Frederic's radiator cooled intercooler.

[Frederic Breitwieser]

> It never ceases to amaze me that you seem to have always tried something

I have friends who like to experiment, and are total "gearheads", whereas I am
one in name only, and I happen to like bizarre projects that are over my head :)

> your experiments on intercooling using radiator fluid?

Well, what Dr. Plecan suggested, since I'm building a stump puller, towing
vehicle, hauler, its much different than a mid-engine sports car (my other
really slow going project), therefore other considerations come into play
(Bruce, feel free to step in here and correct anything I quote you on <G>).  His
idea was to connect the radiator output (cooler coolant) to a "Y", and send most
of it off to the engine, and a smaller portion to the intercooled intake I made,
thus keeping an approximate intercooler temp (inside the manifold) at about
100-110 degrees.  This means your intake charge temperature will always be above
this temperature, unless you drive in the artic :)

The idea is to go for consistancy, rather than ultra-low intake charge temps.
The intake charge temp can be 200-300 degrees post turbo due to the compression,
and heat from the turbo housing (mostly compressing the air of course), so its
still a significant drop.  And if you have a decent cooling system in working
order, maintaining the 100-110 degree coolant temp leaving the radiator is not
that difficult to do... most cars do this all the time, which is why they have a
radiator fan that turns on and off, etc, etc, etc.

So from a tuning standpoint, once the engine warms up, air charge temperature is
more constant than with any other type if intercooler system, though maybe not
as low as one would think is ideal.  Bruce led me to believe (or I interpreted)
that the differential between the intake charge and the intercooler temp is very
important.  And trying it, I found Bruce's suggestion, or theory, is in fact a
good one.  I didn't test this with turbochargers, as I haven't fabricated
anything for them as of yet, however I did introduce 200 degree heated air into
the intake plenum and the intercooler did drop the temperature 50-60 degrees.
This is uncompressed air of course, i.e. no turbos.

I can't wait to see the results with turbos, as I imagine the drop might be
greater.  I don't understand fluid dynamics enough to really say for sure.  But
a constant post-turbo air temperature, or at least a smaller temp range, would
make tuning a turbocharged EFI motor easier.

> octane though, I get detonation about 6 psi.  I'd prefer not to pay the

One of the things you can do/try, worked for me on the Buick V6 motor, was to
ceramic coat the piston tops up to the first ring groove, as well as the
combustion chambers.  All you need is a toaster oven, "Techline" from summit
racing or equivilant, and you can coat your pistons.  The heads of course being
larger, require something bigger than a toaster oven.  Techline works very well,
and you can increase your c/r and/or your boost pressure with the product - it
keeps all the heat in the combustion chamber which during the exhaust stroke,
blows out.  Also, there is little chance of hot spots forming on pointed areas
or sharp angles inside the combustion chamber.  I also found that radiusing
things makes a difference as well.  Round evering that you can, and move the
pistons higher in the bore to compensate for the material you remove.  Of course
that is more dollars, to have custom pistons made, however for my Buick engine,
custom pistons were going to be purchased anyway.

> You say you sourced your IC water at the outlet of the radiator.  How did
> you hook up the return?  In order for water to flow through the IC, the

    <snip>

> back into the lower radiator hose, preferably as close to the water pump
> as possible.  Even then though, the pressure difference between the inlet

I tried using the heater core lines, but of course this is post engine, so it
would heat the intake air, and tapping the bottom radiator hose partially (two
"Y"' facing each other) resulted in no flow at all, because the plenum
intercooler is mounted at the top of the engine.  I didn't want to run the
entire coolant stream through the intercooler, because its a trans/oil cooler
that i brazed inside, so the piping for fluid flow is much less than the engine
can withstand.  The final version was a "Y" at both radiator inlet/outlet ports,
with a 120V pump on the cold side pumping up the hose to the intercooler, to a
peterson 3 gallon swirl tank, then back into the radiator directly via another
"Y".  I don't know if this is ideal or not, but it did work at least in a basic
sense.  The next step is to figure out how to remove the 120V pump, and use
either an externally mounted belt driven pump, or preferably, the water pump.
The 120V pump is acceptable for testing 'cuz the engine's not in the truck at
the moment, its on a stand.

> cooled.  Is it not hot enough, or not in quantity enough (since it's being
> mixed with cooled fluid from the radiator) for the engine to really notice?

I dunno :)  I went from the radiator through the system back to the radiator.

> More complex? yes.  But still much less so than a dedicated water circuit.
> No pump and no resevoir tank.

Fangling a seperate tank and resivoir tank is actually not that big of a deal.
Make or buy a metal box of approximately the size you figure out to be
appropriate, mount a sailboat sump pump (metal one) inside.  Its a bottom
feeding pump so it has one hose outlet, and that's it.  Attach that to your air
to water intercooler in front of your vehicle, then to the intake plenum
intercooler, then feed that into the top of the tank.  Think about it as a giant
fish tank filter.  And sailboat sump pumps are not that expensive.... 40-50
bucks and they run on 12V of course.

> kind of solenoid valve or something to block flow to the IC unless you're
> under boost?

If I keep this type of system, I plan to "just live with it", because this is
not a race vehicle, and the air temp consistancy is worth something in this
particular case.