What eng T stat F rating do you use ?

[Pentalab]

I have noticed everything from 160 F to 190 F T-stats being used. How low is too low ? Has anybody correlated various T stat ratings with stuff like IAT's.... and /or eng oil temps, eng coolant temps, cyl head temps, etc ? On my SCT-X3, I can adjust the low speed eng fan turn on threshold over a wide range..and ditto with the high speed eng fan turn on threshold. In fact, they overlap by quite a bit in the middle. On paper, it even appears that the high speed threshold can be set to a lower turn on temp, vs the low speed turn on temp. (I have not tested that..yet)

Right now I'm using a 190 F T stat. Low speed fan set to kick in at aprx 204 F.... and I think the high speed fan is set to kick in at aprx 214 F.

Idling in the driveway, (summer time, 73 F day)... the coolant temps creep up to 204F, then low speed fan kicks in.... and temps drop to 194 F....( 2-4 mins)...then low speed fan shuts off. Temps start to rise back up to 204 F, low speed fan kicks in, and the cycle just repeats itself over + over.

I'm assuming IF a lower rated T stat is used, that both the low + high speed turn on thresholds also have to be reduced accordingly ? (I forget exactly how low the SCT-X3 will allow me to reduce the thresholds, but it was quite a bit)

Way back when, (since lost the url), I saw a graph of eng coolant temps vs cyl wear. As temps came down, cyl wear increased by a bunch. The graph, if I remember correctly went from 140- 210 F.

Will the lower T stat rating + lower fan speed thresholds even work.... or will the temps rise anyway, if stuff like sustained and high rpm used ?

 

[07 Boss]

A lower thermostat is not going to lower operating temps. It will may take a little longer for it to warm up but will not lower temps. At 190* your current T stat should be open. A lower temp T stat will be open also so the system should act the same. If you want to run lower temps, have your fans come on earlier but the car is meant to operate at a certain temp range. I believe it is right around 200*.

 

[Juice]

Run the stock temp Tstat.

Running a cooler tstat is something that old carb'd hotrodders did. Run the engine cooler fatten up the mixture = more power at the cost of increased engine wear. A cold running engine is also hard on the oil, increasing the need to change oil more frequently.

 

[eighty6gt]

less delta between coolant temp and rad temp = less btu removed

 

[RED09GT]

I always wonder why companies like livernois and kenne bell recommend a cooler thermostat.
Lots of ecoboost tuners recommend the cooler t-stat as well.

I have not seen anything to convince me that a cooler thermostat is either better or worse.

 

[EBABlacknChrome]

Brenspeed recommends a 160* for boosted engines. Not sure why.

Sent from my SM-G930V using Tapatalk

 

[groundpounder]

Jason at DOB also recommends a 160 for his kits.

I run a 180 degree in my Mishimoto radiator equipped N/A mustang. Have my GT500 fan set up to turn on low at 180 and kick to high at 190. Car runs a consistent 195 degrees winter or summer here in Vegas, both cruising down the highway at 80mph (2400rpm) or sitting in traffic.

 

[01yellerCobra]

I always figured the cooler temps helped keep detonation at bay boost/power starts getting cranked up. Along the same lines as running a cooler range spark plug. I would imagine keeping the engine temps down helps keep the radiant heat down for the intercooler system as well.

Just a shade tree mechanics thoughts.

 

[429244]

160 here and I am using a Roush TVS. To notice any real difference, you have to turn on the cooling fans sooner. I can't remember my temps but it is the lowest that you can set with the SCT (I think 170 low & 180 high). The 160 t-stat helped keep IAT temps lower while I was idling in the staging lanes. The down side is I lost about a mile per gallon (if that matters). I suppose the cooler coolant temp also increases the safety margin for detonation but that might just be a feel good guess. I can't prove it.

 

[Juice]

Ofcourse those companies recommend cooler tstats. For safety factor from detonation.

What everyone forgets is that the a colder Tstat, under FULL LOAD conditions, will not be controlling anything. Your equalized temps will be a factor of how much heat your engine is producing (more HP = more temps) and the size and efficiency of your radiator.

