160 Thermostat?
- Thread starter NHRACobra
- Start date
Modsaway - Understand that the thermostat is in the lower remote housing, the stock temp location is in the crossover tube connecting the heads and the temp gauge I'm reading is in the block between 7&8 So there's 20 degrees difference between the temp in the hottest part of the block and the thermostat activation.
If I remember right the fans are set to come on at 195 and 205. When the Evans thermostat housing gets here, we'll see what difference the better flow makes in the temps.
If I remember right the fans are set to come on at 195 and 205. When the Evans thermostat housing gets here, we'll see what difference the better flow makes in the temps.
evil04cobra said:
That O2 sensor is only good during certain times. It makes no adjustments whatsoever when the car kicks into closed loop.
There is an equilibrium involved with the coolant and pressure. Just because it doesn't boil at a certain temp, doesn't mean the pressure doesn't increase with temp. Isn't that basic thermodynamics?
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moridin2004 said:
Wow, talk about back from the dead. I am not sure I follow your first statement, the O2 sensor never makes adjustments anyway, it provides feedback for mixture control. When at WOT strategy, the PCM is certainly running the mixture off of precalibrated tables, but I think you took my previous statement out of context and got confused.
And yes, for any increase in temperature there will be an increase in pressure, that is as simple as it gets, but once again it is taken out of context. The argument in the original post revolves around the efficiency of coolant at a given pressure. To sum it up (again) the primary reason for a radiator cap is to prevent boiling of the coolant during operation.
Mike,
I've been seriously thinking about going with the 160 t-stat, since temps in southern Arizona have seemingly and suddenly taken a turn for the hot lately! I recently had my head replaced, solving the extremely loud tick I had and installed the LDC cooling mod as insurance. I'd like to do more if possible to keep engine temps down somewhat.
I completely agree that fan turn-on temps must be lowered to take advantage of a cooler t-stat. I'm assuming that even with the 160 t-stat, the minimum values for the PCM to attain closed loop operation are still met.
I've read all your comments on this thread and have one question for you. What is your coolant system comprised of, considering you're in Phoenix and we here in Tucson have to live in the same heat?
Willie
I've been seriously thinking about going with the 160 t-stat, since temps in southern Arizona have seemingly and suddenly taken a turn for the hot lately! I recently had my head replaced, solving the extremely loud tick I had and installed the LDC cooling mod as insurance. I'd like to do more if possible to keep engine temps down somewhat.
I completely agree that fan turn-on temps must be lowered to take advantage of a cooler t-stat. I'm assuming that even with the 160 t-stat, the minimum values for the PCM to attain closed loop operation are still met.
I've read all your comments on this thread and have one question for you. What is your coolant system comprised of, considering you're in Phoenix and we here in Tucson have to live in the same heat?
Willie
next time someone has one out, please drop it in a pot of boiling water on the stove. use the wife's candy thermometer and your eyes to see what temp it opens at.
THIS IS NOT ROCKET SCIENCE
THIS IS NOT ROCKET SCIENCE
ModsAway said:
Willie said:
Hi Willie!!
Good to hear from you!!
My cooling system is completely stock, with an low "Fan-on" temperature programmed into the tune. I do not drive the car daily and has seen less that 100 miles over the past few months. If something happenend and I needed to drive it everyday, I would not hesitate to purchase a larger radiator and possibly a slightly cooler t-stat.
Regards,
Mike
Wow, lots of info and opinions and few answers...
I've been around a few times and had the formal education so I'll give it a shot:
Running a 160 should have coolant START flowing at or near that temp. T-stats typically open all the way up within 8-10 more degrees. They have a variable amount of 'open-ness' that allows them to smoothly ramp up and ramp down the coolant flow.
Obviously, 160 is a cool engine temp and that's arguably bad for oil life, but great for making more power with timing/leaner fuel. The trouble is that many folks lose sight of the fact that 160 degrees isn't much hotter than the outside air on a hot day. This could be less than 60 degrees of temp differential between the radiator temp and the outside air. Compare with a 210 stat when it's 32 degrees outside and there is a huge, huge contrast.
Thermal dynamics dictate that a bigger temp differential increases thermal exchange rates, and running a 160 stat is a very very low thermal exchange rate for a given amount of airflow across a given radiator.
In other words, running the 160 is a hard temp to maintain under all operating conditions. Seems great on cold days, and your cooling system seems to fail on hot days (because you want the needle to stay at 160, not climb back up to where it used to run). Thusly, if you run one, it would be greatly additive to include other considerations:
First and foremost, be sure your tune slopes off it's aggressiveness as the coolant temp rises. I've scaled this on all the cars I've tuned and it works great, but takes lots of datalogging and time so unless you tune your own car or have lotsa cash, you may not get every last drop of HP from various temp ranges. At least peg the safe numbers for "coolest" and "hottest" and play it safe in between them.
