Without the tstat, the engine never gets to operating temp... Ive run without the tstat. Even hard driving couldnt get it near the normal range on the gauge.

 

Well I filled the 924S up with water and it has no trouble getting the temp gauge to where it was before and the cabin heat is hot. Me thinks every car, being that they are 20 some years old, will react differently. I'm debating about even putting it back in. This is a hot running car anyways. Rad is probably original.

 

I've never had a car run 'hotter' from leaving out the thermostat. The comment about water moving too fast through the radiator and not cooling off enough ignores the fact that the same water is moving through the block faster stripping heat away quicker than a slower flow. In the end it favors the low end of the temp scale. There is no way possible a thermostat can help 'prevent' overheating, it can contribute to it though very easily.

 

I am not an engineer but what i am telling you is what was taught to me in trade school 1 year ago, and that was first Universal Tech, then Porsche.

Mark

 

When the water moves around the block...its only moving around the block. Yes, its moving fast, but it doesn't leave the block, so it absorbs the heat.

I've had years of school, plus years working at dealers. I was ASE cert. (let it expire). Of course you can do whatever you like. I'm just tell you the facts of how your cooling system works.

 

I have been doing a search for an electric water pump for another car of about 3l in displacement and have found most flow at least 4.5 gallons/min for that application.

Now our system holds what, 2 gallons, so that means an eletric pump is turning over the entire system of coolant two plus times a minute. How much slower is that rate going to be with the t-stat in place, I can't imagine its that much.

The one point I keep getting hung up on is the thermostat is only one of many, many restrictions in the coolant systems. If you take out all of the bends, fittings, hoses and other orifices, then yes, I agree a t-stat will have a dramatic effect on flow rates. But you take out only one of the many restrictions and the cummulative flow loss through all of the restrictions is still there.

To get to the point of all of this, I can't see running without a t-stat "speeding" up the water flow that much to make a difference.

Am I way off base here?

Tom

 

Its not the "speed" of the water...its that it doesn't stop moving. For the radiator to remove the heat from the water, the water has to stop long enough for the heat to transfer to the fins. Its not instantaneous.

And...the problem with electric water pumps is that they don't flow enough water. I'm not going to pull a number out of my *** for what a belt driven pump flows, because I don't know exactly, but I know electric pumps don't move enough water.

Race cars use mechanically driven pumps....well, water cooled drag cars don't, but they only run for a few min at a time. Race teams will do anything for more power, and they don't use electric pumps to free up HP. And, with all the auto manufacturers searching for better MPG on thier cars, none of them use electric water pumps. Moving water around takes alot of HP, thus lowering MPG, and they still have to use a mechanically driven water pump.

I think if you research this more, you'll find that an electric pump is not what you want on the street.

 

Corvettes used to use coolant injectors (still might..idk) to spray water through the heads. It worked on the same principle as A/C. Turning a liquid into a gas (not really, but a fine mist) disapates heat. But even with that, the engine still used a mechanical water pump to move the water through the block and radiator.

 

I have also been taught the same thing, I graduated from Porsche factory trainging just over a year ago, and UTI about 18 months ago, what you are saying is EXACTLY what i was taught in school.

Mark

 

Please don't take this as arguing, I just want to understand this.

If you want the water to stick around and absorb as much heat as possible, why are there so many high output water pumps being sold for SBC's? I know this is not the topic at hand, but I think it is on a parallel to help explain it.

With everything being the same in said SBC, with the same pressure relief cap/valve on the overflow tank, same internal engine cooling system, same radiator and same thermostat and now you add a high output water pump water are you doing to the system as a whole? You are moving more water through the system. And to move more water in a system that stayed the same, it has to more faster.

This goes in hand with removing the thermostat, allowing the water to move faster through the system because of less restriction.

Thoughts?

Thanks
Tom

 

You're on the right track...just not the right train.

hi-flow pumps are a waste of money because the system can only flow so much.

Your thinking is correct. Stock system, stock radiator, the water can only move as fast as that system will allow. Which is usually the same as what the stock pump will flow.

