180 degree thermostat rethink

[ub3r l33t dud3]

i know that the 180 degree thermostat works for getting more fuel to the engine, but i was thinking, why has no one ever changed the signal to ecu to make it think that it is running colder, ie. 180 degrees, instead of changing the actual operating temperature (a different thermostat). then you would get the additional fuel, but also get the added efficiency of operating in the temperature that the engine was designed to run at in the first place.

i know the added temp might not be good in the turbo application but for an n/a builder it could be a few much wanted HP. can any one think of a reason why this wouldn't work?

obviously the engine fan would be an issue but if you had a car built for the track the fan should be on a switch. a drag track that is lol.

[knightmoves]

you got my head scratching!!!!! In no way does a thermostat increase fuel. the performance it does give is keeping the motor cool so it reduces the chance of detonation. it also keeps the air charge from getting to hot. if you need more fuel you need to look at a fuel pump,FPR, maybe E manage blue or megasquirt.

[OL'grouch]

If you have fuel injection, you don't have a choke. The computer compensates for a cold engine by injecting more fuel. This is "open loop" mode. If you run a cooler thermostat, the computer will never know the engine is warmed up. It will run rich, waste fuel, be down on power and generally not run as good as it can.

[Dr. Johny Dodge]

and eventually it may fail due to running to much fuel

my buddy - one who thinks everything in a newer motor is unneeded crap added on -drove his blazer for a little over a year with a bad temp sensor so it ran as if it was winter the whole time

eventually his nice alum head vette small block died from washed out bearings due to excessive fuel going past the rings mile after mile

[ub3r l33t dud3]

i have seen it for the past two years being idolized by people with 3.0's saying that it gave them 1 or 2 tenths of a second because it added more fuel. i have seen it on this site as well, and the only explanation i herd was that it they where doing it cause it gave them more fuel.

i have never planed on doing it because if i need more fuel i will add more fuel a different way. i was mostly bringing the subject up for the people that were already running the "180 degree thermostat mod".

so now im curious to know who is running this anymore. IIRC it has been listed a few times as a "required" supporting mod for turbo charging the 3.0

it looks like the allpar site has changed since i last looked at it but here is dyno chart that still has the 180 thermostat listed as a "mod"



now i dont see anything mentioned about it on the site though. sorry i haven't done much research for the past year or so lol

[knightmoves]

I run a 160. and no I don't run rich nor do I get washed rings. and that thermostat has been in there for 4 years. the only reason I use it is to keep it cooler for the reasons stated above. no matter what thermostat you use as long as the temp sensor is working correctly the ECU will the the correct temp and that being 160. it will just keep the motor from reaching full temp and keep the ECU from moving up the spark and fuel maps to the full temp range. but it is a good mod and works nicely!!!! car is a 95 Chrysler lebaron GTC 3.0 with the 604 trans!

[DPE91]

I never have understood how this mod works to give you better performance. An engine runs and performs better, over the long run, at a higher temp. But just with anything in an automobile it is a balance, you want the engine to operate at peak efficiency, while at the same time you don't want it to get to the point of catastrophic meltdown. Research has proved that higher engine temps actually promote a more stable environment in the engine and the materials themselves. Also you don't want the temp to be so low that it inhibits the atomization of the fuel, which causes an incomplete burn, and in turn hurts performance. The transfer of heat from a metal to the surrounding air is not an instantaneous action, it takes time. The speed of the air entering your engine greatly diminishes the time for heat transfer. Air is also a mixture of many gases and each gas has different rates of expansion and heat absorption, so the transferring of heat to the intake air would be random and at varying degrees no matter what the temp of the engine is. The main contributing factor of high intake air temps is really the restrictive factory air intakes, forcing the air to soak in what is really an oven(the engine bay).

Now a turbocharger or supercharger is a different animal, as we all know the point of these is to cram as much air in as you can. So obviously the intake air is going to spend a lot more time in these heat soaked spaces than in the intake manifold its self. That is why when you do have these the air (in general) is cooled before it enters the intake rather than just before it enters the port in the head or the combustion chamber, which obviously would be tricky to do with a factory head that didn't have such things, and wouldn't really allow the time needed to truly cool the incoming air.

And by time I don't mean seconds, I mean microseconds, nanoseconds, and possibly even smaller increments of time.

Now I do understand why a lower temp thermostat would be essential in drag racing, running hot laps and such I see how lower engine temps could prevent a lot of blown engines. But for a street, road racing, or circle track engine I don't see how a lower engine temp would be vital or preferred.

[ub3r l33t dud3]

i agree with you,did you know in gas turbine engines they will actually heat up the incoming air to get it closer to ignition point to increase efficiency? but the physics of turbine engine are completely different than piston engines. useless fun fact of the evening lol.

in a stock engine that isnt worn out (ie. new) i dont think running it colder would gain much power at all, yes it may cool down the incoming air but remember that the engine was designed to run at a certain temperature, if you cool the engine down it messes with the tolerances of moving parts and can increase friction. now one might argue that the increased friction would be miniscule, but so would the temperature change in the incoming air.

