Re-Routing Skoolie Exhaust Overhead?

[CHEESE_WAGON]

Originally Posted by Bus'n it

I was doing some welding today and went to look at my exhaust setup. Even if I wanted to run the stack through the inside corner of the bus, the air filter intake would be in the way. The exhaust and air intake are both on the same side. I don't think it would be economically feasible in my case.

You may have missed my revised idea in pics, which puts the pipe forward of the engine bay and air intake snorkel. You're looking at a 72" H x 6" W x 3" D channel in a side wall, I think this is doable for most folks. It would really be no different from a stovepipe for a wood stove, maybe less as the depth of recession into the wall could vary.

[Native]

There is a company that makes heat protection products that may be useful in this application: https://engineheatprotection.com/bus/


They have all sorts of interesting products. The wet blanket looks to be a great candidate for a stack wrap.


Note: Never have used the stuff personally, but I am interested in trying it out at some point.

[Free Bird]

If I were to raise my exhaust on my FE I would run it up the outside on the back. the Guarding would bolt on from the outside and the tail lights would be mounted to the guarding. Using this method is much simpler and safer than than internal routing and as far as cosmetics go one can build the guard in any shape or style that suits. It could even match the look of the original back of the bus and contain some storage. The only place where the pipe is exposed to damage is where it exits the roof line, same as any other tall exhaust.

Honestly though most of my exhaust problems are simply bad technique. Ya gotta remember to shut yer doors and windows before ya flash up that beast! Maybe I should print that and paste it to my dash?

The air quality problems that I need most to deal with revolve mostly around dusty back roads.

In regards to maintaining high quality cabin air I plan to do some work on my passenger/driver air intake. I think the way to achieve quality air is through MAINTAINING POSITIVE CABIN AIR PRESSURE.

First thing is to do a little simple maintenance to ensure the exhaust system is not leaking.

Second is to ensure I have decent door seals and to plug up any leaks in the firewall, I'm actually working on that right now.

With that done the next step is to insure adequate flow of clean external air into the cabin. My bus does not have an air filter but I have room for one in my existing intake. Coupled with an upgraded fan system that should keep dust and fumes to a minimum.

If that is not enough I will consider a roof mount auxiliary intake (also filtered). I think that an upgraded air intake will solve the problem of leaky school bus windows and the imperfections of door deigns.

Another consideration which I have not yet researched is rear mounted spoilers, I see them on some of the newer buses. I expect they help keep the rear windows clean and likely reduce the vacuum effect. If so that is probably the first mod I should make as it would reduce the amount of dust and diesel trying to creep through my back door. Maybe somebody out there can give us the lowdown?

[CHEESE_WAGON]

Obviously, almost no one is taking the time to fully read and understand the solution I came up with. Basically my idea is to integrate a channel into the side of the body and nestle the stack into it with heat wrap to keep the heat from creating a fire hazard. It DOES NOT run through the cabin.

[joeblack5]

Here are some pics from how Mercedes / freightliner has handled the issue.

Johan

[Oscar1]

Originally Posted by CHEESE_WAGON

Obviously, almost no one is taking the time to fully read and understand the solution I came up with. Basically my idea is to integrate a channel into the side of the body and nestle the stack into it with heat wrap to keep the heat from creating a fire hazard. It DOES NOT run through the cabin.

Yep I got that part, seems about right to me and not that hard to accomplish.

[Native]

Originally Posted by joeblack5

Here are some pics from how Mercedes / freightliner has handled the issue.

Johan

Am I seeing this correctly ... the exhaust exits at the driver-side rear pointing to the side as opposed to the rear?


Is the pipe wrapped (in a sleave) or is it flex pipe?

[joeblack5]

Yes to the side...yes to the sleeve .

[shorthair]

Cummins has a propane fueled 10 liter that may work well.

