Yep, never heard that comment, but you will have to agree that 1/4 mile time and dyno readings are average HP. The dyno though calculates the instantaneous HP and records it. If you know your car weight and you have a recording accelerometer, you too can calculate instantaneous HP. And if you also record rpm, then you can calculate a plot of HP vs rpm.

 

I'll agree with all of this except that the 160* 'stat will slow warm-up. It won't. The car will warm to 160* at the same rate regardless of whether there's a 160* or a 180* 'stat in there. In either case, the 'stat is closed 'til the ECT reaches 160* (and the 180* 'stat will, of course, remain closed 'til ECT reaches 180*).

As I've said before, and will say again, the only reason I used the 160* 'stat was that it allows me to set fan-on/off temps lower, without having the fans run constantly at idle/low-speed following warm-up, than could have been done with the stock 180* 'stat. Had I not wanted to set my fan-on/off temps at 190/180 & 195/185, I'd have had no reason to change the 'stat temp.

Be well,

SJW

 

Why don't you understand that when the 160 stat opens, coolant starts flowing and the coolant starts transfering heat out of the engine and the engine temperature rise slows down and it takes longer for the coolant to get to 180 deg than if you had a 180 stat and coolant is not removing engine heat ?

 

Yes, but how much time does it take? About 5 minutes.

 

Thank you for answering my original question and without being a smart @#!.

 

From what I experienced with my 1994 LT1, my temps were peaking at 230+ and I hated to hear that gurgling sound when I parked the car after a run in the Florida heat with the A/C in high. So I replaced my thermostat with a 160 and reprogrammed the fans with the Hypertech programmer. Now my car runs in the 180 to 190 range. Again, from what I've experienced (observed in my car), the heat up time is unchanged, but the top end temp is lower now.

Funny how these types of posts get such a huge participation to include the disdain of so many. Equally interesting on how some feel it a duty to read a post like this and make a derrogitary remark when they could have just as easily bypassed the post altogether if they take issue with it.

Like yo momma said, "If you aint got nuthin good to say, .... "

Billy

 

Agreed, I know members such as Nathan, showed dyno runs where it made no difference, and I agree, the dyno will parallel the track readings, all things being equal.
I dont claim to understand why, but my car runs consistanty faster when I leave the line at 160 vs 190-200.
The reason I mentioned Mr. Mojo, and John Mackey is I have seen writings by both, over the years stating this as one of the things to do to lower ET.

 

Datalog the IAT and see if your intake temp is much lower when you run at 160° compared to 200°.

Without airflow over the radiator your temps creep up, a manual fan switch is very easy to install and very inexpensive.

 

Who has a good quality manual fan switch?
cal

 

Radio shack.

 

This article makes sense to me, I didn't write it:


There seems to be much discussion about:

Which thermostat do I use?
Will running my fans all the time hurt anything?
What is normal operating temp?
I put in a 160° thermostat and my car still overheats.


I have some theories that may put some of these issues to rest and help us all understand how our cooling systems work and bring some "myths" to light.

The Basic Theory - of cooling operations regarding thermostats is as follows. With the radiator, engine block, and overflow tank we have app. 17.2 quarts of a 50/50 mixture of antifreeze and water to cool our engines. A few quarts reside in the engine block the rest outside the engine. A thermostat, by closing, separates these two circulation areas whereas the block will heat it's own water first until it reaches the thermostat opening temperature. Then the stat will open thereby increasing the volume of coolant that is being circulated by the water pump. This "dual" system allows us to reach operating temps faster to heat the oil, fluids, and to render the interior heater usuable in a quicker timeframe.

The Stock Thermostat - in our cars is a 195° thermostat. This is by GM design (although a poor one) as GM decided the cheapest way to reduce emissions to meet EPA standards was to increase the heat range our cars operate in. Good for them - bad for us. For us this results in a loss of power, overheating cars, and increased wear to our engines, not counting our nerves.

Normal Operating Temp - on our cars is in fact 195°. Every calibration in the GM tech manual that calls for normal temp at 1000 RPM idle is set to 90° C which converted is 194° F. Exactly why we have a 195° thermostat.

Thermostat Myth - Many assume a 195° thermostat is open at 195°. This is not correct. This is when the thermostat is calibrated to "begin" to open. It will be totally open at approximately 206° and close at 188° in order to try and maintain a 195° "middle of the road" temp. This is known as the operating range.

Ideal Situation - would be for our engines to be cooled totally by the opening and closing of the thermostat. But when this doesn't happen because of increased load (towing, A/C use), underhood mods, or an intense environment our cooling fan kicks in at 234°.

Cooling Fans - on an electric fanned car should not be considered "normal operation". As I said the "ideal" would be totally controlled by the thermostat. Our cooling fan is our "danger zone" or "early warning" or "last resort" or "safety measure". Our fan is saying "your engine is about to overheat I'm going to cool it down for you". Please keep in mind, before anyone gets in a great debate on this issue with me the purpose of this bold and brash statement is to later explain why some cooling mods don't work. Of course our cooling fans ARE a part of our "normal operation" because we DON'T live in an ideal world....... see where I'm going with this?

Be Sure - that if your car is running 260° - don't think that since your fans don't even come on until 234° that you are OK. Antifreeze will boil at 262° at sea level with 15 PSI radiator pressure. You are about to cook something. That is what I mean, your fans kick on at a very late stage.....almost too late.

