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Jon A

180 Thermostat Results (With Towing Data)

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I agree it is the oil temps being up that helps power, ECT temps being down help power.

 

Also, the thermostat rating is when it begins to open, it doesn't click open. A 160 is fully open and flowing fully before the stock thermostat even begins to open. The volume of coolant flow is 100% greater at 193 degrees! That means cruising and moderate or short and heavy acceleration events will remain cool. As stated above, more extreme and/or prolonged heavy use will still raise temps and then require a radiator.

Edited by Higgs Boson

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Yeah, I don't adjust ECT adders either except as you do, in the event of overheat conditions. You were also logging EOT's as well which you know typically don't run parallel to ECT's but it sounds like more testing could be done to validate this finding or theory, but I can't imagine it hasn't been done by now. I guess I can fire up google because since I sold the Dyno it gets expensive for me to play with this shit now.

I only make oil temperature monitoring a regular thing on my Piper Cherokee 235. :)

 

I don't make it a habit to monitor EOT on the dyno unless doing specific part testing and OBD2 monitoring is unreliable as few vehicles have an oil temperature sensor and rely on calculated data.

 

 

Thank you. That explains it. Try testing at the same oil temp and get back to us. You know, the scientific method and all.

 

I don't know if you've ever towed something heavy up a long hill, but when you do the oil heats right up even when the coolant remains cool. Try roadracing in cold weather--the coolant temp can remain very cold and you can still hit 300 degree oil temps. Most of the heat put into the oil is caused by the oil shearing against itself and has a very direct relationship with the engine output at the time--not the engine's coolant temp. These vehicles will only have more of a relationship between the two because the oil cooler is in the radiator.

 

 

Fair enough. When I have the opportunity on a vehicle that is NOT F/I, I will control those variables and report back. I suspect that you'll find the correlation between ECT, EOT and power output to be greater than expected. I would suggest the same to you as well, as scanner data is EASILY manipulated (intentional or not) via adjustments within the tune as well as vehicle modifications. For all you know, your calculated oil temperature is off by 20* or more.

 

The rest of the comment is missing the point. There is much discussion over whether or not a colder temp thermostat (and thus a colder engine) will make more power or not and the data I have collected over the years on thousands of vehicles doesn't jive. Speaking with other professional tuners as well as industry experts, the conclusion has been the same. Whether it helps your piece of mind when towing a heavy load up a grade or not is irrelevant to the power production comments I was quoting.

 

Just to be forthcoming, I have run 160* thermostats on vehicles (2 5.7L, 1 superchargered 6.0L) in the past and have a 180* stat in our 8.1L burb. The 160* stats were all eventually changed back to stock with absolutely no loss in power and the 8.1L has the lower temp stat to help keep the oil cooler and reduce vaporization effects and the resulting MAF damage and combustion chamber fouling that plague those engines.

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Just realized I misquoted the NASCAR temps. They utilize a pressurized coolant system to get combustion chambers as high as possible, running at nearly 300°.

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Show me one of those that serves as an example of a colder engine making more power.

 

One of my very own:

 

Dyno3.jpg

 

Run 24 was what I posted "for bragging rights" because I considered it legit as everything was up to full temp. Run 22 was after the car had sat and cooled off for a while.

 

 

 

 

 

 

With temperatures being equal, a lower air density requires MORE ignition advance.

 

 

Which is exactly what I already said. But you missed the point. If you hold the density constant, the car will make more power with low IAT's running full timing than it will at high IAT's and retarded timing. So saying that pulling timing at a higher temp has nothing to do with the power decrease isn't accurate.

 

 

 

 

 

 

 

I would bet that if you calculated the CFM output of your fans and divided it by the cross sectional area of those fans, you could pretty easily determine the speed of air through them and thus, the point that vehicle speed ends up pushing the air faster through the radiator than the fans can draw.

 

 

If only life was so easy. I hate to break it to you, but when you're driving down the road at 60 MPH you don't have air going through your radiator at 60 MPH. When you study fluid dynamics and heat transfer you learn all about the resistance to airflow of various heat exchangers. A thicker heat exchanger with more densly spaced fins is much more efficient at transfering heat with a given airflow, but since it has a higher resistance to airflow you get less airflow...so does it exchange more or less heat? Of course it's a balancing act and the answer is "it depends" upon a bunch of different factors and will only be correct for a very specific case. Then you throw in some performance curves showing how fans can add to airflow when being assisted by another fan (or the vehicle's movement) like the SAE paper quoted above and you can see this old belief that the fans become irrelevant at some normal towing speed is quite in error.

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good for nascar. can you tell me why my race car runs .15 quicker at 140 degrees vs 190? how about why my vette runs faster at 175 than it did at 215?

