plug to make
it green and could it also have been burned off. Also on
a downstroke wouldnt some collant get into the chamber,
maybe not enough to make the plug green or be seen as
a disproportionate loss etc etc

>Also, since I was running 7% richer than normal and a 
>degree less timing than I normally do, I wouldn't have 
>been taking advantage of the water in the combustion 
>chamber.

Another set of assumptions, inthe chaotic conditions
of a gasket failure you may well have had all sorts
of stratified charge conditions with air/fuel in the
galleries on part of the ignition cycle and any other
quirky dynamics resulting from discontinuous operation.

>You need to advance timing, run more boost, or run leaner 
>to take advantage of water injection.  I was running less 
>boost, richer, and retarded timing.

mmmm, Another set of assumptions, based on disparate collections
of segments of other's experiences (inferred probably).
Adding a mist which cools
charge ahead of a flame front may have other benefits. I've seen
a couple of engines (Normally aspirated) which had water injection,
the chamber was remarkably clean - negligible carbon deposits -
whereas over the same period non WI had terrible deposits !

Who knows what other dynamics were occuring in that split second
before/during/after the gasket blew - I definitely noticed an
increase in oooompf when mine went between chambers 2 & 3 which
really surprised me - it too was naturally aspirated, puzzled me
ever since ~`:o

Theres a chap called Pete on the yahoo nissans13 that built his
own and took some trouble to select nozzles, AFM trigger, boost
trigger etc etc Worth looking up the archives on that group,

rgds

mike



>Oh, here is a jpg of the datalog.  I also have a CSV I can 
>share.
>
>http://autos.groups.yahoo.com/group/NewEngDSM/files/12_52_112datalog.jpg
>
>>Do you normally run a wet manifold ?
>
>I assume that you mean water injection?  I have run it in 
>the past.  But I wasn't impressed with the results that 
>the silly spearco kit gave me.  I'll probably build a DIY 
>kit sometime in the next year, though, if only to spray my 
>rather small 18" FMIC.
>
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