i recently changed my thermo stat out from the stock 195 to a 160 degree, when i had the 195 stat i was running 90 mph and the last time i took the car to the track with the 160 stat i was running 86 mph, i'm trying to determine if it's the temp difference or if i have another problem to look for, any thoughts or opinions are appreciated

 

I wouldnt think that would be your problem but I dont really know a whole lot lol.

 

did you retune it?

i'm a fan of stock thermostats on our cars. the intake manifolds dont heat the air like alum does.

 

^^ im with this guy

there isnt a need for a cooler stat unless your FI. If u didnt have your fans re tuned i would assume there could be some loss, but not 4 MPH. What was the difference in your ETs?

 

Down it the South I prefer the 180 stat. I am not a fan of anything lower than that.

 

Is there a reason you guys dont like that low of a thermostat. I always thought that the cooler the better

 

I was told we didnt need the 160. so i still have the stock one

 

I have always used the stock 186 deg stat from my local Chevy dealer. I also have a Fan Switch.

 

Opposite to common misbelief the lower thermostat is not advantageous on modern engines. It affects the fueling of the program and can inadvertently affect the fuel boiling point during port wall impact ... basically the fuel will not atomize properly, plus the ECM will add extra fuel for the lower ECT. Both can be programmed around. I always recommend a stock thermostat. You want to incoming air as cold as possible, not the coolant. As mentioned before the old carb'ed engines benefited from this because the coolant passed through the intake, which heated up the air charge. Those old engine did benefit from a colder thermostat.

 

I picked up time and mph going to a 160 stat. I aspecially like 160's on stalled auto cars to help with keeping the trans temps down as well. It's all in the tune!!!

 

160 t-stat here, for the past 7 years on my 427ci....down here in HOT *** South Florida.

My engine runs BIG TIME cool. 160 t-stat.

If you get the PCM tuned for the fans to come on sooner and you use a 160 t-stat....and nothing else is wrong with the cooling system, it does nothing but GOOD for the engine.

Problem you may be having is your t-stat is staying open because you're getting too hot and you fall behind the cooling curve. If the fans aren't coming on in time, while in city or stop and go traffic, the coolant will get so hot that it will reach a point of no return and the coolant will keep getting hotter and hotter and never stop circulating, keeping the t-stat open.

I sit in traffic with my 427, A/C on full blast, 95* weather...and my temps will never go above 210. My fans come on soon enough to help cool while sitting still or moving slowly, and the 160 t-stat has chances where it actually closes to give the HOT coolant that just entered the radiator from the engine/heads time to cool down BEFORE going back into the engine/heads to get hot again.

 

i talked to a well known engine builder in my part of the world, he actually agreed that the warmer 195 would help burn the fuel better than the 160, i also retuned it just to lower fans temps and not to add fuel at the lower temps that was the only changes i made to the tune, i belive i'm gonna go back to the 195 when i swap my water pump out in a few weeks

 

both 160* t-stats I have used actually operated in the 170* range which sent the car in open loop hence voiding many commen perceptions of that t-stat. even at colder outside temp 160* got fine heater temps and I THINK oil temps but I don'r have an oil temp guage so i don't know for sure. 1ust took longer to heat up....

 

Ed Curtis posted this up on his site.

Proper Coolant Temperature and Camshaft Life!


Have you ever tried to find what proper coolant temperature is for most automotive engines? There are a lot of people who think they know, but it is difficult to find specifics, even in textbooks. We know we want the intake air to be as cold as possible (for best power) because cold air is denser (there are more oxygen atoms per cubic foot). The coolant temperature, however, is a different matter. The internal combustion engine changes chemical energy stored in gasoline into heat energy that is focused on the piston tops. If the cylinder heads and engine block are too cold, they will absorb much of the combustion heat before it can be used to push the piston down the cylinder. If the engine gets too hot, engine lubricants can break down, as well as overheating of the intake charge can lead to detonation, etc.

