Survey thermostat, no thermostat, gutted , Restrictor?

[BrianB]

Just wondering what choices members have made and its effect on cooling temps. Assuming a larger radiator has been installed,underdrive pulleys, housing bypass plugged.
BrianB

[mazdagt3]

full thermostat... 180 degrees

[Karl Bocchieri]

I also use a stock thermostat with a non pluged housing. Never had a problem, just check it in in the kitchen on the stove. They don't always open at the listed temp. The Mazda factory units seem to work much better than the auto parts store replacements.
If you have the right radiator, and underdrive pulleys, you shoulden't have a problem.

[rlekun]

I use no thermostat, plugged bypass and stock radiator. Honestly the only reason I did this was because the old Racing Beat manual said to. Also Racing Beat's double pulley. Has worked great for 8 years. Since the stock gauge always showed it was running cool, I've never put a temp gauge on it with numbers so I can't give you an op temp.

[eprodrx7]

Brian,
I've gone both ways with the therm. gutted and not. With the gutted one I had a problem with over coolling and the car would get below the 172* mark and run over rich. below I think 160 it starts to foul the plugs. So I put a resistor in place of the thermo switch for the EFI. this worked but and the car never went over rich but it also ran cold and that can be just as bad as running hot. So now I was running with tape all over the grille. Solution was to go back to the stock thermostat. I tworks great.

[BrianB]

John W.?
I plugged the bypass in my housing, I believe the stock thermostst has a foot on it that closes the bypass when its full open and would foul with the plug I've got in there. Maybe I can find a thermostat without one. When I autocross the car the temps go from 180 to 200 on the average run. my electric fan has trouble bringing it back down so I resort to turnig the car off, letting the fan cool whats in the radiator, then turning the car back on to drop the temp.I wonder if a thermostat would restrict the water flow enough at idle to actually improve the cooling in this case. I know that no thermostat can cause overheating due to a too rapid a water flow to effect cooling. At Lime Rock in october (a cool day) the temps read about 170,so maybe the thermostat is the way to go!
Thanks,
B

[mazdagt3]

our old ita car we used a chevy 350 180 degree thermostat with the plugged water pump. worked fine.

one of the most crucial things to remember is to force as much air through the radiator. an air dam with all areas around the radiator plugged off so no air can escape around it.

[BrianB]

I think for the autocross scenario, shrouding the fan to the radiator will make the electric fan more efficient at idle. The cross-sectional area of the openings in the radiator would probably be less than the shroud opening area and not be restrictive on the track where high speed airflow does the cooling.
I'll try the 350 thermostat.
Thanks to everyone,
BrianB

[ddewhurst]

A brief note relative to the speed of air going through your radiator. Think about what the forces of air at 120 miles per hour would do to those thin little fins between the tubes.

Wind tunnel tests have shown that air speed through the radiator is at approx 40 miles per hour max no matter what the speed of the car is.

Have Fun

David

ya but my carb intake is in my rad intake, think of the air pressure at 120 mph

[ddewhurst]

Daryl, where do you find all the extra time for these boards after building three cars simo ?

"ya but my carb intake is in my rad intake, think of the air pressure at 120 mph"

Did ya ask your carb guy about this ?

Have Fun

David