I looked at my hot weather logs (ambient of 90F-100F) and my dragstrip logs, the highest my ECT goes to is about 213F and the CHT goes to 228F. That looks about normal to me, as it is high enough to boil off moisture and contaminants as designed. At the dragstrip on a cooler day, my ECT wasn't higher than 200F and my CHT was hovering under the 210F mark. It doesn't seem like we actually need a colder thermostat, and a lot of the Mustang tuners told me to just run the fans earlier instead of getting a thermostat.

What would the 170F Reische or 160F LMS T-stats do for the ECT and CHT? Which is the better thermostat or is one even needed?

This Topic has been discussed quite frequently in the past and IMO would simply follow your Tuners,specs,recommendations without adding to much confusion and proceed from there and the Topic should be changed to Stock-Reische-Evenflo. LMK .Z

Is there a master Thermostat thread that discusses this? I couldn't find a sticky and I did a text search for Reische.

In terms of coolant temp, the only thing a tune can really do is tell the ECU when to switch from the base cold fuel table to the base fuel table (which is basically 1.00 lambda above something like 90F) or when to turn the fans on sooner. I don't see anything that I can "set" for various thermostats. Which is why I was asking if the thermostats themselves actually did anything for ECT and CHT.

The Reische thermostat has been discussed in detail as far as how it works (cold side vs hot side)
http://www.ecoboostperformanceforum.com/index.php/topic,2490
http://www.ecoboostperformanceforum.com/index.php/topic,2037
Additional threads:  http://www.ecoboostperformanceforum.com/index.php?action=profile;area=showposts;u=917

As far as why a colder TStat is used, it is not necessary for less hi-po tunes.  The EB engine's optimal operating temperature (courtesy of LME) is around 140F, so the closer we can get to it without a severe compromise in emissions and all-weather drivebility, the more power we can extract from it.  That is the line of thought.  Plus the tune usually turns on fans earlier AND longer, which in turn helps not only cooling but fan longevity.

Thanks. That's some good reading, butI haven't seen any convincing arguments or data on why the 160F or 170F is really needed with a high performance tune.

For one, the engine needs to be hot enough to burn off all the contaminants, especially with the EcoBoost fuel dilution issues. I've been setting by ECT fan setpoint to 200F, and it looks like the fans will turn on/off automatically to try to maintain it.

I ended up pulling my 170 tstat because it would be a huge mess if I ever had to do it before taking it to the dealer.  I'm going to see how fast I can go this summer without one.

Quote from: metroplex on January 04, 2017, 04:58:28 PM
Thanks. That's some good reading, butI haven't seen any convincing arguments or data on why the 160F or 170F is really needed with a high performance tune.

For one, the engine needs to be hot enough to burn off all the contaminants, especially with the EcoBoost fuel dilution issues. I've been setting by ECT fan setpoint to 200F, and it looks like the fans will turn on/off automatically to try to maintain it.

Quote from: metroplex on January 04, 2017, 04:58:28 PM
I've been setting by ECT fan setpoint to 200F, and it looks like the fans will turn on/off automatically to try to maintain it.

I did mention fan longevity   But yeah, we have no public data on the combustion process to prove/disprove one way or the other.  You can create your own empirical data with testing different setpoints and changing the oil between setpoints, I suppose.

Im not sure what you are getting at or looking for...there seem to be alot of things that are affected or can be changed in the tune...and what if at the END of a wot run coolant temp is 205 rather than 230 because it was cooler at the start of the wot?

Does that help kr? Will it hurt? What about the spark modifiers and comps for ect? It surely wont hurt the trans fluid that rus through the radiator

You could be less dependent on the fans by letting the radiator do more work

Lowering the fan temp setting to 200 without a stat may not be very beneficial...if we have a 185-195 stock stat then its not even fully open by 200 so you are essentially trying to cool the coolant when its not even flowing

I never ran a stat but i dont see how it can hurt...considering how hot the aircharge temps get when running high boost id say its a good idea...and is fuel dilution really a problem or happen more with DI?..there is physically less fuel delivered in di engines they run leaner by nature and fuel is in the cylinder for less time since its injected on the compression stroke rather than intake stroke

I find that at the end of a WOT run or dragstrip run, the coolant temp isn't the highest. It's the low speed driving around the city that causes all of the temperatures to rise. And I feel the intercooler would benefit from some airflow generated by the fan. Looking at the 200F setpoint, the ECT is definitely kept to this temperature more or less. With enough highway airflow in the 90F summer heat, my ECT can sometimes stay below 195F without the fan ever turning on.

I'm just not sure a 170F or 160F t-stat is all that necessary. With the modular Mustang tuning crowd, they advised against using a colder thermostat and to just adjust the fan controls in the ECU which kind of made sense since a lower temperature thermostat is mainly opening sooner. You're still limited by the heat rejection efficiency of the radiator, engine block, etc...

It's apples to oranges, but I remember running a 160F t-stat in my old Ford 302 - the end result was my engine oil never warmed up enough and would get contaminated extremely quickly in the winter. Fuel injection and ECU controls have improved significantly since then, but I always have to ask.

