04-01-2020, 02:54 PM | #29 |
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Do whatever you want, it's your car, but you should know the big picture when
going to such a low T-stat rating. What I wrote is not gospel, nor the word of GOD, it's observations throughout the car community. Lower temps thermostats do no set the ceiling for the temperatures. Even when the thermostat is fully open, you will still be the mercy of the coolant system's ability to remove heat. The biggest misunderstanding about lower temp thermostats is that people believe they make the engine run cooler. They don't necessarily do that, and do not under heavy load. If you do not tune it for the fans to kick on at the t-stat rating, then it's also not going to work as well for cooling. If you put a 160 in, and do nothing else, it just takes longer for the engine to heat up. The fans still won't kick on till the OEM temp setting is reached. 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 problem with a low temp thermostat then for regular driving is that there are times when the car will be running at a temperature lower than it's design intended. The result is increased wear on the engine's internals. It's essentially the same as if you assembled the engine with clearances tighter than designed for because you didn't follow the directions or your tools were not calibrated properly. 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. Limiting wear isn’t necessarily a big concern with a race engine though, since the expectation is for a short service life anyway. In any car, the floor (opening temp) of the thermostat is completely irrelevant unless you are running a very efficient and large radiator. Once you're out on the track for half a lap or so, your coolant temps are going to be in the 200 range anyway so the thermostat is fully open regardless. So if you want to test this, the best thing to do is get an OBDII scanner and go out in an OBDII car and monitor the ECT sensor and watch how coolant temps regulate and spike as load changes. If the lower thermostat DID bring the temps of the intake manifold down 20 degrees, the actual change in intake temps would be negligible to zero on the road. Regardless, it would take literally a second or two before temps would be regulated by the cooling system, not the thermostat anyway since under load the engine is going to run well above the thermostat fully open mark. Hunting, meaning dramatic changes in coolant temperature, is a common problem with lower-quality thermostats because they allow too much flow when wide open. In a worst-case scenario, hunting can result in a cracked cylinder head from being exposed to such dramatic changes in temperatures, and at the very least it causes a significant reduction in the efficiency of the cooling system. NTCL’s low-temperature thermostats are engineered to prevent hunting. They are designed with a main valve that opens in a more controlled fashion, preventing coolant from suddenly rushing to the radiator and causing the rapid change in coolant temperature associated with hunting. Also, as a note running E85, cylinder temps are lower because of the fuel characteristics. Since you need more ethanol to produce the same results, the combustion chambers are naturally running cooler because of the fuel. Boosted applications, people will go with a higher T-stat instead of lower. Ethanol with lower operating temps can also milk the oil. Oil has to be 210+ degrees to burn off the contaminants. If you run at 160-170 degrees, then the oil temperature wont be high enough to boil the water that condenses inside the crankcase when an engine is shut off and cools. This milks the oil. This means you should be changing your oil more often than the 7500 OCI with a lower T-stat. Again; Do whatever you want, it's your car, but you should know the big picture when going to such a low T-stat rating. What I wrote is not gospel, nor the word of GOD, it's observations throughout the car community. |
04-01-2020, 03:04 PM | #30 | |
Drives: 2014 ZL1 Join Date: Apr 2018
Location: KCMO
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04-01-2020, 03:17 PM | #31 |
Drives: 2013 ZL1 and 2019 Ram Laramie Join Date: May 2017
Location: Milwaukee
Posts: 1,259
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Good post '10. That's what I meant w/o writing for ten minutes. It is also ill-advised to run 1300's, but not bigger rails, or a Melling, or a timing chain. Since my posts go ignored, I'll stop posting here.
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04-01-2020, 04:45 PM | #32 |
fo'shizZL1
Drives: 2017 ZL1 Join Date: Aug 2017
Location: ATL
Posts: 1,281
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I'm curious about the timing chain. Never heard that one. I run a C5R Katech/iwis.
I run a Melling pump, too, but it's been ported, coated, blueprinted. I wouldn't run one out of the box, though.
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2017 ZL1 M6 Black | Maggie 2650 // 103TB // Big Gulp
Past Rides- 2014 ZL1 M6 Red Hot | Tons of mods 2004 CTS-V M6 Silver | Many mods 1995 Corvette M6 Torch Red | A few more mods 1992 Camaro M5 White | A few mods |
04-01-2020, 08:59 PM | #33 |
Drives: 2013 Triple Black ZL1 / 2006 TB SS Join Date: Feb 2011
Location: MN
Posts: 2,250
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Nice copy and paste job. I constantly data log this car (and the same with my previous set up) and I've never seen a 160 t-stat drop ECT 20 degrees. The most I see is 6-8 degrees drop on average. It still reaches optimum operating temp. You also have to make sure not kick on the fans too much and too soon, so it's a balance to get it right. As for oil temperature, I never go WOT until it's fully warmed up.
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04-02-2020, 05:05 AM | #34 |
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No, it was copy a while ago, edit, and paste. I could have said that all, but I already
have an article saved with all that information. I keep a lot of reference materials on cars I have owned, or currently own. I work in a performance shop, we need to have it. |
04-04-2020, 04:54 PM | #35 | ||||
Drives: 2015 ZL1 Join Date: Feb 2020
Location: Little Rock
Posts: 253
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04-05-2020, 02:16 AM | #36 |
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An engine at 185° can run more timing advance safely than one running at 205° so tuning, along
with a low temp thermostat, can make some significant gains. So if you're using a handheld programmer, chip or custom tune then a lower temp thermostat may help. I am sure that everyone has noticed timing pulls with a hot motor/intake. Running an engine cooler has been a thing for high performance since the early days of hot rodding, ask your dad or grandfather. Those guys were pulling their thermostats out or drilling holes in them because they knew they could run more timing by doing so. I used to drill mine back in the 80s. Just a 1/8th hole in the collar, made a huge difference. Sucked in winter. Also, If the engine does not reach a high enough temp for the computer to leave warm-up mode then fuel economy will drop dramatically. If you are going to run E85, you won't need the lower T-stat for the aggressive timing, it's 105 octane fuel. As I said, the other issue is oil temps, it won't be hot enough to burn off moisture and other contaminants in the oil. If you're not doing it for performance, then there's really no reason to go with a lower temp T-stat. It gets into the 100 degrees here in SW PA at times in the summer, and I have always run stock T-stats. If it makes you feel comfortable, then do it. It's really not necessary for daily driving. |
04-05-2020, 04:31 PM | #37 | |
fo'shizZL1
Drives: 2017 ZL1 Join Date: Aug 2017
Location: ATL
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I think the stock rails support a lot of hp. I believe Dave Steck had some good data on this at one point.
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2017 ZL1 M6 Black | Maggie 2650 // 103TB // Big Gulp
Past Rides- 2014 ZL1 M6 Red Hot | Tons of mods 2004 CTS-V M6 Silver | Many mods 1995 Corvette M6 Torch Red | A few more mods 1992 Camaro M5 White | A few mods |
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04-07-2020, 12:46 PM | #38 | ||
Drives: 2015 ZL1 Join Date: Feb 2020
Location: Little Rock
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