What is the science involved in adding another radiator somewhere on the coach to help add cooling power? Either tucked in the front or on the roof near the back...does the water pump need to be upgraded to handle the extra back pressure and volume of the third radiator and coolant? These rear engined coaches obviously have issues staying cool and I'm wondering what one might gain by adding a third radiator? I've seen off-road trucks do this:
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Scott, I have been thinking about that as well. I did some remote radiators for high hp racers using these that worked out real nice > https://www.meziere.com/Products/Cooling-System-Products/Pumps-Electric/Remote-Mount/Electric-Pump-Remote-High-Flow-Inline-Dual-out-55-GPM.aspx (https://www.meziere.com/Products/Cooling-System-Products/Pumps-Electric/Remote-Mount/Electric-Pump-Remote-High-Flow-Inline-Dual-out-55-GPM.aspx)
I have seen a few MCI's with the 3rd side mounted radiators 1 had a rear mounted radiator , the water pumps on a DD are pretty robust they move a lot of water the pump capacity wouldn't be a problem
i don't see much difference between an 8v and a 12v water pump...
Quote from: Scott Bennett on September 14, 2015, 07:40:25 PM
What is the science involved in adding another radiator somewhere on the coach to help add cooling power?
Scott -You already have a big, huge, third radiator on board, including some monster fans to pull air thru it.
You just need to figure out a way for it to pull double duty when needed.
FWIW & HTH. . .
;)
IN the past I have had cars that hated stop and go traffic. If they started to get hot I would turn the heat on and put fan on hi and roll the windows down. I could watch the temp needle drop.Not the most comfy but saved me from overheating and sitting on the side of the road.
Chuck
Mister system would be much easier and should be a must have for most older coaches that heat too much on hills after cooling system is up to snuff.You can buy a lot of water for the price of another radiator and plumbing.
RJ my OTR heater is stripped :(
Chuck, someone on here actually did just that, they had some sort of way to exhaust the heat out the coach. Again, my OTR heat was stripped out.
As for a mister, I replaced my radiators last summer along with a complete coolant change and I saw how bad the corrosion on the original radiators was....misting with water that has minerals in it will eventually be an issue....misting with RO water can cause issues too since its naturally more acid...those radiators are $1500 each so I am protective of them. Has anyone reported deposits or issues with their radiators after long term mister use?
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I am with Scott I do not care for a misting system it's only a band aid IMO
Adding a third radiator to the MCI two side radiator system would be really easy if you have removed the stock OTR AC pump. Just add a radiator plumbed in series with the passenger side top radiator, the output from the stock radiator into the input of the new one, and the output of the new radiator down into the stock return to the bottom of the water pump. It might not be ideal from a thermodynamic efficiency point of view, but it would add a lot of additional cooling capacity. I would lay it down flat(ish) using the AC pump mounts as the mount for the rad, and exhaust it out the bottom into the low pressure area under the bus, I would only add fans if proven to be needed, because the stock air handling system is blowing a lot of air down over the engine anyway.
Brian
MCI missed the boat on cooling the people I know with the MCI cargo buses with a side mounted radiator run the 8v92 without cooling problems then with the high mounted radiators on each side with a 8v92 it always a problem
I had a problem with rising heat early on and often considered another radiator. However, I did several other things first. One was simply to increase the radiator air flow by attaching, when needed, a clamp that allowed the engine doors the stay partially open. The next was to add a full width mud flap just behind the rear wheels. This creates more negative pressure under the engine so it increases air flow through the radiators. The third thing was adding radiator scoops that we had made using Fred Hobbies design. I also added a misting system for times when all else fails. It does not get used much and has not caused any build up yet. However, I clean both radiators with a condenser cleaner spray every spring anyway.
I do not seem to have heat problems anymore. However, I think that changing the way I drive has helped too in that I am watchful to keep the engine rpm between 1700 and 1800 at all times.
I agree with Lin, the best thing I've done is adjust my driving. I may have done some damage in my first couple of years as I we figuring out how to drive this thing. I was still in disbelief that I could drive this thing without any special licencing and not paying much attention to the nuances. Weird how you get in tune with your bus. Craig
Hi Scott,
The previous owner of our MCI 8 took several steps to alleviate cooling problems when he installed the 8V92TA DDEC II. He installed MCI 9 or 102 radiators and blowers; smaller pulley on the blower gear box; 1 of the MCI 8 radiators, with a large 24V, thermostat controlled fan, where the A/C compressor was, with air ducted from a hole in the side and out the bottom; and air scoops on the rear of the high radiator openings.