Radiator size: This has huge benefits that get bigger with a bigger outside air/coolant temp differential.
Radiator airflow: Increasing airflow through the radiator can be acheived with an air dam under the rad support. This creates a vacuum behind and under the radiator that not only pulls more air through, it helps divert it under the engine instead of having it smack the front pulleys and struggle to get out.
These last two are very similar in their benefits but both are more/less effective on a scale that follows that temp differential I keep mentioning.
Another key concept is that the T-stat governs temps until the cooling capacity of the radiator is reached. If the T-stat is already all the way open, temps continue to rise until the temp differential gets large enough to stabilize them. This can happen on a small scale while sitting in traffic or a large scale on the freeway, but on a 109F hot day, 230-240 degrees in traffic is not unreasonable in MFR's eyes, so you could see this temp REGARDLESS of T-stat rating unless you increase airflow or radiator size.
One note I just have to make is that the gent from the first page who said the 160 will not leave coolant in the radiator long enough - he probably heard this from someone (as I have) but this is total BS. The faster the coolant cycles through the block and system (well, until some unattainable-by-normal-water-pumps rate of flow at which the friction alone causes heat) the more heat will be exchanged between the engine block and the outside air, given a constant rate of air through the radiator. There is simply no debating this fact.
It's my suspicion that folks who make this assertion are seeing hot temps on a hot day (because of bad temp diff.) and assuming it has something to do with too MUCH coolant flow, when it's really a lack of cool air. I've argued with my share of parts counter folk on this because of the disservice they provide their customers with the blatant misinformation, but they can't be wrong because they know every part number on their shelves.
Finally, there is no short answer. To change the T-stat alone is not changing the entirety of how your cooling system will behave. It's the same as adding a ported plenum alone and wanting 500rwhp. Balance is the key. It's a system.
I recommend changing the Tstat when you have a good reason to do it, are able and willing to readjust the whole system to accomodate (including re-tuning for more power when it's cool and safety when hot and a recal on the cooling fans), and you are comfortable with the fact that your coolant temps will necessarily become less stable in various operating conditions like freeway vs. city driving, epecially if A/C is on.
Running a higher coolant temp has some benefits:
Consistent tune
Cleaner oil
Hotter heater in the cold winters
...at the cost of less horsepower than you can probably even feel with a butt meter.
Bottom line, I've "been there, done that" over and over and my Cobra has the stock T-stat, some cold plugs (important!), and a conservative tune so that I can beat on it on the hottest days of the year with the AC on and not have a worry in the world.
:beer:
I've been around a few times and had the formal education so I'll give it a shot:
Running a 160 should have coolant START flowing at or near that temp. T-stats typically open all the way up within 8-10 more degrees. They have a variable amount of 'open-ness' that allows them to smoothly ramp up and ramp down the coolant flow.
Obviously, 160 is a cool engine temp and that's arguably bad for oil life, but great for making more power with timing/leaner fuel. The trouble is that many folks lose sight of the fact that 160 degrees isn't much hotter than the outside air on a hot day. This could be less than 60 degrees of temp differential between the radiator temp and the outside air. Compare with a 210 stat when it's 32 degrees outside and there is a huge, huge contrast.
Thermal dynamics dictate that a bigger temp differential increases thermal exchange rates, and running a 160 stat is a very very low thermal exchange rate for a given amount of airflow across a given radiator.
In other words, running the 160 is a hard temp to maintain under all operating conditions. Seems great on cold days, and your cooling system seems to fail on hot days (because you want the needle to stay at 160, not climb back up to where it used to run). Thusly, if you run one, it would be greatly additive to include other considerations:
First and foremost, be sure your tune slopes off it's aggressiveness as the coolant temp rises. I've scaled this on all the cars I've tuned and it works great, but takes lots of datalogging and time so unless you tune your own car or have lotsa cash, you may not get every last drop of HP from various temp ranges. At least peg the safe numbers for "coolest" and "hottest" and play it safe in between them.
Radiator size: This has huge benefits that get bigger with a bigger outside air/coolant temp differential.
Radiator airflow: Increasing airflow through the radiator can be acheived with an air dam under the rad support. This creates a vacuum behind and under the radiator that not only pulls more air through, it helps divert it under the engine instead of having it smack the front pulleys and struggle to get out.
These last two are very similar in their benefits but both are more/less effective on a scale that follows that temp differential I keep mentioning.
