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Old 04-03-2016, 05:11 PM   #131
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Hey, cowlitz. Those air ducts are only to provide an extra avenue of fresh air to flow over the intercooler. I thought about the vaccuum at highway speed and there's just really no practical way I can measure the air flow to see if the intercooler will be getting any noticeable benefit. If the overall benefit is zero, it's still no real loss except for some time and money. This isn't for the engine air intake though.

The engine air intake system will still be in its stock location, pulling from high up on the passenger side of the bus. I did away with the Cyclopac air cleaner and am replacing it with a Donaldson air cleaner system, mounting it up against the ceiling of the engine bay. Then aluminum tubing from the turbo to the intercooler, and then all the way to the intake manifold. It's going to take a lot of precise measuring, cutting and welding to get it right. I'm too paranoid to try to draw engine intake air that low to the ground where the intercooler ducts are.
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Old 04-03-2016, 05:28 PM   #132
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Also, one thing I don't really understand about the layout of the engine compartment is where the air goes after the fan has pulled it through the radiator and intercooler. The fan is within a couple of inches of the bay door, and that door is solid. There's the intake grate on the driver's side, and there's a grate on the passenger side. The only thing I can think is that the air crashes against the back door and then somewhat flows through the compartment to exit on the passenger side providing some minimal engine air cooling. I'd really like to make a grate in the bay door right behind the fan to get that air out of the bay, but not until I can be certain that the air isnt being used for indirect cooling.
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Old 04-03-2016, 05:40 PM   #133
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Remember the area behind the bus is another low pressure area. With the fan(s) creating a high pressure area inside the engine compartment the air will flow out the other side or down and out into the low pressure areas.

The major problem for all bus builders who build rear engine buses is how to cool the engine.

When the Series 50 engine was still in production I wanted to purchase a Thomas Saf-T-Liner RE with one. I thought a 350 HP Series 50 would be an ideal engine to get a bus up the hills around here without slowing down and still have enough HP left over to run a coach A/C system. Thomas would not even consider the option because of the engineering it would take to create a cooling system to do the job of cooling a Series 50.
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Old 04-03-2016, 06:25 PM   #134
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dont some of the busses blow the air Outward from the radiator? maybe the turbo ones dont because of the intercooler?

I remember some city busses that the air into the engine bay was cowled up from underneath the bus into the engine compartment and the fan blew the air from the engine compartment over the radiator and out of the bus.. (not sucking it in over the radiator)...

if you had to you could "catch" the air for your intake and push it into the engine compartment for your intercooler...

-Christopher
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Old 04-04-2016, 09:38 AM   #135
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cadillackid: I *could* put some kind of shallow hood scoop over those ducts to help grab the passing air better, and I may end up doing that. I just like the way the exposed inlets look. The scoop(s) in that area will be something a lot further down the road. I need to find a way to measure air that *could* pass through those tubes. Even if it's just a string with a camera looking at it. That way I could see if the Bernoulli effect of the air mass travelling along the body will work for me or against me. I'm hoping the air will want to conform, however slightly, to the contour of the inlets. The air will have 34 inches of travel to recover after being disturbed by the rear wheel flare. If it doesn't conform, it will do like cowlitzcoach said and create a sucking effect if the fan is off. Since the radiator screen starts about 5 inches after the inlets, hopefully the vaccuum there will be greater and still pull some air through, though it may not pass through the intercooler in that scenario.
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Old 04-04-2016, 11:26 AM   #136
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If you want to get all scientific you could set up a water manometer pretty easily and actually get some numbers on where your bus sucks and where it blows.
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Old 04-04-2016, 11:36 AM   #137
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LOL, Dan. I think it may suck and/or blow in the power to weight ratio and the rusted floor.
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Old 04-04-2016, 11:53 AM   #138
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I am semi serious. Google "water manometer". Very simple to build; you just end up fixing open ended hoses here and there with masking tape to find out what the areas of high and low pressure are. Dead simple.
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Old 04-04-2016, 06:26 PM   #139
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Cool

Exactly how I see it!

Worst case you will have a stalled flow (...NO flow - in other words!)
The sides of cars, trucks, buses are ALWAYS low-pressure areas.

Actually this would be an excellent OUTLET area!

I wouldn't even wait around: Put a scoop on top of the 2 inlets!!

[Unless you can and want to re-route to the roof - and still you should put a scoop on the roof too! I would say - if you have a straight way up to the roof, it wouldn't be much work to cover the openings on the side.... do it now, where you are at it anyway!!]

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Old 04-04-2016, 07:09 PM   #140
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Quote:
Originally Posted by thjakits View Post
Exactly how I see it!

Worst case you will have a stalled flow (...NO flow - in other words!)
The sides of cars, trucks, buses are ALWAYS low-pressure areas.

Actually this would be an excellent OUTLET area!

I wouldn't even wait around: Put a scoop on top of the 2 inlets!!

[Unless you can and want to re-route to the roof - and still you should put a scoop on the roof too! I would say - if you have a straight way up to the roof, it wouldn't be much work to cover the openings on the side.... do it now, where you are at it anyway!!]

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