Ideal temps and fan setpoints?

[CV355]

We finally got our Mach 1 finished, tuned, and on the road.  We had a 180f thermostat installed and a dual Spal electric fan setup.  Both fans can be controlled independently with outputs from the Holley EFI system, so I currently have the on/off setpoints as: 
Fan 1 On:  185
Fan 1 Off:  180
Fan 2 On:  190
Fan 2 Off:  185

The engine seems "happy" around 185-190.  The hottest it has been is 215f when one of the fan harness connectors came loose, shorted, and blew the fuse.  We drove home 7 miles without a fan, not a single drop in the puke tank.  I made an all new fan harness with dual fuses and 6ga primary feed, so that problem should never happen again.  Even with that, at 215 it was running beautifully, oil pressure strong even at hot idle.

I'm averaging about 8-9mpg so far which seems decent for what it is.  484ci with the Procharger F1D.

What's the consensus on operating temps?  Where do you like to see them, and what would you recommend for fan setpoints?

[jayb]

I had the fan temps on my supercharged FE turn on at 180 and turn off at 170.  I figure the cooler temps help keep the engine out of detonation, and also further away from an overheating situation if something goes wrong, both of which are more of a concern with a blower motor than they would be with a naturally aspirated motor - Jay

[CV355]

I had the fan temps on my supercharged FE turn on at 180 and turn off at 170.  I figure the cooler temps help keep the engine out of detonation, and also further away from an overheating situation if something goes wrong, both of which are more of a concern with a blower motor than they would be with a naturally aspirated motor - Jay

Makes sense to me.  What temp thermostat did you run with those setpoints? 

[cleandan]

The ideal temp range depends on your engines use and projected time between rebuilds.
For the vast majority of street engines, performance or not, a range between 185-210 is a great place to be.

We often get misdirected a tiny bit, concerning engine temps, by what drag racers try to accomplish.
They almost always seem to be running as "cool as possible", often in the 156-160 range.
What we forget is they are working towards consistency for each run, not long term engine operation as the drive across town, or the state.

They stage at 150, and by the time they are done with that run they are in the 190-210 range....where they go back to the pits and wait for the next round.
If they happen to go back to back rounds you will see all sorts of methods used to coll the engine between rounds, so going as far as to have dump valave installed to dump the hot water and install cool water.

This, accidentally, leads to some thinking 160 is a good temp because that guy runs fast and consistent.

There is also a big difference between overheating, running warmer than "normal", and controlling the temps.

When you overheat it means the cooling system was not capable of controlling the heat the engine is producing for the duty cycles being asked of the engine.

When you run warmer than normal, but don't overheat, it usually means you are running in high ambient temp conditions (100*F summer drive), low airflow conditions (stuck in traffic) highly loaded conditions (towing at max capacity or autocrossing) or maybe you just had a brief short stop (getting gas or short shopping stop)
None of these "high" temps really matter as long as they are controlled and the temps either come back down, or stabilize at a slightly higher than normal temp.

When you run too cool your engine does not come to full temp, which causes tolerances to be off, oil to retain moisture, and if the engine is computer monitored it can lead to tune issues because the engine thinks it is still "cold".

185*F is a great T-stat temp to run for most engines, and 195* is a close second depending on climate and use.

Mostly though, build your cooling system so it can control the temp wherever you decide to set the T-stat because temp control is the main concern.

[Cyclone03]

I look at it a bit backward,I want the fan off going down the road. TStat 185,off temp 190 on 195,fan 1. Fan 2 On 200 off 205. Fans run off a trianarry switch with AC on so fans only come on when high side pressure is high.

[CV355]

The ideal temp range depends on your engines use and projected time between rebuilds.
For the vast majority of street engines, performance or not, a range between 185-210 is a great place to be.

We often get misdirected a tiny bit, concerning engine temps, by what drag racers try to accomplish.
They almost always seem to be running as "cool as possible", often in the 156-160 range.
What we forget is they are working towards consistency for each run, not long term engine operation as the drive across town, or the state.

They stage at 150, and by the time they are done with that run they are in the 190-210 range....where they go back to the pits and wait for the next round.
If they happen to go back to back rounds you will see all sorts of methods used to coll the engine between rounds, so going as far as to have dump valave installed to dump the hot water and install cool water.

