Got to get a chiller!
Discussion
laugh:
SturdyHSV said:
Thought I'd contribute a bit too, why the hell not!
It is a matter of chemistry that higher combustion temps are better for emissions, but worse for power. The cars run at the higher temperature for emissions reasons.
In my experience, when sat stationary, the car will get to 100C comfortably. It will then continue to rise up to about 110C. Then the fans kick in for a bit, drop it to 100, then go back off. It then rises back to 110 and so on. This was experienced whilst parked in the pairing lanes on a 28C day.
Doing a run with the engine starting at 100+, I was getting a few degrees of timing pulled around peak torque (4500ish rpm)
On that same day, I then adjusted when the fans ramp up to speed (I'd actually already made the tune, I just flashed it on) and sat in the pairing lanes, it happily fluctuated between 90C - 92C, which then led to no timing being retarded.
In this instance, the cooling system was previously not being used to capacity, and so there was scope for more performance. Having a lower stat, I assume, would mean that more of the cooling system's capacity is used earlier (in temperature terms), and whilst operating within the cooling system's capacity, would result in cooler temps and better performance.
Once the cooling system is operating at maximum capacity, aside from any advantage of starting off a bit cooler, then I'd be forced to assume that the temperature is going to rise just the same, and ultimately to the same peak level.
But can we make any connection between water temperature and combustion temperature, or is it just so tenuous that it only exists in internet theory?It is a matter of chemistry that higher combustion temps are better for emissions, but worse for power. The cars run at the higher temperature for emissions reasons.
In my experience, when sat stationary, the car will get to 100C comfortably. It will then continue to rise up to about 110C. Then the fans kick in for a bit, drop it to 100, then go back off. It then rises back to 110 and so on. This was experienced whilst parked in the pairing lanes on a 28C day.
Doing a run with the engine starting at 100+, I was getting a few degrees of timing pulled around peak torque (4500ish rpm)
On that same day, I then adjusted when the fans ramp up to speed (I'd actually already made the tune, I just flashed it on) and sat in the pairing lanes, it happily fluctuated between 90C - 92C, which then led to no timing being retarded.
In this instance, the cooling system was previously not being used to capacity, and so there was scope for more performance. Having a lower stat, I assume, would mean that more of the cooling system's capacity is used earlier (in temperature terms), and whilst operating within the cooling system's capacity, would result in cooler temps and better performance.
Once the cooling system is operating at maximum capacity, aside from any advantage of starting off a bit cooler, then I'd be forced to assume that the temperature is going to rise just the same, and ultimately to the same peak level.
I suspect we may never have any clear answers, but it all sounds a bit like the Emperor's New Clothes to me.
stigmundfreud said:
all the temps are linked, laws of thermal dynamics cannot be avoided
So if the FI boys could "chill" the block would they be able to run more boost by having a lower combustion temperature? I'm not sure that the cylinder temperatures are that seriously affected by the block temperature. We're talking about the possibility (that's all it is)of lowering the water and block temperatures by a few degrees. I think the ambient would have a much greater bearing than anything we're talking about.
Maybe we should run Thunder Road in the winter and we'll all be faster. The FI boys can even run a load more boost too.
RichieSlow said:
I treat every day as a school day and I've read all of the above with interest, pondered it at length, and then decided that I'm with ARAF on this one.
To simplify my conclusion: the relationship between heat generation vs heat dissipation (ie. the cooling system) is not affected in any way by a different thermostat. Fans, radiator and airflow are still the same. Only the warming up phase is different because of the early opening stat, once up to constant running temperature there would be no difference.
Of course, if somebody can show me how they actually managed to record a reduction in block temperature and gained power as a result then I might stop and listen. Do we even know what temperature we should be aiming for anyway?
If I believed everything I'd read on here I'd think that changing the thermostat will gain me 20hp and taking out the air filter will get me 30 more.