[Dirtdoctor]

Run the stack out the back and up, they’re are great stainless steel “protective cages” surrounding them. No chance of grass touching them unless you’re in 2’ high grass and then your wholeExhaust system will be in contact with grass. NEVER put the stack inside. Heating and the possibility of walking up DEAD.

[Brdfrd]

Originally Posted by CHEESE_WAGON

I've considered that, but if parked where tall grass and other foliage is a concern, it is best to keep it within the bus body. Also the possibility of an external stack bolted to the body getting hung up on its surroundings. Besides, I'm wondering if such an arrangement would pass a state inspection. Maybe neither arrangement would...?

Tall Grass or foliage? You already have an exhaust running under the bus, right? So continuing that pipe 6" beyond the body at the rear isn't really increasing any risk. If the exhaust exits a hole in the bumper, like many around my neck of the woods, it would be really simple to add a 90 degree, straight up, to about 8" or so over the roof height. Add a nice chrome heat shield, like a regular truck. This is about the simplest, least expensive way to go--and I don't think it adds any risk whatsoever.

I think you're needlessly complicating things--not meaning to be critical here.

Brad

[Truthseeker4449]

I think your idea is fairly sound but can be simplified. I know the rear vent on a Thomas RE is actually the air intake for the engine. There is a somewhat small duct inside the passenger compartment for this, its on the left in the picture below. They can actually be on either side depending on engine compartment layout, but they do not appear to be well sealed. In a similar vein it may be possible to weld in a corner to create a new compartment to route the exhaust pipe up through the engine hump without taking a huge chunk of the body out. Putting an exterior vent similar to the intake vent on the outside of this box should keep any exhaust from building up in the compartment as a precaution. To prevent the exhaust from being in direct contact with the body or roof, you could make the holes oversize with the bottom serving as a drain for the compartment.

[Unpluggedone]

Maybe not in your budget, but here comes an asthma ready bus

https://thomasbuiltbuses.com/school-...ner-c2-jouley/

[Stu & Filo. T]

I did it, I ran a 5 in pipe from inside the eng compartment thru the roof then installed the 4in exhaust inside of it. Tapped the outside pipe top & bottom, threaded it & installed screws to keep the inner from touching the outer. Installed a scoop to force cooling air down between the pipes.

[Oliveguam]

Wow what a lively post. I had considered doing this with my bus, also what I have proposed to multiple food truck owners to replace their painfully loud air cooled gensets with econo box car engine dcv gensets, (another topic to discuss) and certainly route the exhaust upward away from customers and self... As I digress. I'm sorry to poo-poo the idea to recess a clamshell into the side of the bus ONLY out of laziness, as that seems like an awful lot of work to weld in and seal all those vertical seams. Especially without warpage and still fasten the other half. The simple universal approach to any pre existing bus would be to Install and seal in a single or better yet double wall (for air gap insulation) floor to ceiling open pipe. use roof flashing and tar to seal in outer pipe of any material top and bottom. say 10+ abs, round 12"steel square, or what you, open on top and bottom. steel brackets to suspend inner wall such as cheap 6" chimney pipe and lightly insulate between the two for extra stability. now that top and bottom of Inner pipe is open top and bottom convection currents can flow automatically regulating temp, and evacuating any leaks that may ever develop in your dirty pipe. From there use pipe hangers to locate your dirty pipe (exhaust) as likely 4" in the center top and bottom from different opposing angles to allow flex but center locate. All that said I can understand why this is a big priority and could or should shape purchase criteria. seems more rear engine busses would be easier to lend doing this to less effort. Also might consider transit stye or even a step further and look into cng bus or a cng conversion (using 20% diesel for ignition timing and 80% cng or propane as prime mover cleanly burning up residual soot in process. (much cleaner) I have seen airport/ hotel shuttle buses sporting iron block LS engines also My brother in law found a ridiculous cross between an LS series in a big block form for his trail rig. As I understand it it is only available in med duty trucks. U haul likes them, as they pay maintenance and customers pay the fuel... I think it is 8.2 or 8.3? not sure, but I hear it rivals the cumins 5.9 in hp and torque in gas. Not to say I know much about that subject (I don't) but could be worth the research for you.