Quote from: AJP turbo on January 04, 2017, 05:49:12 PMand is fuel dilution really a problem or happen more with DI?..there is physically less fuel delivered in di engines they run leaner by nature and fuel is in the cylinder for less time since its injected on the compression stroke rather than intake stroke

Fuel dilution is fairly prevalent in the EcoBoost engines. I've pored through a bunch of UOAs at BITOG when I did my own UOA.

I've seen DI UOA's that don't show significant fuel dilution...I'd lean to a mechanical problem if I saw that.

I always see the highest IAT's and ECT at the end of a WOT run and AS SOON AS YOU LIFT the coolant goes back down but when the starting point is lower then the End temp will be lower as well.

It's completely useless to turn the fan temp down if not used in conjunction with a stat.....Think of it this way...Turn your fans down so that they try to maintain 100F coolant....It will never happen and the fans will never shut off...Or even try 170 with the stock stat, again the fans will never shut off.

Fans should always be 10-15 degree minimum above stat rating.

I run a reische 170. I have not had it down the track, but from data logs, do not go over 190 F or so ECT.

I have seen cars with fans running 100% to try and hit a target coolant temperature, the car will never get there, and will have increased load on the electrical system and the fans.

With the stock t-stat, my SHO doesn't run the fan all the time in the summer with the 200F setpoint. It's only with low airflow when the fan really kicks on (city driving, stop/go driving). Looking at my drag strip runs, the hottest temps are recorded about 5 seconds after I lift the throttle, and then it starts to drop due to the cooling system doing its job but it never gets back down to what I started unless I wait a long enough time. In the winter, the ECT never gets to 200F and the fan rarely kicks on even when I don't use the defrost. From my perspective, the stock intercooler is the issue. It doesn't seem to be very efficient and has a hard time rejecting heat. In comparison, the stock intercooler on my Cobalt SS Turbo works like a champ, although at a "mild" 22 psi tune with the stock K04 turbo.

derfdog: Do you have any summer/high ambient temp datalogs that show your max ECT? Is your cooling fan running and/or what's your setpoint?

AJP Turbo: Blackstone has an issue with reading fuel content correctly from what I have read, but if you look at TBN and viscosity - the only oils that can really handle an extended OCI (like 9k miles) would be the Extended Performance synthetics with a Group IV basestock like M1 EP or Amsoil. Otherwise, 6k-7k miles seems to be the common limit - "synthetic" or not.

So what is the stock t-stat rated for? RockAuto lists them at 180F for aftermarket replacement, and 190F for Motorcraft. The modular's used to have 192F t-stats. So if you figure 10F-15F above t-stat rating, that's 200F-205F for the setpoint. Are we seeing substantial reduction in KR with the 170F t-stat?

Quote from: SHOdded on January 04, 2017, 04:37:14 PMThe EB engine's optimal operating temperature (courtesy of LME) is around 140F, so the closer we can get to it without a severe compromise in emissions and all-weather drivebility, the more power we can extract from it.

Wow, 140?? Maybe optimal for power, but I don't think you could reasonably operate there without major cooling system changes.

Luckily, I read through some of this thread before leaving work, so it gave me an opportunity to mess around on my way home.

Air temp in SE Wisconsin was NINE degrees F. I have a 170-degree thermostat.
  - Cruise control set at 70MPH on relatively flat ground (low-moderate load): ECT 185*F/CHT 201*F
  - Coasting from 70MPH (no load) down off-ramp for approx 22 seconds: ECT 171*F/CHT 195*F

Based on this anecdotal evidence, under normal cruise @ 70MPH there's zero benefit for me running anything other than the OE thermostat, since the stat would be open anyways.

HOWEVER, notice under NO load how quickly the ECT temp came down (granted, it's ballz a$$ cold out). Using a lower temp thermostat leaves your cooling loop open for a longer period of time allowing the possibility of rejecting more total heat from the system during no load driving (braking or coasting). More rejection of heat from your coolant leaves more room to absorb new heat generated by higher loads.

If you run high load, WOT all day long, running a cooler thermostat will not help you. In racing/high performance applications, any edge in rejecting heat helps. For me, my daily driving includes a lot of low load, so I think a lower stat probably helps reject some heat between my furious passing maneuvers.

Disclaimer: I also run a surfactant in my coolant, so my numbers may or may not be typical. Not sure if the surfactant helps or not...

Quote from: AJP turbo on January 04, 2017, 06:41:51 PM
...but when the starting point is lower then the End temp will be lower as well.

This. Also why it takes so long to get warmed up in the winter with a 160 stat. Takes a lot longer to get to your "end temp" that provides sufficient heat when you are circulating the entire capacity of your cooling system in sub-freezing weather.

That single scalar you are seeing and using I think for the fan on/off point isn't the only thing that controls the fans....There are tables for TOT(trans oil) and A/C head pressure

I've seen some KR reduction with people with stats but sometimes it's hard to isolate because of fuel quality or pressure drops or spikes or afr changes.

Having the cylinder heads a little cooler will not hurt nor will having cooler plugs which extract more heat from the chamber and head

Chevy ***balt is irrelevant in this piece

The coolant drops as you stated at just after your run not because the cooling system doing it's job but because you aren't  feeding the engine gasoline and creating violent explosions.

I see SHO's in 10f degree ambient temps with a 170 stat go over 200 on wot runs.