Why the 160 degree thermostat?

[DangerZL1]

Should be easy to change, but I think in a previous post that a tune is necessary to prevent throwing a code. Hopefully someone else will clarify this.

[SamHouseIII]

Originally Posted by Mr. iNCREDIBLE

Actually due to EPA efficiency and emission regs most OEMs are rated around 203°

the higher temp makes for better engine efficiency, aka more MPG's

the lower temps make the motor run richer which produces more HP but less MPG.

I would have to check the actual thermostat for sure, I read somewhere 180, in the service manual states;

1. Use a J 24731 - Tempil Stick in order to find the opening and the closing temperatures of the coolant thermostat.

• 1. The 188 tempil stick melts at 87°C (188°F). The thermostat should begin to open.
  • The 206 tempil stick melts at 97°C (206°F). The thermostat should be fully open.

1. Replace the coolant thermostat if it does not operate properly between this temperature range.

http://www.motorward.com/2012/10/joh...ro-zl1-hpe700/#

Link to Hennessey.....most shops do use the 160 temp thermo, however they are also programing the cooling fans to come on earlier/lower temp...

[hognutz]

one thing people always forget about switching T-stat is if you do not alter your fan setpoints you don't get full benefit.

At low speed when you need your fans to maintain temp if they come on too late you 160 t stat does not help at all. you will just gain temp until you get to your fan on point and your fan will only pull it down to the off point.

Many people do not implement the lower temp thermostats correcly because they don't want to tune. If you not willing to tune you need to take manual control of your fans to really get the benefit of it.

[Blown355]

Originally Posted by DangerZL1

Should be easy to change, but I think in a previous post that a tune is necessary to prevent throwing a code. Hopefully someone else will clarify this.

That is correct. It will throw a code "if" the ecu doesn't see coolant tempsof at least 167 degrees after ~7 minutes of runtime. I had to let my car idle for 5 minutes before driving it in the mornings or it would throw a code (and disable the a/c). This was in Texas, in the summer. I finally got tired of having to bring my laptop with me every morning just to clear the code so my a/c would work, so I put an 180 degree thermostat in.
Just an FYI.

[ZO6 Bryan]

I agree with everything ********** said but would add this. The hot mod to do when the factory thermostats were 195 deg to get better emmisions in the late 70's thru the early 90's was to swap in a 180 deg. thermostat. Then the reverse cooled LT1's came in '93 and they had 180 deg. thermostats from the factory. Because they are reverse cooled they needed a cooler thermostat to warm up to 190 deg at the valve head. So then everyone started putting 160 deg thermostats in the LT1's because that would make the car run at 180 deg at the valve head. Now emmissions are better controlled on the LS engines since '98. And they came with 180 deg thermostats from the factory. Which is as cool as you really should need.

[BAD ZL1]

Originally Posted by G-Oil Guy

wow...really?

The 160 T-Stat, as OneSlow said, allows the T-stat to open sooner. This lets the engine coolant circulate through the heat exchanger soon. This leads to lower coolant temps, which leads to lower running engine temps which leads to reduced heat soak which leads to better engine performance.

ALSO reduces the risk/chance of overheating.

Nice sarcasm with the "wow really"...lol. Read further in this posting and you are basically wrong on all accounts. A T stat that opens sooner makes a motor get to operating temp slower, which has zero to do with lower coolant temps, lower running engine temps, and reduced heat soak...none of which has anything to do with reduced risk of overheating..Thanks for the lesson

[tramtwo]

just get some wetter water... I had a tuned setup with a 160 t stat and after a lot of back and forth on this site I don't think it is a good mod for these engines... you can search... plenty posting on the subject by some really smart engine guys.... the debate is split right now the middle some swear by em some think they actually cause premature engine wear problems

[tomster]

On A zl1 you will also benefit from having the cooling fans turn on soomer which will help to cool the heat ex-changer better. FYI you HAVE TO RETUNE to see the gains here. Also if you dont tune you will get a ses light after 3 drive cycles of engine not at operating temp.

[itsadryheat79]

In hot climates like AZ and with the AC on the radiator fans are always running anyway. The key to cooling I've found is flow both air and water. Fan shrouds are a must. The shroud system has to be efficient for idle or low MPH air flow with baffles allowing for more airflow when the fan itself becomes an obstacle at higher MPH.

In a heat exchange flow system a lower T-Stat can make the water always flow and always be hotter than what you'd want. Systems are engineered to be more efficient by allowing the T-stat to restrict water flow. This restriction will suspend the water in the radiator allowing it cool down before it returns to the engine. Generally this engineered restriction efficiency is why it's never a good idea to pullout the T-stat completely.

[Mr. iNCREDIBLE]

Originally Posted by SamHouseIII

I would have to check the actual thermostat for sure, I read somewhere 180, in the service manual states;

1. Use a J 24731 - Tempil Stick in order to find the opening and the closing temperatures of the coolant thermostat.

• 1. The 188 tempil stick melts at 87°C (188°F). The thermostat should begin to open.
  • The 206 tempil stick melts at 97°C (206°F). The thermostat should be fully open.

1. Replace the coolant thermostat if it does not operate properly between this temperature range.

http://www.motorward.com/2012/10/joh...ro-zl1-hpe700/#

Link to Hennessey.....most shops do use the 160 temp thermo, however they are also programing the cooling fans to come on earlier/lower temp...

no I wasn't talking specifically about the Camaro, it might be a 180° I never actually checked, I was speaking in generals, the majority of vehicles, especially the grocery getter 4-bangers are 203° - 225°

your original statement was "most stocks" I took that to mean most cars in general.

[SamHouseIII]

Originally Posted by Mr. iNCREDIBLE

no I wasn't talking specifically about the Camaro, it might be a 180° I never actually checked, I was speaking in generals, the majority of vehicles, especially the grocery getter 4-bangers are 203° - 225°

your original statement was "most stocks" I took that to mean most cars in general.

no worries

[gkitab241]

Originally Posted by **********

Because it adds 25hp and 30 lbs/tq

This is what I found on a quick search:

The Function of the Thermostat & Cooling System Basics

The biggest misunderstanding about thermostats is that people believe they make the engine run cooler. They don’t necessarily do that. The cooling system and load on the engine determines how hot the engine gets, the thermostat fully open will still be the mercy of the coolant system’s ability to remove heat.

Most engines run slightly above the thermostat’s minimum opening temperature under normal loads. Under high loads, they will run at or above the thermostat’s fully open temperature – in other words, under hard driving, the thermostat’s opening temperature is completely irrelevant.

The thermostat can only determine when the cooling system is allowed to start cooling the engine. It sets a floor, not a ceiling on engine temperatures. The thermostat basically behaves like the hot and cold knobs in your shower, if the water is too hot, it turns the cold on a little more and if the water is to cold, it turns up the hot water.By regulating the flow through the cooling system it speeds up and slows down the flow of coolant into and out of the engine block.

In liquid cooling systems, the ability to cool is determined by a number of factors, but the basic keys are the surface area of the radiator (how big/how many small fins), the air flow through the radiator (fans on/off, speed of car), and how quickly or slowly the cooling fluid goes through the radiator. If the coolant spends a small amount of time in the radiator, it loses less heat. If it spends a lot of time there, it loses far more heat. Therefore you don’t want the flow to be too high as the cooling system’s ability to cool the engine will be reduced, not increased.

The thermostat is there primarily to help the engine warm up in the morning. As we discussed in a previous article, the engine is designed to operate at it’s operating temperature. Most engine wear occurs when the engine is cold, once it’s warmed up there is very little wear in a healthy engine. Thus, we definitely want to run a thermostat to allow the engine to warm up as quickly as possible until it reaches our desired and designed operating temperature.

If the engine is below operating temperature, the bearings, rings, and other components are not yet expanded in size and therefore they “bang” against the other metals in the engine more than they would at operating temperature. No good.

So if we don’t run a thermostat at all, it takes a lot of constant load to get the engine properly warmed up and to keep it up to temperature on cold days. We also in some circumstances may experience overheating if flow through the system is too high as the coolant has to spend a certain amount of time in the radiator to actually cool down.

Some race teams do choose not to run a thermostat, but they are the minority. They usually run at least a restriction plate in place of the thermostat to slow down flow and allow some warm up to occur. The reason that they may not run one at all is usually to remove a point of failure in endurance type races. In other words, if the thermostat fails and sticks closed, it could cause a pit stop or end the race. By removing it, they tolerate possible engine wear since they know they’ll be at high loads throughout the race. Their cooling system is usually tuned to compensate for the lack of a thermostat as well.

Running the factory thermostat will on the other hand ensure that the engine comes up to the designed minimum temperature very quickly. Until the engine is up to temperature, there is no cooling occurring. The factory thermostat will not however change how the engine runs under load because the thermostat will be fully open when under load. It effectively isn’t there under load.

So at the risk of sounding like an idiot. Where your horsepower and torque ratings sarcastic or serious?

[bsn]

This is a 11 year old post and that particular poster hasn't been on in over 10 years-don't think your going to get your answer.

[acammer]

It was interesting to look through this 11 year old thread and observe the painful amounts of mis-information. Just remember kids, you can't believe everything you read.

High level overview:

• Coolant still gets to the same temp with a lower temp thermostat . No, if the car has adequate cooling (ie is moving, and/or the fans are properly configured) it will run cooler.
• Low temp thermostats make the car slower to warm up. No, it changes nothing about warm up time, just where the thermostat opens and temps settle at.
• Stock thermostat is 180*F. No, it's 187*F
• 20* of coolant temperate doesn't matter. No, it matters a bunch. There are several tables within the OEM ECU that actually begin altering enrichment and spark advance based on coolant and intake air temperature - and those can have a profound effect on power output. Thermal management is critical on any vehicle, but much more so on a performance vehicle.
• Tuning is required to prevent a code. No - a 160*F thermostat that functions correctly will meet the minimum threshold for "warmed up" by the ECU. Tuning is highly recommended to match fan on/off points for the lower temperature thermostat.