Devek Radiator and Fans.....Installed!
08-09-2005, 01:29 PM
#16
We're into relativism here. What is too cool?
160 F is not.
100 F is.
But you're not going to get your car to run at 100f pretty much whatever you do, though 160 is doable.
160 F is not.
100 F is.
But you're not going to get your car to run at 100f pretty much whatever you do, though 160 is doable.
08-09-2005, 03:11 PM
#17
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Originally Posted by sharkmeister85
Just to complete the circle, what kind of damage results from running too cool (assuming no other mods) and what exactly constitutes "too cool"?
Glenn
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08-09-2005, 03:18 PM
#18
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OK, I'll get some pics of the fans up in a day or so.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
I've been running a cooler t-stat for several years. Although it does nothing to improve cooling on hot days (the reason I put it in), it has had zero adverse effect on the car on cool/cold days. The car runs fine, if not better, at 170 than at 195.
Now, it may be if you run REALLY cold all the time you won't boil off the condensation that can collect in the oil. That's a different issue. Even at 170, the condensation will vaporize, although it will be a bit slower than at 195.
My 99 Durango had a bad spark knock when hot issue from new that was resolved completely by installing a 160F t-stat after the other factory remedies failed to eliminate it. It has huge cooling capacity and rarely if even gets over the 160 t-stat opening (unlike the 928). I cannot find one iota of adverse effect from 3 years and 80K miles of driving like this. Same gas mileage, etc. The spark knock threatened to kill the motor in short order. The cool t-stat looks like it may take many more years to cause any measurable harm.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
I've been running a cooler t-stat for several years. Although it does nothing to improve cooling on hot days (the reason I put it in), it has had zero adverse effect on the car on cool/cold days. The car runs fine, if not better, at 170 than at 195.
Now, it may be if you run REALLY cold all the time you won't boil off the condensation that can collect in the oil. That's a different issue. Even at 170, the condensation will vaporize, although it will be a bit slower than at 195.
My 99 Durango had a bad spark knock when hot issue from new that was resolved completely by installing a 160F t-stat after the other factory remedies failed to eliminate it. It has huge cooling capacity and rarely if even gets over the 160 t-stat opening (unlike the 928). I cannot find one iota of adverse effect from 3 years and 80K miles of driving like this. Same gas mileage, etc. The spark knock threatened to kill the motor in short order. The cool t-stat looks like it may take many more years to cause any measurable harm.
Last edited by Bill Ball; 08-09-2005 at 04:16 PM.
08-09-2005, 05:39 PM
#19
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Originally Posted by Bill Ball
OK, I'll get some pics of the fans up in a day or so.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
I've been running a cooler t-stat for several years. Although it does nothing to improve cooling on hot days (the reason I put it in), it has had zero adverse effect on the car on cool/cold days. The car runs fine, if not better, at 170 than at 195.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
I've been running a cooler t-stat for several years. Although it does nothing to improve cooling on hot days (the reason I put it in), it has had zero adverse effect on the car on cool/cold days. The car runs fine, if not better, at 170 than at 195.
As most have seen a lower temp thermostat does nothing to make a 928 run cooler on a hot day. Once the thermostat opening temp has been reached (and the oil is up to temp) the only thing that keeps a 928 at the right temp are the fans. Temp goes up, triggers fan switch, fans come on, coolant cools down slightly, repeat again and again.
Once up to proper operating temp I seriously doubt whether the thermostat has anything to do with the running temp of the engine.......I would believe its totally controlled by fan action at that point and it would be really odd to have the fans stay on till thermostat intervention is required......just doesn't make sense to do so especially with the dual S4 setup.
08-09-2005, 07:22 PM
#20
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I now run two separate Hayden relays for the fans, and have them mounted low and away (arrow). Temp probes are in the radiator cooling fins. I have them wired hot all the time (protected by 25 amp inline fuses). They will come on after the engine has been shut off and run for a few seconds whenever the temp gets high enough to turn them on. You can have them connected in a key on only configuration too. I originally had them adusted to come on at the 1st white line. I've since adjusted them to come on midway between the lines and it holds steady in the middle even in stop and go traffic w/ac on. When exiting the car, you can really feel the hot air blowing out from under the car. Yes, these move a lot of air. Enough, that I took the auxillary fan out of the front of the condensor, it's just not needed.
08-09-2005, 08:19 PM
#21
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With 93deg thermostat, car ran at near top white line.
Would creep over top white line on hot day with traffic and A/C.
With 75deg thermostat, car would run slightly below middle tween the 2 white lines.