For example: you are doing an HPDE event and find that your car is getting near overheating. If you put a colder Tstat in, it will NOT help. You need a bigger radiator.

What those companies SHOULD be recommending is a BIGGER radiator when you install FI. But since most ppl are into drag racing (short full power pulls) they can get away with stock cooling components.

My setups will always be a ~ 190* Tstat and an oversized radiator. (and water wetter)

Bottom line is a colder Tstat will not make your engine run cooler when it matters, during sustained high load/heavy throttle operation. But it WILL make it run COOLER when just cruising around.

 

[tjm73]

Cooler thermostats is an idea that should die.

 

[429244]

...
For example: you are doing an HPDE event and find that your car is getting near overheating. If you put a colder Tstat in, it will NOT help. You need a bigger radiator.

...

Bottom line is a colder Tstat will not make your engine run cooler when it matters, during sustained high load/heavy throttle operation. But it WILL make it run COOLER when just cruising around.

Juice,
Yes, that is true. However, my answer was short and maybe I should have explained more. My car never overheated with the factory Tstat and cooling system. I was not trying to cure an engine overheating problem. My car has a Roush SC and I simply wanted the car to run cooler due to IAT's and hot soak. I do not participate in HPDE. I drive to the drag strip, drag race, and drive home.
Since we are talking about cooling, what hood is on your car? Did that heat extracting hood help?

 

[Juice]

Juice,
Yes, that is true. However, my answer was short and maybe I should have explained more. My car never overheated with the factory Tstat and cooling system. I was not trying to cure an engine overheating problem. My car has a Roush SC and I simply wanted the car to run cooler due to IAT's and hot soak. I do not participate in HPDE. I drive to the drag strip, drag race, and drive home.
Since we are talking about cooling, what hood is on your car? Did that heat extracting hood help?

Hood is a Cervini Heat Extractor. I have not done any events with it so it's benefits are unknown at this time. The grills also had inserts to completely seal off the hood, (why? lol) making the vents fake. I left them off. I plan on messing with aero, and will be doing testing with streamers to see how air flows around the car. Those vents are in the correct position, and I hope I have airflow coming out from the engine compartment helping with cooling and relieving pressure under the hood. I had no issues with overheating with the stock hood, so any benefit will only show up on the oil temp guage.

As for Roush and others recommending a cooler Tstat, IMO, I'm not sure it is of any significant help with heat soak. The air is passing through the intake at speeds that won't allow it to heat up much. The compression of the air generates most of the heat, not heat soak from the plumbing. I could be wrong here, but that is how I look at FI.

Now for a colder Tstat, and cooler engine temps. That forces the PCM to use AFR that is slightly richer that normal 195* engine temp would. This is where I believe the "safety factor" comes from, and that is the real reason it is recommended. It could be all done in the tune, and just use a standard temp Tstat. But that would require extended dyno/testing/tuning = $$$. Colder Tstat (again, IMO) is just the easier (and cheaper) way to do it.

Now before anyone jumps in here and starts flaming, I've been tuning shit for 40+ years. My last track car is a 91 fox, GT40 340 hp crate engine with Vortec Strim, non-IC @8psi. I've been tracking that combo since 2006, 40 minute sessions on pump premium. Logged more than 10,000 miles on track.

Ps: I've seen some "canned" tunes that made me bust out laughing.

 

[eighty6gt]

Nothing will help.

 

[Pentalab]

Ofcourse those companies recommend cooler tstats. For safety factor from detonation.

What everyone forgets is that the a colder Tstat, under FULL LOAD conditions, will not be controlling anything. Your equalized temps will be a factor of how much heat your engine is producing (more HP = more temps) and the size and efficiency of your radiator.

For example: you are doing an HPDE event and find that your car is getting near overheating. If you put a colder Tstat in, it will NOT help. You need a bigger radiator.

What those companies SHOULD be recommending is a BIGGER radiator when you install FI. But since most ppl are into drag racing (short full power pulls) they can get away with stock cooling components.

My setups will always be a ~ 190* Tstat and an oversized radiator. (and water wetter)

Bottom line is a colder Tstat will not make your engine run cooler when it matters, during sustained high load/heavy throttle operation. But it WILL make it run COOLER when just cruising around.

