Can I run a lower temp Tstat than stock?

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Arrowhead
MegaSquirt Newbie
Posts: 9
Joined: Sun Dec 25, 2005 7:30 am
Location: NY

Can I run a lower temp Tstat than stock?

Post by Arrowhead »

The stock one runs at 205 F. To my recollection, the stats are high for better emissions. It shouldn't be a problem to put in a lower one if I'm controlling the fuel and spark now anyway, right?
Jim
Helpful Squirter
Posts: 111
Joined: Sun Aug 28, 2005 8:50 am
Location: Crystal River , Fla

Post by Jim »

It may not be your thermostat , most T'stats are around 195 ,

Do you have Electric Cooling Fans ? ,
when do they turn on ? , there is usually a high and low speed also .

If you have an engine driven fan , does it have a Fluid Clutch on it ,
they are usually thermostatically controlled .
Also Fluid Clutches do wear out or leak .

If you don't move enough air through the radiator ,
changing the T'stat will do nothing .

Actually achieving a steady 160 degrees usually requires a bigger radiator .

The only advantage to running cooler temps is that you can advance your
Ignition Timing and gain 2 or 3% more power .

If you don't advance your Timing the engine will actually LOSE POWER ,
and require richer mixtures .

If you put in a 160 degree T'stat and advance your Timing ,
and the Radiator and/or cooling fans can't keep up ,
then your engine is going to get hotter than the T'stat rating ,
just like it does right now .
So now you have the Ignition over advanced for a 205 temp ,
and the engine Detonates .

So now you have a car that requires Premium Gas and
gets bad gas mileage and makes 5 more horsepower (when it's cool) .

The engine will actually run more efficiently at 195 to 200 degrees .

I run mine with a 195 degree T'stat on purpose ,
but I also have a huge 3 core radiator and 2 electric fans ,
so it never gets above 200 degrees under the worst conditions .

You also need to look at air flow management into and out of your
radiator and engine compartment , nothing is going to get temps
down if you are recirculating hot air from the engine compartment
back into your radiator .

BTW , it makes your heater work much better .

...................Jim
tebriel
Helpful Squirter
Posts: 79
Joined: Tue May 18, 2004 6:32 am
Location: WI
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Post by tebriel »

I just trimmed the spring that in my tstat to make it run a little cooler. I'm not sure what our stock tstats are supposed to run at, but mine would hold it at half gauge, which isn't stock :) So I just trimmed it and hopefully it'll run cooler.
-teb
bluetrepidation
Experienced Squirter
Posts: 197
Joined: Sun Nov 13, 2005 8:24 pm
Location: Youngstown Ohio

Post by bluetrepidation »

Interesting read Jim.
1999 Saturn SC2 1.9L DOHC 4 cyl NA
MS II Blue Processor w/ 2.684 Beta Code
V3 PCB
MegaTune 2.25
Innovate LC1 WB O2 Sensor
OBD I Saturn Wasted Spark DIS
w/ Cooling Fan and IAC
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