Running the Fans - all of the time is not a great crime. Yes your warmup time will be slightly increase...... big deal. A belt driven fan runs all the time. What will be the most affected is that your electric fan motor is good for X number of hours. By design your fans don't run all the time. In some situations they are OFF most of the time. So running the fans all the time will consume your X number of hours of fan life at a more rapid rate. If you can live with that then there is really no problem......unless of course that last hour of life is in the middle of the Arizona desert 100 miles from nowhere.

Environmental Theory - A 195° thermostatically controlled engine will act differently in Phoenix, Arizona on a 120° day in rush hour traffic, with the A/C on, than say a cold blistery day up North somewhere. In traffic driving will have a different effect than a highway cruise. A/C On vs. A/C Off. Underhood modifications which increase horsepower usually also increase the heat for example headers. Which leads us to the conclusion that the 195° stock thermostat is a "one size fits all". One part - every car. This is where the problems begin and the misunderstandings start. This is why a 160 works better for one person while another gets better results with a 180. But for all practical purposes most owners I have encountered agree - "We have to lower operating temps".

Temperature Momentum - is the last theory I have before getting down to solutions. If you point an airplane nose down at 200 MPH and pull the nose up right before you hit the ground - you will still smash into the ground - belly up. If your boat is headed to shore at 50MPH and you make a sharp left turn, right before the shore, you're still going to hit the shore - you'll just do it pointing left. AND if your temperature has an upward momentum, especially due to abnormal conditions, it is going to peak REGARDLESS of what thermostat you have installed. This is a very important theory to answer questions like "I put in a 160° thermostat and my car still overheats" or someone who says "160 is too cold, your car won't run right"...... not necessarily true.

Which is Why - there is such a great debate on which stat is right for you. The installation of a lower thermostat and an adjustable fan switch that lowers the temps that your fans come on is an "attempt" to lower the operating range of your car. Just because you put in a 160° stat doesn't mean your car will operate at 160°, but what's important is that it will try to. It will "attack" a temperature momentum rise at an earlier stage and in many cases that is enough to solve serious overheating problems. Temperature Momentum at it's late stage is sometimes impossible to overcome. It just has "too much" momentum, and dealing with it early or before it happens is the key to success. And this is exactly why a 160° thermostat may be too cold for the rest of the world but it may be just right for you. There are those that recommend a 160° for summer and a 180° for winter which is why I run a 170° year round.

I am coming to the conclusion ~ that this would be the best guideline I could offer for which thermostat to use:
195° ~ If you live in the Artic Circle
180° ~ If you live in a predominantly cool climate.
170° ~ If you live in a predominantly warm climate.
160° ~ If you live in a "hotter than hell" climate.

 

Every hardware store, Lowe's, Home Depot, Tru Value, auto parts store, truck stop, electronics store, any, and every where, to name a few. All you need is a simple, single pole single throw, "On-Off", 10 amp toggle switch. It wouldn't surprise me to see one in the grocery. Unless you are one of those guys that needs a "kit".

RACE ON!!!

 

SJW,

I didn't realize it was necessary to state the obvious. Of course the engine warms up at the same rate with closed thermostats of different opening points, BEFORE the opening point of either is reached. It is not possible to make everything clear to everyone in every post. Sorry for not typing another paragraph to state the obvious. No wonder so many people have trouble with some of these more basic concepts.

RACE ON!!!

 

What does this mean?

cal

 

This is an opportunity to explain why I was accused of contradicting myself of, in a previous thread. I agree with both positions stated above. Heat is energy and a well warmed up engine is more efficient and more durable. On the drag strip, with a good cool down, the cooler, more dense, intake air can produce more power than the thermal energy loss gives up. This explains why engines, cooled between rounds, can run faster than hotter engines that aren't cooled.

While this applies at the race track for a precious few seconds, it has no application in a DD. The intake air temps are very little different between engines with 180° coolant and 210° coolant. That is why, as JFB reports, "We have had two CFers pay for some dyno time and changed their thermostats in C4's from the OEM stat to a 160 stat and reran the dyno. Both reported that the measured HP was identical with either thermostat.". The dyno measurements are the same, because the intake air has equalized. Aardwolf gets it with, "Datalog the IAT and see if your intake temp is much lower when you run at 160° compared to 200°.". The very short term power advantage of a cool engine on the line at the drag strip doesn't translate into a cooler engine making more power on the WAY (daily driving) to the drag strip. All THAT does is waste gas, wear it out, and gum up it's insides faster, even if it isn't readily apparent.

I hope that clears up my position to those that thought I had contradicted myself.

RACE ON!!!

 

I thought is was self-explanatory. You won't find fan switch kits at most of the sources I listed. That is why I said, "unless".

RACE ON!!!

 

Besides the gasket saving tip you quoted, you might want to add THIS to trackman's in your repertoire of methods for improving the cooling system and lowing operating temps.

RACE ON!!!

 

I was told once that a L98 was made to run hotter, we all know that, and the computer tries to get it hotter with timing and mixture. Therefor if you put a lower thermostat in the car the computer will keep trying to get it hotter unless you change the chip also. I intend on getting a lower temp thermostat and manual fan switch, do I need to ajust the computer as well?

thanks
cal

 

I’m going to really go out on a limb by saying this but, if you want to put a 160 stat. in you car go ahead. If you want a 195 stat in your car go ahead. The world will survive, Mars will not collide with the moon and my corvette will still be red.

 

OK, that is a pretty strong limb you'r on!