It turns out that coolant (usually a 50/50 mixture of coolant and water) has some fantastic properties that are ideal for use in engines. With a properly pressurized cooling system, coolant will not freeze until –30°F, and it won’t boil until +270°F (new oils don’t start to break down until well over 270°F). With these characteristics, engine designers have decided that engines should operate at approximately 210-215°F. Why, you ask? Well, it has to do with operating the engine at a high enough temperature to boil water out of the oil after the engine is cold started. If you have dew on the grass, it is certain that you have water in your oil, as the crankcase is open to atmospheric pressure! You can either remove the water by draining it out the bottom of the oil pan (remember the oil floats on water) or run the engine long enough and hot enough to boil the water out of the lubrication system. Years ago, coolants weren’t as sophisticated and engines were run at 165-180°F, but the oil was changed every 1,000 miles or so. That’s why many old timers think engines should run at 165-180°F. Have you ever noticed that Ford doesn’t put temperature marks on their gauges? They just mark C for cold and H for hot and write “normal” through the center. If you hook up a scan tool to a GM, you will often find that the gauge reads much lower than the coolant temp sensor. That is because they know most drivers don’t understand how hot an engine should run.

So what does this have to do with camshafts? Many enthusiasts erroneously think that the colder their engine runs, the better! If they are not running the engine hot enough to boil the water out of the oil, the oil becomes contaminated and the lifter/cam lobe interface is the highest load point in the engine. Engines running too cool can contribute significantly to camshaft and lifter failure. Think about it: What good does it do to use the most expensive synthetic oil and then run the engine so cold that it is contaminated by water vapor? Another point, piston manufacturers’ piston-to-wall clearance recommendations assume you will be running the fully warmed engine at 200°+F. Run the engine too cold, and you could see some scuffed pistons because the cylinders had not expanded enough to provide clearance.

If your engine will only run its best at the drag strip with the engine at 165°F, you probably have too cold of a spark plug heat range, and you are probably jetted way too rich! If you keep the engine hot (not the intake charge), you will be using more of the heat energy in the gasoline to make power instead of just heating up your block. It does take “tuning know-how” to run an engine at 200-210°F, but you might be surprised how well and how long it runs when you do!! One final point, running a computer managed engine at 165°F compared to the factory 210°F will often cost you as much as 4MPG. That’s because the computer thinks that the engine is not off the “choke cycle” and it is still putting out a rich mixture! Check the science on this and don’t pay attention to the “old wives tales” of the past. Materials and lubricants are much better and different today than in the past!!

from the monthly Crane Newletter

 

I agree with the Ed Curtis post but do you think by having a 160* t-stat in your car means that when it is fully warmed up, it wont go above 160? No, of course not. You shouldn't see much difference between the 2 except in Winter when it takes longer to heat up. It will however keep the car slightly cooler in hot summer months because it simply has more of a head start on cooling. However, if you run the car hard and/or it is unusually hot out then the 160 as well as the 180 or 195 stats would all be stuck open most likely, and once they are open, they all cool the same. It is not some magic potion that keeps your car at or below the rated opening temp. My car still gets hot in the summer, 200+ easy (that is by scanning it, not the idiot gauge). Point is, you are splitting hairs. I think a 160* is fine, what isn't though is running without a t-stat. It would take forever for the car to warm up properly, especially in the winter.

 

I run a 160 here never any problems

 

I've still got my stock one so I guess since I am a tuner and all when I get my car running again I could do a back to back comparison to see exactly which one will make my car go faster... when it's all said and done that's the most important part anyways!!

 

There is a retired GM engineer on CF that developed and tested the cooling for the C5 Corvette. They ran all kinds of endurance testing on the LS1 and he states the optimum temperature is 180 - 195 degrees for coolant and over 200 for oil. Lower temps showed much higher wear on the motor and the cooler the faster the wear. If you belong to CF, just search on "Sweet Spot". His handle is Evil Twin.

 

Doesn't seem right to run a 160* thermostat when normal running temps are nearer to 200*. I mean, what's the point? Fuel atomizes better at higher temps, cold oil doesn't allow as much power as fully warmed oil.

 

"If u didnt have your fans re tuned i would assume there could be some loss, but not 4 MPH. What was the difference in your ETs?"


why would keeping stock fan setting slow you down? sitting still at the track, the coolant will be hot...and the stat will be open regardless of it being 160 or 195.

regardless of whether the stat opened at 160 or 195, the fans won't come on till 210 or so.

don't see how that would slow you down.

i've had a 160 in the past 3 cars, with no problems. i even put a 160 in my Mez EWP that requires bypass holes. other than a slower warm up time...it runs great right around 170-175* moving.