Cooler thermostat = better power and efficiency?

[frogsta]

I've been reading and a there's a lot of different opinions on this. Can anybody clarify whether these would give better efficiency, given that I'm not constantly flooring it?

[L67 Calais]

Well i put mine in yesterday and i can tell you it did nothing performance wise.

[wraith]

Sigh another one who doesn't know how to search.

Oh wow look what I found. What do you know some one just last week asked the same thing

82 degree thermostat?

[ephect]

It can help ur engine run cooler thus unleashing extra power but dnt expect to feel it as u mash the go pedal.

Think of it this way, do more of these small mods and u may gain that extra bit of something.

[PRAVX II S]

whats wrong with the factory one?
engines have optimum temperature range

[BowTie]

Cooler thermos require corresponding adjustments to your ecu tune.

If the engine doesnt detect itself to be up to the correct temp it will be worse than a standard one.

The operating temperature setpoint in the ecu needs to be matched to the thermo.

[savage1987]

Nothing to gain from running a cooler thermostat on any near stock car.

It will actually decrease your engine's efficiency by bumping it outside the temp. range it was designed to burn most efficiently in.


Waste of money.

Sam

[Shearer]

I put a cooler thermostat in an Ecotec V6 almost 3 years ago. No issues with the car since.

Give it a go and see what you think

[seq4x4]

I put one with a few go fast bits and a tune. Rarly make it over a 1/4 heat, worst its been is in bad start stop and makes it to almost half way.

[vscom88]

put 1 in the vs with the custom tune and it made it start hunting on idle
had no heater, yes the car was cooler at operating temp but it still overheated while doing a static burnout

[vsv6dude]

IMO in Australia in a place like Perth climate or hotter there is no issue in running a 82deg thermostat all year round.

In colder climates like Hobart perhaps stick with the stock 91deg on a stock vehicle all year round.

BTW 82deg is the temperature at which the thermostat starts to open.

In the US the 91deg and 82deg thermostats have been used in the Buick 3800 by GM.

I believe it helps to bring the temperature down a bit quicker once you are moving.

If you are stuck in-stop start traffic then it will make no difference and it will be the same as the 91deg once the thermostat is fully open.

[frogsta]

(@Sam) I've heard the VS ecotec runs best at 79 degrees Celsius? I was searching, which was why I found generally a lot of differing opinions. I will be modding the car a little overall but probably not forced induction, and I thought fuel burns more efficiently at a lower temperature too. I'm not necessarily looking for more power, though if it helps I'm happy :P

[savage1987]

My understanding is that the engine temp mainly impacts the mixture developing in the heads, but I have really got no idea. I'm no expert, I just don't subscribe to the 'lower is better' temp gauge theory. Perfect = perfect, not lower = better.

[Brett_jjj]

The standard thermostat is designed by holden to keep the engine running at its optimum temperature, at the optimum temps,emmisions are decreased and power output is increased. I saw a perfect example of this the other week. This guy I know had no thermostat in his VS V6 ute. It was just managing to reach around 70 degrees once it was fully warmed up according to the tech1. He got me to fit a new thermostat and gasket for him, and he couldnt believe the difference in how it ran. It was heaps better then before, I could even tell from the passenger seat that it was running way better then before. It was reaching around the 90 to 100 degree mark in town according to the tech1. Cooler is definitely not better unless you are talking about once the temp has hit 100 degrees or more.

[frogsta]

Oh damn, cheers. I ordered one a few days back, not sure if I'll get around to fitting it but if I do I'll post any differences

[BowTie]

For those that really want a thermo upgrade, Intense Racing in the US do high flow units in standard and lower temps.

They are adamant that without ecu mods, you need to stay with the standard temp.

I'm running one of their high flow standard temp units and it keeps the car warm enough to run properly yet improves the cooling times with a wide open thermo.

This results in a tighter operating temp range keeping the variations to minimum.

Warning: You wont be able to stop at just a thermo. I'm a gold customer with these guys.

http://intense-racing.com/Merchant2/...e=3800_Cooling

[MADDNE33]

I went from a 91c to a 81c in my l67 and it droped the average temp from just under half to a qaurter good easy mod IMO

[frogsta]

Sounds good. I'm not fussed on any performance drops so yeah

[BlackVXGTS]

From graperacing.com. In short, having a low reading on the temperature gauge might make you feel better but it's not doing anything for your engine reliability or power level:

Thermal Efficiency
Before we go into what a cooling system does and how to modify it, you must first understand what the engine does. Plain and simple, an engine makes heat energy and turns it into mechanical energy. Any heat generated that does not get used to make power is wasted energy. How well an engine converts the heat it generates into mechanical energy is known as it's thermal efficiency.

