Engine fan delete?

Topic: Engine fan delete? (Read 6523 times) previous topic - next topic

Engine fan delete?

December 08, 2021, 03:26:33 pm

I see lots of talk about the 50 plus HP that the solid metal fans consume . Has anyone changed to 4 electric fans? Sounds like at least a .5 MPG and most speed per pedal angle.

Re: Engine fan delete?

Reply #1 – December 08, 2021, 04:04:31 pm

Lots of CFMs and juice to run them needed so a second alternator is my plan. I would like to put four fans plus an extra radiator up front on our GV. No room on the bus types. Fans are cheap to experiment with at Pick N Pull. So, a second alternator for engine and fans, the primary alternator for the house batteries with a high amp Blue Seas rotary switch to tie them together if needed in case of an alternator failure.

As it is now, if you have a hydraulic failure, pump or motor(s), you are dead in the water. The electric fans would get you down the road to work on it at your leisure as a secondary purpose. The four fans could be tried to see how effective they are in summer weather.

Several other manufactures use electric fans instead of the very poor hydraulic arrangement used on our coaches. I did see an air cooled diesel German tour bus with a single large fan above the flat engine. It was idling and the fan was off. Rear axle pivoted to leave parking spaces also.

If our fans do use 50 or 60 hp, I expect the MPG gain would be at least the half mpg. Our 350hp Detroit has less than that at the wheels so with the fans in high, the hp loss would seem to be a substantial percent of the total. The rear radiator coaches with the direct drive fans must get better mileage.

At the Sacramento Pick-N-Pull, the electric radiator fans from any truck or car are $37 for the pair so $75 for the total is pretty cheap. Any truck alternator is also a bargain at $28.

Pierce

Re: Engine fan delete?

Reply #2 – December 08, 2021, 05:07:51 pm

I've given thought to electric fans. I've always heard 50 hp to run the fan on diesel rigs I don't know that to be a fact but I do know when a Horton air operated clutch fan defaults to on continuous I can feel the loss of power on a 430 hp engine and have put a pencil to the fuel mileage loss at .5 mpg with all other conditions similar if not the same. I would like a Air clutch fan on the coach but it would be pricey to install BUT may be worth it. Not to get away from mikes original point of trying electric fans which would be cheaper and easier to install. Mentioned Horton air/ clutch because that's where my experience has been.

Re: Engine fan delete?

Reply #3 – December 08, 2021, 06:02:13 pm

If the controllers work on the fans the 50 HP loss would not be continuous just when on high.

Re: Engine fan delete?

Reply #4 – December 08, 2021, 06:15:02 pm

Prevost uses electric fans.
ELECTRIFYING THE FUTURE AT PREVOST | Prevost

Re: Engine fan delete?

Reply #5 – December 08, 2021, 06:18:06 pm

We have these electric fans on the bumper side of the radiator PLUS a nylon fan on the engine water pump on our '89 DD turbo charged 8.2 V8.
MPG towing our 2006 AWD Saturn Vue averages 8-9
Often wondered if removing the nylon fan would make a difference.

Re: Engine fan delete?

Reply #6 – December 08, 2021, 07:11:36 pm

Quote from: craneman – December 08, 2021, 06:02:13 pm

If the controllers work on the fans the 50 HP loss would not be continuous just when on high.

Quite right but we are marginal in summer plus it's all mountains where we live so the fans are at high speed much of the year. We probably do save a bit on the downgrade parts.

Pierce

Re: Engine fan delete?

Reply #7 – December 08, 2021, 07:24:39 pm

My post was referring to class 8 trucks with bigger radiators and much bigger fans. Principal is the same but add another 45 to 50 thousand lbs and the mpg decrease may be less in GV or Uni coach. Still the drag is there and I would much rather see all the horsepower being used to move the coach instead of a portion of it going toward pulling the fan.

Re: Engine fan delete?

