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Discussion Starter #1
I’ve been looking at the Mugen and Spoon thermostats.

Does anyone know if there are different part numbers for the stock thermostats between warmer climates and the UK?

As when I had my VXR you could order a thermostat from a warmer country and it would run around 10°C cooler and was around £30 or so.

So I’m thinking if I can get an OEM thermostat from Australia or South Africa it would have the same effect as an overpriced Spoon or Mugen one.

Just need to find out the part numbers … any ideas?
 

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Discussion Starter #3
Are you having problems with your car overheating?
not quite yet, however it has been bogging down a bit(prob due to higher air temps)

just thought of it as a cheap alternative to the named parts ;)
 

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Thats normal, due to intake temps and the air being less dense, A cool running stat won't help that.

This is what Hondata say on their site.

Tech - Thermostat


It is very important to use the correct temperature thermostat in your cooling system, as the water temperature plays an important part in closed loop fueling operation.
Many people think that running a colder thermostat will keep their engine from over heating or that it will give some performance gain. This is incorrect and will just keep the engine from properly warming up. The engine should be between 185 and 200 degrees when fully warm.
 

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Discussion Starter #5
Thats normal, due to intake temps and the air being less dense, A cool running stat won't help that.

This is what Hondata say on their site.

Tech - Thermostat


It is very important to use the correct temperature thermostat in your cooling system, as the water temperature plays an important part in closed loop fueling operation.
Many people think that running a colder thermostat will keep their engine from over heating or that it will give some performance gain. This is incorrect and will just keep the engine from properly warming up. The engine should be between 185 and 200 degrees when fully warm.
Yes but an OEM thermostat will ensure that it does run to those temps before it opens be the outside temp hot or cold... other wise there would be a lot of cars in warmer climates that never fully warm up.

I thought that there would be a benefit as instead of an engine in the UK running at say 200 degrees.. it would run at 190 which has to be beneficial, as the ecu wont be adding more fuel to cool the combustion .:confused:
 

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I thought that there would be a benefit as instead of an engine in the UK running at say 200 degrees.. it would run at 190 which has to be beneficial, as the ecu wont be adding more fuel to cool the combustion .:confused:

But it doesn't, it has no way to measure and compensate for cylinder temps.

It does compensate for Coolant temps when it is cold using a set of tables but once your up to anywhere running temps the Trim is set to 0
 

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Discussion Starter #7
But it doesn't, it has no way to measure and compensate for cylinder temps.

It does compensate for Coolant temps when it is cold using a set of tables but once your up to anywhere running temps the Trim is set to 0
Yes but surely the ECU monitors coolant temps to be able to switch to closed loop once a set temp is reached? which would lead me to believe you could adjust this temp (not that you would want to)
 

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When you start the car the car is in open loop, once you hit 600rpm, the ecu decides it is started and for 10-30 seconds the car runs in open loop with a combination of fuelling adjustments made by the last short term fuel trim ( last time it was driven) and the cranking tables, these are slowly replaced by the main fuel table.

Thats from Hondatas files, so basically after 30 seconds your in open loop with then adjustments made by the lambda and the ECT tables. Even then once you get to 72c and up there are 0 trims.

Why would you want to be in open loop for longer?
 

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Discussion Starter #9
When you start the car the car is in open loop, once you hit 600rpm, the ecu decides it is started and for 10-30 seconds the car runs in open loop with a combination of fuelling adjustments made by the last short term fuel trim ( last time it was driven) and the cranking tables, these are slowly replaced by the main fuel table.

Thats from Hondatas files, so basically after 30 seconds your in open loop with then adjustments made by the lambda and the ECT tables. Even then once you get to 72c and up there are 0 trims.

Why would you want to be in open loop for longer?
So what you are saying is the ecu times the amount of time it is in open loop (or auto choke as I like to think of it) when the engine is first started :confused:

and does not monitor coolant temp and use that to decide when to switch to closed loop ...

I get what your saying about the ecu switching from a crank table to open loop after 600rpm and the "autochoke" idle around 2k rpm which warms the engine up.

My theory is the ECU adds fuel ... The more fuel added the more the engine is cooled ... so if the coolant temp is lower less fuel will need to be added to cool the engine during combustion ?
 

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I think you are confusing adding fuel to cool the engine and some set ups to add fuel ( map AFR richer) to control cylinder temps and EGTs.

The Ecu adds fuel when cold for safety, when the engine gets to temperature the thermostat opens and water flows through the radiator to cool it, the thermostat opens and closes to keep this temperature constant-ish. If the engine coolant gets too warm the fans switch on until it falls below this temperature.


There is no provision in the Honda map to add fuel to control EGT or cylinder temps.

