AC effectivness at idle

[Dave 2000]

@Richardillard1 Absolutely right, and as technology moves on I think the electric will start to take over, you mentioned your buddies big 4x4, go back twenty years, would it have had an electric fan then, I doubt it.

Also, try not to confuse power with efficiency. Get a big fan and bolt it on the front of your engine and it will out perform a comparable size electric fan, the reason is simple. The connection is direct to a machine creating lots of horsepower. Of course the electric cannot match that unless you get bigger motors, and then the amps go up and then the alternator blah blah.........

Get a magnetic clutch from an AC compressor, bolt it to the water pump, bolt a fan to it, throw in some volts and you have a direct drive fan, again not only better than the electric fan, it will outperform any VC you care to mention as there is no slip.

Now think about this scenario:

Standard 80 'Viscous Coupling' versus my 80 all electric system.

Both cars parked out in the car park, hot day, both engines cold, cars stinking hot inside.

Start both cold engines at the same time, and switch in the AC and pull out into the rush hour traffic and sit or crawl along heading for home.

When you first started up the engines, the VC driven fan on the stock 80 will spin up momentarily and then uncouple, this is because the fluid moves from rest to being suspended, the fan is in fact idling over or freewheeling, it is now waiting for heat to be drawn over the VC before it can re-engage. This is going to take some time, the engine is cold, you are not driving at any speed, and whilst the AC condenser is starting to heat up, the VC will take some time to respond to the small amount of heat that is being drawn over it, why become obvious in the next paragraph.

Now compare that to my car, the AC is instantly cold, that is right now, not in a minute or a few minutes right now, when I want it....now! The electric fan goes to the second (high) speed immediately, the condenser exposed to some serious air flow immediately. What of the stock car? Well the engine thermostat is still closed keeping the engine radiator cold, the VC fan is still idling over but to be fair, it will be drawing some warm air from the AC condenser towards it however, the engine radiator is between the stock fan and condenser, in effect acting as an intercooler, it is cooling the very heat needed by the VC to couple up and drive effectively, and yet the coupling is needed to make your AC work efficiently. Eventually the VC will couple up and pull enough air to cool the condenser, I have no idea how long that will be in traffic but 7 -8 minutes or perhaps more?

Now the traffic is clear and you are on the move, shoot along the highway, the stock VC uncoupled (except at high speed), my electric fan off both AC's systems are working great. Alas, we are now coming to a halt for more traffic, by the time my road speed has dropped below around 30 MPH the sensitive AC trinary switch recognises the pressure change in the AC system, and switches on the electric fan, long before the VC of the stock fan has started to couple up again, already working to maintain a cool cabin, and the process starts over, ad infinitum. I would put my AC temps up against another stock fan 80 any day of the week, it is simply more efficient. There are other benefits that may not appear to be so obvious, my AC is more consistent than with the stock VC, it responds quicker to road speed, if I pull up and switch off, we all know the engine gets hotter when you switch it off, and under bonnet temperatures will climb due to the heat soak. Uh uh, not mine, the sensors pick up the heat soak and switch on the fan slow speed, everything cools down and it switches off, the VC equipped car just sits there cooking. Fancy doing some wading in deep water? Throw a switch and the electric fan is disabled, no rotating blades being dragged into the radiator cowling, bits of plastic flying off into radiator fins puncturing holes as the stock fan tries to pull against water, I have seen it so I know it happens.

I would put my AC temps up against another stock 80 any day of the week, it is simply more efficient, spend a little time reading the link in my sig, check out the research, the data, the install, it's all there. I have never seen the engine get hot enough to call for the second speed, the first speed is easily capable of cooling a wheeling rig during Spanish summers, would it work for a gasoline rig, running through AZ, fully loaded I would not know, but it works for me.

regards

Dave

 

[hammerheadfistpunch]

I love watching a thread snowball.