The widow of the previous owner told us he had a heavy foot and wanted to be able to pass trucks on I70 west of Denver on the way to the ski resorts. The things he did have made it so that I have not ever gotten into a situation where the engine has gotten above 195 degrees F. However, where, and the way I drive has something to do with that. We drive primarily in Minnesota and surrounding states (no mountains), and I don't try to be the first one up a hill, nor do i try to keep up with the speeders on the interstate highways. It is still important to keep the RPMs up to maintain good air flow through the radiators.
Good luck, Sam
I am with Cole on the cooling of the 8v92 or any DD in a bus it should be tied into the radiator with separate hoses from the engine to the radiator like the trucks and off road equipment
My old long gone Crown Supercoach had the big radiator mounted sideways just behind the driver. There was a convenient large trunk on the opposite side from the OEM radiator that would have been perfect for a second large radiator. But the first one did just fine. I do NOT know how well it would have worked with a pumped up Cummins Big Cam engine. Now I will never know. HB
Quote from: HB of CJ on September 15, 2015, 02:08:05 PM
My old long gone Crown Supercoach had the big radiator mounted sideways just behind the driver. There was a convenient large trunk on the opposite side from the OEM radiator that would have been perfect for a second large radiator. But the first one did just fine. I do NOT know how well it would have worked with a pumped up Cummins Big Cam engine. Now I will never know. HB
One member of our Crown group has a 375 HP big-cam in his Hewlett-Packard Crown, and he hasn't reported any cooling issues with the stock radiator.
John
Quote from: Scott Bennett on September 15, 2015, 07:54:44 AM
RJ my OTR heater is stripped :(
Well, that's too bad. . .
Quote from: bevans6 on September 15, 2015, 09:09:30 AM
Adding a third radiator to the MCI two side radiator system would be really easy if you have removed the stock OTR AC pump. Just add a radiator plumbed in series with the passenger side top radiator, the output from the stock radiator into the input of the new one, and the output of the new radiator down into the stock return to the bottom of the water pump. It might not be ideal from a thermodynamic efficiency point of view, but it would add a lot of additional cooling capacity. I would lay it down flat(ish) using the AC pump mounts as the mount for the rad, and exhaust it out the bottom into the low pressure area under the bus, I would only add fans if proven to be needed, because the stock air handling system is blowing a lot of air down over the engine anyway.
I like Brian's idea, but I would add a thermostatically-controlled fan on the bottom pulling thru the extra rad and blowing down under the coach. His comment is correct about all the air movement in the engine compartment, but remember that it's hot air, as it's already come thru the radiators. The extra fan would help compensate for the hot air simply by increasing the air flow thru the unit.
Quote from: Lin on September 15, 2015, 09:48:58 AM
The next was to add a full width mud flap just behind the rear wheels. This creates more negative pressure under the engine so it increases air flow through the radiators.
GMC started doing this with the 4104s way back in 1953. Principal still works today. A little trickier on the T-drive MCI, but still doable.
Quote from: Lin on September 15, 2015, 09:48:58 AM
However, I think that changing the way I drive has helped too in that I am watchful to keep the engine rpm between 1700 and 1800 at all times.
BINGO! Especially when climbing, keeping the engine between 1800 - 2000 on a
partial throttle does wonders for keeping the temps under control.
FWIW & HTH. . .
;)
The driving technique changes between a automatic and a manual transmission with a DD a Allison will heat a DD up under a load if the cooling system is not in good shape the 200+ degrees has to go somewhere
Quote from: Sam 4106 on September 15, 2015, 11:20:46 AM
Hi Scott,
The things he did have made it so that I have not ever gotten into a situation where the engine has gotten above 195 degrees F. However, where, and the way I drive has something to do with that. We drive primarily in Minnesota and surrounding states (no mountains), and I don't try to be the first one up a hill, nor do i try to keep up with the speeders on the interstate highways. It is still important to keep the RPMs up to maintain good air flow through the radiators.
Good luck, Sam
Sam the DDEC's just naturally run cooler than a mechanical engine does they are always searching for the right timing for the fuel and air mixture they don't even sound the same
Just be sure to be able to bypass the cooling benefits in cool or cold weather so as to maintain heat in engine at those times.
I've heard of the mineral build up concerns, however havent seen it reported. I am more inclined to recommend misters for situations where they are OCCASIONALLY needed, not regularily needed. If you overhear on every grade, you've got other issues.
I think I would add gate or other type valves to close off for just that reason
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Hi Clifford,
So, I probably don't need the extra radiator, but I don't think I will remove it. The shutters are in place, and working, on all three radiators so keeping the engine warm in cold weather isn't a problem since we don't drive the bus in the winter anyway. Some of the things the PO did makes me shake my head and wonder," WHAT WAS HE THINKING". The extra radiator isn't one of them.
Thanks for your response, Sam