Adding dash air

[Ronnie]

I get 5.75 mpg on average so if it dropped 3mpg to have air that would 2.75 mpg. that would be truelly awful mileage. Really do not think it would change much on a bus. Maybe others who have it can comment on fuel mileage difference with dash air.

My trips tend to be 800-1000 miles each way, other then some local trips.

[CHEESE_WAGON]

Almost forgot... Couple more things...

For whatever reason, some of these accessory drives had pulleys with five grooves for the belt drive, some had pulleys with six grooves. Make sure this is matched up, a mismatch will keep chewing the belt, though one way will do this faster than the other.

Also, one other way to verify a factory-air-equipped vehicle is there should be a 'Refrigerant Charge Capacity' decal somewhere under the hood. Most of these tend to be weathered, covered in grime or simply peeled off with heat and age, however. Usually on the radiator/fan shroud on most vehicles, though I've seen a few stuck to the heater / evaporator case. Some may even have it underside of the hood near the evaporative emissions certification decal. Look for 'R-134a', that is the type of refrigerant used in all vehicles from the mid-90s on.

Last but not least, if chancing a swap of a used system from a donor, make sure to scavenge all bolts, clamps, mounting hardware, etc. It may just come in handy.

[CHEESE_WAGON]

Originally Posted by Ronnie

I get 5.75 mpg on average so if it dropped 3mpg to have air that would 2.75 mpg. that would be truelly awful mileage. Really do not think it would change much on a bus. Maybe others who have it can comment on fuel mileage difference with dash air.

My trips tend to be 800-1000 miles each way, other then some local trips.

Keep in mind, going by your profile info, Ronnie, not sure if it's up-to-date...

Carburetor is a factor. Diesels and fuel-injected gassers would no doubt do better. Also consider that you have a smaller-displacement V8 than I've seen in most gasser buses, (smallest I had seen otherwise was a GM 366), and it's a proven rule that smaller engines generally work harder to do the same work, hurting efficiency.

Another factor is simply in how you drive it. Not sure of your rig's top speed, but running it wide-open certainly isn't going to help fuel economy. Granted, a Class 8 road tractor pulling 46,000 lbs of freight and a 14,000-lb skoolie are not quite in the same ball-park, but I observed a minimum of 6.4 mpg running OTR at the rate of 500-600 miles per day. All-time best of 9.8, usually averaged 7- 7.5, sometimes 8. Of course, a 10-speed manual versus a 4-speed manual helps greatly, as does highway gearing.

I've heard it said that every 1 mph over 55 decreases fuel economy 2%. Not sure if that's set in stone, but sounds solid to me based on my experience. My daily driver bests its own EPA rating by as much as 22% because I drive 58 in a 65, 63 in a 70, etc.

I'm sure a 345 with a 4-speed and 4.xx-5.xx differential gearing are doing the best they can, given the circumstances, but that is some seriously bad fuel economy. Sounds like it's time for a tune-up. Also, ever try ethanol free to see if it helped any? Assuming it's available in your area.

[Ronnie]

Well have to say it is in line with what I expect from owning other International trucks with a 345.

I have put fuel injection on it and a good DUI distributor. Top speed not sure but have had it up to 80, and normally run 65-70. As far as speed goes I have driven back roads for a few days at a time, long enough to get fuel mileage readings and find it does not make any measurable difference. Not sure why but that is the way it is. So might as well roll with it. It purrs nicely at 70. I do not think just under 6 is that bad. At least gas is cheaper. Pulling a trailer only knocks it down.25 mpg to 5.5mpg.

A more capable fuel injection other then TBI with a more refined computer would get me better mileage, and I might do something like that in the future.

Mine is 5 speed with 2 speed rear.

[CHEESE_WAGON]

While I'm thinking about it... Another thread I posted some useful air-conditioning info on, "Can I still buy refrigerant?"

Originally Posted by Ronnie

Well have to say it is in line with what I expect from owning other International trucks with a 345.

I have put fuel injection on it and a good DUI distributor. Top speed not sure but have had it up to 80, and normally run 65-70. As far as speed goes I have driven back roads for a few days at a time, long enough to get fuel mileage readings and find it does not make any measurable difference. Not sure why but that is the way it is. So might as well roll with it. It purrs nicely at 70. I do not think just under 6 is that bad. At least gas is cheaper. Pulling a trailer only knocks it down .25 mpg to 5.5mpg.

A more capable fuel injection other then TBI with a more refined computer would get me better mileage, and I might do something like that in the future.

Mine is 5 speed with 2 speed rear.