Another key concept is that the T-stat governs temps until the cooling capacity of the radiator is reached. If the T-stat is already all the way open, temps continue to rise until the temp differential gets large enough to stabilize them. This can happen on a small scale while sitting in traffic or a large scale on the freeway, but on a 109F hot day, 230-240 degrees in traffic is not unreasonable in MFR's eyes, so you could see this temp REGARDLESS of T-stat rating unless you increase airflow or radiator size.
One note I just have to make is that the gent from the first page who said the 160 will not leave coolant in the radiator long enough - he probably heard this from someone (as I have) but this is total BS. The faster the coolant cycles through the block and system (well, until some unattainable-by-normal-water-pumps rate of flow at which the friction alone causes heat) the more heat will be exchanged between the engine block and the outside air, given a constant rate of air through the radiator. There is simply no debating this fact.
It's my suspicion that folks who make this assertion are seeing hot temps on a hot day (because of bad temp diff.) and assuming it has something to do with too MUCH coolant flow, when it's really a lack of cool air. I've argued with my share of parts counter folk on this because of the disservice they provide their customers with the blatant misinformation, but they can't be wrong because they know every part number on their shelves.
Finally, there is no short answer. To change the T-stat alone is not changing the entirety of how your cooling system will behave. It's the same as adding a ported plenum alone and wanting 500rwhp. Balance is the key. It's a system.
I recommend changing the Tstat when you have a good reason to do it, are able and willing to readjust the whole system to accomodate (including re-tuning for more power when it's cool and safety when hot and a recal on the cooling fans), and you are comfortable with the fact that your coolant temps will necessarily become less stable in various operating conditions like freeway vs. city driving, epecially if A/C is on.
Running a higher coolant temp has some benefits:
Consistent tune
Cleaner oil
Hotter heater in the cold winters
...at the cost of less horsepower than you can probably even feel with a butt meter.
Bottom line, I've "been there, done that" over and over and my Cobra has the stock T-stat, some cold plugs (important!), and a conservative tune so that I can beat on it on the hottest days of the year with the AC on and not have a worry in the world.
:beer:
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Yes...Ford sets it computers to be optimal at 212-213 for all its internal sensors....Anything other than the stock thermostat will not give accurate readings to the pcm....Maybe a certified ford mechanic will jump in on this conversation.....
ModsAway said:
Thanks Turbocake.
I have a few thoughts.
The car comes with a 180 stat and at normal crusing speeds, say 45-70 mph, my car runs at about 180-185. Seems like it was intended to run at this temp but Ford sets the fans to come on around 220. This means that when you reduce/eliminate air flow, as in stop-and-go driving, the engine runs about 35-40 degrees hotter.
My opinion as to why Ford did this was for emissions reasons: As we all know, a gas engine at idle is pretty "dirty". The hotter the engine runs, the cleaner it becomes. So, at cruise all is well so they can run a cooler temp and obtain a little better performance (and maybe reduce the chance of those 7 & 8 pistons from creating problems).
So, my thought is to leave the 180 stat in there but lower the fan settings to 185 or so. You then have a consistent temperature nearly all of the time. Maybe harder on the oil but many of us change it way too frequently anyway (me included).
I have heard, and maybe incorrectly, that todays hotter engine temps do help with emissions but for engine longevity, the hotter temps are not the best (due to metal fatigue). Also, a consistent engine temp would seemingly be better, for power and easier on the parts, than one that swings from 180-220+.
I did see a dyno test about 10 years ago with a 440 Chrysler that put out a little less than 500 HP at the flywheel. With a 195 stat, it produced about 25 less HP than with a 160. It does help but as Turbocake said, look at the whole picture and the whole system.
I have a few thoughts.
The car comes with a 180 stat and at normal crusing speeds, say 45-70 mph, my car runs at about 180-185. Seems like it was intended to run at this temp but Ford sets the fans to come on around 220. This means that when you reduce/eliminate air flow, as in stop-and-go driving, the engine runs about 35-40 degrees hotter.
My opinion as to why Ford did this was for emissions reasons: As we all know, a gas engine at idle is pretty "dirty". The hotter the engine runs, the cleaner it becomes. So, at cruise all is well so they can run a cooler temp and obtain a little better performance (and maybe reduce the chance of those 7 & 8 pistons from creating problems).
So, my thought is to leave the 180 stat in there but lower the fan settings to 185 or so. You then have a consistent temperature nearly all of the time. Maybe harder on the oil but many of us change it way too frequently anyway (me included).
