Side Radiator Coach Cooling Fans

Topic: Side Radiator Coach Cooling Fans (Read 1470 times) previous topic - next topic

Side Radiator Coach Cooling Fans

August 27, 2021, 09:25:39 am

Has anyone used electric fans to replace their hydraulic cooling fans? How many CFM do the hydraulic fans pull through the radiator?

Would something like these work?

Fans | Be Cool Radiators
These are up to 3140 cfm, about 1/2 HP and use about 26 amps

16 Inch Electric Puller Fan Euro Black Super Duty Be Cool Radiator | Be Cool...
$260 each plus everything else you need. Way less than a hydraulic fan motor, probably less than the rebuild kits.

They make a brushless version too that appears to be variable speed.

Re: Radiator Cooling Fans

Reply #1 – August 27, 2021, 10:32:15 am

So in other projects I have had interest in going with electric fans. Here is what I learned. I understand that our coaches fans are capable of using 80hp. My old Chevy 6.5L diesel used 38hp. Never had on a dyno so don't know first hand. One horse power at 100% efficiency is 746 watts of power as I recall. So that would be 64 amps at 12volts dc for one HP. Just doesn't make sense to run primary cooling fans on electricity when direct drive or hydraulic works so effectively. My current Bronco LS conversion will run two continuous duty fans at 12 amps each. There is a larger fan but they are not rated continuous duty. The numbers are difficult to manage running electric motors IMO

16 INCH ULTRA ELECTRONIC 165 WATT COOLING FAN FFD16-3000CFM SUPER LOW AMP...

Scott

Re: Radiator Cooling Fans

Reply #2 – August 27, 2021, 10:39:26 am

Correct.

You can't reasonably/practically get the CFM with electrical fans.

CAN it be done-- virtually anything can be done-- but may not be practical. Would certainly require a significant alternator and wiring upgrade.

Re: Radiator Cooling Fans

Reply #3 – August 27, 2021, 10:40:37 am

I've pondered this as well, though electric fans tend to take ram cooling of radiator into effect which we are without. Here's a place with heavy truck specific fans:

Turbine Electric Fans for Over-the-Road Trucks and Tractors

Re: Radiator Cooling Fans

Reply #4 – August 27, 2021, 10:59:17 am

Electric fans work great on the front but won't move enough air for our side radiators. They could provide cooling in case of a hydraulic failure by allowing the coach to be driven at lower speeds. Normally, our Detroit has a huge 300 amp sealed oil cooled, brushless alternator with a direct drive. This could supply enough juice for a big fan but our U300 radiator would have to be larger. Our Buffalo bus had a huge radiator with an equal sized AC condenser. Rear side radiators are a bad deal unless you have a sidewinder engine and can direct drive the fan.

I did see a German bus in San Francisco with a big air cooled flat diesel. It had one big electric fan above. It was idling for the AC to keep the interior cool for the tourists when they came back but the fan was not in use as convection was enough at idle. The rear wheels also turned to leave the parking space plus with the fan above, the driver said they could R&R the engine in about 20 minutes as all connections were modular, the air suspension allowed the bus to lower onto a special rolling cradle and then it could be raised with the air to allow the engine to be rolled out and replaced if necessary. Very cool bus.

Pierce

Re: Radiator Cooling Fans

Reply #5 – August 27, 2021, 11:02:46 am

Quote from: Chuck Pearson – August 27, 2021, 10:40:37 am

I've pondered this as well, though electric fans tend to take ram cooling of radiator into effect which we are without. Here's a place with heavy truck specific fans:

Turbine Electric Fans for Over-the-Road Trucks and Tractors

I to thought that we had no ram air effect, but now think that the low pressure area behind the coach actually draws more air threw than we realize. Wish I knew for sure, but?
Scott

Re: Radiator Cooling Fans

Reply #6 – August 27, 2021, 11:09:48 am

So during the entire DIY wax valve conversion I'm still running my background fans speed at basically off. If I could ever make time and figure out how to read fan speed or fan hydraulic pressure I would actually have a clue on what's going on. It seems to work well so I guess I'll kind of loose interest in knowing.
Scott

Re: Radiator Cooling Fans

Reply #7 – August 27, 2021, 11:13:25 am

Quote from: dsd – August 27, 2021, 11:09:48 am

So during the entire DIY wax valve conversion I'm still running my background fans speed at basically off. I
Scott

I hope "basically off" still has some air flow, as you have to have air flow over the CAC, even if coolant temperature doesn't require air flow.

Re: Radiator Cooling Fans

Reply #8 – August 27, 2021, 11:15:56 am

When I installed a OM617 5 cylinder in my MBZ 406D, the engine went forward to where the radiator had been so I put a truck radiator alsmost flat but at a slight angle behind the transmission. Convection worked at idle and enough air blew through it at normal speeds. Worked great. 23 mpg on trips.