 

[bloc]

I doubt electric will ever overtake mechanical in true HD applications because of the sheer amount of horsepower needed.. based on the size of the fan and the unbelievable roar it generates when engaged at 2500rpm, I'd GUESS that the fan alone is consuming well over 30hp on my fire apparatus. It just isn't worth trying to mount and power that large of an electric motor when you have the front of the engine sitting right there.

So.. when the engine isn't there?

Most construction equipment that uses a fan not on the end of the engine runs it by a hydraulic motor.

Some tour busses use right-angle drives and belts to cool the radiator that is on the side of the bus.

BUT.. trophy trucks usually use electric.. with the radiators mounted behind the cab and no good options for powering them mechanically off the engine.



All of that said.. @richardlillard1 and I agree with you on one thing, an aux pusher would help a/c temps at low or no vehicle speed. In fact I'll probably be installing one at some point.

I still maintain VC is a better option for the overall cooling of the truck.


I think I'm absorbing the tendency to go off-topic because of all the diselgate settlement stuff in the tdi forums.. I do not envy the job of the mods over there right now.

 

[inkpot]

Something must be wrong with my rig. With ambient temps above 110, I have Nicole air coming from the vents is about 100 yards. It stays relatively comfortable for the 4 miles I travel on secondary streets, and then it gets really cold once I get out on the freeway. It is as cool of cooler at all times as my wife's Scion with Electric Fans.

 

[Dave 2000]

When my truck is cold and started, after about 30 seconds (to let the fluid that gravity pulled into the friction plates from sitting still pump back to the reservoir) I can literally grab the fan with my hand, hold it stationary, and rev the engine. For all intents and purposes it completely disengages.

So this is the time when your AC is NOT effective at idle right, when the fan is NOT being driven, which is what the title of the thread is right?

Also, a well-set-up viscous clutch can sit nearly anywhere on the scale between freewheeling and whatever it's max lockup is (determined by fluid viscosity, but MORE than enough lockup at ambient temps to remove any mount of heat being added to the system). Not just two speeds. Yes, there is a delay.. which is one reason I don't like the "throw 25-30k cst fluid in there" mentality.. but our systems don't overheat instantly (that is one of the points of having water as a cooling medium.. absorb an enormous amount of thermal energy and act as a heat-sink). So viscous systems are better at slowly finding balance and removing just enough heat to keep the system stabilized.. while drawing no electrical load whatsoever.

The load is carried by the engine, it matters not whether it is electric or VC, you don't get something for nothing here.

Find me an over the road truck that uses an electric fan. Even our fire apparatus with 600 amps of generating capacity is mechanical. Granted, they usually don't use a viscous clutch, generally running an air-actuated selectable clutch (partly for control over intercooler temps).. but NONE of them are electric.

I have offered better alternatives to the electric fan, and would never say it not could not be bettered, just that is more efficient and works better than a VC on an 80, in my application and probably many others. And I mean, why not fit the apparatus you speak off with a VC? People should not be blinkered.........because there are alternatives.

Likewise, most if not all of the 3/4 and 1-ton diesel pickups come with mechanical fans, usually ECU controlled like the fire apparatus and OTR trucks.

Again, no VC, simply an alternative, an electronically controlled fan mechanical fan, your own words defeat what you are saying, the VC on the 80 is NOT the Holy Grail of cooling.

All of this isn't to say adding an auxiliary pusher for low/no-speed a/c or engine cooling is a bad idea.. but what you are asserting just isn't true.. an all-electric setup can't compete with a well-designed and maintained mechanical setup.

And the 80 system is that right? The well designed system that we are discussing, the one that needs a particular radiator, the one that needs 'Tools' VC mods, the one that must have bits of tatty sponge wrapped around it to work?

, and no, the big manufacturers aren't installing those on heavy duty trucks.

No, what the manufacturers are doing, Land Rover, BMW, Mercedes are fitting well designed electric or electric/mechanical setups.