This, accidentally, leads to some thinking 160 is a good temp because that guy runs fast and consistent.

There is also a big difference between overheating, running warmer than "normal", and controlling the temps.

When you overheat it means the cooling system was not capable of controlling the heat the engine is producing for the duty cycles being asked of the engine.

When you run warmer than normal, but don't overheat, it usually means you are running in high ambient temp conditions (100*F summer drive), low airflow conditions (stuck in traffic) highly loaded conditions (towing at max capacity or autocrossing) or maybe you just had a brief short stop (getting gas or short shopping stop)
None of these "high" temps really matter as long as they are controlled and the temps either come back down, or stabilize at a slightly higher than normal temp.

When you run too cool your engine does not come to full temp, which causes tolerances to be off, oil to retain moisture, and if the engine is computer monitored it can lead to tune issues because the engine thinks it is still "cold".

185*F is a great T-stat temp to run for most engines, and 195* is a close second depending on climate and use.

Mostly though, build your cooling system so it can control the temp wherever you decide to set the T-stat because temp control is the main concern.

Good info, you sort of touched on a point I was going to bring up earlier.  About 20 years ago, I was on a small local Mustang forum and everyone was pushing 160 thermostats except for the one resident engine builder who was laughing at that approach for the exact reasons you listed.  I've always had "180 is fine" in my mind, but I've had some engines that liked to live around 220-230.   

As for my intended use- literally just cruising around town comfortably and reliably.  That's all I intend on using this car for.  I installed an oversized aluminum radiator with a dual Spal fan setup and shroud.  On a full day on the dyno, it never went a degree above 180.  On the street with the fans set up the way they are, it's at 182-185 reliably.  I never saw the 2nd fan kick on until I was stuck in a line of cars at a stop sign, but temps came down quick. 

I live in SC, so it does get hot...  Not AZ or FL hot, but still toasty.

[jayb]

I like to run a 160 degree thermostat.  This puts the engine at 160 on the highway, assuming the radiator is up to the drill.  Around town, it will cycle between 170 and 180 with the electric fans turning on and off.  Cooler water temps mean more power, because the intake charge isn't heated up as much in the intake manifold.  Now, if I was expecting to get 100,000 miles out of my engines, I'd probably run a 195 thermostat.  But even over many years, its unusual to have even 15,000 miles on one of my engines, before I pull it out to rebuild and change a few things.  So the extra longevity from running a higher temp is not something I care about.

[Rory428]

Have to agree with Jay, I run 160 Tstats on my "hot rod" type cars, and older vehicles. I would rather have my engine running 160-175 most of the time, as if I do get stuck in a traffic jam on a hot day, I have to believe having 30-40 degrees of safety margin before boiling over is preferable to only having 10 or 15 degrees of "wiggle room". And drag racers, especially Stock and Super Stock racers run their engines much cooler than CV355 mentioned. Pretty rare to see a Stocker or S/S car staging with over 120 on the temp gauge, in fact, many of the faster guys has "chillers" which pump ice water thru the cooling system in the pits or staging lanes, often stage at 60-80 degrees F, especially if there is a heads up race, or attempting to set a record, or improve on a qualifying position.
Concerning engine wear, in 1990, I did a ball hone quickie rebuild , with new rings on the factory installed standard pistons on my 1975 390 PU engine. Yes, It had a 160 thermostat, and that is where it normally ran, other than in hot (100+) air temps. I drove that truck until I sold it to another racer in 2014, who is still using it to haul his race car. So, if a standard bore 390 from 1975, is still running fine, and uses no oil between changes, after 33 years since the low buck rebuild, and the bores and pistons have been in service for over 45 years, I have to say that if this supposed "premature" engine wear hasn`t happened yet, when should it be a concern?

[CV355]

I like to run a 160 degree thermostat.  This puts the engine at 160 on the highway, assuming the radiator is up to the drill.  Around town, it will cycle between 170 and 180 with the electric fans turning on and off.  Cooler water temps mean more power, because the intake charge isn't heated up as much in the intake manifold.  Now, if I was expecting to get 100,000 miles out of my engines, I'd probably run a 195 thermostat.  But even over many years, its unusual to have even 15,000 miles on one of my engines, before I pull it out to rebuild and change a few things.  So the extra longevity from running a higher temp is not something I care about.

