160 T-Stat to low?
Ive found the ls style engines run much tighter tolerances than an old style small block. I was suprised what some of the limits were while assembling my bottom end. I could see it being a problem if its running too cold, tolerances get tight and it takes much less for a bearing to seize.
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I found my tstat opens in the 180 range, my fans are set to come on at 187 and shut off at 183, but I find that on highway the car tends to cool itself to below that. I notice that once I stop within 2-3 mins of idling the fans will come on. The tstat is stock still so I was a bit surprised at that.
LOL... Just because you have a 160 therm in there doesnt mean the engine is now running at 160* There is nothing wrong with the 160. I had someone try and tell me an oil cooler will ruin and engine as well because it wont let the the oil work properly. Rubbish!!
Ive found the ls style engines run much tighter tolerances than an old style small block. I was suprised what some of the limits were while assembling my bottom end. I could see it being a problem if its running too cold, tolerances get tight and it takes much less for a bearing to seize.
Besides that fact, your gas mileage will reduce significantly using a colder tstat if your computer isnt set up to run that colder temp. Your computer probably doesnt get into closed loop operation till a hotter temp.
Besides that fact, your gas mileage will reduce significantly using a colder tstat if your computer isnt set up to run that colder temp. Your computer probably doesnt get into closed loop operation till a hotter temp.
Last edited by StevieZ; Aug 3, 2008 at 05:50 AM.
There is someone on Corvetteforum by the name of "Evil-twin", who is retired from GM but worked on the Corvette cooling system. Perhaps rather then accusing me of "making it up" you should educate yourself on the testing GM did with lower engine temps and the resulting engine damage (some within 10 K miles) that occurred once the temp started dipping below 180 and oil temps were not over 200. You can run your car at any temp you please, but the advice I gave the OP is sound and based on GM test results. What long term testing have you done with your lower thermostat? Have you done any oil analysis to back up your claim that 160 is OK?
The OP (or anyone else) has the ability to tweak the thermostat and keep the motor within a good temperature range with a simple shim, which cost less than $1. That is what most aftermarket thermostats do and most are not tested for opening temperature. So unless you test the ones being sold you really don't know what you have.
The OP (or anyone else) has the ability to tweak the thermostat and keep the motor within a good temperature range with a simple shim, which cost less than $1. That is what most aftermarket thermostats do and most are not tested for opening temperature. So unless you test the ones being sold you really don't know what you have.
There is DEFINITELY a performance gain with a 160. You make more HP when running cooler. Proven fact and an engine runing at 185* to 190* will NOT deteriorate because "the oil is too cool". Your engine will not run below 180 with a 160 T-stat. The lowest my coolant temp gets with an oversized SLP rad and a 160 is 185. PS: My 160 T-stat opens at 167
Last edited by StevieZ; Aug 3, 2008 at 05:52 AM.
There is someone on Corvetteforum by the name of "Evil-twin", who is retired from GM but worked on the Corvette cooling system. Perhaps rather then accusing me of "making it up" you should educate yourself on the testing GM did with lower engine temps and the resulting engine damage (some within 10 K miles) that occurred once the temp started dipping below 180 and oil temps were not over 200. You can run your car at any temp you please, but the advice I gave the OP is sound and based on GM test results. What long term testing have you done with your lower thermostat? Have you done any oil analysis to back up your claim that 160 is OK?
The OP (or anyone else) has the ability to tweak the thermostat and keep the motor within a good temperature range with a simple shim, which cost less than $1. That is what most aftermarket thermostats do and most are not tested for opening temperature. So unless you test the ones being sold you really don't know what you have.
The OP (or anyone else) has the ability to tweak the thermostat and keep the motor within a good temperature range with a simple shim, which cost less than $1. That is what most aftermarket thermostats do and most are not tested for opening temperature. So unless you test the ones being sold you really don't know what you have.
I read that too on Chevytalk
I just bought a OEM from the stealership and stock is 195* Supossedly more complete combustion at that temp. Therefore, maybe emmisions has something to do with it?
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"Besides that fact, your gas mileage will reduce significantly using a colder tstat if your computer isnt set up to run that colder temp. Your computer probably doesnt get into closed loop operation till a hotter temp."
i've run 160 stats in my last 2 cars.
