Getting the motor hot faster.
 

I am driving a stone stock 1995 Ford SHO Taurus learning a lot from this site, I'll tell you that. Anyway, on my way to work today I was thinking about putting some rad cover to heat the thing up faster being I looked at the temp guage a half way to work and it was still cold!

Then something hit me, what the heck is a rad cover going to do when theoretically the water in the motor isn't even going thru it until the thermostat opens!

How can you get the motor to heat up faster?

Brian

1) Grill block is always one of the easiest things to do...

2) Sometime you can find thermostats that open at a hotter temp that you could replace yours with...

3) If you want to spend money, I heard a block heater helps a ton... You hook it up like an hour before you start driving and it pre-heats the engine block for you...

A grill block will help slightly because even if the coolant isn't flowing through the radiator, it is still transfering heat out through the engine block itself at a much slower pace. By blocking the grill you also slightly reduce the amount of air passing over the engine itself, this will help even if it is only very slightly.

Using a hot air intake will help as well as the engine will be sucking in warmer air with each revolution instead of colder air that contributes to cooling as well.

Ok, here's the thing -

People always think that the thermostat doesn't open up until the engine is already up to temp. While this is partially true, it's also partially false.

On a full warm-up cycle, depending on conditions, the thermostat could open 5 times... It could open 10 times... Hell, it could open 35 times.

What actually happens in your coolant system is that the local (near the thermostat) coolant heats up. This causes the stat to open, allowing the water pump to push the coolant through the stat, into the radiator, where it is cooled.

Ok, so the coolant gets cooled by the radiator, right? Right. What happens to the already cold coolant that was in the radiator when the hot coolant displaced it? Oh... it goes back into the engine. Cold coolant hits the thermostat, and it closes, right? So now the engine has to heat the coolant back up to temp, open the thermostat, and allow the pump to push it out into the radiator... So that coolant leaves, and some of the already warmed coolant goes back into the engine... so the stat stays open? Nope.

Remember, the first set of coolant was in the radiator. What does the radiator do again? It cools - that's right. So now, the coolant that was already heated once has just cooled down (here's the good part) a lot. Which means the engine has to heat it back up, to open the stat, to allow it into the radiator, to be cooled, so the already cooled coolant can flow back into the engine, to be heated back up, so on, so forth.

So, you can see that a grille block will help warm-up times in this manner. It will prevent the radiator from cooling the heated coolant so much/so quickly, meaning less heat energy has to be wasted back into it each time there is a thermostat cycle.

You think this happens even with the water pump cycling the water in the block? I would think it would be enough flow to eliminate hot spots... thats its job after all. Perhaps at low rpms... I can't say for certainty.

No, I don't mean that there are hot spots, I was just explaining the cooling cycle that happens in the engine.

The water pump is constantly moving coolant, even if the stat is closed, so there aren't hot spots in the engine block. When the stat opens, it creates a new circuit which was previously cooler than the coolant in the block, which is then re-heated by the waste heat of the engine block.

I over-simplified it because it's a fairly difficult concept to comprehend at times. There isn't two specific sets of coolant at all times, since the coolant is turbulent, it is constantly mixing. What happens, though, is that the coolant heats up because of the block heat, and that opens the stat, which allows the coolant into the radiator, where it cools. The previously cooled coolant enters the block, and when it touches the stat, the stat closes down to prevent the coolant from flowing into the radiator to be cooled again.

If you boil-test a stat, you'll see that at a specific temperature, it will *pop* open semi-violently. As you lower that temperature, it will slowly close back down. If you quickly douse it in colder water, it will snap shut with the same force.

The stat's job is to modulate flow at all times, so it doesn't just open and stay that way when the engine warms up.

Also, under dynamic operation, an engine will heat and cool consistent with load (lagged response, obviously), which means that the coolant will be more or less heated by the engine, accordingly. This means that the thermostat needs to be somewhat dynamic in it's ability to restrict coolant flow in order to keep the engine cooled (or heated) properly.

Hopefully, that made it more clear, instead of making it more obscure. :confused:

I don't think it presents much of an issue, as the coolant in the block is circulating. By the time the thermostat starts cycling like that, the engine is up to temp, and the t-stat is keeping it there. On my Jeep, the upper rad hose stays stone cold until the coolant temp on the gauge hits about 180*, then the t-stat starts to open a little.

