Yes, lower temp T stat will start to open at a lower temp, and will allow the engine to run cooler at normal cruse type speeds.

With a 160 T stat, your normal cruze temps should be around 185-190, isntead of the normal 200's instead.


Once you start to get on the motor, it going to run at the normal 200+ temps instead.

As for bring the fan on at a lower temp to try to keep the motor under 200 during hard use , you are play with fire.

OEM settings


Hence the fan was never meant to keep the motor cooler than it normal 200'ish run temp and when you are driving the fan that much harder, the first thing that happens is the fan connector on the passenger side of the radiator burns up/melts first.



So you get a wild idea that instead of having the connector melt up again, your going to just solder the wires together, and this just moves the heat to the PWM connector to not only melt that connector, but to take out the PWM as well.

So now with a PWM melted up, you not only over size the wiring, but install a PWM that can take the heat long term instead. "A" for effort, but you get a F, since again, the vet radator fan itself was never meant to be run full time, and now the radator fan gives up the ghost quickly next.

So I'm not saying that you can't lower the fan turn on point a few degrees and run it a tad bit more, but the stock radiator cooling system is never going to hold the temps during full tilt boogy down below 200 degrees.

To do this, you need a hell of lot more cooling itself of the radiator (dewitt), dual fans to draw enough air across the radiator that are up for the challenge, as well as the needed upgraded PWM that has it main power thicker gauge wire running all the way back to the battery (with a fuse link a few inches off where you connecting to the main 12v power source)


And one last thing, if you are running the car is colder temps, do not run a 160 temp T stat. The problem is the engine does not want to come up to heat since the T stat is starting to open up at the lower temp, and even chance cold shocking the motor to cause cylinder damage to the pistol cylinder wall (same reason that you don't rev the motor until the oil temp comes up to 175*).

So the short version, the 160 T stat allow allows you a touch more power off cruse/sitting at a stop light for for a short burst since the motor is a touch cooler, but one you start to get into the motor, your back to the normal working temps of the motor and the tune/hp for the motor at those temps (hence even on the dyno, by the second or third pull without allowing the motor to cool back down under 200+, the 160 t stat will not even show a power gain; besides the first pull when the motor was at below 200* isntead).



Its kind of like how the Vararam CAI works from a dead stop.
Hence when the motor start to pull in hot air, it cause the timing to be retarded.
Attachment 48334173

So sitting at the light sucking in hot air into the the motor with the stock system, it's half way down the track until you are moving enough colder air into the engine bay to cool the air back down enough for the motor to stop pulling timing.

With the CAI that is drawing it air in from the outside of the car, the initial burst is full timing advance with the motor drawing in colder air from the start~to end of run, so only the outside actual air temp (if above 86*) itself timing is just pull through the run isntead.

 

I live in South Texas and we have 100 + degrees for a few months also.I have a cam,headers,intake and tuned.I'm always checking my temps while on a cruise i keep my coolant temp in my DIC all the time and it runs around the mid 190's and at a signal light it will go to 203 then my fan goes up to 70%.My engine oil will get up to 217 after a while,but it takes a lot of miles before my tranny temp gets to 170 degrees.I've read on this forum that the tranny temp should be 170 or above before you go wot..Note...I use a 180 T-Stat.

 

Trans temps below 150, in my experience, will have shifting issues at WOT. It's things like extended shift times, and hitting the rev limiter, that are caused by insufficient fluid volume. If my temps are too low (I prefer 160 +) while sitting in the staging lanes, I'll shift to drive and rev to around 1500 while on the brakes. I've already overfilled the trans to compensate for a brief surge of fluid to the rear of the pan during the initial launch.

The ideal trans temp for both performance and longevity is 175 +/- 15. If you are highway driving, the torque converter is locked, so you won't get or need 175. For low speed and stop 'n go traffic, the converter heats the fluid, which is when and why it needs cooled to stay near the ideal range. Your trans cooler is in the radiator, which is supposed to help maintain that 160-190 range. The only thing we see is the coolant temp at the front of the left head and the trans temp at the bottom of the trans pan.

 

Very true...