Yowza! 70-80? Might take all day to get to that speed, but that bus hauls some serious a**! Taking that into account, and a fairly small-displacement engine, 6-ish is pretty respectable. I was expecting more in the neighborhood of 55-60 max. Not sure how the 5+2 setup works, but if it can be shifted on-the-fly (always wondered this), I can imagine that would contribute to some reasonably decent numbers. Hell, my B700 got 6-ish at around 70, but it had a nice, big, torquey 429, with a granny-low 5-speed.

I will say this, sometimes back roads can actually be worse on mileage if there are lots of curves and hills that keep you back and forth between throttle and brakes, even though the speeds are lower... Steady, constant throttle and smooth acceleration is the key. As I said, it's all in how you drive them. I'd say yours is probably about as good as it's going to get without upgrades. However, I have to wonder how it would do at 55-60 vs 70-80...

However... This thread has drifted a bit... Sorry, OP... BTW... I called a local dealer parts department and floated the theoretical of a dealer-equipped kit being available for an '02 3500, they said they didn't really do that sort of thing anymore. Maybe they're on the money, maybe someone somewhere knows something they don't. Just thought I'd pass it along...

[cadillackid]

interestingly enough my dash air does little to affect my fuel economy in my DTA360 Wind and driven speed have a LOT more to do with my MPG.. maybe .5 at most.. and my long trips in summer the compressor may run 100% duty cycle with the evaporators working at full load.. esp in my DEV bus..



going over hilly terrain in. my opinion the A/C is actually more efficient as its energy used for a positive purpose vs having to stab the brakes.. I can definitely tell the A/C is there on downhills.. i fill like I stab the brakes much less than when its off.. again wind has much more effct than A/C on that too..



I poersonally LIKE the idea of a small engine driven system separate because it can be left running usually more economically than leaving the main engine run.. as it is now on those really hot days I let the bus run at a 900 RPM idle when im parked going in for dinner someplace .. im guessing that bigger engine in mid-idle mode probably uses more fuel than a pony engine would running the A/C.. though i dont know for sure..

-Christopher

[alpine44]

Originally Posted by cadillackid

interestingly enough my dash air does little to affect my fuel economy in my DTA360 Wind and driven speed have a LOT more to do with my MPG.. maybe .5 at most.. and my long trips in summer the compressor may run 100% duty cycle with the evaporators working at full load.. esp in my DEV bus..



going over hilly terrain in. my opinion the A/C is actually more efficient as its energy used for a positive purpose vs having to stab the brakes.. I can definitely tell the A/C is there on downhills.. i fill like I stab the brakes much less than when its off.. again wind has much more effct than A/C on that too..



I poersonally LIKE the idea of a small engine driven system separate because it can be left running usually more economically than leaving the main engine run.. as it is now on those really hot days I let the bus run at a 900 RPM idle when im parked going in for dinner someplace .. im guessing that bigger engine in mid-idle mode probably uses more fuel than a pony engine would running the A/C.. though i dont know for sure..

-Christopher

In the OTR trucking industry they make a compelling economic case for APUs that provide cooling and electricity. Granted, their main engines are much bigger and often subject to anti-idling laws.

JoeBlack is working on an pony engine driven A/C system for his converted transit bus and I just got out of my shop tinkering with a battery bank powered system for my much smaller vehicle.

I verified with a window A/C that 5000 BTU cooling from ~500 Watt electric will keep my four legged companions more than comfortable while I run errands.

Just finished the adapter between a brushless DC motor and a variable displacement compressor. Still need to build a driver stage for the PWM control of the compressor displacement valve and the condenser fan motor and write a couple lines of code for the overall system control. Then, I can put the stuff in the vehicle and start testing.

That will also immediately guarantee pleasant temperatures in my neck of the woods - until something breaks.

[CHEESE_WAGON]

Right you are. The only issue with an APU, as I see it, is that most are electronically controlled, and all of them have their issues. Thermo-King's Tripac is the best one out there, but I have seen a motherboard or two fail, which kept it from starting. Also have seen a flaky alternator make one shut down at random for weeks until it was discovered... Either could prove exceedingly frustrating and could mean an expensive trip to a TK service center. Maybe carry a spare alt and control motherboard with you, or cobble together your own control system... After all, it's a 2-cylinder diesel, which means fuel and air, can't be that complicated. At least not until the greenies get DEF and DPF systems slapped on those too...

[alpine44]

Originally Posted by CHEESE_WAGON

Right you are. The only issue with an APU, as I see it, is that most are electronically controlled, and all of them have their issues. Thermo-King's Tripac is the best one out there, but I have seen a motherboard or two fail, which kept it from starting. Also have seen a flaky alternator make one shut down at random for weeks until it was discovered... Either could prove exceedingly frustrating and could mean an expensive trip to a TK service center. Maybe carry a spare alt and control motherboard with you, or cobble together your own control system... After all, it's a 2-cylinder diesel, which means fuel and air, can't be that complicated. At least not until the greenies get DEF and DPF systems slapped on those too...

