thermostat..to use or not?

[J101]

"SO WHAT PURPOSE OF LOW TEMP. THERMOSTAT????
It use for racing engine to produce more power. Most important must have progammable ECU to tune back yor engine to get the power of cool engine. While the eng temp drop, air entering the engine less creating a denser fuel/air charge thereby developing more power. Cooler induction air is less prone to induce spark knock so the ECU can run more aggressive ignition timing resulting in greater power."

so many racing engines in ZTH i believe :p its not a good idea to run without the thermostat, as the engine requires a minimum operating temperature to function properly and efficiently. running a motor too cold may not cause the immediate damage as running it too hot would, but it damages it non the less. u need to generate heat to generate energy to develop power. running cold in open loop will definitely takes more fuel and running rich plus sometimes it hard to engage vtec. but when u have a good ems, that way everything is run off preset values and you dont get strange things like lower mileage, vtec not engaging etc.

a spoon or mugen thermostat would be ideal along with a fan switch, maybe a new koyo radiator as well. cant get much "cooler" then that. it has to come in a combination for this "cooling" system. cheap no good, good no cheap my friends.

again this topic is very subjective, i believe honda engineers design it for a reason and spoon/mugen/sard design it also for a reason, for the track.

 

[shiroitenshi]

Hmm.. someone resurrected this thread, and I've learned more since then about what thermostats does.

Well.. I think the thermostat is simply a valve that opens fully at a preset temperature. In which case, this also indirectly say that it opens faster.

It's so that the water temp can be maintained at a preset range. the water/coolant is heated up by the working engine (ie the sleeves are dipped in coolant, after all) and when it reaches the thermostat temp, it opens so that water flows to replace the water that was heated up by the block (and the head of course, I forgot to mention this because I'm simplifiying it). Naturally this doesn't happen fast enough that you will see rapid temp changes (rapid temp changes of materials usually get cracking). So the thermostat isn't actually an on off temp switch but a valve that slowly opens as the temp rises to regulate coolant flow. Naturally the flow is always there just the speed of the flow is different, because your water pump works the moment you start your engine, and the thermostat just makes sure not too much gets past.

in which case, when you have a high performing engine, naturally the water heats up faster due to higher combustion temps, etc. So the normal termostat would probably not be able to open fast enough to regulate the temp, because by the time it opens the valve fully, the water may have heated up past that optimum point. So they're made to open at lower temps, so the temps can be regulated at the preset level where the engine works the best.

In which case, a running without a thermostat simply means that you can't regulate the temperature based on ambient temp (aka outside temp). Example would be, that on very cold days, the water temp may be low because the water is being cooled rapidly by the radiator (I don't think malaysian temps are that low, but consider this instance as purely academic) and since the thermostat isn't there, that very cool coolant gets into the engine and naturally you would get a VERY cool running engine (which isn't truly desirable, as J101 said). This is what I mean that the thermostat's function is to regulate temps regardless of ambient, as even on a very cold day, it will regulate the coolant flow so that water temp stays at the optimum mark. I don't think the rating on the thermostat is the optimum operating temp, but rather at what temp the valve opens fully. (if this is incorrect, please correct me)

on hot days, your engine will run cooler, but it's probably cooler than the optimum mark, so engine performance may not be at the optimum. (Common theories around the net says it's related to emmissions as well, but I dunno that one la.) But what if the outside temp is high? your coolant are being flowed through the radiator too quickly to enjoy the cooling afforded by the radiator fan when your car is not moving.

Like mr bear mentioned, without thermostat, your coolant is always flowing at the same speed as what your water pump can pump. This may or may not be a good thing, as flowing too fast also means that the water cannot stay inside the radiator coils for long to enjoy the cooling effect. But sometimes you will see that the engine is cool, probably because your car is moving, and the cold outside air (below 30C) is helping to cool down the radiator as well.. I don't think you'll see the same effect if the outside temp is in excess of 40C though..


In which case, if there's nothing wrong with the cooling system, but the engine are running slightly higher than stock compression engine and coolant temps are higher than normal, esp. when you start to drive it hard, a thermostat will probably help lower the temp to a constant level, usually around the level of 80-90 C plus (well.. 1.3 bar radiator cap.. I guess the boiling temp is raised for a reason, so it could be in the near or a little past 100C)

I haven't been able to take out the engine coolant temp(ECT) sensor to actually calculate the actual temp so I can log it with the auxbox, but I get a constant max voltage (very slight deviations) when I'm at the operating temp, and no matter how I drive it, it will not pass that mark. The ECT seems to stay at a constant temp no matter if I drive it hard or slow.

And that is also why before I'm trying to log everything that a stock engine does so I can learn a lot more on what makes the B-series tick. Of course, I could do it by trial and error, but the fun in modding for me is finding out how it works. :P

Woah.. long stuff for something so minor as the thermostat.

 

[shiroitenshi]

The thermostat is a device to control the temperature only AND NOT A COOLING DEVICE.
Cooling element is radiator, cap & coolent. If your cooling system only can cool the engine to 80'C, so the 68'C thermostat cannot function, it will open all the time just like not using thermostat. So you must upgrade radiator, cap & coolent to transfer more heat, then the thermostart start funtioning to control the temp. at 68'C. Get what i mean?? You also need to set back your FAN control to on the fan at around 68'C.

IF YOU USING STOCK ECU, NO NEED TO COOL DOWN YOUR ENGINE!!!!! COZ THE ECU IS TUNE FOR THAT TEMPERATURE OF ENGINE!!!! JUST MAINTAIN THE COOLING SYSTEM AT OPTIMUM PERFORMANCE.