The problem. I had briefly considered this with my bus as a LOT of prime real estate under the bus better used for tankage is taken up by a rangy meandering exhaust slowly snaking itself allllll the way back making large tank mounting difficult. the reason I wont is its a huge mess topside. After we put a mercedes diesel into my jeep we put a cartoonishly scaled 4" straight pipe up the side of the jeep with a heat shield and a flapper. problem being, condensation formed and mixed with exhaust soot = a weak acid that leaves nasty soot stains all over a new soft top, and accelerates all the stitching of said top to rot out fast. (face palm) Next the solution was a side dump forward of the rear wheel was employed... also bad idea. Right rear tire would paint out black with soot and unrepairable pitting corrosion rendered that wheel unusable over two years. Now my jeep sports Exhaust that snakes all the way back over the axle and out the rear (and a muffler) and my bus will follow suit. I cant imagine the headache of more than existing soot scum to scrub off with the ever much larger bus and having to do so on the roof? yikes. Glad I learned some of these lessons with a cheap jeep before scaling up.

lastly with a genset I personally intend to run a diesel as due to simply, I have one already laying around. I intend to mount it front bumper-ish to eliminate redundant hardware, fuel filters, air filters and coolant system all piggybacking off the main engines systems for simplicity of maintenance. Perhaps run one of two reefer pumps on it as well. That said that is MY priority. Otherwise I would look for a cheap lpg/gas dual fuel (vertical exhaust) out of similar concern due to exhaust mess and breathing hazzard as when parked we are all victim of wind direction. Change of direction = change of carbon monoxide risk factors. I have grown weary of tinkering with carbs in life hence one reason I love diesels. I suggest propane is next best thing for ease of maintenance, and being able to shift to Gas (yuk) is a good backup when lpg isn't cost effective or available.

[Stu & Filo. T]

Originally Posted by Stu & Filo. T

I did it, I ran a 5 in pipe from inside the eng compartment thru the roof then installed the 4in exhaust inside of it. Tapped the outside pipe top & bottom, threaded it & installed screws to keep the inner from touching the outer. Installed a scoop to force cooling air down between the pipes.

Oh & I removed the muffler so it's straight off the turbo

[cadillackid]

Originally Posted by Stu & Filo. T

Oh & I removed the muffler so it's straight off the turbo

straight pipe baby!! I love the sound of the turbo!!!

[JackE]

Originally Posted by Stu & Filo. T

Oh & I removed the muffler so it's straight off the turbo

With it coming out the top, did you notice any additional volume not having the muffler? I'm wondering if my 8.3 would benefit from loosing the muffler. I had the same idea as you to run the exhaust pipe through a larger pipe out the roof. Do you think the snorkel running fresh air down between the two is necessary? When sitting idling, I don't imagine there is any benefit to having that set up.

[CHEESE_WAGON]

So, I would like to share some info I have recently come into that changes the whole ball game.

Apparently, unlike gasoline / LPG / CNG engine exhaust, diesel engine exhaust is heavier than air and will simply settle to the ground regardless of where it is dumped. So running a diesel's exhaust above the roof will just veritably cloak the vehicle, creating an invisible cloud of exhaust fumes that surround the vehicle as they settle to the ground. This is probably the primary reason my doctors have told me not to return to trucking, and most of the reason I just had to pass up a dream deal on a dream bus. I hope that all members read this post, because this is something that you all need to know for health reasons.

I have no info on how long it takes for the exhaust to fall from 6-10 feet above the ground to actually reaching the ground, but I'd say this goes a long way in explaining why my bronchial infections increased in frequency and severity in late 2016. Reason being that until then, I had driven trucks without APUs, pulling dry-van trailers, but went to work for a refrigerated freight company with APU-equipped trucks.

Here's the science.

