GEN 2 anyone running a 170 thermostat?

[baugustine]

I’m coming in late to this discussion and will avoid the negatives in the last few pages but will comment on the original topic.

I work on vehicles for a living, and have done OBD since 1993 so I have a working knowledge of both the software side and the repair/tuner side. With that background:

Lower temp thermostats were used in the OBDI and early OBDII systems by both tuners and DIY performance folks to pick up a few ponies without a ton of mods. It works on a TBI or PFI system only because the lower coolant temps will fool the calibration to think its not yet up to operating temp, which is 220-240F. It will add more fuel, period. (Yes, fuel mileage goes down, and yes long-term you will wash down the cylinder walls, and yes you will put more fuel in the cats). Unless you re-tune the motor, the negatives far outweigh the pros.

Fast-forward to GDI, and lowering coolant temps will amplify the cons, even with a tune. If the OEMs could run best-case scenarios (economy, emissions, power) at 180 they would but the engines are optimized at 220-240, which is why that is where they run them. Ask any owner of a Gen1 GDI (VW, Kia, GM) about the cylinder heads having to come off at 15,000 miles to be walnut blasted for carbon removal and you will see they are very different in nature.

In summary, this is not your fathers 3800 SFI Oldsmobile or your Uncles’s 5.0 Mustang and should not be tuned the same way. Save your $ for useful stuff like a bed extender or tonneau cover...

 

[zemuron99]

If the OEMs could run best-case scenarios (economy, emissions, power) at 180 they would but the engines are optimized at 220-240, which is why that is where they run them. ...

Willing to accept your credentials, and comments, up to this point. I don't think our engines are optimized here, as I regularly only see 208-215 on mine, which is completely stock, even in summer. If we're already running 20+ degrees below optimum, will 10 more from a 170 t-stat make that much difference? Also, one site I was looking at last night as part of my response stated an engine enters closed loop around 150. Not sure that applies to our engines, but would like to know where that happens just to understand it better.

 

[baugustine]

Willing to accept your credentials, and comments, up to this point. I don't think our engines are optimized here, as I regularly only see 208-215 on mine, which is completely stock, even in summer. If we're already running 20+ degrees below optimum, will 10 more from a 170 t-stat make that much difference? Also, one site I was looking at last night as part of my response stated an engine enters closed loop around 150. Not sure that applies to our engines, but would like to know where that happens just to understand it better.

You can see exactly when your engine goes into Closed Loop with a $99 scanner from the parts store. Almost all modern engines use an Air Fuel sensor upstream on the cat (as opposed to a HO2S) and they are heated/active in less than 15 seconds after startup. I’ve seen vehicles go into CL way less than 150 if ambient air temp is above 60 (warmer climates). What are you reading ECT values with? The coolant gauge on the cluster is shunted and does not provide actual values. Ford (and most OEMs) changed the IPC strategies to not show real temperature because most consumers would freak out if they knew the actual temperature on a warm day with the AC on. My father did not believe me on this and I connected my scan too to his 2004 Mach 1 and let it warm up. The temp guage on the IPC went up to the 12:00 position ( in normal) which was about 190 then the ECT continued to climb. Fans came on at 220 but the guage never left the 12:00 position. Scan tool is the only way to actually know (or a thermal IR gun).

 

[TwizzleStix]

You can see exactly when your engine goes into Closed Loop with a $99 scanner from the parts store. Almost all modern engines use an Air Fuel sensor upstream on the cat (as opposed to a HO2S) and they are heated/active in less than 15 seconds after startup. I’ve seen vehicles go into CL way less than 150 if ambient air temp is above 60 (warmer climates). What are you reading ECT values with? The coolant gauge on the cluster is shunted and does not provide actual values. Ford (and most OEMs) changed the IPC strategies to not show real temperature because most consumers would freak out if they knew the actual temperature on a warm day with the AC on. My father did not believe me on this and I connected my scan too to his 2004 Mach 1 and let it warm up. The temp guage on the IPC went up to the 12:00 position ( in normal) which was about 190 then the ECT continued to climb. Fans came on at 220 but the guage never left the 12:00 position. Scan tool is the only way to actually know (or a thermal IR gun).

