Frederic's radiator cooled intercooler.

[d houlton x0710]

Frederic wrote:
> 
> It was a leftover from my twin-turbo Buick V6 project.  Anyway, inside
> the plenum is a 2" thick transmission or oil cooler, that I sized the
> inside dimensions of my plenum around, as once welded, I wanted an
> air-tight fit.  All pressurized air from the turbos will blast into the
> upper plenum, go through the intercooler, then into the lower plenum,
>...
> 
> What the intercooler will be attached to hasn't been decided yet.  I did
> some preliminary experiments on a Buick V6 engine using radiator coolant
> as the "intercooling fluid", and while I didn't document this even
> remotely well, I will state that this actually works.  Kudo's to Bruce
> "Grumpy" Plecan who drilled the idea into my head.  The idea is to tap
> the radiator fluid pre-engine post-radiator since the coolant is about
> 100-110 degrees at this point, and the fresh air post-turbo is closer to
> 200 degrees.  While not the absolute best design, Bruce was right in
> saying that the intercooler temperature would be more consistant,
> therefore providing consistant performance, and is MUCH easier to plumb
> than a Peterson coolant tank, a box of ice, a 12V marine sump pump, or
> any other creative solution you come up with.
> 


Frederic,

It never ceases to amaze me that you seem to have always tried something
that I've wondered about or wanted to do.  Can you expand a little more on
your experiments on intercooling using radiator fluid?

I am in desperate need of an intercooler.  An air/air unit won't work for
me.  An air/freon unit (using a A/C evaporator) sounds quite slick, but I
don't know enough about A/C systems yet to know how well this would work.
An air/water unit is the best solution, but has the complexity of a 2nd heat
exchanger, pump, coolant tank, etc.  I had thought (briefly) about using
radiator fluid instead but dismissed it without much thought (afterall, 
radiator fluid is hot right?).

I'm not necessarilly looking for hp gains here, I just want to remove heat
to avoid detonation.  I have a turbo'd 4 cyl that peaks about 9 psi.  On 87
octane though, I get detonation about 6 psi.  I'd prefer not to pay the 
ransome, er, cost that is, of premium so I'm using water injection right
now.  Even that's marginal though and I rarely allow it to go over 6 or 7
psi but it's hard to do and I can never floor it.

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
return would have to be at the low pressure area at the suction of the
water pump, which is basically the bottom of the radiator.  The only way I
can see this working is if the source of the IC water was the bottom of the
radiator tank opposite the lower rad hose, and the outlet of the IC dumped
back into the lower radiator hose, preferably as close to the water pump
as possible.  Even then though, the pressure difference between the inlet
and outlet water for the IC would seem to be pretty low to have significant
flow.  I would have thought you'd need a booster pump as well to feed the
IC.  Is this not the case?

What about the return water from the IC?  This is now going to be hot 
again, and it's dumping right into the water pump inlet without first being 
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?

And finally, if all this does work well, then couldn't you get similar 
results as a seperate air/water system by running the inlet water for the
IC through a secondary exchanger like a tranny or oil cooler before reaching
the IC?  Since it's a relatively small amount of water, this could 
substantially knock down the 100 - 110 water temp before reaching the IC.
More complex? yes.  But still much less so than a dedicated water circuit.
No pump and no resevoir tank.

Oh, and finally.  Assume you're cruising a long stretch of freeway where
you're not hardly ever in boost.  The intake temp will likely be much cooler
than the 100 - 110 degree radiator outlet temp so your intercooler becomes
an interheater.  Do you just plan on living with this or do you use some
kind of solenoid valve or something to block flow to the IC unless you're
under boost?

thanks

--Dan
houlster at inficad.com
http://www.inficad.com/~houlster/amigo.htm