First, the APU is designed to be used to power an auxiliary electric HVAC system separate from the main cab's system. It is a simple generator powered by a one or two-cylinder diesel, and they are largely not emission-controlled. This creates a plume of diesel exhaust directly under, behind, and around the rear of the sleeper cab, and I am quite sure the cabs are not airtight, which could certainly allow a small amount of diesel exhaust into the cabin slowly, which is enough to create a problem for an asthmatic.

Secondly, the refrigeration unit on the trailer is also powered by a diesel engine, typically 2, 3, or 4-cylinder units. These are not emission equipped either. But to make matters worse, they also use off-road diesel. To clarify, this is the same basic fuel which was replaced by emission-friendly ULSD for highway engines, but is still legal for and therefore is common in non-taxable highway use, which refrigerated trailers fall under. So between the APU, and the refrigerated unit, my sleeper cab was being immersed in diesel exhaust the entire time I slept, which explains why my infections became worse and more frequent. Not to mention there were at least 25-50 others surrounding me, compounding it.

So what this all means is that diesel exhaust not only triggers and exacerbates asthma and other respiratory issues, it also is a known cause as well. Therefore, my proposed idea of routing exhaust overhead does absolutely nothing to accomplish the desired purpose with a diesel engine, as the exhaust will simply settle back down to ground level anyway. So this post, quite frankly, proves this thread moot, with science. Unfortunately, until better fuels are discovered that can deliver power without environmental and health concerns...

I have long railed against diesel emission controls due to their quirkiness and the general unreliability of the engines. And I am by no means retracting any advice given other members here to avoid such engines. I still stand by my statements that they are, in fact, less reliable than their predecessors. However, my advice to skoolie owners / builders in the future is this...

You may not be able to avoid diesel power for the time being. However, I would like to make a few suggestions, for your own health and safety, as well as that of others.

First, don't run your diesel chassis engine any more than necessary. I now understand why 'no-idling' laws exist, but many do not understand that this is a problem for commercial truckers, as they need heat and air-conditioning to rest comfortably so they can drive safely. I have been in that position, forced to choose between a fine and resting comfortably, which isn't a choice when you have asthma that is triggered by heat.

Secondly, try to choose propane, natural gas or gasoline generators. To your lungs, a diesel generator will be no different than running your chassis engine. Piping gas / LPG / CNG generators' exhaust upward will help keep their exhaust from causing health problems.

Thirdly, most of you have buses with massive space and underbody storage -- use it for larger battery banks, and more solar panels. Yes, I realize that solar is not a long-term everyday solution, but the less you have to run a generator, the better off you'll be.

Fourthly, consider a propane conversion if your travels are within a limited radius.

I say this because I have been struggling with asthma all my life and did not even know it was asthma until I turned 41 in 2017. I was hard-headed and disobeyed doctors' orders by returning to trucking, but learned quickly that they were right. And believe me, you don't want the respiratory problems I have. I wouldn't wish them on my worst enemy.

[Oliveguam]

Originally Posted by CHEESE_WAGON

So, I would like to share some info I have recently come into that changes the whole ball game.

Apparently, unlike gasoline / LPG / CNG engine exhaust, diesel engine exhaust is heavier than air and will simply settle to the ground regardless of where it is dumped. So running a diesel's exhaust above the roof will just veritably cloak the vehicle, creating an invisible cloud of exhaust fumes that surround the vehicle as they settle to the ground. This is probably the primary reason my doctors have told me not to return to trucking, and most of the reason I just had to pass up a dream deal on a dream bus. I hope that all members read this post, because this is something that you all need to know for health reasons.

I have no info on how long it takes for the exhaust to fall from 6-10 feet above the ground to actually reaching the ground, but I'd say this goes a long way in explaining why my bronchial infections increased in frequency and severity in late 2016. Reason being that until then, I had driven trucks without APUs, pulling dry-van trailers, but went to work for a refrigerated freight company with APU-equipped trucks.