-consistently did 26mpg with my 305TPI auto on the highway with the higher factory gears
-consistently got 28mpg with my 96 LT1 M6 on the highway stock gears
-consistenly get 25-26mpg with my CAMMED LS1 now.
only car tuned in any way is the LS1
as for closed/open loop....how does a 20* difference in operating temperature affect a function that only comes into play at well below 150* (i think the cutoff is 130* but not positive)??
watched my scanner many times in south florida heat. constantly moving, albeit slower speeds and the coolant never reads less than ~180*, even sitting and idling with my fan switch on HI, it barely pulls it down to 176-177*.
i highly doubt the make-or-break point for oil performance is only 20* below the factory operating temp.
and time for the engine to heat up is almost identical. everything is the same till the temp hits 160*....and within the next minute or so (after the stat has opened) its up in the 180s....how is that slow? how is that bad?
i've run 160 stats in my last 2 cars.
-consistently did 26mpg with my 305TPI auto on the highway with the higher factory gears
-consistently got 28mpg with my 96 LT1 M6 on the highway stock gears
-consistenly get 25-26mpg with my CAMMED LS1 now.
only car tuned in any way is the LS1
as for closed/open loop....how does a 20* difference in operating temperature affect a function that only comes into play at well below 150* (i think the cutoff is 130* but not positive)??
watched my scanner many times in south florida heat. constantly moving, albeit slower speeds and the coolant never reads less than ~180*, even sitting and idling with my fan switch on HI, it barely pulls it down to 176-177*.
i highly doubt the make-or-break point for oil performance is only 20* below the factory operating temp.
and time for the engine to heat up is almost identical. everything is the same till the temp hits 160*....and within the next minute or so (after the stat has opened) its up in the 180s....how is that slow? how is that bad?
I didn't install a 160* stat. with my last set of mods because of the negative things that I read.
The more I read I think I will just do it, because of the benefits it will give being FI.
I agree with Steviez, my track times are better when my engine is cooler.
The more I read I think I will just do it, because of the benefits it will give being FI.
I agree with Steviez, my track times are better when my engine is cooler.
My numbers were off in the above post, the oil temp where problems start is lower than what I stated. My suggestion is that before making a decision, take a spin over to Corvetteforum and search the archives for the term "Sweet spot". You are looking for posts by "Evil"twin", who is retired from GM. The point is that there is an optimum temperature range that the LSx motor can run in without losing power or causing excessive wear. His point was oil temps too low cause a lot of issues, including excessive cam wear on a stock motor. Put in stiffer springs and a faster opening cam, things get worse. But we never see any threads on excessive cam lobe wear here on LS1tech.
My only suggestion is to read up from the guy who helped design the system then make an informed decision. The 160 stat in and of itself isn't bad, as long as you know when the car is out of the safe window so you can make adjustments. Evil-twin actually runs a 160 himself in the summer, but reverts to the stock in the winter to keep the engine within the correct temperature window.
My only suggestion is to read up from the guy who helped design the system then make an informed decision. The 160 stat in and of itself isn't bad, as long as you know when the car is out of the safe window so you can make adjustments. Evil-twin actually runs a 160 himself in the summer, but reverts to the stock in the winter to keep the engine within the correct temperature window.
My numbers were off in the above post, the oil temp where problems start is lower than what I stated. My suggestion is that before making a decision, take a spin over to Corvetteforum and search the archives for the term "Sweet spot". You are looking for posts by "Evil"twin", who is retired from GM. The point is that there is an optimum temperature range that the LSx motor can run in without losing power or causing excessive wear. His point was oil temps too low cause a lot of issues, including excessive cam wear on a stock motor. Put in stiffer springs and a faster opening cam, things get worse. But we never see any threads on excessive cam lobe wear here on LS1tech.
My only suggestion is to read up from the guy who helped design the system then make an informed decision. The 160 stat in and of itself isn't bad, as long as you know when the car is out of the safe window so you can make adjustments. Evil-twin actually runs a 160 himself in the summer, but reverts to the stock in the winter to keep the engine within the correct temperature window.
My only suggestion is to read up from the guy who helped design the system then make an informed decision. The 160 stat in and of itself isn't bad, as long as you know when the car is out of the safe window so you can make adjustments. Evil-twin actually runs a 160 himself in the summer, but reverts to the stock in the winter to keep the engine within the correct temperature window.
I ran a 160 when i was cam only, I also had the fans to come on at that temp as well. The only differance between the stock T stat and the 160 was a *15 differance. I never let my car run cold at the track I allways ran at operating temp so between 199-200* at the track my times where ok. with the 160 T stat temps where between 180-195 times where the same. It felt stronger but no really big change. Now crusing in texas heat with the ac on. The stock T stat temps would creep up to 210,On the 160 T stat I would see 195-200. All temps where seen through a data logger in real time. Oh and crusing at 70 -80 mph temps would hover around 190 with the 160 t-stat.
