: Thermostat - stock vs. 160 questions



TriTexan
06-15-12, 03:27 PM
A lot of mods I see swap the stock thermostat for a 160 degree stat. My question is why? I know the initial logic is that it improves heat dissipation. But how much does it matter? What I mean is that cooling capacity is partly a function of the cooling aparatus - the size of the radiator, etc. And 200 degree coolant running thru the radiator will bleed heat faster than 160 degree coolant, assuming the ambient air temp is the same. In the end, isn't the cooling capacity about the same? That is, aren't we just running the coolant at a lower temp? And why did the GM engineers not put a 160 degree stat in a 550 hp engine to begin with? I can only assume that there is a reason why they wanted a 550hp engine running with a 200 degree stat to begin with. Our engines seem to generate a ton of heat and I can't imagine the engineers didn't notice this during mule testing. Is there something about the engine that makes it operate more efficiently with a 200 degree stat? Or does it create lower emissions or something? I guess stats are roughly equal in cost, so there's little price difference in choosing one over another (unlike forged internals, for example). So why did they pick what they did for the stock one?

I'm also curious what stock is...my display seems to show a coolant temp of right at 200 - is that correct? That is, the stock stat is 200? I just want to understand a little more about the rationale for choosing the temp of thermostat to install. To me it seems an almost universal trend that manufacturers choose a 180 to 200 degree stat and anyone looking at mods automatically swaps that out for a lower temp. Any insight on the engineering and design choices for the stock versus aftermarket options? And even better, does anyone have any real-world measurements of one temp versus another? That is, something like a dyno run done using the stock versus 160 to show if there are any torque, HP, or other differences....

larry arizona
06-15-12, 03:50 PM
The main advantage to a 160 tstat versus the 195 T stat is that when you add the 160 AND get your fans reprogrammed to come on earlier and stay on longer you can reduce the underhood temps by 30 to 40 degrees. Just running a 160 stat with no fan tuning does very little.

GM can't do a 160 stat and meet emissions standards.

larry arizona
06-15-12, 03:54 PM
with less latent heat under the hood and an cooler running engine, slightly higher timing could be added to a custom tune. Also the lower underhood temps help you IAT2 temps. Not huge gains but worth it for a $26 Tstat and a gallon of coolant

TriTexan
06-15-12, 04:36 PM
The main advantage to a 160 tstat versus the 195 T stat is that when you add the 160 AND get your fans reprogrammed to come on earlier and stay on longer you can reduce the underhood temps by 30 to 40 degrees. Just running a 160 stat with no fan tuning does very little.

GM can't do a 160 stat and meet emissions standards.

Good points on changing the fan programming...obvious now that you mention it but I hadn't thought about it.

I figured emissions could be a factor, too. Are you surmising that they can't meet emissions and the 195 was chosen for that reason, or is that something you know pretty firm?

Crystal Red CTS-V
06-15-12, 05:10 PM
Stock thermostat is 190 (I think). Emissions and fuel economy are the primary reasons for the modern "hot" thermostats.

Tedboss1
06-15-12, 06:26 PM
Have look at this thread on the same topic:
http://www.cadillacforums.com/forums/2009-cadillac-cts-v-performance-mods/243509-160-thermostats-worth-changing.html

larry arizona
06-15-12, 06:34 PM
TT, hotter thermostats causes higher engine operating temps is fact for improving emissions. Started back in the mid 70's.

larry arizona
06-15-12, 06:38 PM
again, without fan programming it is largely useless, Well worth it if you are getting a tune anyway. Screw emissions anyways

TriTexan
06-16-12, 01:16 AM
Ok, that pretty much makes my decision. In Houston where it's hotter than blazes anyway, even without other mods I would think a lower thermostat and a fan programming change seems like a totally good idea. I'm not completely in the "screw emissions" category with Larry, but let's face it - if I were a total tree hugger I wouldn't be driving one of these to begin with...so I guess with summer coming on in full force, that'll be my first mod.

larry arizona
06-16-12, 07:49 AM
TT I like trees I really do HA, but I also like fast cars. I choose fast cars over trees. Everyones lawnmowers still put out more emissions in one use than most modern cars do in a year. Not terribly worried about the added emissons my V puts out with a 160 tstat. I tried to get "GLBLWMR" as my plate but it was already taken in michigan.

6speeder
06-16-12, 09:56 AM
again, without fan programming it is largely useless, Well worth it if you are getting a tune anyway. Screw emissions anyways

That's not always true. If you are at speed (45 mph+), airflow into the radiator is enough without the fan coming on to make the car run cooler. You may not see it on the stock gauge because actual ECT varies wildly from what the gauge shows, but the ECT will be cooler with a 160 and stock fan settings.