Here's the science.

First, the APU is designed to be used to power an auxiliary electric HVAC system separate from the main cab's system. It is a simple generator powered by a one or two-cylinder diesel, and they are largely not emission-controlled. This creates a plume of diesel exhaust directly under, behind, and around the rear of the sleeper cab, and I am quite sure the cabs are not airtight, which could certainly allow a small amount of diesel exhaust into the cabin slowly, which is enough to create a problem for an asthmatic.

Secondly, the refrigeration unit on the trailer is also powered by a diesel engine, typically 2, 3, or 4-cylinder units. These are not emission equipped either. But to make matters worse, they also use off-road diesel. To clarify, this is the same basic fuel which was replaced by emission-friendly ULSD for highway engines, but is still legal for and therefore is common in non-taxable highway use, which refrigerated trailers fall under. So between the APU, and the refrigerated unit, my sleeper cab was being immersed in diesel exhaust the entire time I slept, which explains why my infections became worse and more frequent. Not to mention there were at least 25-50 others surrounding me, compounding it.

So what this all means is that diesel exhaust not only triggers and exacerbates asthma and other respiratory issues, it also is a known cause as well. Therefore, my proposed idea of routing exhaust overhead does absolutely nothing to accomplish the desired purpose with a diesel engine, as the exhaust will simply settle back down to ground level anyway. So this post, quite frankly, proves this thread moot, with science. Unfortunately, until better fuels are discovered that can deliver power without environmental and health concerns...

I have long railed against diesel emission controls due to their quirkiness and the general unreliability of the engines. And I am by no means retracting any advice given other members here to avoid such engines. I still stand by my statements that they are, in fact, less reliable than their predecessors. However, my advice to skoolie owners / builders in the future is this...

You may not be able to avoid diesel power for the time being. However, I would like to make a few suggestions, for your own health and safety, as well as that of others.

First, don't run your diesel chassis engine any more than necessary. I now understand why 'no-idling' laws exist, but many do not understand that this is a problem for commercial truckers, as they need heat and air-conditioning to rest comfortably so they can drive safely. I have been in that position, forced to choose between a fine and resting comfortably, which isn't a choice when you have asthma that is triggered by heat.

Secondly, try to choose propane, natural gas or gasoline generators. To your lungs, a diesel generator will be no different than running your chassis engine. Piping gas / LPG / CNG generators' exhaust upward will help keep their exhaust from causing health problems.

Thirdly, most of you have buses with massive space and underbody storage -- use it for larger battery banks, and more solar panels. Yes, I realize that solar is not a long-term everyday solution, but the less you have to run a generator, the better off you'll be.

Fourthly, consider a propane conversion if your travels are within a limited radius.

I say this because I have been struggling with asthma all my life and did not even know it was asthma until I turned 41 in 2017. I was hard-headed and disobeyed doctors' orders by returning to trucking, but learned quickly that they were right. And believe me, you don't want the respiratory problems I have. I wouldn't wish them on my worst enemy.

Cheese-Wagon, as always this is a good read, I too am a dinosour hung up on "dirty diesel" I understand the the days of easy to work on engines are numbered. This is a compelling arguement as to why on a personal level. I apreciate you writing more into this as being aware of risks and bennefits make to inform better decision making. Much of my life has been spent focusing more on saving of time money ect through ease of build or service. Sadly not putting much proirity onto my personal health. The weak link in electric based systems is in the batteries, but we live in intiresting times as things on that front are rapudly evolving at present. In the meantime adapting to solar wind and thermal barier techology as it is for now is atill worthwhile. Also I have wondered about propane or natural gas as prime movers with diesel. Using injector system as timed ignition system to ignite metered intake fogging system. It was a crossover system that was being proposed in port of Long Beach when I last lived in commiefornia. I feel that may be worth your looking into. Personally in spite of bus dreams I feel as long as I am living in the tropics I feel wood gas and fisher troppe processes have my intruige.