Reply #8 – December 08, 2021, 07:37:27 pm

Our first coach, a 83 Bluebird FC 35 with Cat 3208 (front radiator), the previous owner removed the factory fan and put in 2 electric fans that covered 90% of the radiator. It ran hot way too often.

Re: Engine fan delete?

Reply #9 – December 09, 2021, 01:08:55 pm

Well I hope that this one works better. I have 4 -14 in fans coming along with 2 controllers . I will stage the fans and use a high mounted switch for the first set and a lower mounted switch for the second set.
I wont throw out the solid , direct drive metal fan .

Re: Engine fan delete?

Reply #10 – December 09, 2021, 03:38:42 pm

Sounds great, just put in a couple of electric fans and be good to go, but to move the same amount of air it will take the same HP. No free ride. When you need full fans the electric will never come close, yet. If they would manufactures would be using. Currently I have my hydraulic fans at almost idle during normal use and will ramp up to 100% when required. Fans also ramp up during braking and retarder use and for inlet air temperature as needed at 150 degrees IAT. Your not going to deleat the power steering pump so just maintain it and use. Eventually they may have powerful enough fans but currently I can't afford.
Scott

Re: Engine fan delete?

Reply #11 – December 09, 2021, 04:01:21 pm

I have a rear radiator and direct drive fan . Full on all the time. The fans that I will try are rated 2200CFM at 9 amps each. Wired to my extra alternator and coach batts.
I may run one all of the time , , the next 2 on a thermo switch and the last one on another thermo switch.
This has worked in the past on many cars but as you say, it takes some power from somewhere. Ijust see no reason to use 50HP when cruising in the cool evening air. I picked up over .5MPG on my old chevy van while towing . This should be similar or more . Hard to say at this point.
I find it hard to believe that with all of us car peeps and racers on here, that no one else has done it .

Re: Engine fan delete?

Reply #12 – December 09, 2021, 07:05:42 pm

Quote from: Protech Racing – December 09, 2021, 04:01:21 pm

I have a rear radiator and direct drive fan . Full on all the time. The fans that I will try are rated 2200CFM at 9 amps each. Wired to my extra alternator and coach batts.
I may run one all of the time , , the next 2 on a thermo switch and the last one on another thermo switch.
This has worked in the past on many cars but as you say, it takes some power from somewhere. Ijust see no reason to use 50HP when cruising in the cool evening air. I picked up over .5MPG on my old chevy van while towing . This should be similar or more . Hard to say at this point.
I find it hard to believe that with all of us car peeps and racers on here, that no one else has done it .

So I used to have a 1995 Chevy suburban with a 6.5 diesel. As I recall a 32hp fan. A proper fan clutch was so important to the fuel economy and cooling. Bad fan clutch would slurp fuel or run hot. A good one made it work right. Played with the thermostat and was amazed at the difference in air flow a little tweak would make.
Good stuff. Bronco with LS conversion will have twin 18 inch fans drawing 20 amps each. Dual alternators too

Re: Engine fan delete?

Reply #13 – December 09, 2021, 07:35:06 pm

Quote from: dsd – December 09, 2021, 03:38:42 pm

Sounds great, just put in a couple of electric fans and be good to go, but to move the same amount of air it will take the same HP. No free ride.

But the hydraulic system IS going for a free ride taking power both at the pump and then two motors. The efficiency is a lot less than a direct fan drive and less than an alternator/electric fan combination. Plus, if the hydraulic system fails, you can be stuck somewhere for a lengthy time. We were dead in the water when one of our hydraulic hoses let go. Even with one electric fan failure, the coach can be driven.

Pierce

Re: Engine fan delete?

Reply #14 – December 09, 2021, 09:05:43 pm

Quote from: Pierce & Gaylie Stewart – December 09, 2021, 07:35:06 pm

But the hydraulic system IS going for a free ride taking power both at the pump and then two motors. The efficiency is a lot less than a direct fan drive and less than an alternator/electric fan combination. Plus, if the hydraulic system fails, you can be stuck somewhere for a lengthy time. We were dead in the water when one of our hydraulic hoses let go. Even with one electric fan failure, the coach can be driven.