It is way passed my bed time, and this is a great discussion, and always love a good debate, in fact I might start another thread about using Optima batteries, that normally hooks a few in with that one.

regards

Dave

 

[Dave 2000]

I doubt electric will ever overtake mechanical in true HD applications because of the sheer amount of horsepower needed.. based on the size of the fan and the unbelievable roar it generates when engaged at 2500rpm, I'd GUESS that the fan alone is consuming well over 30hp on my fire apparatus. It just isn't worth trying to mount and power that large of an electric motor when you have the front of the engine sitting right there.

Agreed.



BUT.. trophy trucks usually use electric.. with the radiators mounted behind the cab and no good options for powering them mechanically off the engine.



All of that said.. @richardlillard1 and I agree with you on one thing, an aux pusher would help a/c temps at low or no vehicle speed. In fact I'll probably be installing one at some point.

Agreed

I still maintain VC is a better option for the overall cooling of the truck.


Agree to disagree on that one


I think I'm absorbing the tendency to go off-topic because of all the diselgate settlement stuff in the tdi forums.. I do not envy the job of the mods over there right now.

Not looked in over there, might give that a miss?

Night all

regards

Dave

 

[Dave 2000]

I love watching a thread snowball.

But with decent AC it won't melt!

Now I must turn in, I need my beauty sleep, well so I am told.

regards

Dave

 

[1972FJ55]

Something must be wrong with my rig. With ambient temps above 110, I have Nicole air coming from the vents is about 100 yards. It stays relatively comfortable for the 4 miles I travel on secondary streets, and then it gets really cold once I get out on the freeway.

Same with mine. I had cool air blowing out the vents before I'd get out of the parking lot, even at 100+ degree days. Best A/C of any car I've owned.

 

[richardlillard1]

Oh. I got sucked into summer mud.

How did I let this happen?

 

[richardlillard1]

Something must be wrong with my rig. With ambient temps above 110, I have Nicole air coming from the vents is about 100 yards. It stays relatively comfortable for the 4 miles I travel on secondary streets, and then it gets really cold once I get out on the freeway. It is as cool of cooler at all times as my wife's Scion with Electric Fans.

Need me some of that Nicole air. What's her number? Or is this a supercharger thing?

 

[inkpot]

Need me some of that Nicole air. What's her number? Or is this a supercharger thing?

I'll never tell.

 

[bloc]

So this is the time when your AC is NOT effective at idle right, when the fan is NOT being driven, which is what the title of the thread is right?

The load is carried by the engine, it matters not whether it is electric or VC, you don't get something for nothing here.

I have offered better alternatives to the electric fan, and would never say it not could not be bettered, just that is more efficient and works better than a VC on an 80, in my application and probably many others. And I mean, why not fit the apparatus you speak off with a VC? People should not be blinkered.........because there are alternatives.

Again, no VC, simply an alternative, an electronically controlled fan mechanical fan, your own words defeat what you are saying, the VC on the 80 is NOT the Holy Grail of cooling.

And the 80 system is that right? The well designed system that we are discussing, the one that needs a particular radiator, the one that needs 'Tools' VC mods, the one that must have bits of tatty sponge wrapped around it to work?

No, what the manufacturers are doing, Land Rover, BMW, Mercedes are fitting well designed electric or electric/mechanical setups.

My AC is perfectly effective at idle. Especially when it is hot out in Austin, like now. The startup roar is enough to get the AC working great until I get moving. My example of how I can stop the fan under those specific conditions was to refute your assertion that a VC "can't" completely disengage.

When the load is carried by the belts directly, it isn't taxing an already inadequate (for many people on here) charging system.

I never claimed the VC was the holy grail, just that you were wrong in claiming HD manufacturers are moving away from electric fans, and that a VC can't completely decouple. I pointed out examples of truly HD vehicles that aren't electric (go ahead, pretend there's a similarity between your setup and an ECU-controlled electrically clutched belt-driven fan). I will add that a properly setup VC is superior to your electric setup, even if it's not cheap aftermarket quality. Add an auxiliary condenser fan and it'd be EVEN BETTER. Many land cruisers went cumulatively billions of miles with their original viscous couplers and had both working AC and didn't have overheating issues.