That's why most of the guys were running 160s, but they had quite different builds.  The engine builder was laughing at most of the guys doing it on daily driven stock or mildly modified mod motors.  I think I was running a 180 for a while until we finished the turbo 5.4 build, and then switched to 160 because it was mainly strip oriented.

For my FE build, I'd love to say it'll last 100k miles with the way I drive, but the likelihood of putting even 2000 miles on it in a year is low.  100k would happen long after my life expectancy... 



 

[CV355]

Have to agree with Jay, I run 160 Tstats on my "hot rod" type cars, and older vehicles. I would rather have my engine running 160-175 most of the time, as if I do get stuck in a traffic jam on a hot day, I have to believe having 30-40 degrees of safety margin before boiling over is preferable to only having 10 or 15 degrees of "wiggle room". And drag racers, especially Stock and Super Stock racers run their engines much cooler than CV355 mentioned. Pretty rare to see a Stocker or S/S car staging with over 120 on the temp gauge, in fact, many of the faster guys has "chillers" which pump ice water thru the cooling system in the pits or staging lanes, often stage at 60-80 degrees F, especially if there is a heads up race, or attempting to set a record, or improve on a qualifying position.
Concerning engine wear, in 1990, I did a ball hone quickie rebuild , with new rings on the factory installed standard pistons on my 1975 390 PU engine. Yes, It had a 160 thermostat, and that is where it normally ran, other than in hot (100+) air temps. I drove that truck until I sold it to another racer in 2014, who is still using it to haul his race car. So, if a standard bore 390 from 1975, is still running fine, and uses no oil between changes, after 33 years since the low buck rebuild, and the bores and pistons have been in service for over 45 years, I have to say that if this supposed "premature" engine wear hasn`t happened yet, when should it be a concern?

You guys are slowly convincing me to abandon my old way of thinking...    I may split the difference and run a 170...  But I'll test out a few more rides.  Went for about 15 miles last night and the temps never left 180-185 once it warmed up.

I can guarantee I'll get stuck in traffic around here.  We live in a very rural "Mayberry-like" town surrounded by suburbs and a city 25 miles down the road.  Lots of light gridlock at certain times.  I'd rather be safe than sorry.

[Jb427]

i run a 160 when do you hear of an engine having to be rebuilt because it was running too cool

[CV355]

i run a 160 when do you hear of an engine having to be rebuilt because it was running too cool

I am going on a 60 mile drive tomorrow in 90f weather, so I'll get to see if the 180 holds up.  The radiator and fan combo seems to be fine, and I'll use Jay's setpoints for on/off so the fans are constantly on.

[mbrunson427]

I saw you had a little trouble with your wiring..... I just used one of these MSD solid state relay deals on my Galaxie and it worked out great so I figured I'd share.

holley.com/products/electrical/wiring_and_relays/parts/75643

Being that you have a Sniper, you can wire the fan wires straight to the ground input side of this relay module.

On my galaxie I used this for fuel pump, gauge lighting, and overdrive. Have one spare terminal now I'm thinking about using for an electric fan.

[Phil Brown]

I was always told that the higher temp thermostats and running temps were for emissions reasons and an effort to increase gas mileage. The automakers did start using them it the mid 70's when all of the emissions stuff started getting crazy.
For me, the old stuff gets 160°, newer whatever lets the computer think that it's warmed up

[fryedaddy]

heres a good point for the 160 guys,ethanol fuels boil in the carb at high temps,and we all know what that causes.i could see it boiling through the sight holes on the side of the carb.thats why i keep mine cool,plus it runs better,win win

[Falcon67]

I run my race cars at 180.  Including the dragster on methanol, I stage at no less than 180. Less wear and tear IMHO.  Even more important in a street engine to run on the warm side.  Remember that hot water cools an engine better than cold water.  Especially with an aluminum radiator - they work better with more Delta T between the coolant and the air passing over it.  And also - electric fans need pass-by venting at speed.  Otherwise when running they will act about the same as a 16" piece of cardboard in front of the radiator.  Also, it's kinda hard to keep a race car around 160 here when in summer the pit surfaces are running 130F plus.