Yes, the engine is simple but the electric and electronic systems require some complexity to ensure comfort.

The big issue I have with the Thermo King and Webasto APUs is their overall noise level and the incessant cycling of the engine rpm. I dread to be anywhere near these things when trying to get some sleep on a rest area.

Similar issue with the Webasto and Espar cab heaters in my own vehicles. The older ones would start, heat the space up, then drop to low output, which was still too much, and then shut off. Minutes later, restart while wasting precious battery energy for the glow plug. You got to be awfully tired to sleep through this inefficient racket.

After the transistor/relay control module of the Webasto HL32 in my Vanagon broke and the replacement cost turned out to be astronomical, I built my own micro controller that runs the mini furnace from barely staying lit to full power seamlessly. Instead of cycling and restarts, the amount of combustion air and fuel is adjusted to the actual heat loss of the vehicle. I also fixed the issue of excessive smoke from the heater in certain conditions by making the air/fuel ratio altitude dependent and for the ignition phase also temperature dependent.

I think it took Espar another decade to offer this in their more expensive heaters. In other words, for the prices of these products, the customer could expect a little more state of the art technology IMO.

I do not mind sophisticated electronics if I roll my own, because I am the resident expert and can get to the cause of a problem faster than any expensive service tech. I also know that the purchased components were selected for low cost and good availability. That reasoning applies to the whole idea of building my own RV. DIY, do it right, and don't build anything from Unobtainium.

[junkyardroad]

Originally Posted by Danjo

Do you have the AC dials on the dash?

I do not, however the controls are available for about $150. I have installed ~8 Vintage Air units in old cars and have a pretty good idea of how it all works. I'm on the fence about trying to add oem a/c to a non equipped model or just going all after market.. I tend to lean toward factory unless the underdash box is different. There are very few junkyards around here anymore.

[Ronnie]

More states are getting into the 5 minute idling law, so a genset running a/c is becoming more common. I too do not like hearing them run when we are in truck stops. Would rather hear the truck engine run. I do think the RV gensets are a little quieter and easyer to bear when sleeping.

Since we generally avoid( but not all the time) the desert southwest in summer, we normally turn off the a/c and genny just before going to bed and open windows. Usually cool enough to be comfortable with some fans blowing on us.

Will have to say having the a/c run off the generator is nice when we stop for lunch or dinner to keep the air going while we cook and eat, without running the bus engine.

A pony driven compressor sounds good if a/c is the only goal. However I want backup power for my solar panels. Although so far they have done everything I have needed.

Something else I have found for a/c in a vehicle that does not have it's own system is an electric compressor meant for electric cars. These are about $500. I do not know what capacity they are. Or how much 12 volt current they need, other voltages are available too. Being that they are meant for a car you would most likely need to put a curtain or wall behind the driving area to keep cool. So just tossing this idea out there without really knowing the viability of it.

[CHEESE_WAGON]

Originally Posted by junkyardroad

I do not, however the controls are available for about $150. I have installed ~8 Vintage Air units in old cars and have a pretty good idea of how it all works. I'm on the fence about trying to add oem a/c to a non equipped model or just going all after market.. I tend to lean toward factory unless the underdash box is different. There are very few junkyards around here anymore.

Don't waste your time, then. Unless you can verify the other components are, in fact, there, which would mean the control head was replaced by someone who wasn't paying attention (not likely, these don't go bad often). Vintage Air MAY have a solution for you, but otherwise it's likely a fool's errand.

Reason being that an A/C-equipped vehicle control head sends a signal to the ECM / PCM to tell it A/C is needed. The PCM subsequently sends its own signal to the A/C compressor clutch relay and high-pressure / low-pressure cutout switches to control the compressor. It also adjusts the Idle Air Control Valve to prevent stalling with the extra load.

Chances are, the wiring for the non-equipped control head is different and will not have the extra wire for this signal. Trust me, if it did not have factory A/C, you are likely p*ssing in the wind trying to make it so. You'll be having to not only wire for the head control signal to the PCM, but all the outputs from the PCM, not to mention a heavy-duty 25-30A relay for the compressor clutch. Not saying it's impossible, but it's not likely this will be smooth sailing.

Being that it is a bus, you'll be much better off installing an underbody unit with standalone controls, or perhaps your own home-brewed system using an APU or generator.

[CHEESE_WAGON]

Originally Posted by Ronnie

More states are getting into the 5 minute idling law, so a genset running a/c is becoming more common. I too do not like hearing them run when we are in truck stops. Would rather hear the truck engine run. I do think the RV gensets are a little quieter and easyer to bear when sleeping.