Whereas what you have posted here is accurate for almost any vehicle with an analog "looking" temp gauge. They are for the most part, just analog idiot lights for overtemp. However, the FORScan software allows us to turn on the display for actual temp in degrees F, even while the "gauge" bar stays right at center optimum. In practically all ambient weather with oem thermostat, the actual coolant temp runs around 205. Mine runs ~205 to ~217 on the highway cruising at 80mph. The closed loop activation targets can be altered quite easily with the HPTuners or Cobb Tuning software.

 

[baugustine]

Whereas what you have posted here is accurate for almost any vehicle with an analog "looking" temp gauge. They are for the most part, just analog idiot lights for overtemp. However, the FORScan software allows us to turn on the display for actual temp in degrees F, even while the "gauge" bar stays right at center optimum. In practically all ambient weather with oem thermostat, the actual coolant temp runs around 205. Mine runs ~205 to ~217 on the highway cruising at 80mph. The closed loop activation targets can be altered quite easily with the HPTuners or Cobb Tuning software.

Agree with everything you said. My comments about gauges were general in nature so other readers would be able to apply some of their experiential knowledge with how the things are engineered behind the scenes. A good tuner can also "tweak a lot of things", but unless there are specialty applications (racing, etc) I'm not sure why anyone would?

Cruising at 80mph with ECT in the 205 to 220 range is exactly what it is supposed to do. Sitting in Houston, stopped on I-10, 105 degrees and 100 % humidity (w/AC on) will be a very different use case. That is one of the many use-cases where turn-on of fans becomes an issue. The original question about a 170 deg thermostat does not change, and the temperature when the thermostat begins to open and performance gains are a different topic. My answer, and the answer of many before me, was putting in a lower temp thermostat is a waste of time and money on this motor, and the driver will see no appreciable gain in anything performance-wise. I stick to that original position.

 

[TwizzleStix]

....My answer, and the answer of many before me, was putting in a lower temp thermostat is a waste of time and money on this motor, and the driver will see no appreciable gain in anything performance-wise. I stick to that original position.

I agree 100%. The only “gain” is in their head, but that’s enough for most on this forum

 

[Gsteve]

Yup... unless you live in someplace really hot and racing or towing it’s a waste of time

 

[dewalt]

What is shut down temperature on this motor?

 

[dhmcfadin]

Lots of misinformation in this thread.

A cooler thermostat is not used to make the operator feel better by looking at a smaller number on a gauge. A cooler thermostat is used for the following reasons. Each is individual but they all work together.

1. Cooler EGT’s due to cooler block temperatures. HUGE for a forced induction motor. Why do you think the diesel guys watch their EGT’s religiously? The compression of air generates a tremendous amount of heat. You can easily cook a set of pistons or valves by not keeping EGT’s down.

2. Cooler block temperature allows the truck to run more timing thus making more power more efficiently.

3. When racing or baja or even driving hard, temperatures can easily see 350+ degrees in certain parts of the block. This is extremely common. With the stock 195 thermostat, it opens at about 190 and sets the truck to run, during normal driving, at about 210. Go do some mock 1/4 miles runs or 0-60 or WOT driving. You will see that 210 ping 250 easy depending on how hard you push the truck. In other parts of the engine, that number is significantly higher. With the 170 degree stat, it opens right at 170. Right off the bat, you have a 20 degree buffer to help curb those extremely high block temperatures and EGT’s. Heat is the ultimate enemy for any internal combustion engine.

It should be obvious that with a cooler thermostat on a fuel injected turbo engine that a tune should always be used. For those that say a cooler stat does nothing, they are just not fully informed. Ultimately, a cooler stat on a forced induction motor is pretty much a must if you want your engine to have some type of consistent power across different environments and temperatures.

Another way to significantly lower EGT’s even further is to run larger turbo adapters but this post is about thermostats.

 

[Gsteve]

Ok. So has anyone figured out if they actually fit?