SO WHAT PURPOSE OF LOW TEMP. THERMOSTAT????
It use for racing engine to produce more power. Most important must have progammable ECU to tune back yor engine to get the power of cool engine. While the eng temp drop, air entering the engine less creating a denser fuel/air charge thereby developing more power. Cooler induction air is less prone to induce spark knock so the ECU can run more aggressive ignition timing resulting in greater power.


Coolent information.

-cheap coolent are not cooling yr engine. the chemical inside the coolent(glycol base) just for anti-rust & anti-freez. So just pour a bit to your radiator for anti-rust & lubricate water pump. Pure water have batter cooling than water mix with coolent, but pure water will corrode the system faster.

- hi performance coolent like redline water wetter, lubeguard Cool-It & other hi performance coolent is good for cooling. But it will cost u $$$$.. hehe.. wanna know how it cool the engine, use google.com to find yourself.. :p

nice.. participate more in tech discussions please.. let's go beyond just 'what colour code is spoon yellow', is cam X better than cam Y, or etc.

Let's talk more about why they work the way they do.. (^_^)

Yo, fellow kelantanese.. Want go TT?

 

[J101]

Woah.. long stuff for something so minor as the thermostat.

hehe..too much racing parts used on the streets that creates ambiguity. i dun blame the user either :p

 

[Enthusiast]

Do most of you warm up your engines in the drive way for atleat 5 - 10 minutes in the morning before you drive out? becoz tats wat ive been doing, untill i read this article.....

this article says that it actually has the reversed effects, something to do with excess build up of carbon due to morning start and idle warm ups.......it recommended the best way to warm up your engine is to actually just wait around 1 minute for oil to pump up and then just drive off slowly untill it reaches optimum working temperature......

any comments on this?

 

[shiroitenshi]

Do most of you warm up your engines in the drive way for atleat 5 - 10 minutes in the morning before you drive out? becoz tats wat ive been doing, untill i read this article.....

this article says that it actually has the reversed effects, something to do with excess build up of carbon due to morning start and idle warm ups.......it recommended the best way to warm up your engine is to actually just wait around 1 minute for oil to pump up and then just drive off slowly untill it reaches optimum working temperature......

any comments on this?

I dunno, but I'm the type that does the second type.. start engine, and drive slowly, till the temp gauge reads the normal level, then drive normally.

Sometimes I warm it up, but that's probably not so often.. maybe like a week or two once.

 

[drive4fun]

Regarding the coolant information:

Before when I was using only water the temp on my b16a is always showing slightly above 1/2 and it never got any higher then that. Then my friends are all telling me that I should put coolant into it as it helps cool the temperature faster/better because their protons water temp are always slightly below 1/2. So I decided to take their opinion into consideration and poured coolant into my rad. Now sometimes after long distance drives or extreme reving and after that if I idle my car idle the temp will go as high as 3/4, but after a while it will eventually drop back the its normal temp which is slightly above 1/2.

As for the thermostat I have thought before of removing it then I was unsure cause removing the fan switch and directly connecting the wire to the fan will cause the fan to start everytime you start you engine. So after I enquired with my mech friend his response was "if you remove the switch and your fan starts everytime you start your car, then your fan wear and tear also faster, spoil also faster in exchange you won't face the problem of overheating cause even if your fan dies on you, you will know. Unlike if its being controlled by a thermostat your fan life span is longer cause it only runs when it reaches a certain temp, but you risk overheating and if your fan dies on you when you car is in idle condition. And he also told me not to remove the thermostat cause apparently that thing controls the flow of water/coolant to the engine block for us Honda engines.

 

[shiroitenshi]

I don't know why most honda owners are having cooling problems. my car is now 240,000+ in terms of mileage, and my temp is still around 87 at most (hondata reading) and the water temp on the dashboard is showing a little below 1/2 mark.

I've replaced the radiator twice during the course of ownership (both times not due to overheating, but cracks and leaks.

Water pump, maybe the 3rd/4th time.

And of course, I use only filtered water for the coolant, mixed with Motul Inugel. The bottle is like RM60, but well, I don't flush the radiator often, so it's not a big expense.

Last I opened the engine, was when I got leaking valves, and the jackets around the sleeves were like super clean. See below, that was just opened, and I didn't clean the sleeves on purpose for this picture, actually this picture was for showing signs of detonation and how it looks like on pistons.

Yes, those are detonation signs, on B16A stock pistons.

Compression test, Skunk2 new valves gives 0.5more, so now I have a
11SCR B16A :P

How many valve grind ppl give you the oppotunity to check leaks? with water some more. (theory is, water molecules bigger, so if it leaks water, it will leak air.)

The best test is still by vacuum, but I don't have that equipment.

 

[drive4fun]

No idea why we have this problem but everything was good before I started filling the rad with coolant. This is what the watertemp on my dashboard looks like after a few laps or long distance cruise

The temp will drop gradually once the fan kicks in. I dunno bout you guys but everytime the temp reaches that high its like a nightmare, and when that happens driving isn't pleasent anymore cause I will keep looking at the temp gauge:hmmmm:

 

[shiroitenshi]

Do a radiator flush, or get the radiator changed, perhaps the cooling system is blocked, I think, because in my experience, the stock engine and even an 11.8 comp B20 will never get that hot. Only 12+ comp cars get really hot with all the ignition retard we put in for running with regular fuel.

Of course, maybe your water temp sensor is spoilt also a possibility.