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Old 06-03-2015, 05:16 PM   #15
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Quote:
Originally Posted by Crasher View Post
Generally, but not always, when the hp gets to 450 or above, it will have a side radiator. This allows for cooler air flow, but also a larger radiator needed to cool the added heat from more hp. Some use a hydraulic fan, however, ours is belt driven through a gear box. Some 400 hp coaches use a side radiator and a few 450 hp ones use a rear one. I have never seen a 500 hp or higher with a rear radiator. They just can't keep all of those pony's cool.
One of the salesmen I spoke with said that side radiators are a 25-35 HP drain on the engine due to driving the fan. Along with the anti-smog stuff, which also robs power, only higher HP engines are still using side radiators. Most others use a rear mount.

Don't know if that is true but it sounds reasonable.
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Old 06-03-2015, 06:48 PM   #16
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Quote:
Originally Posted by Rocky68D View Post
One of the salesmen I spoke with said that side radiators are a 25-35 HP drain on the engine due to driving the fan. Along with the anti-smog stuff, which also robs power, only higher HP engines are still using side radiators. Most others use a rear mount.

Don't know if that is true but it sounds reasonable.
I have heard similar claims usually from a saleman that didn't have a clue what he was talking about. Some will claim a 70 hp loss. In our case the side fan is driven by a belt from the crank shaft through a 90 degree gearbox. There is a very slight power loss through any gearbox. A rear radiator fan is driven by a belt from the crankshaft too, but no 90 degree gearbox. The fan clutch kicks the fan into high at 212 degrees and off at 180 degrees. I do not feel any change in performance nor do I see a change in torque or hp on the VMspc screen. Any mechanically driven takes power and a hydraulic fan will take more due to it's inefficiency. I will continue to rely on the engineers that design the cooling system to determine what is the best for any given hp.
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Old 06-04-2015, 09:01 AM   #17
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Sure, a side radiator setup does indeed take some engine power to drive the fan. But a rear radiator setup also takes some engine power to drive the fan.

Quote:
Originally Posted by Crasher View Post
I will continue to rely on the engineers that design the cooling system to determine what is the best for any given hp.
Agreed. The salesman will say whatever it takes to make the sale.

Q: How can you tell when a salesman is lying?
A: His lips are moving!

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The part of this whole discussion that is confusing me is that it seems to me that a rear radiator is larger than a side radiator. At least there's a lot more available surface area on a rear setup. So it would seem that a rear radiator would offer more cooling, yet the higher horsepower engines generally have side radiators?

What am I missing here?
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Old 06-04-2015, 02:04 PM   #18
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The entire bottom of the engine compartment is open. That is where rear radiator MH's get the air from, kinda like a vacuum cleaner. Side radiators exhaust the air in the same way, out the bottom. The louvre in back is to keep negative pressure off the door, so small latches can be used and the door is not pulled open by opposite direction vehicles.
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Old 06-04-2015, 02:29 PM   #19
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My 2014 Tuscany has full open grill in the rear. Rear radiator
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Old 06-04-2015, 06:29 PM   #20
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The part of this whole discussion that is confusing me is that it seems to me that a rear radiator is larger than a side radiator. At least there's a lot more available surface area on a rear setup. So it would seem that a rear radiator would offer more cooling, yet the higher horsepower engines generally have side radiators?

What am I missing here?
The rear radiator is using pre-heated air from the engine compartment to cool the radiator. The side mounted radiator is drawing ambient air from outside the engine compartment and exhausting it through the engine compartment.
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Old 06-04-2015, 06:51 PM   #21
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Pretty simple stuff. The correct answers are kind of all mixed in here. A rear radiator coach is used for smaller HP engines. Usually the max engine is the ISL engine rated at 370 -450 HP. The larger engines demand more/cooler air flow and require a side radiator.

"Coma" gives a perfect analysis.....a rear radiator is a giant vacumn (that's why many have engine screens to keep from sucking stuff up that will puncture the radiator). They suck up dirty/hot air from under the coach and push it out through the radiator and charge air cooler. Consequently, they don't cool as well. They also use horsepower to turn the engine fan.