The engine books I've studied, and the instruction I've received, discuss incomplete combusion as a cause of oil contamination. As the oil is loaded up with gasoline, a solvent, it underlubricates the engine components and accelerates wear. Doesn't matter how good the oil is, it can't do its job if its being washed off the surface it's supposed to lubricate.
The engineering thinking is that combustion chamber heat is A Good Thing(tm) as pertains to combustion efficiency. The guys who made serious power with aluminum heads did so by moving the water jackets away from the chambers, thus retaining more heat in the chambers where it could be used to increase combustion efficiency.
If I was going to twiddle with my engine operating temps, I'd sample the engine oil and have a lab (Blackstone, for example) scope it. If I saw out-of-range quantities of fuel in the results, I'd either go hotter on my chamber temp or I'd lean down the fuel:air mix. And then I'd re-sample after a few hundred miles. Only after I nailed down this issue would I bother dyno testing to see if I made more power...because giving up engine longevity isn't my priority.
Thinking on this issue may vary, but there you have a snippet of conventional wisdom.
We are talking about a 20* + or - with the different t-stat. I have a hard time believing there is a difference between 180* oil, and 195* oil. My car runs great with the 160 t-stat. I get better gas milage that my buddy that has almost the same set up with the stock t-stat. I wouldn't use one in the winter, due to the fact it won't heat up. If we were talking about the difference between 100* and 200*, there is a problem. And I don't see oil really effecting combustion chamber temp. Contamination will not happen with a lower t-stat. Like has been said, your car will still be running around 180*. Your temp is more dependant on your fans.
The thing I haven't seen covered yet is the mechanism of oil contamination and resultant engine damage due to lower combustion chamber temps.
The engine books I've studied, and the instruction I've received, discuss incomplete combusion as a cause of oil contamination. As the oil is loaded up with gasoline, a solvent, it underlubricates the engine components and accelerates wear. Doesn't matter how good the oil is, it can't do its job if its being washed off the surface it's supposed to lubricate.
The engineering thinking is that combustion chamber heat is A Good Thing(tm) as pertains to combustion efficiency. The guys who made serious power with aluminum heads did so by moving the water jackets away from the chambers, thus retaining more heat in the chambers where it could be used to increase combustion efficiency.
If I was going to twiddle with my engine operating temps, I'd sample the engine oil and have a lab (Blackstone, for example) scope it. If I saw out-of-range quantities of fuel in the results, I'd either go hotter on my chamber temp or I'd lean down the fuel:air mix. And then I'd re-sample after a few hundred miles. Only after I nailed down this issue would I bother dyno testing to see if I made more power...because giving up engine longevity isn't my priority.
Thinking on this issue may vary, but there you have a snippet of conventional wisdom.
The engine books I've studied, and the instruction I've received, discuss incomplete combusion as a cause of oil contamination. As the oil is loaded up with gasoline, a solvent, it underlubricates the engine components and accelerates wear. Doesn't matter how good the oil is, it can't do its job if its being washed off the surface it's supposed to lubricate.
The engineering thinking is that combustion chamber heat is A Good Thing(tm) as pertains to combustion efficiency. The guys who made serious power with aluminum heads did so by moving the water jackets away from the chambers, thus retaining more heat in the chambers where it could be used to increase combustion efficiency.
If I was going to twiddle with my engine operating temps, I'd sample the engine oil and have a lab (Blackstone, for example) scope it. If I saw out-of-range quantities of fuel in the results, I'd either go hotter on my chamber temp or I'd lean down the fuel:air mix. And then I'd re-sample after a few hundred miles. Only after I nailed down this issue would I bother dyno testing to see if I made more power...because giving up engine longevity isn't my priority.
Thinking on this issue may vary, but there you have a snippet of conventional wisdom.
Combustion chamber temp affects combustion efficiency, which in turn affects oil purity.
Oil purity affects engine longevity.
Hope that does a better job of explaining the process.
Looked around, found a couple of posts by ET:
"Running at 160 in the winter is a NO No with an LS1/6. Thats why I run a 190 in the winter with stock fan settings. I have seen the damage caused by too cold of engine temps. The sweet spot on an LS1/6 is 190 coolant and 210 for oil temp. This allows for proper lubricity of the oil, correct bearing clearances, and positive oil flow.
Keeping a C5 in the sweet spot is difficult in the summer time. Running at 160 in the winter is disaster long term. Bearing wear, carbon build up, ping, knock retard, poor performance, reduced gas mileage."
"...