 

NASCAR cars run nose to tail at full throttle with very little airflow going through the radiator so they run hot by nature. all fast drag cars run cold coolant temps. NASCAR has to run high pressure coolant systems to raise the boiling point because rules dictate body shape and radiator size, which is tiny. They don't run hot because it's better, they do everything they can to run cool because they are forced to.

 

Do a little research on why things are the way they are, don't just throw out some numbers. Heat is the enemy of power production, always has been, always will be. It's very basic thermodynamics.

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Damn, I'm the special kid licking the windows in this conversation.

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One of my very own:

 

Dyno3.jpg

 

 

 

Where's the information showing intake air temperatures or even ECT for that matter? Without test conditions and appropriate probes, there is just not enough data for that to be relevant,,,

 

 

 

Which is exactly what I already said. But you missed the point. If you hold the density constant, the car will make more power with low IAT's running full timing than it will at high IAT's and retarded timing. So saying that pulling timing at a higher temp has nothing to do with the power decrease isn't accurate.

 

 

I think you're missing the bigger picture there. With density constant, a lower IAT cannot occur without pressure increasing at the same time. Watch your scanner some time and you'll see that on an 80 degree intake air temperature pull, you'll see your air mass (density x volume) sit at around .88-.89 multiplied by your kPa/100. Increase air temperature to 110* and your air mass will decrease by a proportion of (80+460)/(100+460). Pulling timing at a higher temperature is a necessity to match the change in MBT. Power is lost due to the density drop. Plain and simple, unless you are preparing to disprove the ideal gas law...

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good for nascar. can you tell me why my race car runs .15 quicker at 140 degrees vs 190? how about why my vette runs faster at 175 than it did at 215?

 

NASCAR cars run nose to tail at full throttle with very little airflow going through the radiator so they run hot by nature. all fast drag cars run cold coolant temps. NASCAR has to run high pressure coolant systems to raise the boiling point because rules dictate body shape and radiator size, which is tiny. They don't run hot because it's better, they do everything they can to run cool because they are forced to.

 

Do a little research on why things are the way they are, don't just throw out some numbers. Heat is the enemy of power production, always has been, always will be. It's very basic thermodynamics.

 

Sounds to me like you have other issues going on.

 

Regarding the Nascar situation, my source regarding their operation is an individual that was closely involved with the Roush-Yates team in exploring the move to EFI and the challenges that would be presented. Not exactly wikipedia.

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a cooler thermostat is not going to make much difference with on the road temps in the summer time with the a/c going..etc (towing). The truck is going to run hotter than 180F anyway. In the winter it might make some difference given the mod to the on/off on the electric fans. Not much gained on modern engine by changing the thermostat to a cooler settting...etc. You would be better served in my view to go with a larger capacity radiator if one was offered for your specific model truck. (Stock engine)

 

Once you exceed the temp of the cooler thermostat...thats it and you are dependeant on the fans and radiator at that point and its going to be very common to be over 180F towing or driving on the road in teh summer with the a/c on. The lower rated thermostat has not positive benefit at that point. In general the a/c will add 10 degrees F to the operating temp of the engine.

 

In the winter the truck most likely will run cooler, but it might screw with your fuel milage too...

Edited by Elbert

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Once both thermostats are wide open, it the cooling system has the same capacity.

 

Exactly. The only difference is the colder stat offers a ~20° cushion in real world operating conditions when not pushing the truck hard. Probably 1-2 minutes to get from 175 to 198 when pushing it real hard.

 

Incorrect. Maybe after I've explained it for the 1000th time the lightbulbls will come on.... The cooling systems are operating at the same capacity once the thermostats are wide open and the fans are running full speed. This occurs at 244 degrees with the stock system. At every temperature below that, the modified system is operating at a higher capacity. If 244 degrees is never reached, the modified cooling system has been superior 100% of the time. Being vastly superior for a range of 40 degrees before 244 degrees means the likelyhood of ever reaching 244 degrees is greatly reduced.

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Incorrect. Maybe after I've explained it for the 1000th time the lightbulbls will come on.... The cooling systems are operating at the same capacity once the thermostats are wide open and the fans are running full speed. This occurs at 244 degrees with the stock system. At every temperature below that, the modified system is operating at a higher capacity. If 244 degrees is never reached, the modified cooling system has been superior 100% of the time. Being vastly superior for a range of 40 degrees before 244 degrees means the likelyhood of ever reaching 244 degrees is greatly reduced.

But at highway speeds there is more air going through the radiator than what the fans can pull no?