There is merit in what Steve says, but as a Doubting Thomas I can't see an engine managing to stay at or around 71 deg C when being used spiritedly.To simplify my conclusion: the relationship between heat generation vs heat dissipation (ie. the cooling system) is not affected in any way by a different thermostat. Fans, radiator and airflow are still the same. Only the warming up phase is different because of the early opening stat, once up to constant running temperature there would be no difference.
Of course, if somebody can show me how they actually managed to record a reduction in block temperature and gained power as a result then I might stop and listen. Do we even know what temperature we should be aiming for anyway?
If I believed everything I'd read on here I'd think that changing the thermostat will gain me 20hp and taking out the air filter will get me 30 more.
As has been said by a few, it's a cheap theory to check, so that's my next course of action. It'll have to wait a while though....
RichieSlow said:
But can we make any connection between water temperature and combustion temperature, or is it just so tenuous that it only exists in internet theory?
I suspect we may never have any clear answers, but it all sounds a bit like the Emperor's New Clothes to me.
I'd say water temperature is at least vaguely indicative of how hot the block is. The hotter the block is, the hotter the pistons, the hotter the valves, the hotter the cylinder linings, the hotter the air flowing in, all of which contribute to higher temperatures in the combustion chamber, and thus an increased likelihood to knock, meaning retarded timing and loss of power.I suspect we may never have any clear answers, but it all sounds a bit like the Emperor's New Clothes to me.
The temperature of the actual combustion process itself I would 'assume' is lower if the temperature in the surrounding chamber is lower. I would assume otherwise if it was unrelated to combustion temperature or inversely related, manufacturers wouldn't run the engines hotter to skew the process towards emissions, and those after performance wouldn't want things cooler for more power?
RichieSlow said:
I treat every day as a school day and I've read all of the above with interest, pondered it at length, and then decided that I'm with ARAF on this one.
To simplify my conclusion: the relationship between heat generation vs heat dissipation (ie. the cooling system) is not affected in any way by a different thermostat. Fans, radiator and airflow are still the same. Only the warming up phase is different because of the early opening stat, once up to constant running temperature there would be no difference.
Of course, if somebody can show me how they actually managed to record a reduction in block temperature and gained power as a result then I might stop and listen. Do we even know what temperature we should be aiming for anyway?
If I believed everything I'd read on here I'd think that changing the thermostat will gain me 20hp and taking out the air filter will get me 30 more.
To simplify my conclusion: the relationship between heat generation vs heat dissipation (ie. the cooling system) is not affected in any way by a different thermostat. Fans, radiator and airflow are still the same. Only the warming up phase is different because of the early opening stat, once up to constant running temperature there would be no difference.
Of course, if somebody can show me how they actually managed to record a reduction in block temperature and gained power as a result then I might stop and listen. Do we even know what temperature we should be aiming for anyway?
If I believed everything I'd read on here I'd think that changing the thermostat will gain me 20hp and taking out the air filter will get me 30 more.
RichieSlow said:
So if the FI boys could "chill" the block would they be able to run more boost by having a lower combustion temperature?
I'm not sure that the cylinder temperatures are that seriously affected by the block temperature. We're talking about the possibility (that's all it is)of lowering the water and block temperatures by a few degrees. I think the ambient would have a much greater bearing than anything we're talking about.
Maybe we should run Thunder Road in the winter and we'll all be faster. The FI boys can even run a load more boost too.
You're missing the point.I'm not sure that the cylinder temperatures are that seriously affected by the block temperature. We're talking about the possibility (that's all it is)of lowering the water and block temperatures by a few degrees. I think the ambient would have a much greater bearing than anything we're talking about.
Maybe we should run Thunder Road in the winter and we'll all be faster. The FI boys can even run a load more boost too.
These valley blower guys have a huge chargeheater bolted to their engine. This is always imparting circa 100degC into the water of the cooling system.
The environment where all this water resides, reservoir etc has a huge lump of aluminium sitting at 100degC too.
Ambient temps recently have also been a lot higher.