 

Great info! Thank you!

 

More rpms might mean the water pump is turning faster, but it also means that the engine is creating more heat. It is also how the engine is loaded.

 

I'm in Phoenix, AZ. With a 180 degree T-stat and fans adjusted to come on (low) at 195, max summer temps are 205 in stop and go traffic (AC on full and 115 degrees outside).

 

Dano, I don't know where you live (empty profile), but in the desert only a bone stock C6 will survive the Summers if driven gently. Once the mods start, cooling is the first issue to address. It's all about the airflow, since the air is the final resting place of the heat created. Removing the FRC's is the first step and a lower temp T-stat is next, quickly followed by turning the fan on early. We do things like removing the rear hood seal, which allows an escape route when stopped and an ambient entrance when moving. Unfortunately, a CAI like the Vararam, blocks some of the direct airflow while helping to increase power and therefore more heat.

Just for reference, my OEM fan connector died around 75K miles and the GM replacement died about 20K later, due to having lighter gauge wires than the original. I then did the bypass of the wimpy wire with one gauge heavier than OEM, which has survived 7 Summers. My fan is programmed to begin at 20% at 192* and incrementally increase to 90% by 203*. I also have a 160* T-stat.

To illustrate the airflow requirement, even on a typical 110* day, my coolant temps will stay in the 186-190 range while driving at a steady 70 mph on the freeway. The fan is on only because the AC is also on, but the fan is really being pushed by the airflow, instead of pulling it. If I get onto regular stop 'n go streets with normal traffic, the coolant shoots up in the 210-220 range and fan has already peaked at 90%. If the traffic is heavy, it's easy to see 230-240. When it goes that high, I turn the AC off, drop the windows, and turn the heater on maximum to gain additional airflow.

The stock 186* T-stat (high enough to pass federal emissions) will also force the fan to run under the same conditions and peak at 90% duty cycle when over 135*. At first, you'd ask why the 160* T-stat? The reason is not the worst case scenario, but it's for the average conditions to allow the engine to run cooler. In cold ambient temps the 160* T-stat will keep the engine temps at least 170*, which is close to the 180-190 range for best efficiency.

Increasing the coolant capacity only works if the area for airflow increases at a greater rate. I'd rather see 4 smaller fans pulling air through 90% of the fin area, than the current big fan only effectively covering 70%.

 

My 2008 oem tune file!

ECT Spark table 212*F starts pulling timing. The ECM pulls 1-2* at that temp depending on spark airmass (g) value.

No guessing here.

 

Where are you finding that? In the service manual?

 

No, I pulled my ECM tune file using HPtuners software program.


Engine - Spark - ECT spark - Base Table

 

can a tuner change the coolant and IAT temps that the ECU will start pulling timing? ie can he raise those temps?

 

HP Tuners is what I expected. I just looked at mine and then at a stock tune to see the difference. Apparently, I changed the whole 212 column to 0 so long ago, it never occurred to me to look there.

Yes, see my response to Mike above. My ECT table is all 0's up to 230*. I also have no timing reduction in my IAT table until 104*. Both the 86* and 95* columns are zeroed out.

The only time I want to be assured that my spark is not compromised is at the track. It makes no difference to me on the street.

 

Yes, however at the risk of detonation. On boosted applications they will raise the IAT table values, but may leave ECT’s alone. It all depends on the application and what the tuner is comfortable with. These tables are designed to protect the engine.

 

The bigger culprit is the IAT, not the coolant temp. I've seen insulation installed on the radiator shroud and under the CAI to keep it cool at low speed and lights. I may look into blocking the heat from the radiator hoses under the MAF sensor with a plate or something,

 

Interesting how GM put a MAF sensor above the radiator hose? I had a Halltech MF103 air intake which relocated the MAF sensor forward of the radiator. MAF Forward, MF103, and along with the Beehive shroud both worked together keeping IAT's down.

 

Yes it is interesting and especially for me gathering this great information. I always thought it was more about coolant, than ITA temp. Off course Coolant does have an effect. Thank you!

 

A lot of good info in this thread regarding radiators, thermostats, and cooling.
This post is spot on: