Thermostat Question
02-22-2008, 10:28 PM
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Thermostat Question What temp thermostats are you guys running? I'm thinking about putting an SLP 160 degree in my 07 MCSS. I live in southern illinois. Lowest temps are in the single digits. Anybody have any problems with a 160 thermostat throwing check engine lights??? Can you adjust fan on/off temps with the HP tuner program? I am planning on doing quite a few bolt on mods to my car. Thanks for any advice.
02-23-2008, 06:56 AM
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You can run a 160* thermo with the stock tune. I also believe that you can also adjust the turn-on points for the fans with the HP software. Hope this helped.
-Mike
-Mike
02-23-2008, 04:11 PM
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I've talked with GM techs, and they say that these cars like to run a little warmer to perform the best... and to not use a 160* t-stat which will stay open all the time and not actually allow the coolant to "cool off" to actually cool the engine...
here's some additional info I have:
============================
What effect the 160 stat has on the engine/computer depends on different factors. In terms of achieving closed loop operation, the oxygen sensor plays a more important role - it will not function until the exhaust temperature is at least 660 degrees F. To a degree this is a function of the coolant temp, so it is possible that abnormally cold coolant temps can prevent closed loop operation.
If the coolant reaches 160 degrees, there should be no problem, as the torque converter lockup AIR, and EGR function at temps over (approximately) 150 degrees F. The trouble is that overcooling (and subsequent chronic open loop operation) is much more likely with the colder stat, since you are running that much closer to the "crossover" temp. This is especially true in colder climates, where the ambient temperature can contribute to the overcooling problem. A 160 stat is probably not a good idea if the ambient temperature is below 75 degrees F, or if a significant percentage of the driving time is spent on the highway. In that case, go with the 180 instead.
Aside from loss of converter lockup, AIR, and EGR operation, overcooling can cause an abnormally rich air/fuel ratio, which at best will make your fuel economy and performance suffer, and at worst will destroy the catalytic converter. In any case, the colder stat is not much good without changing the temperature at which the radiator fan activates. During city driving, the fan will simply wait until the coolant reaches 225 degrees F to turn on, which is what you were trying to avoid in the first place.
==========================================
there is a "middle ground" where both optimum performance as well as minimal wear share similar characteristics. That "magic" number lies in the 175-180 degree range, which requires a 180 degree thermostat..
The all too commonly used 160 degree thermostat is way too low to be considered for performance or engine longevity. As the chart illustrates, engine wear increased by double at 160, than at 185 degrees. So then, why do the 160's exist in the first place? The 160's were commonly used in older, open loop cooling systems where only 6 pound radiator caps were used, and low 212 degree boiling points were experienced. In contrast, modern cooling systems can see upwards of 260 degrees in coolant temperature with radiator pressures exceeding 45 pounds. Many early hot rodders found the 160's to be better performing than the 190's, however, the in between "180" appears to satisfy both ends of the spectrum. The correct water temperature is required for the cylinders to achieve a minimum specific temperature in order to allow a fully homogenized Air/Fuel mixture to combust efficiently. Guess what the minimum number is… right! 180 degrees. Even so, you might see some still recommending the lower 160's, for no other reason than to possibly get that last drop of horsepower out, at the high price of dramatically reducing the life of the engine and it's internal components.
================================================== =
here's some additional info I have:
============================
What effect the 160 stat has on the engine/computer depends on different factors. In terms of achieving closed loop operation, the oxygen sensor plays a more important role - it will not function until the exhaust temperature is at least 660 degrees F. To a degree this is a function of the coolant temp, so it is possible that abnormally cold coolant temps can prevent closed loop operation.
If the coolant reaches 160 degrees, there should be no problem, as the torque converter lockup AIR, and EGR function at temps over (approximately) 150 degrees F. The trouble is that overcooling (and subsequent chronic open loop operation) is much more likely with the colder stat, since you are running that much closer to the "crossover" temp. This is especially true in colder climates, where the ambient temperature can contribute to the overcooling problem. A 160 stat is probably not a good idea if the ambient temperature is below 75 degrees F, or if a significant percentage of the driving time is spent on the highway. In that case, go with the 180 instead.
Aside from loss of converter lockup, AIR, and EGR operation, overcooling can cause an abnormally rich air/fuel ratio, which at best will make your fuel economy and performance suffer, and at worst will destroy the catalytic converter. In any case, the colder stat is not much good without changing the temperature at which the radiator fan activates. During city driving, the fan will simply wait until the coolant reaches 225 degrees F to turn on, which is what you were trying to avoid in the first place.
==========================================
there is a "middle ground" where both optimum performance as well as minimal wear share similar characteristics. That "magic" number lies in the 175-180 degree range, which requires a 180 degree thermostat..
The all too commonly used 160 degree thermostat is way too low to be considered for performance or engine longevity. As the chart illustrates, engine wear increased by double at 160, than at 185 degrees. So then, why do the 160's exist in the first place? The 160's were commonly used in older, open loop cooling systems where only 6 pound radiator caps were used, and low 212 degree boiling points were experienced. In contrast, modern cooling systems can see upwards of 260 degrees in coolant temperature with radiator pressures exceeding 45 pounds. Many early hot rodders found the 160's to be better performing than the 190's, however, the in between "180" appears to satisfy both ends of the spectrum. The correct water temperature is required for the cylinders to achieve a minimum specific temperature in order to allow a fully homogenized Air/Fuel mixture to combust efficiently. Guess what the minimum number is… right! 180 degrees. Even so, you might see some still recommending the lower 160's, for no other reason than to possibly get that last drop of horsepower out, at the high price of dramatically reducing the life of the engine and it's internal components.
================================================== =
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
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06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
Last edited by 06MonteSS; 02-23-2008 at 04:16 PM.
02-23-2008, 10:23 PM
#5
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our Monte SS/Impala SS/GXP LS4's come stock with a 187 degree t-stat... so no need to change in my opinion... stock works just fine....
__________________
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
06MonteSS / DiabLew Tune
2014 Camaro 2SS/RS - LS3, 6-speed manual, short-throw performance shifter, NPP dual-mode performance exhaust, 1LE front splitter, ZL1 rockers, Z28 Rear Spoiler, all paint-matched Red Rock Metallic, BMR strut tower brace, Cold Air Inductions cold air intake, Apex Motorsports, Inc. catch-can, Custom DiabLew Tune
www.diablewtune.com -- www.diablocustomtune.com -- www.diablocustomtunegm.com
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