Pierce

But if the hydraulic system failed your still stuck no steering. DWMYH
Scott

Re: Engine fan delete?

Reply #15 – December 09, 2021, 10:00:14 pm

If anywhere near 50hp is required to cool the engine under full load........ even 30hp......... it would take some very large 12v motors to make this much HP. Not to mention the size of the alternators to produce that much amperage. No free ride, power is power, yes efficiency comes into play, but is it enough to justify the cost?
The Prevost electric fans sound like a good idea, but look very costly and complex. I'll keep my hydraulic setup, its worked flawless for over 25 years and when it fails, I'll get it fixed and hope for another 15 or 20 years of service.

To each his own and "do what makes you happy" I welcome and encourage the different ideas and hope that they work for those who put forth the effort and expense to try them. In my opinion, Foretravel developed a cooling system that has worked for many years on our coach and I cant fault them for that. If it fails tomorrow, I'll complain about the money it will cost to repair it but that is what I'll do. Heck..... I may give out before the original pump and motors do.

Re: Engine fan delete?

Reply #16 – December 09, 2021, 10:24:10 pm

Quote from: FourTravelers – December 09, 2021, 10:00:14 pm

If anywhere near 50hp is required to cool the engine under full load........ even 30hp......... it would take some very large 12v motors to make this much HP. Not to mention the size of the alternators to produce that much amperage. No free ride, power is power, yes efficiency comes into play, but is it enough to justify the cost?
The Prevost electric fans sound like a good idea, but look very costly and complex. I'll keep my hydraulic setup, its worked flawless for over 25 years and when it fails, I'll get it fixed and hope for another 15 or 20 years of service.

To each his own and "do what makes you happy" I welcome and encourage the different ideas and hope that they work for those who put forth the effort and expense to try them. In my opinion, Foretravel developed a cooling system that has worked for many years on our coach and I cant fault them for that. If it fails tomorrow, I'll complain about the money it will cost to repair it but that is what I'll do. Heck..... I may give out before the original pump and motors do.

One HP is 746 watts at 100% efficiencies. So 50 hp would be 37300 watts at 13.8 volts equals 2702 amp draw. My math is not 100% correct but close enough for me to see electric fans won't work. I also really like hydraulic winches and there is always someone saying they won't work with a stalled engine, yep there right. Always cracks me up.

Re: Engine fan delete?

Reply #17 – December 09, 2021, 11:30:28 pm

I added a second radiator to my rear radiator coach that has a 6V92. The coolant that exits the drivers side of the engine flows to the side radiator and the coolant from the other head goes to the rear radiator. I use six 12 inch fans with the highest air flow I could find at the time (2007). They pull about 80 amps and my testing back then showed the (smaller) side radiator cooled better than the rear radiator. The rear radiator is fed warmer air as it flows over the engine first. I also think the rear radiator fan is starved for air; there just isn't much room around a V configured engine. The electric fans for the new side radiator have a custom shroud which is critical so the whole radiator surface has air drawn across it.

The fans are wired to the house battery and I removed my battery isolator so the alternator only feeds the start batteries. When I climb grades (and the fans are on) I make sure the boost switch is off so the fans don't load the alternator and engine. On the downhill I switch the boost switch on to recharge the house batteries and (theoretically) help slow the coach.

I have always thought if I have any issues with the rear radiator, I will toss it and add a second side radiator to the other side. I think I would need a second alternator (or a bigger one). Maybe put it where the engine driven fan is now.

I have heard the 50 hp number get tossed around and I personally think it's an exaggeration.

Re: Engine fan delete?

Reply #18 – December 10, 2021, 01:58:49 am

Quote from: dsd – December 09, 2021, 09:05:43 pm

But if the hydraulic system failed your still stuck no steering. DWMYH
Scott

Scott,

No, it`s a U300 with a PS pump at the forward end of the Detroit and it's own fluid supply.