If it only opens a little, it's in need of replacement. It should reach temperature, then open fully.

The thermostat cycles open and closed from the time the engine first reaches temperature, which is long before it is actually warmed up. That's why it's called the warm-up cycle.

Following the OE temp gauge on most vehicles doesn't get you very far, they're somewhat muted because the average user doesn't like to see variations in the temperature of their engine. Fact is, your engine is almost never "rock steady" in terms of temperature. Temps are dynamic by the nature of engine operation.

I'll have more time later, if this isn't entirely helpful, but I've got to go, I have some money to make. :)

I don't think the water "cycles" in the block at all. I think Christ is right on the money. Think about it, the heater doesn't do crap until the thermostat opens, because the cold water is just trapped in there. The water pump is "sucking" coolant in from the bottom of the radiator. That water would have to have a place to go, if the thermostat is closed it doesn't, so the pump is just spinning it's proverbial wheels.

I don't think there is much power behind the water pumps design. I have always wondered this, and I have always assumed that the pump sort of "moves" water around but not with a whole lot of force.

I can certainly see that if the water gets hot enough right at the thermostat as Christ says and it opens allow some hot water thru then the pumps push is enough to let some of that cold water sneak past the thermostat. But it makes total sense that the thermostat MAY (not completely convinced that it will do as Christ suggests) but it makes a heck of a lot of sense.

Brian

Sorry my last post was writen while Christ was already answering it.

Brian

Thermostats work over a temperature range. For example, a 180* t-stat will start opening when it hits 180*, but won't be full open until about 195 - 200.

Also, my OEM temp gauge reads actual temp. It does vary with fan cycling, etc. in traffic.

In addition, in most vehicles, the heater core is part of the engine's internal cooling loop (inside the thermostat). In mine, even before the t-stat opens, for example, with the temp gauge reading 130*, I can get warm air from the heater if I turn it on. Every other vehicle I've driven has been the same way. The water pump still moves coolant in the block, even with the t-stat closed. The flow is just less, due to a typically small bypass hose.

All this makes sense too as it doesn't really contradict what I said. I didn't mean that the heater was on the other side of the thermostat, only that the water wasn't moving well thru it, thus the water wasn't hot.

I just talked to my brother who is the mechanic of the family. :) I never had to learn much about mechanics being I was a bodyman and he was a mechanic (shop owner for 30 years) and he agreed with most everything said here.

First off, the thermostat isn't FULLY opening until "around" the advertised degree, taking 10 or more degrees before it fully opens. The rad cover is most importantly (as already pointed out here) to not allow air to go thru the engine compartment speeding up the motors heating.

I have never talked to him about this stuff and it was darn interesting to hear how much he understood about it. Being he is much more of a racer than an ecomodder it was darn interesting being we are just talking about facts regarding the funtion of a car.

He did say that if you have any wonders about the thermostat, put on in a pot of water on the stove and monitor the temp while watching it open.

All very interesting stuff, thanks guys!

Brian

Something just dawned on me! I was trying to figure out how to KNOW if the water was circulating and something hit me. The coolent is under pressure. With every pound of pressure it raises the boiling point 10 degrees (as I remember that is the number). Well, if you were to be able to open the system it would allow a much faster warm up, wouldn't it?

Brian

I've run engines at idle to warm them up when working on them, both normally and with the rad cap off (purging air from system). Having the cap off doesn't seem to warm them up any faster. Changing the boiling point has no effect on warmup time. Plus, if you do boil the coolant, you have BIG issues.

Or instead of theoretical discussions, you can try the experimental method. Just put the block in - on my Insight it's just a piece of coroplast that slides between the radiator and the A/C condenser - and see if the engine warms up faster. It does on the Insight - on a cold day, it takes about 5 miles of the road into town to hit 195F with the block, without it takes 10-12. YMMV, of course.

I know this is impractical, but a waterpump that is driven by an electric motor would help it warm up quick, make it cycle when cold & run full time when it's hot.

LOL, 90% of what we do ecomodding is "impractical". :) But does it get you further on a gallon of gas?