The side radiator draws cool/clean air in from the side of the coach and blows it across the engine and out the other side behind the driver's rear wheels. That's why louvres on the rear of the coach aren't as important. Monaco did have an issue for a few years on their Camelots and above, because the engine compartment was taller than the rear louvre openings. Heat was getting trapped and baking the bedroom. So....the rear louvres on a side radiator, are typically there to vent heat when the coach is stopped.

A gear box or belt/gearbox are needed on the side radiator to run the engine fan. A would guess the HP used to drive the side radiator is probably 10-20 HP than a rear.
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Old 06-04-2015, 08:15 PM   #22
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Pretty simple stuff. The correct answers are kind of all mixed in here. A rear radiator coach is used for smaller HP engines. Usually the max engine is the ISL engine rated at 370 -450 HP. The larger engines demand more/cooler air flow and require a side radiator.

"Coma" gives a perfect analysis.....a rear radiator is a giant vacumn (that's why many have engine screens to keep from sucking stuff up that will puncture the radiator). They suck up dirty/hot air from under the coach and push it out through the radiator and charge air cooler. Consequently, they don't cool as well. They also use horsepower to turn the engine fan.

The side radiator draws cool/clean air in from the side of the coach and blows it across the engine and out the other side behind the driver's rear wheels. That's why louvres on the rear of the coach aren't as important. Monaco did have an issue for a few years on their Camelots and above, because the engine compartment was taller than the rear louvre openings. Heat was getting trapped and baking the bedroom. So....the rear louvres on a side radiator, are typically there to vent heat when the coach is stopped.

A gear box or belt/gearbox are needed on the side radiator to run the engine fan. A would guess the HP used to drive the side radiator is probably 10-20 HP than a rear.
I disagree with your theory of the air flow of a side radiator. My radiator is on the "Drivers Side" and pulls air in from that side and it exits out the rear of the coach. That big vacuum effect is still there at the rear of a side radiator coach and helps the cooling air exit out the rear. There are no louvers on the opposite side of the fan, but even if there were, the vacuum at the rear would still overcome any air trying to escape that direction. Instead of dirty air coming from underneath the coach there is clean air coming in from the side, and both styles exit out the rear.
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Old 06-04-2015, 08:37 PM   #23
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The rear radiator is using pre-heated air from the engine compartment to cool the radiator. The side mounted radiator is drawing ambient air from outside the engine compartment and exhausting it through the engine compartment.
Bingo.

But if you read the OP's question, it's not about side or rear radiator. He's asking about exhausting heat from engine compartments in side radiator coaches !
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Old 06-04-2015, 08:48 PM   #24
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It's happy hour so I hope this makes sense to anyone reading.

There are rules about posting during HH.
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Old 06-04-2015, 11:48 PM   #25
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"Crasher"..... you're saying that your coach defies physics? So your coach sucks air in from the driver's side, enters the engine compartment and then makes a right turn and goes out the back??? Have you ever stood on the passenger side at idle and felt the air blowing out?
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Old 06-04-2015, 11:56 PM   #26
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You guys sure have some very nice looking coaches.... Just beautiful.
Mr. D, I have read about your Cummins ISX engine woes. I hope those are all solved now. The model that you have is the one that I would love to own some day.
US TOO!!

Now the DW's health enters into everything!
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Old 06-05-2015, 12:43 AM   #27
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One of the salesmen I spoke with said that side radiators are a 25-35 HP drain on the engine due to driving the fan. Along with the anti-smog stuff, which also robs power, only higher HP engines are still using side radiators. Most others use a rear mount.

Don't know if that is true but it sounds reasonable.

Also sound like someone who has never driven any unit with a belt driven, clutch fan, when that fan locks up, any fan that moves the amount of air that an engine takes to stay cool takes power.
There have been posts from gas coach owners who think their transmissions are slipping when there clutch fan come in.
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Old 06-05-2015, 01:12 AM   #28
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My side rad 370 ISL 2001 Dynasty has an air scoop 7' by 9" on the rear roof top that is ducted down and exits air over the engine. The faster you go the more air flows over the engine. I feel that this side radiator / roof top air scoop combo is the perfect answer to rear engine heat control. Mine has never ran hot even climbing the Grape Vine and Tehachapi grades in summer heat.
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