Went with 75 deg thermostat.
Higher temp. Higher pressure. I say that cause 1 1/2 week into 93 deg thermostat,
the used Behr blew it's sidetank seal. Maybe the Behr was on it's last legs. But the
90+ ambient temps and running over the top white line probably didn't help it's
longevity.
My uninformed observation.
Ernest (NYC) Running cool.
Would creep over top white line on hot day with traffic and A/C.
With 75deg thermostat, car would run slightly below middle tween the 2 white lines.
Went with 75 deg thermostat.
Higher temp. Higher pressure. I say that cause 1 1/2 week into 93 deg thermostat,
the used Behr blew it's sidetank seal. Maybe the Behr was on it's last legs. But the
90+ ambient temps and running over the top white line probably didn't help it's
longevity.
My uninformed observation.
Ernest (NYC) Running cool.
08-09-2005, 08:39 PM
#22
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Originally Posted by Bill Ball
OK, I'll get some pics of the fans up in a day or so.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
And, I don't get the temperature precaution thing. The car is designed to run just fine over a range of temperatures. My car runs great when the temp gauge is at the first white line (170?), as it is on cold days, or the second white line (195?) or even above that, as it often is on hot days. I see these remarks that running at some temp or another will mess up you car, but the car runs the same regardless. The mixture is adjusted for temp, etc.
Post #14 here
And... coincidentally... from Post #14 here:
NOTE: ENGINE OILS - the Anti Wear (AW) components in the oil's additive package including the Viscosity Improver (VI) (especially in mineral oils) is activated by temperature and the sooner the oil temperature is above 80C the better. An oil's IDEAL operating temperature range is roughly about 85C-110C and the 928 engine is VERY EASY on its engine oil if it is of the correct quality rating A3/B3 and viscosity (typically 5w-40) for the temperature the vehicle is used in
I thought sure there was more, but I can't find it now. I thought that at some point a thorough explanation of what happens to oil that is run at less than 85°C was posted but I can't find it.
08-12-2005, 12:41 AM
#23
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Hi,
this information may be of some help in this thread and contains data from about 150 temperature readings taken off my S4 with an IR reader in an ambient range of -5C to 43C. All readings were obtained using the same test protocols (engine on minimum of 30 minutes, same read position and etc)
OILS
The ONLY oils officially Approved and Listed are synthetics of Group 3 and above
These may be referred to as "hydro-cracked" lubricants and at the lowest end they are called "semi-synthetic"
These oils, and especially Group 4 and 5 types, will tolerate elevated temperatures with ease
To become Porsche Approved and Listed they must pass special Porsche developed test protocols covering viscosity integrity (at high temperatures 100C & 150C), foaming, volatility etc.
Certain engine oils (some Amsoil types and etc.) thicken with use more than others and these non Approval Listed oils should not be used IMO
OIL TEMPERATURE
All engine lubricants require heat and pressure to activate parts of their additive package
This is especially so of Anti-Wear (AW) chemicals! In a general sense these commence to function at around/above 50C depending on the formulation
On engine warm up the oil trails the coolant temperature by about 10-15C until both stabilise In a 928 using the correct viscosity (0w-40 or 5w-40) this will be evident by the reduction of OP at idle speed to around 1.5-3bar.
As the 928's engine oil cooler/intercooler thermostat opens at 87C it may be that the oil spends much of its life around 87-100C depending on use. In normal use I have never recorded an oil temperature above 98C even at high speed and at an ambient of 40C
Thicker oils (only one SAE50 oil is Approved - M1 5w-50) may take slightly longer to heat up and will operate at a slightly higher temperature of perhaps 1 to 2C. Some non Approved SAE50 oils (15w-50, 20w-50) may operate up to 10C+ hotter than the correct viscosity Approved lubricants
Engine oils that are thinner than SAE40 (0w-40 or 5w-40) such as 10w-30 etc are not Approved
ENGINE TEMPERATURE
IMHO the 928 needs to operate in a "core" range of around 91-95C and slightly above at times. It will too if all of the cooling, air flow and lubrication systems are working as designed. In an S4 the coolant "overheat" warnings are issued at 118C and 120C - this means the engine is designed to be tolerant of temperatures beyond 100C and up to say 115C
Many sensors on a 928 are dependent on the factory thermostat being fitted - this thermostat remained the same during the 928's production life span
The 928s cooling system has enormous capacity when viewed in total as a "complete" system (coolant subsystem, air flow subsystem, lubrication system) and is largely untapped by the average owner during normal use. Even at an ambient of 35C my S4's flaps are still at 30% and fan speed around 75%!