A front radiator or two is this winters project for the U300. Pick-n-pull has late radiators with fans really cheap. Just have to figure out how to get larger hoses to the front. The heater hoses are not quite large enough. The U300 is a perfect 3 season coach but I hate having to watch the temp gauge in our mountains in summer. Just a few degrees more ambient are enough to bring the temps up to 200 or more.

Nice thing about the Detroits, they don't have intercoolers but an aftercooler below the big blower so don't need the fan air.

Pierce

Re: Radiator Cooling Fans

Reply #9 – August 27, 2021, 11:27:07 am

The 60hp claim is disputed frequently. But when hydraulic fan motor efficiency (very low) is figured in maybe. How much air (max cfm) is actually moved by these fans? I think that is where to start.

My 240 amp 40si brushless Deco alternator uses less than 12 hp at max output.* Plenty to run a couple electric fans. If it takes 60HP from the engine to drive the hydraulic pump to turn a hydraulic motor to get whatever CFM it gets that is much more.

More of a mind experiment at this point. Perhaps there was no electric fans available 20-30 years ago to do the job efficiently or reliably.

* my math ... 240 amps x 14.5 volts max = 3480 watts / 746 watts/hp = 4.7 hp / 72% alternator efficiency = 6.5 hp. Plus belt drive inefficiency. So what I read that said less than 12 HP seems about right.

Re: Radiator Cooling Fans

Reply #10 – August 27, 2021, 11:39:10 am

Roger,

Not only the loss from the hydraulic fans but the pump loss on top of that plus the friction loss in the hoses. All adds up.

We used all 318 hp to pump 1000 gallons of water per minute with direct drive to the pump. Using the deck monitor, it took max HP to pump 250 gpm at 80 psi.

Pierce

Re: Radiator Cooling Fans

Reply #11 – August 27, 2021, 11:43:01 am

I believe the HP numbers were for when the controller failed and the fans went on high all the time. The wax valve conversion eliminated that unless on high.

Re: Radiator Cooling Fans

Reply #12 – August 27, 2021, 12:00:37 pm

Quote from: craneman – August 27, 2021, 11:43:01 am

I believe the HP numbers were for when the controller failed and the fans went on high all the time. The wax valve conversion eliminated that unless on high.

That's why we do so well in 3 seasons. I charged up and out of Death Valley coming back from Q in winter without even looking at the temp gauge but in summer, it's first gear. When the temps are high, the controller goes to high speed so uses more HP and creates more heat. I think 4 electric fans across the face of the radiator would keep it cool most of the time on the flat and in the mountains when the temps are cool. But everything loses efficiency at high altitude, any kind of high humidity and high outside temps. But this is all a guess about electric fan installation. I know Kent Speers utilized a small front radiator and even with a smaller engine, I seem to remember Brett installing one.

We have all the room in the world up front but the bus style coaches utilized that room up front for the generator, etc.

Pierce

Re: Radiator Cooling Fans

Reply #13 – August 27, 2021, 12:45:33 pm

Its on my list to investigate. I used to tow a two car trailer all over the east coast with a 305 Chevy van. I replaced my driect drive fan with 2 electrics and picked up .8 MPG solid and never overheated. The Thermo stat switch is adjustable and could be tapped to a upper hose . ' Worked swell.
The air flow in the rear of our busses is not easy to direct or figure out . I plan to tuft test my bus soon before any fan mods. It is entirely possible that air would enter the rear radiator opening without the fan running .
My vision may include a small air scoop into the side, and a set of fans in the rear, if air does exit the rear as hoped.
There is no real reason to run the 50HP fan all of the time . It must cost almost a 1MPG and some outright straight-line performance .
My custom race car/truck had a rear mounted radiator and tuft test showe3d that the air went backwards, from the top , through the radiator.

Photo Sharing. Your Photos Look Better Here. This pic is from Sebring at about 125MPH. If you look closely , you 'll notice a small tell tale over the bed flowing up, from the rear radiator. The opening in the pas door is the air duct leading under the rad. The air flow went backwards until I extended the roof to the edge of the large wing . The wing's primarily mission was to draw air through the radiator . I should have just allowed the air to flow backwards..
The entire project was to endurance Road race a Ford Ranger( to optimize the rule set ). At this point the front to rear balance was 49% front.
The new owners moved the wing to the rear of the chassis, added new stiffer rear springs springs , etc. Got slower each time ...

Re: Radiator Cooling Fans

Reply #14 – August 27, 2021, 01:16:12 pm

Fan requirements for FRONT radiators with "60 MPH forced air" are completely different than side/rear radiators with zero forced air.

Adding a front radiator with electric fan and "T-ing" into the hoses to and from the dash heater core is a pretty inexpensive way to add cooling capacity.

Re: Radiator Cooling Fans

Reply #15 – August 27, 2021, 02:06:33 pm

Our rear radiator coach has three electric fans plus the nylon engine driven fan.
Two of the electric fans are on the rear of the radiator and the remaining electric is on the desert cooler radiator for the transmission.
Never had a high temp reading yet. (knock on wood)
Stand behind the coach when these fans are running and you will get dried off and dehydrated quickly. The air flow coming out is very high!
Also, whenever I wash the coach I back flush the radiator fins by squirting water with my garden hose at full faucet pressure.
Standing inside the coach, with the bed platform raised, every spring I check that I can see light coming thru the radiator so I know it isn't clogged. If it is I clean and degrease the radiator.