Oh, and their fans didn't burn up on water crossings because they forgot to turn off a switch.

When it comes to Rover/BMW/Mercedes it has more to do with fuel efficiency (most auto engineers would give up a testicle to gain 1MPG for cafe standards), packaging, noise reduction, greater control of operating conditions, etc. Besides.. they are rover/bmw/mercedes. Guess what's still viscous/mechanical? LX570. Also the Nissan Patrol. Yes, with aux condenser fans. They've addressed the inadequacies of a VC system.. but left the VC as the heart of the system.

So apparently Toyota and Nissan think the viscous coupler is actually the holy grail of cooling. Or at least better than an all-electric setup.

Edit to add: the clutch setup you mention is basically what all of the HD manufacturers are doing now (some electric/pneumatic/mechanical), but they have much more ability to design/program in control methods than you or I, making suggesting it pointless.

 

[Tools R Us]

@Richardillard1 Absolutely right, and as technology moves on I think the electric will start to take over, you mentioned your buddies big 4x4, go back twenty years, would it have had an electric fan then, I doubt it.

Agree, electric fan setups are "techy" new and evolving. Well, my 1976 Rabbit had it, have been driving and working those systems since that time, so maybe new in automotive terms? The tech has been around long enough to be well understood.

Also, try not to confuse power with efficiency. Get a big fan and bolt it on the front of your engine and it will out perform a comparable size electric fan, the reason is simple. The connection is direct to a machine creating lots of horsepower. Of course the electric cannot match that unless you get bigger motors, and then the amps go up and then the alternator blah blah.........

Agree, a mechanical setup easily has the potential of being far more powerful than any realistic electric setup. This is evident by looking at how vehicles are designed. For an electric system, the coolers are thin, have a large surface area, large grill opening, etc, do everything possible to reduce airflow restriction to help the relatively weak fan. For a mechanical setup, coolers can be thicker, more condensed, etc, this is allowable because of the more powerful mechanical fan. Which one sounds like the '80 series, right, it was designed to be mechanical fan dependent, needs a powerful fan.

That said, with enough resources either can be made to work, what is best depends on on the goals, intended use. If the goal is to be "techy", new, prove a point, cool hobby project, etc, a complicated electric setup wins, hands down, no debate. Most of the rigs that I'm around are taken to remote places, often in or crossing desert, so it's critical to have a powerful, simple, reliable, solid, cooling system. There is no logical, sane, factual, debate (not that those would happen here) that ends with a complicated electric setup being anywhere close to the solid reliability of a stone simple mechanical setup.

It's great that you made it work for your use, and want to share, that doesn't make better or even indicate that it would work for others. Others may not be willing to compromise their rig as much is you. When sharing, please attempt to have some semblance of fact! It's painfully obvious that you don't understand clutch fan operation, not going to debate all of the fallacies, but:

You criticize the clutch for having slip, that was one of the design breakthroughs, benefits that made the clutch so desirable!

From a stop, with a hot interior, your A/C is instantly cold! This is a huge breakthrough, up till now this would have been considered impossible, there are likely some auto manufactures that want to talk with you!

Minutes for a clutch to react, surely you jest, or that isn't how they work here. Sensor placement is critical to good cooling operation, cooler output air temp is one of the more logical, solid choices, has been successfully used on just about every type of fan setup. The '80 clutch has the option of tuning, both power and temp "on" range, so is fully adjustable to meet the need.

Do you use metric time, that maybe some of the confusion, not something I understand?

 

[Tools R Us]

... Oh, and their fans didn't burn up on water crossings because they forgot to turn off a switch. ...

Yep, have seen more electric fans in radiators than clutch fans. On a properly driven ford, a clutch will turn off, automatically. Some electric fan setups have a switch to turn them off, good as long as you remember to turn it off. When stuck in water, the electrics often don't like being submerged, get the rig out, only to find that it overheats due to in-op electrics. Been there, passed on the shirt.