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Where's the information showing intake air temperatures or even ECT for that matter? Without test conditions and appropriate probes, there is just not enough data for that to be relevant,,,

 

On the crashed hard drive about two laptops ago. It's relevant because I told you what happened. Just because I don't have the exact temp difference down to the last degree doesn't make it irrelevant, just not worthy of a technical paper. I pretty vividly remember the reason the best dyno the car ever put down was relegated to the trash heap, that's not something one forgets. You haven't posted a single graph or number from your uncontrolled single test with multiple variables changing.

 

 

 

 

I think you're missing the bigger picture there. With density constant, a lower IAT cannot occur without pressure increasing at the same time.

 

 

No, you are. I clearly said when run at a higher pressure the very first time. So now for the third time--when the car can make more power when running at the same density, stating that the density alone is entirely responsible for the power loss is nonsensical.

 

 

 

 

Just realized I misquoted the NASCAR temps. They utilize a pressurized coolant system to get combustion chambers as high as possible, running at nearly 300°.

 

 

NASCAR cars run nose to tail at full throttle with very little airflow going through the radiator so they run hot by nature. all fast drag cars run cold coolant temps. ...

 

 

Yes, here's how it works: A much larger cooling system is required to get an engine producing that much power to a lower steady state temp. If the larger radiator weighs 10 lbs more and the additional airflow costs 25 HP worth of drag at 200 MPH but the engine only makes 10 more HP at the lower temp, what do you do? You run the smaller cooling system and resulting higher temps because that's what makes your car faster. This is an example of how a little bit of information can be a dangerous thing. One piece of data plucked out of a very complex problem without an understanding of the context can give very false impressions.

 

Whether it helps your piece of mind when towing a heavy load up a grade or not is irrelevant to the power production comments I was quoting.

 

What exactly do you think is the subject of this thread? After stating several times that nobody is going to care if they have an extra 5 HP (even if you were right) when they have to slow down to keep temps in check, pull over to the side of the road or stare at a warning light while hoping for the best, why are you even arguing in this thread?

 

While it is more rare with these vehicles than it is with some others (Ecoboost, Ecodiesel, etc), it has happened to members here. Tell me, are the Ecoboosts still making an extra 5 HP when they enter "Reduced Engine Power Mode?" Try selling that to those guys.

 

The arguement you've started would be well suited to a thread where you tell people the secret to faster 1/4 mile times is idling the engine with your fans shut off to heat it up to 240 right before your run! Why don't you go try and sell that to some drag racers who might care. You could offer them custom tunes to do just that!

 

 

 

I only make oil temperature monitoring a regular thing on my Piper Cherokee 235. :)

 

 

One guy in this very thread has noted his truck has given the "High Oil Temp" warning while towing and you mock those who care about their oil temp? Inappropriate.

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But at highway speeds there is more air going through the radiator than what the fans can pull no?

 

Go back and read post #21.

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Jon, given the assistance the fan has on keeping temps lower, would an engine driven fan, like the big clutch fans of earlier models provide more margin? They have many times the air moving capability of electric fans.

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Clearly you see me as more of an enemy than an ally. I'm in here because two individuals emailed me about it. If you look back at what I posted and what it was in response to, it was regarding some of the performance claims made. Not about your heating concerns. Despite what your post was initially about, these other subjects came up and my comments were clarifying in that regard. My post was about the purpose of higher temperature thermostats and the impact of IAT on power output.

 

I did comment on the efficacy of electric fans running at highway speeds as well, I'll delete that and all other comments on my end if it will end this mindless bickering. My post says that MOST calibrations will disable fans at speed. That includes all trucks with fan control from 1998 to 2013 (as verified this evening). I don't have a 2014 in front of me to verify as well, so I will take your word on that until I do.

 

 

 

No, you are. I clearly said when run at a higher pressure the very first time. So now for the third time--when the car can make more power when running at the same density, stating that the density alone is entirely responsible for the power loss is nonsensical.

 

Density is density. I think you're getting hung up on timing as the producer of power when it is only a determination of when the burn is needing to be started to reach peak pressure at the appropriate point ATDC. If you were able to lower the temperature while keeping density constant, you still have the same mass of oxygen and thus the same mass of fuel. Torque potential is directly correlated to fuel mass. Timing absolutely changes because that hotter air charge would burn more quickly and requires timing retard to achieve peak cylinder pressure at the appropriate point ATDC.
This argument is a moot point without being able to test in a controlled environment, which neither of us can do at this late of time. I will see if we can get that done on a friend's engine dyno test cell, with an appropriate boost increase in a follow up run to match an increase in temperature.

 

 

One guy in this very thread has noted his truck has given the "High Oil Temp" warning while towing and you mock those who care about their oil temp? Inappropriate.

 

Quite a stretch attributing what I am concerned with logging to that gentleman's concern, don't you think? My stated concern about it in an aircraft is due to oil being used not only for lubrication but also for cooling. An engine failure while flying is a life or death situation...

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