Miatapower List Archive

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Mail From: (email redacted)

Convinced that the Miata cooling system can be improved upon, I've moded it=
=20
once again=E2=80=A6=20

History: Mod 1 - re-route heater outlet hose to radiator inlet - worked OK,=
=20
but took too long for engine to warm up.=20

Mod 2 - installed re-route hose before heater core regulated by a PermaCool=
=20
oil cooler thermostat plumbed as a three-way valve. Heater core outlet=20
plumbed to mix manifold (OEM routing). This worked OK in hot/warm weather,=
=20
but took way too long to warm up after weather turned cool (60* ambient).=
=20
Removed PermaCool valve.

Current Mod 3 - installed new bypass line from rear of motor to radiator=20
inlet. Installed Tee fitting to supply heater core. Installed normally clos=
ed=20
12v solenoid valve on heater bypass/re-route line. Operated valve with manu=
al=20
switch in cockpit. With valve closed (OEM coolant routing) temp "gauge" hit=
s=20
straight up (~160*F) in about 1 =C2=BD miles. Open valve and gauge drops ba=
ck to =C2=BD=20
way between "C" and straight up (~140*). Close valve and drive a couple mor=
e=20
miles, open valve again and gauge drops back about half as much. Drive 5=20
miles, open valve and gauge stays put.=20

I soon tired of manual operation of the bypass valve, so I installed an=20
electric cooling fan thermostat to operate the valve. I lashed the bulb to=
=20
the heater supply Tee fitting with safety wire. I also pit a light in=20
parallel with the valve placed in the cockpit so I could observe the=20
operation of the bypass valve.=20

Drove the car with valve closed, after five miles I set the thermostat to=
=20
open the valve, and it has been working great all week. I can't really=20
comment on any gains in overall cooling capacity, as I don't have the test=
=20
equipment, but I'm sure there is some gain without the continuous=20
re-circulation of the rear cooling loop. I am convinced that flowing coolan=
t=20
from the rear of the head into the radiator is bound to considerably improv=
e=20
the cooling of cylinders 3 & 4.

Jim in Tucson

This read-only message was archived from a public mail list.
Mail From: (email redacted)


> I'm still confused of your mods... I've tried to look at your diagrams, but
> since I have not really looked at how the oem cooling is routed I'm lost...
> do you have pictures of before and after ??
>
>

I'll try to get some pics, but for now this is what I have. This is a diagram
of OEM coolant flow.
<A HREF="members.aol.com/jimcbride/oem_routing.jpg">
members.aol.com/jimcbride/oem_routing.jpg</A>

And this is a diagram of my current flow.
<A HREF="members.aol.com/jimcbride/jim_routing.jpg">
members.aol.com/jimcbride/jim_routing.jpg</A>

Remember, these are diagrams of flow - not pictorials, or illustrations of
component layout, or anything else - just flow. Or, if you don't care much
for diagrams just use a flashlight to follow the flow of the hoses on the
motor itself. As long as you know that coolant is flowing out the front and
back of the head, the rest is pretty easy to follow.

Jim in Tucson