 

[Dave 2000]

Morning all. Looking over the last couple of posts and reading them, I realise that I had managed to throw in some sarcasm, it was not intentional. Being up late (for me) and working with a very 3rd world internet connection just added to my frustration, so I apologies unreservedly if I offended anyone, debate is good, and I admit to being over zealous in defending a system that works.

I have never compared my install to systems to anything other than the VC. I do recognise the all electric tech had been around for years, I was fitting Kenlowe fans to 3.0 V6 Ford Capri's in the late 70's and they worked....for a short time. I was fitting V8's in anything that stood still long enough and they too got electric, but there was no AC. and again the components were quite short lived. The liquid sensor probes would fail, motors would heat up and melt and the systems were in effect unreliable. And as Tools pointed out, manufacturers were already fitting them to every day cars. The initial reason IMO, was because smaller cars were being fitted with transverse engines, the electric system was a simple get around. As I spent more and more time working on cars, I recognised the factory installed fans were quite reliable, the unreliable area was in the switching of them.

Along comes after market fans, some manufacturers spouting CFM claims that would make your head spin.......if you believed them. Those sucked in by the hype paid the price with failure after failure, the internet is now used to pick out the poorer designed units and they are again gathering interest. I have read over and over of electric fans systems that have failed, and without doubt an electric system adds complication and there is more chance of failure, if you are not prepared to do it properly.

My fan was sourced second hand from a Lincoln Mk VIII, it worked for that big beast, and if as bloc said it saved 1 MPG then for someone only getting 8 or 9 MPG that is a great improvement however, it does show the electric system as being more efficient than a VC. Economy for an 80 owner owner is not even thought about IMO until recently. Now I know it does work I shall purchase a new fan motor, I was unsure if it would work so why spend out on new components that may be thrown away? I spent time working with switch temperatures, switch positions, laser guided IR temperature guns, temperature gauges on top and bottom hoses and so forth, why? Because I tend to swim against convention, if I think I can improve something that 'should' work then I will give it my very best shot. In other words I do not 'follow the crowd', something that seems to happen all too often on forums, and of course, as in human nature there is the 'sayers' and 'no sayers' and the defenders of something they may have purchased. Witness the all wheel drive versus PT debate, IMO AWD is the way to go , and again there will be those who have purchased and used the PT system and wish to defend that decision rightly or not.

So, if the standard 80 VC system has worked for years and years, and then it fails, the engine start to overheat, then why do people not just go to Mr T and order another one, I mean it has worked for millions of miles right? It seems there are people out there like myself, Landtank for example. He has taken a system that has worked well for years and elected to modify it, why? Because the OE system was not good enough? Because he thought he had a better idea? Or he simply thought it would be a good idea and make some beer money? It matters not, what does matter is he did it, he got off his arse and made it work, and hopefully made a buck or two, for this effort he should be rewarded.

Tools mentioned I have compromised my engine, how? I have fitted not only an additional fan switch, but also a warning of water loss. My coolant level drops an inch and I will know about it, my oil pressure falls below 20 psi I will know about it, those without an oil PRESSURE light, and the oil pressure gauge you have already been 'trained to ignore', will only know when something goes bang. Low water, oil pressure, getting too hot, I will know about it, buzzer and light, my modifications to suit me.

The 80 is a tough beast but why so many head gasket failures? Overheating? Faulty VC's? Bad design? Why the dumbed down coolant gauge? Was there a problem with the original design? Mine is diesel, and the big end bearing were known fail, they are changed and forgotten but still a design or specification error, the handbrake adjusted and working for the yearly inspection, and soon after needs attention, the early models having inadequate service brakes, if they were that good why do they generate hundreds (thousands?) of posts? I along with thousands of others love my cruiser, and would not compromise it. I have simply improved/modified it as will many more, whether it fits the cut of your suit matters not, it works for me.

