Thread: 180 T-Stat

Originally Posted by Sabrewings

Yes... it sits still any time it is closed (which is during the entire warm up cycle, which is what my post was referring to). This is with the exception of the small amount routed to the heater core. Once you've hit your warm up temp, the tstat can settle at a partially open position to keep the temperature constant for the load. Going down the highway it isn't constantly opening and closing.

And, the coolant in the radiator doesn't move until you first hit operating temp. Don't believe me? Hold the upper radiator hose. It will stay ice cold on a winter morning until the tstat hits operating temp then you will feel a rush of extremely hot coolant. Every vehicle I've owned or worked on has done this (dead give away on when it's good to bleed). There are tons of reports in northern Canada where they're recommended to run a small hole in their tstat to gently warm the radiator coolant prior to the opening of the tsat. Yes, engine damages have been reported from this happening.

Ever looked at specifically how coolant is routed through the engine? The heater core is somewhat "parallel" to the radiator. It has one hose on the higher pressure side of the pump and one on the lower pressure side. It can pick up enough heat during the warm up cycle to give you heat. But overall most of the coolant in the engine is at a stand still. Yes the pump is pumping but due to its design (centrifugal veins) it can pump against a near solid wall of water without caring.

The entire time you're driving before you hit your operating temp your radiator coolant is just sitting, the same as most of the coolant in the block. Once that tstat finally opens (yes, it does seal 100%) then it starts to displace the hot coolant in the block. This is where you get cracked blocks from sudden temperature changes. If the car was flowing coolant through the radiator the entire time, then drilling it should have little to no effect and I can tell you it has a major effect on warmup time. Simply due to having to heat a lot more coolant during the warm up cycle, and having to keep it warm if you're driving.

And running without a tstat would never have the "-15*F coolant meeting 250+*F parts" effect because all the coolant would heat evenly because none would be isolated (either in the radiator or in the block).

I think you're under the impression when the tstat is closed there is still some flow to the radiator with the stock tstat. This is simply not the case, and is why we have drilled tstats in the first place (to prevent heat soak on parts like the heads which can lead to knock). I've already seen a drop in knock with a stock temp tstat but drilled due to the heads remaining at the intended coolant temp and not getting too hot during the warm up cycle.

Here's more info for you, from Wizbang:

I guess maybe I am not explaining myself well enough. I in no way think that coolant will cycle through the engine or radiator with the t-stat closed. I realize that it won't go through a closed t-stat. But, the coolant in the engine, during warm up, does not just sit there. It moves in the engine. Take a glass of warm water, put in ice. The water looks like it is sitting still. But the molecules are moving inside the glass. As the ice adsorbs heat and the water cools off, it will sink to the bottom. And the warmer water will raise to the top. Same thing happens in your engine. The water is not "sitting" in your engine. There is no "wall" of water at your water pump. Even with the t-stat closed, the water inside your engine is moving. Yes, not moving to the radiator. But by no means is it sitting there.

I am not disagreeing that a drilled t-stat may not be beneficial. I am sure it is. I personally don't have an opinion on that. But this entire thread is about the need to 180° stat, which I don't see one.

As for running without a t-stat, it has been proven that running without a t-stat will increase the surface temperature of your heads. The coolant is flowing too fast to transfer sufficient amount of heat from the heat, causing a substantial increase in cylinder head temperature. Your cooling system needs to be regulated to slow down the flow of coolant to increase the time the coolant is in contact with the cylinder head. This allows enough time for the heat to be transferred from the head to the coolant. Otherwise, the coolant is moving too fast for heat transfer to take place.

Again, I know there is no flow to the radiator when the t-stat is closed. But like I explained above, the coolant by no means sits in the engine. There is movement of the coolant due to the heating. And substantial movement inside the engine. But no, it doesn't flow to the radiator.

Originally Posted by TDCRacing

Sorry but im going to have to dissagree with you now. You just said you dont see any point in keeping you're engine cool? Shoot just run the damn thing without water then. You say you don't see the point but you use one at the track? Why? I know why because you told me. But that cintridicts what your trying to get across to us.

You're comparing apples to oranges here with the nascar thing....Do you rebuild you're engine every time you come back from driving you're car?? Nascar does....why dont you?

Guess you don't belive in cold air intakes either huh? Just a big gimmick??

Go ahead and unplug that fan on the computer that you're typing on right now....see how long it lasts....Why do you think the computer rooms that the test equipment run in on military bases are ice cold? Come on man...Heat is a killer of almost everything....even people...

Ever heard of heat stroke?

AGAIN...i'll agree that you probably won't see an increase in fuel economy...and that adding a thermostat wont give you any kind of performance increase. I personally belive that it won't even combat KR...

You say the coolant doesent sit in the heads? You're wrong. Coolant sit's in the entire engine untill the thermostat opens...What you think it just by passes the thermostat somehow? Thats what it is there for. To stop coolant flow untill a certain tempeture is met.

If you want to prove you're self wrong next time you're out before you start you're car up for the first time take the upper radiator hose off...No coolant comes out while the engine is running until the thermostat is open. Therefor what is the coolant doing??

SITTING!!

Again, I must not have conveyed my thoughts correctly. Your engine needs to be kept cool, yes. Hence the cooling system. I understand that you can't run without coolant in a normal car. But there is no reason to make your engine run cooler that stock temp, in a daily driver, on the street. I thought I tried to explain that. But I will try again.

Like I said, yes, you need to keep your engine cool to keep it from overheating. But putting in a cooler t-stat than stock is making the engine run too cool. You will lose performance and lose economy. So what is the reason that you want a cool t-stat on a street driven vehicle?

Again, I tried to explain why you would want one on a track vehicle. Heat soak is a major problem on track cars. But not really an issue on street cars. Unless you are drag racing on the street for money or something, I don't see this as an issue. But for a daily driver, cruiser, weekend warrior car, heat soak when you are sitting in traffic isn't really a problem because you don't need to got WOT immediately afterwards. And if you do, the couple tenths that you lose due to the heat soak won't make much of a difference.

As for the NASCAR thing. Yes, I understand they build a different engine everytime. But I have seen engines after they have been in a 500 miles race. the bearings don't look any worse than my truck with 150k miles on it. They still need to run their engine in a way that it will last. They can't take a chance and build engines and race them that they will only last 1000 miles, because they are only going to run 500 and rebuild it. They are using the same technologies that are in our engines. And they run at elevated temperatures to get more power. And their engines hold up just fine. Not saying that I want to run my engine at 230°+, but my point is that there is no point to putting in a cooler t-stat, it goes completely against logic.

As for your statement about CAIs, as I mentioned before, that is totally different than keeping your engine cool. A most efficient engine is one with the cool fuel, and hot exhaust. Again, heat loss to the cylinder walls takes away from the work the heated gas is doing on this piston. The greater the heat loss, the less work, therefore less power, and less efficiency. Read up on the Otto Cycle, thermodynamics, and its efficiency and you will see this correlation. But cooler intake air is totally separate from the cooling system, and t-stat temperature. You want cool air/fuel mixture, and hot combustion and exhaust.

As for the last couple statements, like I said above, I know there is no coolant flow through the t-stat to the radiator when the t-stat is cold. But I also know that the coolant by no means sits still inside the engine. This is basic fluid dynamics.