160 degree thermostat

[Guest greimann]

I run a 160 thermo because I have about 10.5:1 compression and it helps control detonation. Cooler temperatures also are better for a denser air/ fuel mixture and hence, more power. I don't think you should worry about longevity issues with a 160.

 

If you think about it, any modification that adds power trades off a little longevity, but thermostat changes are a relatively minor issue.

[Guest dankinzle]

I remember reading a thread a while back about something like this. I think that a higher thermo will increase power, as will cooler air. But, a lower thermo makes it easer to control temperatures. I run a 160 just to keep temperatures down, especially during the summer.

[Owen]

I just read something on this a couple of hours ago. I think it was 160 for better emissions and mileage (opens sooner) and 180 deg for more power.

 

Owen

[Mike C]

Like most things, it depends. Emissions go lower as combustion chamber temperature goes higher. Power goes up with higher chamber temperatures as well. However, detonation is more likely to occur with higher chamber temps, so compression ratio has to be lowered or ignition timing retarded, which both lower power output. Having a thermostat with a higher temperature actually keeps the water in the radiator longer so it goes back into the engine cooler to some degree, but to some extent that is equalizing. You should experiment with thermostats just like ignition timing and carb jetting to optimize what works best for your engine. I have 180's in most of mine which seems to be a good winter/summer compromise in that it stays cool in the summer but the heater works in the winter.

[Guest the_dj]

I've read that it can help make more power. I talked to my dad about it and he expressed concern that it could make the engine not last as long because clearances wouldn't be where they were designed to be under heat expansion.

 

If it will make my motor die sooner and not do much good, I'll not get it. But is it a worthwhile investment? Should I or should I not switch to a 160 degree thermostat?

 

Thanks,

Sam

[Guest Anonymous]

I'm pretty sure for max power a little hotter is better. I base this on the fact that my racing radiator uses a cap of 22-24 pounds (no not in my datsun, I went 13lbs the heater core won't take much more) meaning they are attempting to raise the boiling point which leads me to believe they are running on the hot side in racing applications. I run a 180 and it seems like a good compromise, and it also gives you a second or so more if your cooling systems stops working to read the gauges and go WTF . (yeah 160 probably would give even more time, but I think you give up power going that low).

 

Regards,

Lone

[Phantom]

Thermostat temperatures are relative and are usually determined by engine design. You will note that the newer engines run temperatures up around 210°F. A higher thermostat temperature will actually improve cooling in an engine. That statement should freak a few people out.

Heat rejection is based on several things but the differential temperature between heat exchange mediums (coolant in radiator and air) is one of the primary ones. The higher the differential the more heat can be rejected into a given amount of air. A good example of this is when someone has a 160°F thermostat installed and the engine "overheats" in hot weather by rising about 20° above the normal thermostat set point. The engine/radiator have found their heat rejection equilibrium point which happens to be higher than what the thermostat was designed to control at. Engines also run more powerfully and cleaner at higher temperatures. Ideally they wouldn't be cooled at all but the current technology materials can't take those temperatures. Using a lower temperature thermostat is usually done to bandaid some other problem on a car - timing is off, etc. Recommendation - run the highest tmeprature thermostat recommended by the OEM for that radiator/engine combination.

[blueovalz]

One other comment (and I hope any metallurgist can verifiy this) I'd like to add is something I read reference cylinder wall wear verses temperature. If I remember correctly, it was stated that cylinder wall wear was increased with cooler temperatures, and visa versa. The reason this caught my eye when I read it was because I've always noticed that whenever a piece of stock that I am machining starts getting too warm, it seems that that I have to work harder at getting the material off (grinding and drilling, etc). After reading the cylinder wear data, it clicked.

[Guest greimann]

In the cutting / grinding process, metal can be heated up to and beyond its melting temperature if a cooling / lubricating medium is not used adequately to carry away the heat and reduce the friction of the chip on the tool face. The increased effort to cut a hot piece of metal you experience is more likely to be caused by a tool that has overheated and become dull, or a heat treating effect of the metal at the point of cut.

 

Temperatures below the tranformation temperature of the metal will have no effect on the metalurgical properties.