I have heard, and maybe incorrectly, that todays hotter engine temps do help with emissions but for engine longevity, the hotter temps are not the best (due to metal fatigue). Also, a consistent engine temp would seemingly be better, for power and easier on the parts, than one that swings from 180-220+.
I did see a dyno test about 10 years ago with a 440 Chrysler that put out a little less than 500 HP at the flywheel. With a 195 stat, it produced about 25 less HP than with a 160. It does help but as Turbocake said, look at the whole picture and the whole system.
ModsAway said:
Not on the 04 and I don't intend to unless I see significant reason... but I can offer some advice (it's long but relevant).
-background-
On my 5.0, I had an aftercooled vortech SQ (the quiet S trim) and a real thick BeCool radiator. I chose to run the MkVIII fan and shroud (modified to fit correctly and worth it as the fan was the strongest avail at the time, though I think our terminators have something even better) and the challenge was making it all physically fit in there - which led to not having anywhere for the air to go.
Front to back: Heat exchanger, AC cond., Radiator, Fan.
The electric fan wouldn't fit because of the huge crank pulley so I modified the mount brackets for the condensor and the little rubber feet for the radiator. I also trimmed the inside of the (GT) front bumper so the heat exchanger would sit further forward.
Once done, the bottom of the HE/Cond./Rad. all sat far enough forward to give me 1/8" clearance between the electric motor and the crank pulley.
Then the problem became getting the air out of the engine compartment, so I went to a junk yard and got an air damn off a 78 oldsmobile (no joke) and it almost fit perfectly, but the point is that it was 3x's as tall and far stronger than the stock air dam. I trimmed it, cleaned it, and mounted it with shims to give it a forward bias because it hung too low and would scrape even on road bumps. The forward rake got it off the ground for low speed stuff but at high speed it would bend down and get closer to the ground, making it work even better. I don't think the newer mustangs even have an air dam.
The combo was great - the electric kicked ass at a stand-still. Even at idle the air dam prevented a lot of air from looping around/under and recirculating through the radiator. Turning the fan off on the freeway and letting the air dam do it's job was incredible for the high-speed cooling. I could let the car sit and saturate for like 5 minutes with the AC on and get on the freeway and literally watch the temp needle drop... whereas before it would slowly decline.
I could never get the car to stay at 160 with the AC on on a hot day, but once it hit 190 it would stop climbing, so I reset some CT/timing slopes to accomodate a 190 running temp and set things super conservative above that.
Colder days had a GINORMOUS effect on these cooling mods and I actually had to stick cardboard in front of the radiator... obviating the incredible degree of impact of temp difference on thermal transfer.
Simple concept, understated impact in all automotive circles.
I would do some sort of air dam first and the radiator second. Even if the air dam is not enough, it will help the bigger rad once you get it.
:beer:
whitestang04GT said:
My training and experience with EEC-IV systems can support the assertion that this is untrue. If it was true your car would go apeshit on a cold startup... but that's taking your words at face value. I think the point you were trying to make is best answered below:
Running closed loop or including certain parameters of operation could easily be (and probably is) triggered by reaching a certain operating temp. There are rarely cases where all the programming in any PCM is completely understood, except by those who worked on the programming at Ford. Certified Ford mechanics, to my knowledge, know nothing of this level of detail. They're there (no offense) to make the service dept. money, not study PCM code.
V8Mustang said:
Don't forget mileage... CAFE has Ford up a creek and alternators these days put out serious juice. The downfall of that juice is the effort required to spin the alternator when it's called upon for duty (nevermind the kinetic to electric conversion inefficiency) and those fat ass fans can pull some serious current. Every time they turn on there is a spike and it even pulls your idle down if you listen. It's worth it for mileage ratings alone to leave that "damn fan" off until it's absolutely necessary, at least for Ford. I'd rather have my fan stop when the thermostat starts closing up (185 or so I guess).
the force is strong with this one...
I suspect this scenario:
1) Tune engine to reach 500 hp
2) Celebrate
3) Change T-stat and leave timing alone
What? Leave timing alone? Nono, you need to back off the timing because of the higher temps. If they really got it all outta this 440, it should be cautiously close to the edge of detonation.
Then they raise running temps via T-stat. Even if they don't lose power from more conservative timing (which would be a certain outcome) and try to keep the power by leaving the timing alone, they then get into a strong likelyhood of inaudible detonation costing them power. Been there, done that too.
At best, it's still a 440 Chrysler that I doubt had EFI. There could have been a dramatic effect on the carburation from the increased engine temps. Our engines have a lot of differences that actually support the idea that hotter is better because the oil flows more easily, and EFI keeps the tuning super consistent compared with yesteryear.