[CV355]

We got in about 50 miles in 92f heat (felt hotter, sun was direct and there was an "air quality" issue in effect) on Saturday with about 20 miles of stop and go traffic.  Fans kicked on and stayed on the entire time, temps slowly crept up to 207/208 and never really got any hotter.  I suppose the thermostat becomes somewhat of a moot point.  It was definitely a stress test for driver and car since I have no AC.  The car actually did better in the stop and go traffic than the highway.  I guess all the extra airflow at 60mph doesn't make up for the fact it's running 2800rpms vs fan flow and 1200rpms around town.  Wouldn't have been my guess but that's how it went.

On an 80f day, the temps hover at 185. 

The only potential issue I ran into was that with both fans running, hot idle, voltage drops to around 12.3-12.5v and the Holley EFI system throws a yellow "caution" but not full warning.  13.6-14.4v at idle/cruising otherwise.  100amp March alternator.  I might have to look into a 130-140.  This is also without the headlamps on, but I'm about to run an LED conversion so the draw will only be 2.2 amps.

[CV355]

I saw you had a little trouble with your wiring..... I just used one of these MSD solid state relay deals on my Galaxie and it worked out great so I figured I'd share.

holley.com/products/electrical/wiring_and_relays/parts/75643

Being that you have a Sniper, you can wire the fan wires straight to the ground input side of this relay module.

On my galaxie I used this for fuel pump, gauge lighting, and overdrive. Have one spare terminal now I'm thinking about using for an electric fan.

That's clean!  I wound up using two typical waterproof relays and hid them down behind the passenger headlamp.  The problem I ran into was that two factory crimps were not sufficient, so I remade the subharness.  I was looking at the Spal inverter kit for soft start but it was pricey.

[CV355]

I run my race cars at 180.  Including the dragster on methanol, I stage at no less than 180. Less wear and tear IMHO.  Even more important in a street engine to run on the warm side.  Remember that hot water cools an engine better than cold water.  Especially with an aluminum radiator - they work better with more Delta T between the coolant and the air passing over it.  And also - electric fans need pass-by venting at speed.  Otherwise when running they will act about the same as a 16" piece of cardboard in front of the radiator.  Also, it's kinda hard to keep a race car around 160 here when in summer the pit surfaces are running 130F plus.

https://www.northernradiator.com/HIGH_PERFORMANCE/SEARCH_BY_VEHICLE/FORD/MUSTANG/1969/Z40121

Here's the shroud and fan combo I am running.  This is as large as I can go for fans.  The fan housing is 1/8" from the blower belt right now and there's absolutely no room to go without modifying sheet metal or shimming the motor mounts back (also risky, headers are in a sweet spot with the steering linkages).   

I understand what you are saying about the pass-by venting.  There are some formed vents in there, but do you think that's enough?  I thought about adding a chin spoiler to help direct some air flow upward but to your point it's just hitting a solid face in a way.

Sorry for all of the stacked replies, the edit button isn't working for me for some reason.

[Falcon67]

OEM LT1 Camaro, mid 90s IIRC.  31x19 Summit dual 1" core aluminum.  Will fit Fairlane, not a Mustang.

[CV355]

OEM LT1 Camaro, mid 90s IIRC.  31x19 Summit dual 1" core aluminum.  Will fit Fairlane, not a Mustang.

I can't get a fan that deep in my engine bay.  I am trying some VP Madditive to see if that drops temps a few degrees.  It's just the 90f days where it seems to be an issue.  I drove it around in 80f weather two weekends ago and it never got above 185. 

[randomologist]

A little late to the thread here, but I run a 180* thermostat as I drive my car in the fall and spring quite a bit and here in Minnesota, that means I need heat. My fan controller doesn't independently control 1 fan at a time, both fans come on or neither comes on, but a resistor controls high/low in the fan assembly.