Now why bother to strive with all this chargecooling bits and pieces, then making extra work for them by having such a warm engine ?
Likewise some have complained about problems with excessive oil temperature...again, as well as the job the oil has to do and heat it gains from this....it's surrounded by metal at 100degC too. Even up to 110degC, as the LS from the factory runs insanely warm.
So if we drop to a 70degC stat...we have just improved all of those problem areas by a huge amount. For virtually no cost.
And warmup phase is no shorter or longer...well it would be shorter because it's only rising to 70deg
Again you're basing your comment on the notion that 100degC is normal.
It is only normal where you wish to retain OEM temperatures. The engine will warm up exactly as it did before, only it will reach 70deg and stay there ( give or take ). This is the new normal, it is not a problem, and it is not a delayed warmup phase. It is normal.
In much the same way your new engine making 800hp isnt a problem, it's normal.
It isnt the same as the factory normal, that doesnt mean it's wrong. It's just different.
ARAF said:
There is merit in what Steve says, but as a Doubting Thomas I can't see an engine managing to stay at or around 71 deg C when being used spiritedly.
As has been said by a few, it's a cheap theory to check, so that's my next course of action. It'll have to wait a while though....
Then you need to fix whatever is wrong with the cooling system. It should have no difficulty doing that.As has been said by a few, it's a cheap theory to check, so that's my next course of action. It'll have to wait a while though....
stevieturbo said:
ARAF said:
There is merit in what Steve says, but as a Doubting Thomas I can't see an engine managing to stay at or around 71 deg C when being used spiritedly.
As has been said by a few, it's a cheap theory to check, so that's my next course of action. It'll have to wait a while though....
Then you need to fix whatever is wrong with the cooling system. It should have no difficulty doing that.As has been said by a few, it's a cheap theory to check, so that's my next course of action. It'll have to wait a while though....
The other thing to consider running hot...
Water boils at 100degC. Once it boils, it will have zero cooling ability as far as the engine goes.
Now yes it runs under pressure so will boil at a slightly higher temp etc etc...
But if the engine is only running at 90deg, 80deg, 70deg....then there is far less chance of that water ever boiling. You've just given yourself lots of headroom in that area.
I would never even contemplate taking a tuned car on track with the engine sitting at 100degC.
Temperatures are only ever going to go one way, and at 100degC to start with, you dont have any good places to go.
Water boils at 100degC. Once it boils, it will have zero cooling ability as far as the engine goes.
Now yes it runs under pressure so will boil at a slightly higher temp etc etc...
But if the engine is only running at 90deg, 80deg, 70deg....then there is far less chance of that water ever boiling. You've just given yourself lots of headroom in that area.
I would never even contemplate taking a tuned car on track with the engine sitting at 100degC.
Temperatures are only ever going to go one way, and at 100degC to start with, you dont have any good places to go.
stevieturbo said:
The other thing to consider running hot...
Water boils at 100degC. Once it boils, it will have zero cooling ability as far as the engine goes.
Now yes it runs under pressure so will boil at a slightly higher temp etc etc...
But if the engine is only running at 90deg, 80deg, 70deg....then there is far less chance of that water ever boiling. You've just given yourself lots of headroom in that area.
I would never even contemplate taking a tuned car on track with the engine sitting at 100degC.
Temperatures are only ever going to go one way, and at 100degC to start with, you dont have any good places to go.
Water expands at quite an alarming rate, just before it boils, so the system will be under a lot of stress from 105 to 115 deg CWater boils at 100degC. Once it boils, it will have zero cooling ability as far as the engine goes.
Now yes it runs under pressure so will boil at a slightly higher temp etc etc...
But if the engine is only running at 90deg, 80deg, 70deg....then there is far less chance of that water ever boiling. You've just given yourself lots of headroom in that area.
I would never even contemplate taking a tuned car on track with the engine sitting at 100degC.
Temperatures are only ever going to go one way, and at 100degC to start with, you dont have any good places to go.
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