The cooling system takes heat from the engine, heat that ideally could have made power, so the cooling system actually takes power from the engine. It is a necessary evil, without a cooling system, the engine will overheat and the internal parts will have a very short life.

A cooling system will also reduce the chances of detonation. With new cooling systems and coolants, it is possible to run today's engines hotter, which increases thermal efficiency. If you take less heat away from the engine, there will be more energy available to make power. Any heat that is radiated off the engine, and out the exhaust system is also wasted heat energy
that did not get used to make power, which reduces thermal efficiency. The average engine has only a 25-30% thermal efficiency, so 70-75% of the heat generated never gets used to make power. An average 250hp gasoline engine is actually burning enough fuel to make about 1000 hp, making it a very inefficient machine.

Cooling System Goals
Most people seem to think that all a cooling system needs to do is keep the engine from overheating. But what is not realized is that if the engine runs too cool, thermal efficiency is lost and power is reduced. Many will argue that an engine has more power when it is cold, but that is only due to the fact that the intake air is colder and denser, actual BSFC (Brake Specific Fuel Consumption BSFC is a measure of fuel efficiency) is higher.

Remember that an engine’s whole job is to make heat and turn it into mechanical energy. Running the engine as hot as possible (limited by the detonation limit) will increase power and provide a lower BSFC. If the coolant begins to boil, steam pockets will form and detonation will limit power (by forcing you to retard timing to less than optimum or run the engine cooler). Most of today's high output street motors using a water/ethylene glycol mixture will be limited to about 200° F before detonation becomes a problem (unless other steps are taken).

Another goal of modifying the cooling system is to even out the temperatures of the whole engine, which is not easy to do. All it takes is one hotter cylinder to run into detonation to limit the engine’s power. It only takes 1 cylinder to limit all of them. Most high performance engines are close to detonation to begin with, so a good cooling system is a must.

Nucleate Cooling Phase
As coolant flows through the system it absorbs heat from the engine parts that it comes in contact with. As it does this some of the coolant will boil and form tiny steam bubbles (absorbing a lot of heat in the process) on the internal engine surfaces.

When these bubbles get larger they become a flow restriction and the flowing fluid pushes them away from the surface and that process starts over again. The process is called the Nucleate Cooling Phase.
When the coolant boiling point is too low or the flow rate is too slow, these bubbles can become too large and form steam pockets that insulate that surface from being cooled. This usually happens around the combustion chambers, the hottest parts of the engine. Once the steam pocket forms the surface will rise in temperature (even though the coolant is not overheating) and cause that part to overheat, which can cause detonation and / or other problems.

[vsv6dude]

For those that really want a thermo upgrade, Intense Racing in the US do high flow units in standard and lower temps.

They are adamant that without ecu mods, you need to stay with the standard temp.

I'm running one of their high flow standard temp units and it keeps the car warm enough to run properly yet improves the cooling times with a wide open thermo.

This results in a tighter operating temp range keeping the variations to minimum.

Warning: You wont be able to stop at just a thermo. I'm a gold customer with these guys.

INTENSE-Racing.com: INTENSE™ High Performance 3800 Thermostats

Running too high flow rate is probably not a good idea as there is insufficient time for heat exchange to occur.

My reading has been that correct coolant flow rates is more important to allow the radiator to do its job properly.

Running an 82deg with the correct (design flow) flow rates and using a 180deg F theromstat will do no harm.

Running a 165deg F or colder is where problems start to occur.
At least that's what I have read on the US sites where enthusiasts are running these, they are failing the annual emissions testing.

[acarmody]

To much flow is bad, too cool of temperature is bad. Well here is an idea, there are literally hundreds of thousands of commodores running perfectly fine with the stock spec thermostat, cars that are everyday drivers, dyno queens, and drag kings. Isn't that proof enough that the stock unit is more than good enough?

[vsv6dude]

From graperacing.com. In short, having a low reading on the temperature gauge might make you feel better but it's not doing anything for your engine reliability or power level:

Thermal Efficiency
Before we go into what a cooling system does and how to modify it, you must first understand what the engine does. Plain and simple, an engine makes heat energy and turns it into mechanical energy. Any heat generated that does not get used to make power is wasted energy. How well an engine converts the heat it generates into mechanical energy is known as it's thermal efficiency.

The cooling system takes heat from the engine, heat that ideally could have made power, so the cooling system actually takes power from the engine. It is a necessary evil, without a cooling system, the engine will overheat and the internal parts will have a very short life.