, I have to laugh at all those shade tree mechanics, and wanna be's out there with their mythological thoughts on this issue. When we developed the oil monitoring system we tested many engine scenarios, we tested oil and coolant temps, we saw the damage done by cold temps. To get the HP out of this car the oil has to be lubricious. The sweet spot is in fact 180/190 coolant and 200/210 oil.
I'm sitting here thinking about giving a seminar on this issue but I figured why argue with so many experts.
I've given my Expert opinion on this subject, what more can I do."
"While it is true and everyone knows this we design the run temp from a stock LS/X to run high enough to squeak by an emissions tax.. it was a prime directive.
Also we took advantage of this hotter temp to design tolerances that in this environment would be more advantageous to the engine output... AS I have said many times, the actual sweet spot of this car for engine output "while maintaining internal integrity" is 180/190 coolant... 200/210 oil..... anything lower than that will cost you down the road... because the tolerances are compromised with too cold of engine temp.
The only reason anyone who knows anything about this motor is a 160 will Help to maintain the sweet spot under competitive driving conditions. If you drove this car at sustained 160/170 temps all year round the engine would self destruct internally.. we have already proven this on our test mules.
The one thing I tell all the newbies on this forum is be careful who you listen too... there are many idiots on this forum who have a preconceived notion about automotive technology... I always say
"Be careful who you listen too"
Naturally a guy in Florida who sees 70 80 and 90 degree days could take advantage of a lower stat in the effort to keep their car in the sweet spot...
Conversely, you wouldn't want to run a 160 stat up in Bismark North Dakota....in -20 degree days, We build cars for both environments...
WE use algorithms written to cover the span of cars driven in Florida too that why we have two fans, and two temperature settings, fans running under the air conditioning loop.
This is almost common sense, except for some of the ******* found here.
This is a great car right out of the box.... Can you tune it up for your particular driving environment ??? absolutely!!!!"
"Running at 160 in the winter is a NO No with an LS1/6. Thats why I run a 190 in the winter with stock fan settings. I have seen the damage caused by too cold of engine temps. The sweet spot on an LS1/6 is 190 coolant and 210 for oil temp. This allows for proper lubricity of the oil, correct bearing clearances, and positive oil flow.
Keeping a C5 in the sweet spot is difficult in the summer time. Running at 160 in the winter is disaster long term. Bearing wear, carbon build up, ping, knock retard, poor performance, reduced gas mileage."
"...
, I have to laugh at all those shade tree mechanics, and wanna be's out there with their mythological thoughts on this issue. When we developed the oil monitoring system we tested many engine scenarios, we tested oil and coolant temps, we saw the damage done by cold temps. To get the HP out of this car the oil has to be lubricious. The sweet spot is in fact 180/190 coolant and 200/210 oil.
I'm sitting here thinking about giving a seminar on this issue but I figured why argue with so many experts.
I've given my Expert opinion on this subject, what more can I do."
"While it is true and everyone knows this we design the run temp from a stock LS/X to run high enough to squeak by an emissions tax.. it was a prime directive.
Also we took advantage of this hotter temp to design tolerances that in this environment would be more advantageous to the engine output... AS I have said many times, the actual sweet spot of this car for engine output "while maintaining internal integrity" is 180/190 coolant... 200/210 oil..... anything lower than that will cost you down the road... because the tolerances are compromised with too cold of engine temp.
The only reason anyone who knows anything about this motor is a 160 will Help to maintain the sweet spot under competitive driving conditions. If you drove this car at sustained 160/170 temps all year round the engine would self destruct internally.. we have already proven this on our test mules.
The one thing I tell all the newbies on this forum is be careful who you listen too... there are many idiots on this forum who have a preconceived notion about automotive technology... I always say
"Be careful who you listen too"
Naturally a guy in Florida who sees 70 80 and 90 degree days could take advantage of a lower stat in the effort to keep their car in the sweet spot...
Conversely, you wouldn't want to run a 160 stat up in Bismark North Dakota....in -20 degree days, We build cars for both environments...
WE use algorithms written to cover the span of cars driven in Florida too that why we have two fans, and two temperature settings, fans running under the air conditioning loop.
This is almost common sense, except for some of the ******* found here.
This is a great car right out of the box.... Can you tune it up for your particular driving environment ??? absolutely!!!!"
As I said.... I run a 160* with coolant operating temps running between 185 to 190ish. So I guess I am running in what everyone is calling "the sweet spot". As for driving in the winter... heck I run ET streets so I don't even drive in the rain!! I'll drive my car from May to Oct and then it goes away for the winter. If you are driving your car during the summer months, then a 160 is the way to go. IMO. Also, I change oil every 2500 miles and oil contamination has never been a problem and I DID the oil analysis to know that for a fact.