Where you're getting stuck is the thermostat. It IS a restriction, but its restricting the flow to the radiator....which is where you want the water to move slow. You want the water to hang out in there to get heat transfered to the air.....it doesn't matter if the water moves at mach 2 around the block, because its contained in the block, gathering heat. When the thermostat opens, you want the water to fill it up slowly...then when the cool radiator water hits the thermostat in the ***, it closes, trapping the hot water in the radiator.....to get cool

I live in the desert. It regularly gets over 110 outside here. I run a 190 thermostat in my cars. WHY THE F WOULD I DO THAT?!?!?!?! Simple. The thermostat stays closed longer, making the water in the radiator cooler. My engine runs at the top mark (not the red...the top "normal" mark) and doesn't budge. I sit in traffic, out in the sun, at 2pm....hottest part of the day, and the temp doesn't wiggle. I've had people tell me I'm crazy. They put in a 160 so thier car will run cooler in the summer. Well, thier car does run cooler....untill it starts to over heat. Then, there's nothing to stop it, cause the water in the radiator doesn't get to cool off below 160....the thermostat stays open all the time and the water keeps trucking through the radiator at full speed....and gets hotter and hotter and hotter.

I know people will argue with me on this...they always do. And thats fine. This is how every single water cooled engine on the earth works, and if you do some real research, you'll find the same thing.

PS....running a hotter temp thermostat will help lower your emissions (if you're having trouble passing)....and also, makes more HP. Its not a turbo, but it makes higher combustion temps, which makes the combustion air expand more, and burn the fuel more completely (efficiently)...which is whats making your HP. Race cars typically run between 230 and 240 coolant temps just for this reason. Its all about volumetric efficiency, and the water temp is a part of that.

 

I;ve had no t-stat in my car for about 8 months now and there is no problem. It stays between the cold and the 1st line when driving. In traffic for a while will heat up and the fans will kick on cooling it down. I have an A/F guage installed in my car and even though the engine is cold the mixture is still stoich, not running rich at all. I see no problems with running with out a t-stat in at all to be honest.

And changing the t-stat isn't hard at all to be honest. Just gotta get a pair of 45 degree snap ring pliers. I got a set that you can adjust the angle, 45, 90, whatever. 10$ at my local autoparts store, AutoZone I think it was.

 

It has nothing to do with the fuel/air mixture. Its the combustion process.

Hotter combustion temps make your engine more efficient. It more completely burns the fuel, and the air is at a higher temperature....meaning it expands more....which is how an internal combustion engine works......Your engine isn't as efficient as it could be.

I'm not saying you'll get 10 more MPG....but I would bet you see a difference in it, if you did install a thermostat.

 

Oh I understand from a MPG sense. I wasnt reffering to that. Usually when cars are cold the ECU makes the mixture slightly more rich. I was reffered to that to let people know it does not affect the A/F ratio.

 

This is simple... really it is. I'll explain it like I did to my 6 year old. (not saying we're all 6 year olds....just making a point.)

An engine is a simple air pump. It sucks air in, gets it hot by burning gas in it, then when the air expands from being hot (cause hot things expand), it pushes the piston down (or plunger, as my son calls it). Then when the piston comes back up, it pushes the hot air out the other side.

No ****...we all know that right? But you have to do that in the most efficient way possible. The colder the air comes in, the more dense it is (meaning, more air (by mass) will fit into a space if its cold than it will if its hot.).... so cold air in = more power, cause there's more of it in the cylinder.....now, it has to get as hot as possible to expand the most it can. This is done through correct fuel mixture (14.7 lbs of air to every 1lb of fuel), set off at the correct time (some degree BEFORE top dead center so the fuel is completely burned away just AFTER TDC) so the air is at full heat (expansion) right when the piston is ready to come down.... very simple.

Now, everything done to and engine to make more power is effecting this process. How the air comes in (manifolds, carbs, turbos, air filters, air boxes, port/polish, 4 valves, camshaft), The temp of the incoming air (innercoolers, cold air boxes), How the fuel is burned (more spark, bigger spark). The Correct mixture of fuel to air (MAF, AFM, O2 sensor, jets in a carb), and how the hot air exits the engine (Headers, cats, exhaust pipe size, mufflers)...it all is just making the simple "suck, squeeze, bang, blow" process work better.

Having hotter water in the engine makes the air easier to make hotter, because it doesn't have to overcome the heat of the surrounding metal as much. (the engine is 190, and the combustion temp is 1,200...vs the engine being 160). LIke I said, a 30 degree difference isn't going to add 40 HP, but every little bit helps..... The game is, always was, and forever shall be... EFFICENTCY!!!