Eliminate thermostat. Good idea or not?

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SteinOnkel
Posts: 1000
Joined: Tue Feb 19, 2019 9:31 pm
Your car is a: 1978 124 Spider 1800

Re: Eliminate thermostat. Good idea or not?

Post by SteinOnkel »

If I turn up my wiper speed setting, the temperature and gas needles also go up :D

Nothing like a precise measuring device, eh?

TwinFast's approach with the laser thermostat is much, much more accurate.
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Eliminate thermostat. Good idea or not?

Post by 18Fiatsandcounting »

SteinOnkel wrote:If I turn up my wiper speed setting, the temperature and gas needles also go up :D

Nothing like a precise measuring device, eh?

TwinFast's approach with the laser thermostat is much, much more accurate.
Ahh, the joys of Fiat electrics! Nothing like the poor connection of a bad ground being resolved by turning on another switch or device with a better ground, right? In any event, you've found another way to (apparently) add gas to your tank. Now, if your wiper speed control went all the way to eleven, that would so totally rock your gas mileage! :lol:

-Bryan
TwinFast
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Your car is a: 1978 Fiat 124 Spider

Re: Eliminate thermostat. Good idea or not?

Post by TwinFast »

SteinOnkel wrote:A thermostat in "fully open" setting will still restrict flow more than not having one at all. This is why you are overheating. Guys, it's not complicated. The factory did not put in a thermostat because they needed to get rid of them. An internal combustion engine is designed to run most effectively in a certain temperature range. This is dictated by the engine design and achieved with the thermostat. Removing it is a completely asinine bandaid "fix".
Thanks SteinOnkel, I finally purchase and install a new thermostat and the cooling is definitely much much much better than without ...
The car reach the operating temperature faster than before but stay around 190°F all the way out. when i stop in a traffic jam it increase slowly and he fan come on at the right side of the 0 of 190. Note that the fan switch in the low temperature one . It activates the fan at 180°F ... when the engine temperature is around 195° :shock:
Fiat 124 Spider 1.8L 1978
Jaguar XKR 4.2L 2009
Harley Davidson Fat Bob 96Ci 2011
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Eliminate thermostat. Good idea or not?

Post by 18Fiatsandcounting »

Keep in mind that your temperature gauge, or its sending unit, or the fan turn-on switch, may not be all that accurate. In fact, I'd be surprised if they were consistently accurate to within 10 degrees F. Also, the fan turn-on switch and the sensor for the temperature gauge are located in very different parts of the engine, so you might at the same time have 180 degrees at the fan switch and 195 degrees at the gauge sensor.

-Bryan
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MikeHynes
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Joined: Fri Sep 17, 2010 5:55 am
Your car is a: 1980 Spider 2000
Location: Central Il.

Re: Eliminate thermostat. Good idea or not?

Post by MikeHynes »

Don't Want to be cotrary but I had a discussion with a cooling system engineer about this. I was told that the faster the coolant flows through the system - the better it cools. I was told that it was not necessary to slow the coolant flow down in order to allow "time" for the heat/cold to transfer.
Of couse it takes more HP to pump the coolant faster so it's a tradeoff.
I don't use a thermostat in my racecar, to keep flow high, and it takes a long time to warm up. But once it does, the temp remains stable - mostly. YMMV but I would advise using a thermostat in a street car and making sure the coolant system is in good condition (radiator is clean and not plugged).
18Fiatsandcounting
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Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
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Re: Eliminate thermostat. Good idea or not?

Post by 18Fiatsandcounting »

Mike, upon thinking about it some more, I think you are correct. One factor I hadn't considered until now is that faster coolant flow also increases the turbulence of the flow, which helps to equalize the temperature throughout (just like stirring a pot on the stove helps to get everything to the same temperature). On the other hand, the presence of a thermostat would also increase turbulent flow as the fluid goes through its opening, so that would work to help mix things up as well. On the horsepower issue, it seems that the water pump would require more HP to "push" the coolant through additional restrictions in the system such as a thermostat. I'm sure entire textbooks have been written in automotive engineering on the subject of cooling system designs! :)

I was just recalling some work that I did with fluid-to-air heat exchangers where faster fluid rates actually hurt the overall heat transfer, but that was long ago and I'm guessing there was another factor going on. I definitely agree with your statement that a street car should use the thermostat as designed, and the cooling system should be maintained.

-Bryan
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