It's like a friend of mine who is a avid cyclist. The other day he bought two new bolts for his water bottle cage. They are made out of titainium or something and save him a couple of ounces! They cost 10 bucks or something and they save him a couple of OUNCES of weight. Impractical, yep, but he bought them. That and a zillion other things and he can go faster and further than before. :D

Brian

You are as right as rain, and I will be doing just that this weekend.

Thanks, Brian

Cycling the water pump on and off is a BAD idea. The off cycles would have to be very short, and only at minimal to no throttle. Otherwise, you'd get hot spots around the cylinders, when the rest of the block is cold, and that could make for a warped or cracked block or cylinder heads.

never cover the radiator.. even my dad in his rig climbing through way below zero in northern maine learned a lesson on this..

never ever cover the radiator.


given the SHO is a flyin sideways at 1500 degrees on the backside...
the problem must be something stuck open in the cooling system. Try checking thermostat, even fluid levels, bad guage, clogged heater...all kinds of stuff.

the sho is the top 1 in all crazy sideways hot rods.. there is not a chance in heck it takes awhile to warm up...unless there is an error. find the problem.. do not cover it up. :thumbup:

Instead of turning the water pump completely off, you would want it to turn slowly. Just fast enough to prevent hot spots. That might actually be pretty fast, which could explain why electric water pumps haven't caught on.A grille block outperforms a radiator block, aerodynamically. But it's harder to execute, so cover 90% of the radiator in the winter if you don't have a grille block. When I do a radiator block, I cut a few small holes in the cardboard (or coroplast) so if the cooling fan does kick on (which it hasn't below 74mph), air can still flow through.

Such a lack of understanding of something so simple.

The thermostat is located at the "last stop", the furthest point away from the water pump in the cooling system, where the coolant has absorbed the most potential heat. It serves one function: to make the decision of where to send the hot coolant - to the radiator and then the water pump inlet, or directly back to the water pump inlet. If the temp is below opening temp, this choice is to the water pump. At opening temp, the path to the radiator begins to open and the path directly to the water pump (bypass) begins to close. By 10F above opening temp, the bypass is fully closed and the path to the radiator fully open. The water pump never stops circulating coolant through the block. This is why your heater slowly starts to blow hot long before the thermostat opens. Block pressure only varies by water pump RPM, regardless of whether or not the thermostat is open or closed. This pressure can be as high as 40 psi at redline.

Putting a grill block does nothing except allow less heat to escape from the engine block itself. I'd say the difference will be barely noticeable if at all. All I would do it install a good OEM (reliable) thermostat, possibly a 190F or 200F if available, to make sure it is functioning properly. And maybe a block heater if that's your bag. A grill block will only help aerodynamics and make your engine overheat sooner.

Thanks, I'll check it all out.

Brian

I have been thinking about this comment and came to the conclusion that EVERYTHING about "ecomodding", "hypermiling" or what ever the terms, are pretty friggin simple! I mean, do we need a forum or web site to tell us to take our foot off the gas and brake, or to air up our tires, or to not stop and leave the engine running? I really don't think we do being it IS so simple.

Yet here we are discussing such things.

Brian

What exactly denotes how "simple" something is?

Do you have specific background and training in, say... aeronautics? Because I'd be willing to bet there's some arrogant flight instructor out there that supposes you're not too bright (the inference you made here) because you can't explain the location of the thrust control on a F-18.

What about the Geologist who thinks that volcanic flows and tectonic movement cycles are easy to understand?

If you didn't mean that as an insult, I'm sure I'm not the only one that read it that way...

If you really want to have the engine at operating temp the a circulation tank heater is your animal. Costs a but more then a block heater but is miles better at preheating. I have a 1500 watt model on my Prius, an 80% grille block, and an engine blanket to keep in the heat. I have an aftermarket temp gauge to keep an eye on things. 45 minutes to 70˚C which is the temperature at which the Prius shuts off the engine. I'm saving 5 minutes of warm up time and getting about 25% better FE on my short commute.

There are two distinct advantages to grille blocking:
1: Aero
2: Slightly faster warm up and heat retention once warm

Both increase efficiency.

My Prius has not overheated on me and plenty of others on this site will tell you that a grille block will not instantly make your car overheat. You should watch it though to see how your car reacts. My minivan has overheated only in warm weather up long hills but then I have a manual fan so that's my fault. Even with the block the fan cools it off quick.

