160 thermostats
Team Owner
Joined: Jul 2002
Posts: 37,048
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From: This city NEVER sleeps! Frank's back yard!
Originally Posted by AutoCutter
Just going to a 160 is not going to change your overall temp's in the long run. All a 160 will do for is open sooner then the stock and as a result the coolant will stay cooler for a longer period; however, the ultimate temp you will see is going to be equal to the cooling ability of your car. There are SEA studies that suggest a colder stat may not be good for the engines' life span, but I suspect that in the real world it really doesn't make a much of a difference.
Race Director
Joined: Oct 2004
Posts: 10,516
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From: Virginia Bch VA
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
Originally Posted by crabman
I have 200 tons of refrigeration on my boat and have many years of real world trying to make something get cold. Really thats what your talking about, refrigeration, because refrigeration is nothing more than trying to make things get colder. Imagine my case. I have 4 holds full of fish. its about a half million lbs of fish between them. They would be comparable to your engine, I pump seawater into them till they are slightly presssurized, about 4psi max. And then turn around and start recirculating that water through my flooded freon chillers and back to my tank. That seawater is my coolant and my compressors are my means of chilling the coolant comparable to wind/fans in your car. From there I need only adjust my vavles on the circulation to optimize the flow for maximum cooling. This is comparable to your thermostat and consists mainly of slowing down the flow (I have the cabability to move 6000 gns a minute which is far beyond the amount of flow required for the task) till I have achieved maximum heat transfer from the fish to the seawater. I say transfer because refridgeration does not add coldness, it removes heat. We transfer that heat from what we are cooling to a medium (freon in your fridge, seawater in my tanks, coolant in your car, etc.) which we then take someplace and in turn affect a cooling of that medium (using a radiator, refer compressor, etc) so we can circulate it back into the thing we are trying to get colder and it can pick up more heat. This is the process made simple as it must be for a lowly fisherman to understand. Now the thing is that in order to maximize cooling the cooling medium must be allowed enough time to grab as much heat as is practical in the situation. If you slow it down too much it will have largely, or completly, if given enough time, expended its ability to pick up heat (as the temp difference gets closer the energy transfer slows down) and you are better off getting it back to your compressor or radiator where it can be cooled again. The point being you reach a point where you are better off getting your cooling medium back and using your refridgeration/radiator to turn it into a more viable cooling medium rather than letting it pick up heat at a lower rate as the delta closes between the temp of what your cooling and your coolant. You can also go the other way. If I increase my flow too much I cant maximize my ability to cool the medium within which I am affecting the energy transfer. Maximum cooling is achieved when I best balance these two competing factors. I am sure that the smart folks on here can explain the science far better than I can but that is the real world of the situation.
I'm signing on for your next trip as long as you offer all you can eat Crab, Crab 
Racer
Joined: Nov 2004
Posts: 298
Likes: 0
Couple quick engineering notes:
If the inlet and outlet temp of the radiator were the same temp, very little heat would be transferred. To determine the heat transfer for the radiator, you would multiply the flow rate by the enthalpy of the water into the radiator minus the enthalpy out of the radiator, or
heat transfer rate=flowrate *(enthalpyin-enthalpyhout)
Since in both cases we are looking at liquid water, the enthalpy is mainly based on temperature, therefore if the temperature is the same heat transfer is low. The exception would be if we were comparing steam into the radiator to liquid water out at the same temperature, this would be a rather large heat transfer because of the state change.
The thermostat controls the flowrate in the above equation, with a max when open and a min when closed.
I've never messed with a thermostat, but I'm curious now and may try it out in a pan, does it open quickly or slowly? On www.howstuffworks.com, which is an excellent site, it states that a wax pellet melts at the temp specified and changes from a solid to a liquid (melts), based on that I wouldn't think it is that variable but more of an open/shut thing, but I'd have to see one in action to be sure.
Also, from a simple efficiency standpoint, a lot of energy is lost with combustion engines through heat, so from a very simple view a colder engine should be more efficient; however, the properties of friction/oil etc... come into play complicating matters....not to mention gumming up the engine with things that don't burn completely...
From a pollution standpoint, the hotter the engine the better, ironically the hotter we make it the lower the gas mileage. Older cars typically ran cooler, sometimes in the 150-160s.
If you interested check out www.howstuffworks.com article on cooling system, link below. It has an awesome animation that shows the flow path during warmup and normal operation on page 2
Finally, I wouldn't mess with your thermostat, it is a matched system.
http://auto.howstuffworks.com/cooling-system.htm
If the inlet and outlet temp of the radiator were the same temp, very little heat would be transferred. To determine the heat transfer for the radiator, you would multiply the flow rate by the enthalpy of the water into the radiator minus the enthalpy out of the radiator, or
heat transfer rate=flowrate *(enthalpyin-enthalpyhout)
Since in both cases we are looking at liquid water, the enthalpy is mainly based on temperature, therefore if the temperature is the same heat transfer is low. The exception would be if we were comparing steam into the radiator to liquid water out at the same temperature, this would be a rather large heat transfer because of the state change.
The thermostat controls the flowrate in the above equation, with a max when open and a min when closed.
I've never messed with a thermostat, but I'm curious now and may try it out in a pan, does it open quickly or slowly? On www.howstuffworks.com, which is an excellent site, it states that a wax pellet melts at the temp specified and changes from a solid to a liquid (melts), based on that I wouldn't think it is that variable but more of an open/shut thing, but I'd have to see one in action to be sure.
Also, from a simple efficiency standpoint, a lot of energy is lost with combustion engines through heat, so from a very simple view a colder engine should be more efficient; however, the properties of friction/oil etc... come into play complicating matters....not to mention gumming up the engine with things that don't burn completely...
From a pollution standpoint, the hotter the engine the better, ironically the hotter we make it the lower the gas mileage. Older cars typically ran cooler, sometimes in the 150-160s.
If you interested check out www.howstuffworks.com article on cooling system, link below. It has an awesome animation that shows the flow path during warmup and normal operation on page 2
Finally, I wouldn't mess with your thermostat, it is a matched system.
http://auto.howstuffworks.com/cooling-system.htm
Racer
Joined: Nov 2004
Posts: 298
Likes: 0
Another thing to note, if you did manage to change the operating temperature of the engine, it may mess with the emission systems. The emissions system is fairly complicated as well, there are four O2 sensors that monitor the emissions of your vehicle and vary the amount of fuel injected based on what they sense. If you change the operating temperature of the engine, it could mess them up. It may be ok since the engine computer knows the coolant temperature, but you may get a service engine light if your on the border or well below it....
7th Gear
Joined: Jul 2002
Posts: 7
Likes: 0
From: Ferndale WA
Thermostats
I realize that being a C-4 owner that I'm now swimming with the big fish. But here's my experience. I was running a 185 degree therm. in my 89 6spd - until I had the intake manifold gasket replaced last month. The shop replaced my 185 degree with a 195 degree and sure enough the temp. does remain more constant. It also takes longer in traffic to get into the 215 - 220 range - and once I'm running at normal speeds again the temp quickly goes now to 194 - quite abit quicker thatn the 186 degree therm. 