A cooling system will also reduce the chances of detonation. With new cooling systems and coolants, it is possible to run today's engines hotter, which increases thermal efficiency. If you take less heat away from the engine, there will be more energy available to make power. Any heat that is radiated off the engine, and out the exhaust system is also wasted heat energy
that did not get used to make power, which reduces thermal efficiency. The average engine has only a 25-30% thermal efficiency, so 70-75% of the heat generated never gets used to make power. An average 250hp gasoline engine is actually burning enough fuel to make about 1000 hp, making it a very inefficient machine.

Cooling System Goals
Most people seem to think that all a cooling system needs to do is keep the engine from overheating. But what is not realized is that if the engine runs too cool, thermal efficiency is lost and power is reduced. Many will argue that an engine has more power when it is cold, but that is only due to the fact that the intake air is colder and denser, actual BSFC (Brake Specific Fuel Consumption BSFC is a measure of fuel efficiency) is higher.

Remember that an engine’s whole job is to make heat and turn it into mechanical energy. Running the engine as hot as possible (limited by the detonation limit) will increase power and provide a lower BSFC. If the coolant begins to boil, steam pockets will form and detonation will limit power (by forcing you to retard timing to less than optimum or run the engine cooler). Most of today's high output street motors using a water/ethylene glycol mixture will be limited to about 200° F before detonation becomes a problem (unless other steps are taken).

Another goal of modifying the cooling system is to even out the temperatures of the whole engine, which is not easy to do. All it takes is one hotter cylinder to run into detonation to limit the engine’s power. It only takes 1 cylinder to limit all of them. Most high performance engines are close to detonation to begin with, so a good cooling system is a must.

Nucleate Cooling Phase
As coolant flows through the system it absorbs heat from the engine parts that it comes in contact with. As it does this some of the coolant will boil and form tiny steam bubbles (absorbing a lot of heat in the process) on the internal engine surfaces.

When these bubbles get larger they become a flow restriction and the flowing fluid pushes them away from the surface and that process starts over again. The process is called the Nucleate Cooling Phase.
When the coolant boiling point is too low or the flow rate is too slow, these bubbles can become too large and form steam pockets that insulate that surface from being cooled. This usually happens around the combustion chambers, the hottest parts of the engine. Once the steam pocket forms the surface will rise in temperature (even though the coolant is not overheating) and cause that part to overheat, which can cause detonation and / or other problems.

So having provided the sea of information what is the verdict ?

It is understood that the function of the thermostat is to get the engine to correct operating as fast as possible for engine oil additives to work, emissions reduced, fuel economy etc.

Is a 180deg F thermostat suitable for a street driven ecotec engine ?

Or is the stock 195deg F thermostat the go ?

Or only supercharged and modified engines require the 180deg F?

I am using a 180deg F for 7 years and in hot climates such as Perth using this one all year round works well.
I think this is the absolute minimum temperature (180deg F) for the engine to operate efficiently within its design parameters.

[wraith]

Use the stock thermostat. Really is no point to going colder.

[DAKSTER]

A thermostat has one function and one only. It stops or severely restricts waterflow until the engine reaches operating temperature, at which point it opens fully and allows an optimum water flow through the engine.

The operating temperature of the engine is controlled by the fans, which are in turn controlled by the computer.
Installing an 82c thermostat should make no difference to your engine whatsoever, except for allowing full water flow q few seconds earlier than would be usual. To lower the actual operating temperature, you need to alter the computer, not the thermostat.

[ephect]

ok i knew there was a reason for going cooler thermo that related to performance. not a performance increase more as a perventative measure to ensure performance is mantained.

taken from MACE's website

KEY BENEFITS

•Drops engine temperatures by 10°C
•Prevents damaging overheating and improves performance
•DIY installation
•Super-affordable performance modification


WHY

Heat is the single biggest killer of performance, and excess heat can actually damage your engine and its internal parts.

Avoiding heat in its various forms will not only help you boost your engines performance, but also ensure that power levels are consistent and reliable.

A cheap way to reduce coolant temperatures in your Ecotec V6, L67 supercharged & Buick V6 engines is by installing one of our 82°C cooler thermostats.


WHAT

Factory-supplied thermostats for the Ecotec V6, L67 supercharged V6 & Buick V6 start to open at 92°C. This is far too hot for a performance application.

At this temperature, your engine could begin to suffer from pre-ignition (detonation) or at the very least the ECU will retard the ignition timing to prevent detonation robbing you of precious horsepower.


HOW

Our 82°C cooler thermostat opens much earlier than the factory item, allowing coolant to flow through the engine from the radiator much sooner. This limits the peak engine temperature by 10°C, preventing overheating.

With your engine running consistently cooler, your horsepower levels across the rev range will be more consistent and reliable which is especially good for boosted applications or even when towing on hot summer days.