Water pump is internally driven. Normally, Detroit's alternators are 300 amp, sealed, brushless, oil cooled and gear driven so the engine has zero belts. My old Buffalo's fan was a direct drive with the A.C. run off a PTO.

Detroits also come with silicone lifetime hoses.
Pierce

Re: Engine fan delete?

Reply #19 – December 10, 2021, 09:16:40 am

30 hp for solid fans on car engines are dyno numbers . Replacing the engine fans with electric is the norm for all new cars and many trucks.
The relevant number required is not the hp but the CFM value .
Also when the CFM is needed. . The mechanical fan draws all of the time. The electric fans will draw when the thermo switches ask for cooling .
Of course there are amps required to run 4- 9 amp fans .

Re: Engine fan delete?

Reply #20 – December 10, 2021, 11:16:42 am

Quote from: JohnFitz – December 09, 2021, 11:30:28 pm

I have always thought if I have any issues with the rear radiator, I will toss it and add a second side radiator to the other side. I think I would need a second alternator (or a bigger one). Maybe put it where the engine driven fan is now.

I have heard the 50 hp number get tossed around and I personally think it's an exaggeration.

Really nice and neat job you did. +++

I think the loss including the hydraulic system is between 50 and 60 hp. Those are two huge fans on ours.

With the stock muffler removed and a resonator installed, there is plenty of room on the driver's side for a radiator installation.

But, lots of room in the nose on a GV plus ram air eliminates the need for a fan unless in traffic.

Pierce

Re: Engine fan delete?

Reply #21 – December 11, 2021, 08:49:38 am

The electric fan has been tried by someone at least once on many of the RV and heavy truck forums I belong to. Most were dismal failures. Some were marginally successful depending on the definition of "success". Since it is impossible to say that I saw every post on every attempt, I will not presume there were no complete successes. All of that said, a few things stick out.

The technology is ever changing. What didn't work yesterday may be feasible today.
Newer vehicles are being designed to use electric cooling from the ground up and will therefore have better results.
Front radiator vehicles are vastly better candidates for electric conversion.
4 stroke, lower heat rejection engines are better candidates than 2 stroke, high heat rejection engines. Think the S60 vs the 8V92.
Vehicles with flexibility on radiator size and configuration fair better that those with no options; ie, better results are obtained if a copper finned radiator can be replaced with a larger aluminum one.
Vehicles used in on the East Coast and The Plains will have better results than those used in the Rockies.

There are other considerations but these are easily observable from the post I have read.

Personally, I don't have the time to fool with this particular innovation so will continue to use and fix the OEM system.

TOM

Re: Engine fan delete?

Reply #22 – December 11, 2021, 10:10:28 am

Do you have links ?

Re: Engine fan delete?

Reply #23 – December 11, 2021, 10:58:48 am

With diesel exceeding $5/gal in some places, any way to bring the cost down is welcome. A fuel card, reducing the fan loss, "Smart Way" verified tires and keeping the coach speed down are ways of helping a little.

The addition of a couple of electric fans is going to make the coach able to be driven at lower speed in case of hydraulic failure. Newer technology will have to include increased electrical output as trying to retrofit fans with our single alternator is not going to be effective. The failure of some to implement electrical fans successfully may be the failure to consider all the components necessary to build a alternative cooling system.

As far as Foretravels go, both the 2 cycles and 4 cycles have encountered cooling problems. I remember some small 5.9 Cummins owners installing front radiators to supplement cooling.

But the biggest failure of RVs today is not utilizing the front of the coach for ram air. This does not have to be ugly as VW Vanagons have done this forever and rear engine Porsche models do this today without sacrificing any aesthetics.

Even the European and Mexican buses have managed to drive their cooling fans without resorting to the clumsy and inefficient hydraulic system that RV pusher manufacturers have defaulted to.

Pierce

Re: Engine fan delete?

Reply #24 – December 11, 2021, 11:55:37 am

Pierce, something weird here (besides me) because I never know when our two big electric fans on our rear radiator are on. I go back there to disconnect our towed and both fans are running but nothing shows on the gauges.

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