I think there are many benefits to running an engine cooler and although I can't prove it, I do think mechanically there are long term benefits. Here is my common sense reasoning that may be worthless.

I am pretty sure the auto industry runs newer cars at a higher temperature to assit with emmission standards. I say this because the faster the Cats fires off, the cleaner your exhaust is. Most cars have a certian temp where they run in a closed loop mode like during start up where they are actully running a little rich.

Heat is the number one enemy of an engine because of all the interesting things heat can do to engine components. Excessive heat also breaks down the protective properties of oil, even synthetics, so cooler is better as far as lubricants are concerned. If your oil breaks down you loose wear protection, which could lead to an engine that runs hot over and over again having a shorter life span. Heat is not the friend of plastic, rubber, aluminum, etc. So if you can lower the operating temperature of engine, you are also lowering the underhood temperature as well.

And last but not least, lowering the normal operating temperature of the engine also means I am not wearing my AC out just trying to stay cool in this car.

 

The cats are heated by the exhaust gases, which are very hot (1200 F). Engine coolant temperature has little or no effect on cat temperature. However, the engine's fuel burn will be less than complete in a cool combustion chamber, ie the cool surface quenches the flame, letting unburned fuel exit the combustion chamber with the exhaust gases. This does increase HC emissions, but it also decreases power and performance because unburned fuel doesn't contribute to chamber pressure, engine torque, and engine power. For best power and performance, the chamber needs to be hot enough to promote complete combustion, but not so hot that it promotes detonation. For small block Chevy engines, that corresponds to a coolant temperature in the 180-190 degree range. Cooler and you get incomplete combustion, higher and you can't run the ideal amount of spark advance for best power.

Your oil also needs to be at a certain temperature to perform properly, as do other engine components which are designed to have certain clearances at a certain temperature. That's why you shouldn't get on the engine until it warms up to its design operating temperature. Your engine is a heat engine and needs to operate at a certain temperature to perform properly. Cold is not good. Too hot is not good either. The engine needs to operate at the [b]right[b] temperature.

 

 

running rich is actually worse on the enviroment than running lean.

 

OK, if running cooler causes incomplete burn, then why change to a lower temp thermo at all, even on the track?

 

Two reasons:

1. Even with a lower temp thermo, the operating temps do not get cool enough to cause an incomplete burn. So long as you stay between 180 - 195 degrees, you're OK.

2. The lower temp thermo not only keeps your operating temps down, but it will reduce the amount of temperature spike that you get at idle, low speeds, or under hard driving. Last time I was at the track, as I pulled up to the burnout box, the car in front of me broke at the line. It took them 5 minutes or so to roll it off the line, meanwhile I'm sitting there waiting, and the temp spiked up well over 215 degrees. If I had a low themp thermo at the time, the temps never would have gone over 195.

 

even though it spiked, how long did it take to return to normal ?

one slow launch down the strip, just enough get airflow, then open her up ?

 

That's why my new thing is to not get caught at the end of long staging lane lines anymore, even once I do the thermostat and fans on my C6.
If I can work it I will either be first in line before anyone gets there or once the day/night wears on I'll sit it out until I can be, no more half hour long periods idling my way to the start line. Only problem then is having the trans, rear and possibly even coolant temps be TOO cold to make a pass.
That is one of the things that makes track rental days so much better but my relatively easy to launch, mid 12 second car doesn't quite justify a $160.00 - $200.00 layout just to make some time shots LOL.

 

Shopdog,
You bring up some great points which lead to more questions
With a 160 degree stat, the car should be running right in the heat range you stated 180-190 degrees, that is not where it runs with the stock stat. So the first question is why do the manufacturers run cars at such a high temperature if not for emmission purposes? Second question, if we know an engine running at a cooler temperature can handle a little more timing, which helps in the power department, why don't the manufacturers do this as well? Third, the synthetic oil these cars use does provide some cold start protection via the really low viscosity rating that as I understand, changes to a higher viscosity rating with heat. I do understand lower weight oil also means less drag on the engine, but with the oil viscosity that low, I wonder if this is as much of a factor as it use to be. Asking because I do respect your opinion and I have gained some good knowledge from many of your comments in the past.

 

At the track, I had to wait a while between runs, so I just parked it for an hour. I didn't keep track of the temps.

On the road, it will get up to 190 at a long light, maybe 195 if I'm waiting in the drive-thru line at a fast food joint. Takes less than a minute to drop back to 180 or so at 60 mph.

 

is it correct to assume, at least that's the impression i'm getting, that it takes less than a minute at road speed to drop the temp back down to the 180 range when using the 'stock' thermostat ?

while at the track do you think it may have helped if you did a quick ramble around, after the run, to get temps back down where you wanted them.

i don't like waiting, idling, for more than three cars, i'll shut her off and wait if there is more than three, or if there is a 'big hold-up' in front of me. i.e. anytime something out of the ordinary happens that slows the flow of traffic.

 

Zig, no it is not correct to assume that. Once you get up to operating temps, the stock thermo will never let you get back to 180, as it closes around 195. The 160 thermo will allow the operating temps to drop from 195 back to 180 within a minute or less, if you're at highway speeds. If you're in slower traffic, it will get down to 185 or so pretty quick, linger there for a while until you pick up some speed.

At the track, it's no too easy to "ramble around" at 60 mph, or even at 30 mph, especially on a crowded day.

 

i was under the impression that you hadn't switched it out, yet.

sorry, didn't mean to imply one should drive around the pits, etc. at 30+.

trolling the long way back to your spot with the a/c running, to try to keep the fans at 100%, is all i meant.

my point was simply, the airflow caused by movement was/is good for at least a 15 degree drop in temps.

 

it was 6 tenths.....with the nitrous shot

 

I've been paying closer attention to the cooling temps, and in the 30min street drive to work, my temps run in the high 190's even with exterior temps of 57F. I never see the temp get less than mid 180s even with moderate prolonged speeds (45 to 55). I've already ordered my new thermo. which will go in at the same time as my new (used) catback and new (used) xpipe and thermal abs. I'm not looking for increased perfomance, but longetivity and actual muscle car sound.

Has anyone experienced any ADVERSE results from installing a new 160 thermo?

 

REPLY: No adverse affects from using my 160 ; i swear its a bit peppier. When its 57 f. outside, i typically run 172 - 178 going 45 mph in 3rd,4th, or 5th gear. The radiator fan wont come on as often because you have more time before it is engergized when using a 160 f stat. Its got to help longevity of the motor running some 20 f cooler ; the oil temp gets just as hot (190-200 f. roughly) when its 57 f outside, but takes a bit longer getting to that temp.