On the other hand, in my tuning experience, nothing helped get those extra few degrees (of timing advance) like cooler engine temps (or more octane) ... its all a balance though. Cheating the extra power with cooler temps is inconsistent for real-world driving and becomes counter productive when you start sacrificing engine life (nevermind the increased loads because of the extra power you're making) to make a few more ponies.
:beer:
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anyone thought about just leaveing the t-stat out???
You are probably right. And, yes it was carbed.
I am glad someone else knows about inaudible detonation. Drove me crazy years ago and no one seemed to realize it happens even if one cannot hear it - let alone those with loud exhaust.
95YellowGTBeast said:
This can practically substitute for race gas in any given tune, so long as the coolant stays cold cold cold... God only knows when long term running will bring temps up to your radiator's capacity and ruin your fake octane/blow your motor.
It's literally playing russian roulette with any hi output engine, especially if the weather is warm or hot.
Then whenever you're putzing around the oil is too cold and you're polluting your oil many times over what is normal.
In short, leaving the T-stat out vs. race gas does a half-ass job, is harder to R&R, and leaves you in a precarious situation with no safety net and the potential for worsened long term wear.
Race gas, at worst, will ruin your O2 sensors if you're running 116 leaded pure... but you can usually fill up on pump and climb a long hill in a tall gear to clean em off again.
There simply is no good reason to not run a T-stat.
As for inaudible detonation, it's definitely not talked about enough... probably because no one can hear it they'd half-ass care if they could hear it. All the more reason to look for an unmodded used car if you're looking to buy.
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Interesting reading, and very good info here. Thanks to all involved.
I have an Autotap/PDA arrangement that I run full time. I watch it pretty close on trips (if for no other reason than to pass the time on the highway). I have made a few observations concerning coolant and intake temps, and will use the trip I took today as an example.
Car fully warmed up, ambient temperature ~85-90F, fairly humid day. I have a completely stock cooling system, stock HE setup, and a simple K&N on the mass-air meter (relavent for IAT1 readings).
Going down the highway in the above conditions at ~75 mph, the coolant (via the ECT) stayed between 188 and 192. In town, it would climb to ~204-ish, never getting higher than that today. The temps would then start to come down to the high 190s (fan doing its job, I'm sure). Once back up to cruising speed, the temps came back down to ~190 within a minute or two.
Of note, if I was following a line of cars in traffic, I could see the difference in coolant temp (read a few to sometimes several degrees higher).
I have no real issues with those temps (though the weather will get hotter around here still, so we'll see). I do however intend to have my low speed fan come on 5-10 degrees sooner.
Intake temps....
IAT1 would run right at ambient going down the road, and shoot up to well over 100 in traffic - often 110-120. It took several minutes to get back down to ambient.
IAT2 stayed around 125-128 going down the highway. In town, it would quickly rise to 140+, never getting above ~145. It came down faster than IAT1 on the highway, but not as fast as ECT.
Not really related to this discussion - but still a cooling issue, I just ordered an LFP HE. I intend to log IAT2's with the stock and aftermarket HE on the same afternoon to try and get a feel for what it is worth.
I have an Autotap/PDA arrangement that I run full time. I watch it pretty close on trips (if for no other reason than to pass the time on the highway). I have made a few observations concerning coolant and intake temps, and will use the trip I took today as an example.
Car fully warmed up, ambient temperature ~85-90F, fairly humid day. I have a completely stock cooling system, stock HE setup, and a simple K&N on the mass-air meter (relavent for IAT1 readings).
Going down the highway in the above conditions at ~75 mph, the coolant (via the ECT) stayed between 188 and 192. In town, it would climb to ~204-ish, never getting higher than that today. The temps would then start to come down to the high 190s (fan doing its job, I'm sure). Once back up to cruising speed, the temps came back down to ~190 within a minute or two.
Of note, if I was following a line of cars in traffic, I could see the difference in coolant temp (read a few to sometimes several degrees higher).
I have no real issues with those temps (though the weather will get hotter around here still, so we'll see). I do however intend to have my low speed fan come on 5-10 degrees sooner.
Intake temps....
IAT1 would run right at ambient going down the road, and shoot up to well over 100 in traffic - often 110-120. It took several minutes to get back down to ambient.
IAT2 stayed around 125-128 going down the highway. In town, it would quickly rise to 140+, never getting above ~145. It came down faster than IAT1 on the highway, but not as fast as ECT.
Not really related to this discussion - but still a cooling issue, I just ordered an LFP HE. I intend to log IAT2's with the stock and aftermarket HE on the same afternoon to try and get a feel for what it is worth.
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