This is what I alluded to in post #1. I will leave the oem 190F T-stat in there for now. IAT's are a non issue with my small M90 + 5.8 psi boost....and 94 octane tune. The HE on the 2010 M90 is 18" tall x 21" wide. HE gets hit with air from both upper + lower grilles. I installed the 7 bar upper grille, (upper fog lamp delete).. and eliminated 2 x 90 deg bends into the cai grille intake. The oem upper grille is highly restrictive.

What I found that did reduce under hood temps a good 40 F, was right after the JBA ceramic coated LT's were installed. Minimal heat from the 8 x ceramic primaries. Hi-flow cats now reside below my bum on both sides. Oem cats were located towards base of eng bay..and would typ run at 1200 F..and 1850 F at WOT. My steeda (black) front STB would run burning hot to the touch previously. Now it's luke warm at most.

I can see some advantages for some applications using a 160F T-stat. But mainly cruising around town, lotsa short trips, some hwy short trips, even in summer, but mainly a lot of night driving, both winter + summer. You need to get the oil temps etc, high enough to evaporate any moisture. A 170 or 180 T stat would have less issues, but probably would not be low enough to show some merit.

 

[RocketcarX]

What I found that did reduce under hood temps a good 40 F, was right after the JBA ceramic coated LT's were installed. Minimal heat from the 8 x ceramic primaries. Hi-flow cats now reside below my bum on both sides. Oem cats were located towards base of eng bay..and would typ run at 1200 F..and 1850 F at WOT. My steeda (black) front STB would run burning hot to the touch previously. Now it's luke warm at most.

This is way into red-zone territory in a turbo diesel AT THE MANIFOLD with a shit pile of boost, I can't imagine your cats ever got that hot 2 foot further from the head, much less 1200*.

 

[Pentalab]

This is way into red-zone territory in a turbo diesel AT THE MANIFOLD with a shit pile of boost, I can't imagine your cats ever got that hot 2 foot further from the head, much less 1200*.

You are no doubt correct. I was going by the cat temp readings from the OBD port, using one of my 3 x aeroforce gauges. The obd is using the rear O2 sensors to derive the temp readings..+ some algorithm. The cats get damned hot though. Once the ceramic LT's were installed, the gauges read 100F hotter. The internal temps are higher with the ceramic coatings. An IR point and shoot thermometer would work, but even that would only provide for outer surface temps. On 2nd thought, the aeroforce gauges might be indicating double the actual temps. When reading FPDC via obd port, the readings are exactly one half of the real thing.

 

[07 Boss]

Juice,
Yes, that is true. However, my answer was short and maybe I should have explained more. My car never overheated with the factory Tstat and cooling system. I was not trying to cure an engine overheating problem. My car has a Roush SC and I simply wanted the car to run cooler due to IAT's and hot soak. I do not participate in HPDE. I drive to the drag strip, drag race, and drive home.
Since we are talking about cooling, what hood is on your car? Did that heat extracting hood help?

Want your car to run cooler? You have to increase efficiency. An electric H2O pump will lower operating temps. My cyl temp gauge sits one notch below where it used to. Changing fans to come on earlier will help too but I have found the best success is with increasing the flow of coolant.

 

[429244]

Want your car to run cooler? You have to increase efficiency. An electric H2O pump will lower operating temps. My cyl temp gauge sits one notch below where it used to. Changing fans to come on earlier will help too but I have found the best success is with increasing the flow of coolant.

I have never used an electric water pump. I am considering it. If I install an electric water pump, can I use it to cool down the engine between rounds at the drag strip? If you run your electric pump with the engine off, does the coolant flow or does the tstat stop the flow?
Thanks for the help.

 

[LikeabossTM]

I have never used an electric water pump. I am considering it. If I install an electric water pump, can I use it to cool down the engine between rounds at the drag strip? If you run your electric pump with the engine off, does the coolant flow or does the tstat stop the flow?
Thanks for the help.

I'm going to take a wild guess here and suggest that the t-stat will stop it after it cools down to 160 ish...