In theory if you over cooled the engine too much the ecu would add more fuel as it still thinks its "warming"
 

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Discussion Starter #11
I think you are confusing adding fuel to cool the engine and some set ups to add fuel ( map AFR richer) to control cylinder temps and EGTs.

The Ecu adds fuel when cold for safety, when the engine gets to temperature the thermostat opens and water flows through the radiator to cool it, the thermostat opens and closes to keep this temperature constant-ish. If the engine coolant gets too warm the fans switch on until it falls below this temperature.


There is no provision in the Honda map to add fuel to control EGT or cylinder temps.

In theory if you over cooled the engine too much the ecu would add more fuel as it still thinks its "warming"
So you agree that using an OEM thermostat that has been designed by the manufacturer for the same engine... just to run slightly cooler in a hotter climate but within ECU parameters would be beneficial?

So when tuning the ecu you wouldn't need to run richer to reduce cylinder temps ;)
 

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No I dont your not getting my point, the cooling system of the vehicle is to cool the block and head not the combstive charge. How are you going to measure cylinder temps per cylinder when tuning?

Look at Paul Wests comments on a thread in TDIs section tonight by Mebster, that car had a faulty o2 sensor and was running so lean the engine was running hot- did it add fuel to compensate- NO.

Like i've said a few times, the factory ecu does not add fuel to cool the EGT or intake charge etc. It adds fuel during warmup for safety and so if you open the thermostat sooner ( colder stat) you risk forcing the ecu into this state for longer thus increasing fuel consumption.

Vice versa in your last point say coolant temp is 100c for example and at the point of combustion the fuel/air charge ignites to 600c ( again for example) is reducing the coolant temp to 90c going to make a difference to EGT. On boosted cars extra fuel is added to richen the mixture for safety and to lower cylinder temps, from around 13.2AFR to 11circa for a charger maybe richer in some cases, thats a lot of fuel.

Or do the tuners on here fit new stats???? ;)
 

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Discussion Starter #13
No I dont your not getting my point, the cooling system of the vehicle is to cool the block and head not the combstive charge. How are you going to measure cylinder temps per cylinder when tuning?

Look at Paul Wests comments on a thread in TDIs section tonight by Mebster, that car had a faulty o2 sensor and was running so lean the engine was running hot- did it add fuel to compensate- NO.

Like i've said a few times, the factory ecu does not add fuel to cool the EGT or intake charge etc. It adds fuel during warmup for safety and so if you open the thermostat sooner ( colder stat) you risk forcing the ecu into this state for longer thus increasing fuel consumption.

Vice versa in your last point say coolant temp is 100c for example and at the point of combustion the fuel/air charge ignites to 600c ( again for example) is reducing the coolant temp to 90c going to make a difference to EGT. On boosted cars extra fuel is added to richen the mixture for safety and to lower cylinder temps, from around 13.2AFR to 11circa for a charger maybe richer in some cases, thats a lot of fuel.

Or do the tuners on here fit new stats???? ;)
well why didn't you just say that 10 posts ago lol,

Yeah I see where your coming from. so in short the Spoon and Mugen products are pretty useless ... especially for the price!
 

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Especially the price lol

Think of it this way, the air passing through the radiator only has so much cooling capacity, all these things do is open sooner, it wont affect temperature much at all.

Even on track etc in blazing heat I have never had an overheat issue, sitting in traffic idling etc no problems, stock cooling system is 100% :)
 

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Discussion Starter #15
Especially the price lol

Think of it this way, the air passing through the radiator only has so much cooling capacity, all these things do is open sooner, it wont affect temperature much at all.

Even on track etc in blazing heat I have never had an overheat issue, sitting in traffic idling etc no problems, stock cooling system is 100% :)
Yeah I was just trying to justify why I would need one .. especially when a cheaper alternative would be to source an OEM part from a warmer climate. Ive seen the mod on quite a few big power Corsa VXR's 380-400bhp+ so thought it must do something maybe with a different rad with a thicker core?

It is also quite amusing how TDI sell them ;)
 

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It is also quite amusing how TDI sell them ;)
TDi sell them because they are available for the older series cars and have been for about 10 years now. Fact is on the newer IVtec motors you actually need to be running slightly hotter for efficiency of the system.
If your that worried you buy a better radiator as its ultimatly the efficiency of that which control the systems temperature and not the thermostat.

You will find its actually detremantal to general running as well. The way you will see it is in winter. The thermostat will open earlier than it should and you won't have nice warm blowers. They will be cold. Engine also doesn't get upto full operating temperature so stays on "choke" all the time so your economy goers to crap as well.
 

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Discussion Starter #19
Ha cheers guys.

I'm always sceptical about taking advice about a product from someone that sells it.

However tdi state you don't need it and it could do more harm then good. Good to see there are some honest traders still about ;)


Sent from my iPhone.
 
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