I have low speed set to start 190*, auto shutoff just over 180* so the thermostat is trying to control the engine temperature rather than the fans.
I have high speed set to come on at 200*, decreases to low at 190*

160* thermostats struggle to provide enough heat on the freeway with my Vintage Air Gen IV setup below 50* outside in my experience with the Vintage Air Gen IV conversion I have in my 69 Mustang. I also haven't noticed an advantage for the 160* vs. a 180* thermostat for street driving using my stock 427 FE. Once the thermostat is fully opened, it's all up to the radiator and fans. If the radiator and fans aren't up to the task, the temp will rise and the amount of added red light time I have between 160* and 180* is all of about 2 stoplights. Once that happens, the two thermostats are identical in traffic. The 180* thermostat is superior at cooling when I come off the freeway, though because the thermostat doesn't have to cycle as much so the coolant in the radiator is colder and more efficient at shedding engine heat.

[Dr Mabuse]

I always keep a closed system, by using a coolant recovery tank, and matching coolant recovery radiator cap.

Engine operating temperature is closely related to cylinder wall wear (among other variables):

[cammerfe]

Experience with my '63 ICB Effie/390 PI. I used a factory radiator with a large top tank but the radiator itself was only two tubes thick. When I got the truck, the '64 390 PI was already installed. the fan was a plastic flex unit and was spaced back from the rad in such a way that it undoubtedly did nothing. (There was no shroud.)

I had some experience with overheating while driving in traffic within the Detroit city limits and dumped the plastic fan for an electric item that I believe I bought at Gratiot. It was unitized such that the blades were formed with circular self-shrouding as part of the design. When I installed it, I used the mounting arrangement that passed posts through the core and held the entirety within a quarter inch or so of the back side of the rad fins. There were built-in anti-vibration pads also incorporated. Part of the package was a temp probe that was to be installed in contact with the tank and triggered the on-off switch. I was time-limited and had a convenient hole in the dash apron so I put in a simple toggle switch instead, to be used until I could do a completion. I discovered, however, that since I had a direct-read mechanical gauge and could therefore monitor the possibility of high temp, I never bothered to put in the probe. We don't get much higher temps than low nineties here in southeastern Michigan, and unless I was stuck in traffic, the engine never got much over 190. I'd simply flip the toggle and within several seconds the temp would be back in the 180s.

Problem solved.

KS

[cleandan]

We got in about 50 miles in 92f heat (felt hotter, sun was direct and there was an "air quality" issue in effect) on Saturday with about 20 miles of stop and go traffic.  Fans kicked on and stayed on the entire time, temps slowly crept up to 207/208 and never really got any hotter.  I suppose the thermostat becomes somewhat of a moot point.  It was definitely a stress test for driver and car since I have no AC.  The car actually did better in the stop and go traffic than the highway.  I guess all the extra airflow at 60mph doesn't make up for the fact it's running 2800rpms vs fan flow and 1200rpms around town.  Wouldn't have been my guess but that's how it went.

On an 80f day, the temps hover at 185. 

The only potential issue I ran into was that with both fans running, hot idle, voltage drops to around 12.3-12.5v and the Holley EFI system throws a yellow "caution" but not full warning.  13.6-14.4v at idle/cruising otherwise.  100amp March alternator.  I might have to look into a 130-140.  This is also without the headlamps on, but I'm about to run an LED conversion so the draw will only be 2.2 amps.

This suggests your cooling system is able to control the temps the engine is producing....which is exactly what you want.
Running temps in the 210* range are perfectly safe and nothing to worry about specifically because it got to that temp, but was controlled, rather than slowly creeping higher and higher.

Look into maximizing airflow through the radiator to increase cooling even more.
If there are air passages allowing incoming air to pass around the radiator try to block those to force the air through the radiator.
Also look into helping hot, under hood, air from being trapped under hood. If you can get it to flow out, even just a bit, it will help greatly with overall temp control.

The voltage drop is not a function of alternator amp capacity, unless of course you literally are drawing more amps than your current alternator can produce.
Look into all your electrical amp draws and add them up to figure out what is required from your alternator.

This voltage drop may be a function of a voltage regulator needing some adjustment rather than an incompatible alternator output.

[TurboChris]

This suggests your cooling system is able to control the temps the engine is producing....which is exactly what you want.
Running temps in the 210* range are perfectly safe and nothing to worry about specifically because it got to that temp, but was controlled, rather than slowly creeping higher and higher.