[Dr. Johny Dodge]

really the purpose of trying to run the engine cooler is to reduce stresses on the motor
none of us work well when hot and the same goes for motors too

also , heat closes tolerances and tightens things up - that INCREASES friction

if you have ever heard a piston engine start up in an aircraft you would know they make a huge amount of noise - this is due to the tolerances being loose - looser than a car engine
this goes away as the engine warms up and the slop between the parts is reduced due to thermal expansion - that is because they are designed to run at a constant and very open throttle position for hours on end - see what happens if you let your car engine run at 3/4 throttle for 15 -20 hours

and we all know what happens when things get to hot - they seize up

also , an engine that runs cooler has more potential left to do "work" - more so than an engine that's running hotter

[ub3r l33t dud3]

Quote:

Originally Posted by Dr. Johny Dodge really the purpose of trying to run the engine cooler is to reduce stresses on the motor none of us work well when hot and the same goes for motors too also , heat closes tolerances and tightens things up - that INCREASES friction if you have ever heard a piston engine start up in an aircraft you would know they make a huge amount of noise - this is due to the tolerances being loose - looser than a car engine this goes away as the engine warms up and the slop between the parts is reduced due to thermal expansion - that is because they are designed to run at a constant and very open throttle position for hours on end - see what happens if you let your car engine run at 3/4 throttle for 15 -20 hours and we all know what happens when things get to hot - they seize up also , an engine that runs cooler has more potential left to do "work" - more so than an engine that's running hotter

you are right about the tolerances getting bigger, i had a little to drink last night sorry lol (there is a reason i dont drink drink).

just for argument sake an formula one car's engine is effectively seized when it is cold be cause of the tolerances being so tight, they have to pump warm coolant and oil to heat it up to get it to turn over.
also,most airplane engines are air cooled, the lack of temperature control means that the tolerances have to be bigger do to that fact. that is why an old air cooled vw engine sounds like it is going to fall apart all of the time. but those are just a few exceptions to the common rule.(sadly) our engines are not f1 engines lol

but yes you are right, i wasent thinking when i wrote that. sorry lol

[MRAL]

I run a 160 thermostat in mine. The only reason that I do this is because at the end of a bracket race they tend to start running the rounds with less time in between to let the cars cool down. The cooler temp thermostat helps to cool the engine faster for me. But I have seen no performance gain from doing this. I also have a adjustable fan control so, I can compensate a little bit for the cooler thermostat when I am driving on the street.

[c2xejk]

Quote:

Originally Posted by ub3r l33t dud3 just for argument sake an formula one car's engine is effectively seized when it is cold be cause of the tolerances being so tight, they have to pump warm coolant and oil to heat it up to get it to turn over.

I believe this is because of the aluminum block. It dimensionally changes more than the steel crank or rods... ie. as it warms up, the heads move further from the crank. In a race engine, it is "acceptable" to have to preheat the engine so that the aluminum expands enough that the pistons and rods do not make contact...

This is not relevant to a 6g72 using a 160 thermostat...

[Dr. Johny Dodge]

^ ah , but what would life be without tangents ??

[DPE91]

@ Dr. Johnny Dodge
It seems like you are describing the effects of a overheated condition. An engine running at the proper temp will perform perfectly even if it is 210* or 215*(which many new vehicles that is their operating temp), and I doubt the 15* degree change in operating temp is going effect your engines performance at all. Not to mention the alloys that are used in today's engines including the 90's are thermo dynamically more stable than those of the past, if they weren't how could an engine run for a 100k miles with an aluminum head and a cast iron block with out ever having to change the head gaskets, also how could an aluminum block engine even run with it's cast iron liners or thermo hardened cylinder bores. Your right there is a point where the engine gets too hot and it's performance will drop, but the 195* factory operating temp is not causing any extra drag on the engine because the engines tolerances are designed to work with that operating temp. And also our body temp is a lot lower than that of car's operating temp, not to mention if your body temp fluctuates much more than plus or minus 5* that can start complete body shutdown, your engine can operate perfectly fine at 10* or 15* higher than its normal operating temp. Not to mention the oil that manufactures spec for the motor is designated as such because of the operating temp(and other factors), when oil heats up it flows better, if it is cold it less likely to flow, now that 15* in oil temp will make a difference in engine longevity. I know for a fact in NASCAR they wont even crank the engine till the oil and coolant are both above 200*. If it ain't broke don't fix it.
An air cooled engine versus liquid cooled are two different ball games, they generally serve different purposes for the most part. An old radial piston engine is stuck out there in the wind there is air constantly flowing over the engine. Plus an air cooled engines operating temp is designated by the temp of the air around it rather than the degree that a thermostat opens at.
Unless you sit with your car running for extended periods of time, for example at a drag race where you thrash your car and then slow to a "crawl", you wont need the lower temp thermostat. The thermostat does not effect power enough, if any at all, to worry about it as a performance mod, but for cheap security to keep the engine from over heating at the drag track it makes total sense. And your factory cooling system is designed to balance the temp so that the engines metals stay thermo dynamically stable while not allowing over heating, if you don't trust that factory cooling system to your keep engines temperature under control from day to day then you need to build an entire car from scratch then.

@MRAL
I understand why you would use a 160* thermostat, you run your car all out for a few seconds then coast the car around to sit in a line for the next run. Or are running back to back heats. Not a lot of air flow when your just sitting still, so i see that your lower operating temp would save the engine from getting to a point of overheating.

Thermal expansion can be modeled as a function and that function is not continuous to infinity at some point the metal will expand to a certain point and either combust or melt. And I am sure with the money spent in R&D they would take those into account.

[Dr. Johny Dodge]

... I'm not the one who said you would make more power running just a few degrees cooler

in compareing us to motors , all I was saying is that everything works better in it's "happy operateing range"

F1 and nascar motors would be built to opperate under stresses much different than we find driveing down the highway for a few hours or driveing from stoplight to stoplight

so in effect different opperateing conditions call for building with diff tolerances

now , my truck usually runs at about 194 - 196 on a not to hot day
hot ish for my truck is 212

now if my truck ran 180 ish , I would have more reserve if I were to demand the truck make some kind of effort that would cause it to generate more heat that usual - like pulling a heavy trailer up a steep & long hill