Note: If the engine takes longer to reach the core temperature more engine wear can occur
The following temperatures are the average of about 150 readings from my 928 database;
Core: 93C
Top radiator hose: 73C
Lower radiator hose at thermostat: 82C
IMHO I believe that the 928 engine is at risk of struggling to get to the thermostat's crack point (87C) under certain circumstances and to hold a normal "core" temp of around 91C+
I hope this is of some help
Regards
this information may be of some help in this thread and contains data from about 150 temperature readings taken off my S4 with an IR reader in an ambient range of -5C to 43C. All readings were obtained using the same test protocols (engine on minimum of 30 minutes, same read position and etc)
OILS
The ONLY oils officially Approved and Listed are synthetics of Group 3 and above
These may be referred to as "hydro-cracked" lubricants and at the lowest end they are called "semi-synthetic"
These oils, and especially Group 4 and 5 types, will tolerate elevated temperatures with ease
To become Porsche Approved and Listed they must pass special Porsche developed test protocols covering viscosity integrity (at high temperatures 100C & 150C), foaming, volatility etc.
Certain engine oils (some Amsoil types and etc.) thicken with use more than others and these non Approval Listed oils should not be used IMO
OIL TEMPERATURE
All engine lubricants require heat and pressure to activate parts of their additive package
This is especially so of Anti-Wear (AW) chemicals! In a general sense these commence to function at around/above 50C depending on the formulation
On engine warm up the oil trails the coolant temperature by about 10-15C until both stabilise In a 928 using the correct viscosity (0w-40 or 5w-40) this will be evident by the reduction of OP at idle speed to around 1.5-3bar.
As the 928's engine oil cooler/intercooler thermostat opens at 87C it may be that the oil spends much of its life around 87-100C depending on use. In normal use I have never recorded an oil temperature above 98C even at high speed and at an ambient of 40C
Thicker oils (only one SAE50 oil is Approved - M1 5w-50) may take slightly longer to heat up and will operate at a slightly higher temperature of perhaps 1 to 2C. Some non Approved SAE50 oils (15w-50, 20w-50) may operate up to 10C+ hotter than the correct viscosity Approved lubricants
Engine oils that are thinner than SAE40 (0w-40 or 5w-40) such as 10w-30 etc are not Approved
ENGINE TEMPERATURE
IMHO the 928 needs to operate in a "core" range of around 91-95C and slightly above at times. It will too if all of the cooling, air flow and lubrication systems are working as designed. In an S4 the coolant "overheat" warnings are issued at 118C and 120C - this means the engine is designed to be tolerant of temperatures beyond 100C and up to say 115C
Many sensors on a 928 are dependent on the factory thermostat being fitted - this thermostat remained the same during the 928's production life span
The 928s cooling system has enormous capacity when viewed in total as a "complete" system (coolant subsystem, air flow subsystem, lubrication system) and is largely untapped by the average owner during normal use. Even at an ambient of 35C my S4's flaps are still at 30% and fan speed around 75%!
Note: If the engine takes longer to reach the core temperature more engine wear can occur
The following temperatures are the average of about 150 readings from my 928 database;
Core: 93C
Top radiator hose: 73C
Lower radiator hose at thermostat: 82C
IMHO I believe that the 928 engine is at risk of struggling to get to the thermostat's crack point (87C) under certain circumstances and to hold a normal "core" temp of around 91C+
I hope this is of some help
Regards
08-14-2005, 12:24 PM
#25
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Not to be a downer, but I had a lot of problems with those Hayden controllers on two fans. One 16" fan seemed okay but two 12" fans would burn it out, so if you start having on-off problems you should probably go for a heavier unit.
08-14-2005, 03:19 PM
#26
We had a choice?
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Yes, one relay unit was not enough for two fans. I burned the relay out in about 3 weeks. Bought another relay for the unit and added another separate unit. Each fan has it's own relay unit and temperature probe. No problems since.
Sorry Chuck, I won't be at Marble Falls this year. That is the Scout weekend for my deer hunt on the Aransas Wildlife Refuge (Federal) the following weekend. My Son and I have had this planned for a year. I thought I could come up on Saturday, but my son reminded me of my previous obligation. Any other weekend in September would have been a go.
Sorry Chuck, I won't be at Marble Falls this year. That is the Scout weekend for my deer hunt on the Aransas Wildlife Refuge (Federal) the following weekend. My Son and I have had this planned for a year. I thought I could come up on Saturday, but my son reminded me of my previous obligation. Any other weekend in September would have been a go.