On the Prius the T-stat is the lowest coolant point on the block and sits right beside the water pump.

It ticks me off to think that I have had a few Prius "totals" (collision damage exceeded value of car) leave my bodyshop with a "thermos" on it! DARN IT, now it will be a friggin year before I see another I can grab.

I don't plan on making any big changes with the SHO, it is going to be sold as soon as my 59 Rambler motor is back in it (it's being rebuilt). When I get that car up and running I am going to go nuts with the mods.

I am going to look deeper in to a quick grille cover on the SHO though. And without a doubt be doing some testing on my way to work everyday with the coolent temps under different conditions.

Brian

I am amazed at what I have learned here. It's like a lot of things in life, until you REALLY get into it you just don't understand how little you know compared to someone who has made it a passion before you.

Pro-sports for instance. You could think you know a lot about baseball and was a .400 hitter in highschool and college, walk up to the plate against a major league pitcher, even the lamest out of the bull pin and you will look like a friggin fool!

I have always practiced what I thought to be "hypermiling" for years I have watched people race to stop lights past me and laughed, thinking I knew so much. As it looks right now I am my first tank of gas since really getting into this site and I am looking at a MINIMUM 25% increase! TWENTY FIVE PERCENT!

You can quote me on this, I use it often at work.

"When working with the public, there are two things you need to remember. 1. The public is a bunch of ignorant morons. 2. YOU and I are one of them!"

In other words when we walk into a business to buy a product or service we know nothing about, we look just as stupid as the people who come into our place of work who know nothing. For God's sake, give them a break!

And by the way Mechman, my butt ain't hurt or anything. It really is no big deal and I thank you for your contribution to the discussion on the funtions of the water pump and thermostat.


Brian

Experiment trumps theory. Get a car with a ScanGauge (so you can see exact temperature, rather than the ballpark estimate of most OEM "gauges"), try driving with and without radiator block, see how long it takes the engine to warm to operating temperature.

As I said above, it works in my Insight, but YMMV.

Then of course is the fact that different cars may react different as well!

Brian

I did this with my Caravan - I blocked every hole available in the front of the van, and worked my way up the mountain near my house, locked in first gear at nearly redline, under load the whole time (very steep hill). At the top of the hill, I waited for 10 minutes, to allow heat soak because it's only 2 miles up there, parked facing a large enclosed trailer (to defeat wind). The van was previously driven, and only had about an hour cool down time before I took off up the mountain.

After 10 minutes, I checked the temps of my Caravan with my Actron 9190 scan tool... 210*F. I had a 190* T-stat installed. I later did the same run without the blocks installed, and the temps, under the same circumstances, were 206*F.

I don't think I had anything to worry about.

...in military driving school, they teach you that when the engine overheats, to immediately stop and shut the engine off...ie: "...turn OFF the FIRE..." that's the quickest way to cool down an engine, short of flooding everything with a hose and water.

...the quickest way to get an engine to warm up is to (ta,dah!) don't let it cool down, ie: use engine block heater, etc. while it's parked.

...also, using a "100%-closed" grille shutter at first also works, but you need to be very careful that it doesn't "stay" closed and also that it doesn't "stick" in some position.

I didn't at all mean it as an insult. And I apologize if I insulted anyone.

I've always been taught to run cabin heater at full blast and leave the engine idling so the water pump is still turning. I guess that's the difference between a small three or four cylinder with a big heater core, and a military truck which might burn more fuel at idle than I do at load.

The difference is also there when considering that your engine is aluminum, the military engines of old are not.

Aluminum will warp if not cooled under controlled circumstances. You could completely destroy your engine if you were to just shut it down, because it wouldn't cool evenly.

Iron engines aren't like that. You can overheat an iron block, and run it that way for a good long time, and not really suffer any irreparable engine damage.

However, if your goal is to use less energy, that's being more than a little counter-productive. Your monthly gas bill goes down a buck, your electric bill goes up two.

Not to nitpick but using a block heater is generally less energy wasteful than not. Of course it depends on how much gas you save vs how many KWH you use and the cost of those KWH.

You can calculate the cost benefit fairly easily. Even if it's more expensive you can feel good that it's reducing emissions.

I'm lucky to have very cheap, clean electricity here in BC so I can blast away with the block heaters.