Re: Radiator Cooling Fans

Reply #16 – August 27, 2021, 04:40:41 pm

I added an electric race car fan to my 1981 Foretravel that seemed to help a bit. It had a 3208 cat with a rear radiator.
Perhaps more important is keeping your radiator clean.
Oil and other liquids become dirt magnets and can drastically affect a radiator's cooling ability.

Re: Radiator Cooling Fans

Reply #17 – August 27, 2021, 04:48:31 pm

Quote from: wolfe10 – August 27, 2021, 11:13:25 am

I hope "basically off" still has some air flow, as you have to have air flow over the CAC, even if coolant temperature doesn't require air flow.

I would say very very little, but that being said I think this may be more of a problem in colder weather. By the time I'm at freeway speeds I'm typically at temperature already and I would think the fan speed has already started ramping up, but unknown. I have IAT protection but have never seen it triggered into operation. Saw my highest continuous IAT last week on 50. 114 degrees. 105 oat. Turning the radiator fans to hi made zero difference. I have no way of bypassing the wax valve control.
Scott

Re: Radiator Cooling Fans

Reply #18 – August 27, 2021, 04:54:38 pm

The outstanding question remains, what are the CFM ratings of the hydraulic fans that would need to be replaced by electric fans. Side radiators are different from front or rear radiators, granted. But we are considering the possibility of replacing existing hydraulic fans on a coach with a side radiator with electric fans. It seems to me that equal CFM is a good place to start. Temperature controls and variable speeds would be nice but we have to start with a minimum necessary requirement for sufficient cooling.

Re: Side Radiator Coach Cooling Fans

Reply #19 – August 27, 2021, 05:08:40 pm

Roger- the new Prevost's are using electric fans. I'm not sure how many CFMs , though- but it can be done.

Re: Side Radiator Coach Cooling Fans

Reply #20 – August 27, 2021, 05:12:22 pm

It may be related to radiator size (and shape) and fan size and the number of fans. It might be possible, worth consideration and thought.

ELECTRIFYING THE FUTURE AT PREVOST | Prevost

Re: Side Radiator Coach Cooling Fans

Reply #21 – August 27, 2021, 05:30:57 pm

I'm not saying it can't be done, I'm say I can't afford to build up a redundant system capable of powering fans to gain 4% of fuel cost to return on investment. I'm not going to run 200k a year. Might be plausible if I did. Does anyone privately? Probably get a better return inflating my tires and slowing down 10 mph. At least my tire are inflated correctly. I'm trying. Guess you could retain hydraulic system and overcool with fans to prevent hydraulic from assisting and power with your solar, now it's starting to make sense, heck forget the 12 volt and run ac fans at 120 volts. Hum, maybe your on too something after all.
Scott

Re: Side Radiator Coach Cooling Fans

Reply #22 – August 27, 2021, 06:30:05 pm

Quote from: Roger & Susan in Home2 – August 27, 2021, 05:12:22 pm

It may be related to radiator size (and shape) and fan size and the number of fans. It might be possible, worth consideration and thought.

Good find! The radiator looks bigger than ours but so is the coach. With an extra alternator, this might work with four electric fans on our coach. I was about to take the AC compressor off and that would be a perfect spot for the alternator. Could go directly to the engine batteries only a couple of feet away. Get rid of the isolator and use a 200 amp battery switch instead.

Pierce

Re: Side Radiator Coach Cooling Fans

Reply #23 – August 27, 2021, 07:04:10 pm

It is just a though exercise. Maybe never comes to pass until you have to replace a hydraulic fan motor (if you can get one) at more than $3K each ... or maybe 2.

Even if the fans only use 40 HP replacing them with electric fans which might only use 5 HP to power the alternator for the extra load is significant. 35 HP is ~10% of what gets to the road now according to dynamometer tests done at Cummins on my coach.

Maybe just add a regulated 120v engine mounted generator to run fans and AC. Just wondering out loud. Its raining today.

It is hardly worth thinking about if the OEM fans on side radiator coaches move 15K CFM. But no one seems to know.

Re: Side Radiator Coach Cooling Fans

Reply #24 – August 27, 2021, 08:57:09 pm

Naturally, the cost of replacing either the pump or motors is a big factor but I always worry about a failure leaving us stuck somewhere. Since our coach spends quite a bit of time in Mexico, I wonder if they even have access to any of these parts. Many thousands of engines and even Allison facilities there but I don't know of any buses south of the border that use the hydraulic fan system.

We have quite a few Pick-n-Pulls in our area and the cost of a double set of electric fans from late vehicles is really cheap along with large alternators from late PUs. Less than $100 for four fans and about $30 for big single wire alternators. Just have to plan it now.

Pierce

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