Does this statement apply to Aluminum block / head FE's as well? Mine tends to run to about 210 on the freeway on a 80 degree day. I was assuming that was higher than it should be and with summer coming I was planning to upgrade to a better radiator and electric fans. Wouldn't be a bad thing if I didn't have to. 

Anyone tried this controller? My brother swears by it. It's a nice set up. Soft start, PWM, etc.

https://www.autocoolguy.com/

[Falcon67]

OEM LT1 Camaro, mid 90s IIRC.  31x19 Summit dual 1" core aluminum.  Will fit Fairlane, not a Mustang.

I can't get a fan that deep in my engine bay.  I am trying some VP Madditive to see if that drops temps a few degrees.  It's just the 90f days where it seems to be an issue.  I drove it around in 80f weather two weekends ago and it never got above 185.

Yes, that is an issue for Mustangs with the lower hood profile.  Basically, I found that when I used the car as a street/strip car that it was easier to control the temp with a 195 thermostat.  Trying 160, and in the summer here even 185, it was difficult to keep a hot street car with 450+HP from creeping temp in traffic.  It's nothing here in summer to have road surfaces run 130+.  It was 112F on the back porch here Monday and San Angelo set an all-time record temp of 114F yesterday.  The basic issues are having enough radiator surface area and moving enough air across the core.  Aluminum seems to like hotter temps - more Delta T - between the core and ambient air.  The cores in aluminum radiators are larger with more surface area - usually 1", dual core - than copper, and the fins are less dense to allow more air to cross the core.  The issue with a thick copper core and dense fin count is getting air though the thing.  I found that out the hard way with a $$$ custom copper unit years ago in Houston.  I required a deep flute Flex-a-lite "salad slicer" 18" engine driven fan with a shroud to pull enough air though the thing to control engine temp.

I once had a Griffin cooling system engineer tell me the "simple" thing to remember - hot water = cool engine. 

[Urgefor]

Anyone tried this controller? My brother swears by it. It's a nice set up. Soft start, PWM, etc.

https://www.autocoolguy.com/

I haven't used that controller, but I can say I am happy with the PAC-2800BT from Dakota Digital to control the 2005-2014 Mustang performance cooling fan (M8C607MSVT) from Ford.  With minor modifications, the fan was a perfect fit for the stock copper radiator in my '66 Galaxie.  I'm not huge on apps for this and that, but being able to connect to the controller using my phone in 5 seconds or less for configuration, etc., is pretty handy.  Made adjusting fan setpoints a joy since I could work with those while driving around town (as a passenger of course  ).

For anyone still using the OE copper radiator in their FE powered mid '60s full sized car, I added some pics of the Ford fan mentioned above with the radiator out of the car.  Hard to get a good understanding of how well it fit the radiator and the fairly shallow depth of the fan while it is installed in the car.

 

[TurboChris]

While the bluetooth aspect sounds cool. The dakota digital is a two speed controller. The cool thing about the PWM (Pulse With Modulation) controllers is they are variable from 10% to 100%. And Soft start so no giant draw when they start up.  So you only get the exact amount cfm you need to keep it at the preset temps. I think that tech is the some of the "latest greatest"

[/quote]


I haven't used that controller, but I can say I am happy with the PAC-2800BT from Dakota Digital to control the 2005-2014 Mustang performance cooling fan (M8C607MSVT) from Ford.  With minor modifications, the fan was a perfect fit for the stock copper radiator in my '66 Galaxie.  I'm not huge on apps for this and that, but being able to connect to the controller using my phone in 5 seconds or less for configuration, etc., is pretty handy.  Made adjusting fan setpoints a joy since I could work with those while driving around town (as a passenger of course  ).
[/quote]

[Nightmist66]

Anyone tried this controller? My brother swears by it. It's a nice set up. Soft start, PWM, etc.

https://www.autocoolguy.com/

I have the NB-100 in my car. I mounted it in the passenger fender behind the headlights to keep it hidden. I really like it. Soft start, only runs the fans as fast as needed to keep a set temperature, runs for up to 1 minute after shut-off to help cool down, turn the knob to set temp where you want it, and the bypass feature so you can cool down before a run or etc.

[TurboChris]

I'm also considering these guys .... pretty impressive tech.

https://deltapag.com/collections/accessories/products/temperature-speed-controller