rad and coolant

[Robert Harris]

Course if you use the available ceramic coatings for piston crowns, valves, 
ports and chambers, plus the manifolds, Dave Vizard claims about a 10 % 
increase in power and economy plus it has the effect of significantly cooling 
the intake charge and reducing the detonation - to the point he claims its 
possible to run an 11 to 1 street engine on 91 octane.  This is because much 
less heat makes it to the metal to be wasted in cooling.  This with a little 
filling of the blocks bottom would work wonders without complicating shitting 
on multiple cooling systems.  Just my obnoxious .02$ worth.

If the first ingredient ain't Habanero, then the rest don't matter.
Other Obsessions: Ferro-Equinary , 1972 "Killer Whale" Mustang
Currently Interred in the Peoples Democratic Republic of California - Stalag 
Montclair
Puck da guns - ban Politicians!!!!!
Robert Harris <bob at bobthecomputerguy.com>


-----Original Message-----
From:	Johnny [SMTP:johnny at johnny-enterprises.com]
Sent:	Friday, October 17, 1997 6:44 PM
To:	diy_efi at coulomb.eng.ohio-state.edu
Subject:	Re: rad and coolant

Tom Cloud wrote:
>
> >The 195 thermostat does increase the rad efficiency. The engine is going
> >to be making the same waste heat for a given power output regardless of
> >the thermostat. With the higher thermostat, you are going to be able to
> >dump more heat at the radiator. I have also found that the engine runs
> >better and makes more poop with the higher thermostat. Probably cleaner
> >too.
> >
> >-j-
>
> interesting, both engine emulation software packages I have show
> more hp & torque with lower coolant temps -- and certainly with
> unheated manifolds (talking carb manifolds, obviously)

Ya, you gotta forget about heating the intake, that's a no-no for sure.
But other than that, the hotter the better... to a point. My drag cars
all ran filled blocks with water only in the heads. Water passages in
the block were full of metalized epoxy. The combustion gasses don't cool
as much as the piston retreats down the bore that way. Makes for more
combustion pressure and more sustained combustion pressure. On street
cars you can get away with filling the block about half way up. Reverse
cooling has a similar effect in that the hottest water is at the bottom
of the cylinders.

Of course, if you take this too far, you will get preignition/detonation
from the combustion chamber being so hot. But up to that point, the
hotter the better. Generally speaking, aluminum heads can usually run
more compression and more water temp with the same fuel and ignition
advance as compared to iron heads with all else being the same (which of
course is impossible ;). Because the aluminum heads transfer combustion
heat to the water faster, you can take more advantage of higher water
temps, which allow the bottom of the cylinders (the power robbing end)
to maintain a higher temp, which robs less gas expansion from the
combustion that way. Add to this reverse flow cooling, and all of a
sudden you can use 10:1 compression on pump gas and getting more power
out of it than you would otherwise. Too bad reverse cooling is such a
pain.

To get this back on the EFI track, I suppose that for a few more dollars
you could plumb the heads seperate from the block, cut the flow between
the two completely off, and the have the ECU monitor cooling temp in
various places on the engine and regulate valves in the cooling system
to keep the heads cooler and the basement hotter. Or I should say, keep
the heads whatever temp they can be without contributing to detonation,
and then keep the block a certain percentage hotter than that, whatever
you can get without having the too much warping or crackage or stress
between the two. Use 2 different thermostats maybe.

Oh hell, the Devcon fill is so much easier and cheaper. ;)

-j- (get one on a real dyno and try it for yourself ;)