Assuming your still awake and your eyes have not glazed over?

Whether we like it or not gentleman (ladies?), our 80's were flawed long before they left the factory, I along with others will do whatever is necessary to ensure we keep it as long as possible. If a mod you do works for you and your particular circumstances great.

And a little food for thought, look under the bonnet of the majority of DD vehicles equipped with AC that have a VC controlled mechanical fan, you will find an additional electric one fitted, hmmmm I wonder why?

regards

Dave

PS. No time to proof read so E&OE have to be expected.

 

[Dave 2000]

Er landtank for fan? Sorry about that, I had shut down the machine and then realised what I had done. Hate using the cell for internet but had to get the name right.

Regards

Dave

 

[Tools R Us]

... Tools mentioned I have compromised my engine, how? ...

You had what is likely the most simple, reliable setup of the breed, the diesel requires almost no electrical power to run, and the manual trans allows for roll starting. It had a lot of options, for instance, in the case of electric failure, could travel a long way home with very little electrical power. The cooling system was very simple, durable, rock solid reliable, with only a couple of points of possible failure.

Took that and converted it to a system that has a ton of possible failure points, far more delicate, less reliable and requires significant amperage to run. Not only is it much more likely to fail, once that happens, has fewer options for getting home.

Again it comes down to intended use, if it's intended to stay in range of tow service, no big deal, fiddly stuff is fun. If the intention is to go places where services are not available, it is highly compromised, and alternator failure greatly reduces the range, fan motor dies, no cooling, etc. If fiddly techy stuff is the goal, why not remove that archaic boat anchor motor and replace with an electric, with lots of sensors, could be more efficient? Or could simply buy a Prius, they have lots of techy sensors and are efficient?

 

[Dave 2000]

You are right Tools, the VC is very reliable, but does not always work, plenty of 'is my fan clutch going bad?' posts out there.

Your are right again about going to distant places, I rarely do. Having said that I still have the old alternator which will bolt straight on, I also will keep the old fan motor as well when the new one arrives.

The problem is change Tools, people do not like change. Look back at the 12v starter mod to get rid of the 24v system, I queried way back what four...ish years? Anybody who read the post were seriously negative and now, I get emails asking how it is done, or where can they get parts from? I did it and it worked, it was not innovative, but I did it anyway.......because I could.

I would also argue by using the all electric system it is more efficient, not necessarily more powerful but more efficient. And I have yet to test it in anger, that will change in the next few weeks when the temps here are at maximum. I mentioned about AC effectiveness at idle (the thread title), and lo and behold we had posts about how good their AC is when they have just started up, of course this is nonsense. Even bloc explained quite nicely, that after about 30 seconds his clutch is disengaged, he could even grab it with his hand, there is simply not enough 'drive' to pull air though the condenser, and then through the cold radiator, you have to drive to move air or wait for the drive to the fan to re-engage. I certainly will not try the same example by putting my hand into the blades of my electric fan. I agree he was correct, in saying that adding an electric fan helped with the inadequacies of the VC, which I think most do exist? If not why the fluid drive system of the Jeep? The electric 'lock up' of the Discovery? The all electric of the Mercedes?

I completely agree that less is more when it comes to reliability but, will maintain that by choosing the components carefully the risk is minimal, and this could run forever, and we all have a life to lead, we will have to agree to disagree here and move on.

Now Tools about that Prius comment, now THAT is a really low blow mate, no need to get downright nasty!

regards

Dave

 

[1972FJ55]

I mentioned about AC effectiveness at idle (the thread title), and lo and behold we had posts about how good their AC is when they have just started up, of course this is nonsense...

Sorry, but your assumption is incorrect.

 

[Dave 2000]

Sorry, but your assumption is incorrect.

And you do have evidence to counter my claim? Because you have researched, installed, tested and documented that evidence as have I over the last year or so, and you are about to produce it.

regards

Dave