Something else I have found for a/c in a vehicle that does not have it's own system is an electric compressor meant for electric cars. These are about $500. I do not know what capacity they are. Or how much 12 volt current they need, other voltages are available too. Being that they are meant for a car you would most likely need to put a curtain or wall behind the driving area to keep cool. So just tossing this idea out there without really knowing the viability of it.

Unfortunately, the relatively small size of the APU engines, and the fact that they are twin-cylinder, they are notorious for vibration at low RPM and need at least slightly raised RPM in order to run smooth, possibly to even stay running. Also keep in mind that these are spinning a generator used to power an electric compressor (similar to what is outlined in the second part of your post), and the generator, too, needs RPM to do its job.

The electric car setup is probably similar, if not the same thing as the HVAC used with APU setups. When you get right down to it, a refrigerator is as well. Most refrigeration units, are, in fact, electric-powered. APU's and gensets are simply there to provide the power. Automotive systems are engine-driven simply because it is more convenient to the application, and saves weight. I drove refrigerated freight for awhile, and through checking over the reefer units on the trailers, some were set up like a genset / APU, some were set up to drive their compressor directly via its small engine.

The key is what sort of voltage is required. Some use 110VAC, some use 220VAC, some 240VAC, some 12, 24, or 48VDC. If attempting a swap, you definitely don't want to mismatch voltage output vs requirements.

One other thing -- Freightliner Cascadias have been increasingly using an ENTIRELY electric APU (meaning it has its own separate battery bank instead of a generator), the system is marketed under the name ParkSmart -- it is a Freightliner exclusive AFAIK. It might sound like a good idea to swap one of these, but they're sort of like Lucas-Girling brake systems -- they work great, until they don't.

Nothing wrong with an electric compressor, that's the way many have been done for years, but I would power it with some sort of generator. I know someone who has been chasing problems with a ParkSmart for a couple years now. It's supposed to stay on for about 10 hrs, but hasn't run for over 5 hrs at a time for nearly three years now. Naturally, no one can figure out why.

I had one of these myself that completely quit about two weeks after I got in the truck, and after nine hours in a dealership service waiting area, I was told that a harness installed at the factory was incorrect and not allowing the chassis engine to recharge the batteries...

[cadillackid]

I beg to differ on the wiring.. on a van chassis the factory wiring is often there as most come standard with A/C asnd are ordered wit hthe A/C DELETE option on the order form.. the controls are different, the evaporator box may be different and the PCM will have A/C Delete programmed in so as to not throw a code when missing the AC compressor clutch resistence check..

older vehicles definitely had none ofthe equipment.. but newer vehicles often do... i dont know about the OP's van specifically..

as ive mentioned before adding A/C is tough if the van was built without it. remember im the guy that adds A/C to EVERYTHING I drive if it doesnt have it..



going to a junkyard and looking for factory parts is the best solution.. but before you head off with the toolbag do research and purchase the real and correct wiring diagrams and service manual info for the vehicle you are working with... you can learn a lot about what is present and what isnt by studying the diagrams and then investigating in your dash and under the hood..



sometimes the after-market A/C companies Hack up the factory wiring to use for their own use so they dont have to run new... and that makes things more difficult.. this is a project I myself wouldnt hesitate to take on if I wanted A/C, however if you arent familiar with adding options to a moder nvehicle that never had them then be carewful and do lots of homework first...



Alpine has it right with electronics.. I love building my own because I know how to fix it WHEN it breaks... and stuff will break.. my home HVAC system is a pretty elaborate Zoned system I built back in 2009 using customized minisplits, zone dampers, a central variable speed blower and central midulating gas furnace (for the cold months).. I hacked the minisplit comms protocol and built my own interface boards and wrote all the software.. the result is I have spare boards.. and also have all socketed IC's, and lots of diagnostics if something goes wrong..



my red bus Glass-cockpit project is going the same way, build my own boards and write my own software..

as for variable displacement compressors, ive thought about utilizing one, however I like the large capacities of the Sanden SD7HD15 enhanced.. (its rated a little over 11 KW at rated speed.. however it puts out quite a bit more than that )..

why not run a TxV with a near 0 minimum? if your condenser is sized correctly you'll just flood the coil with liquid when the TxV goes to its near zero setting.. it doesnt run up the head pressure...



Joe's system has a TxV although I think he plans to vary the sopeed of the engine which sounds like annoys alpine..

yeah alpine has the right idea.



APUs - I cant figure out why they havent been able to tackle the noise aspect yet.. maybe they dont care because they are designed for Semi trucks and not campgrounds..



the quiet and efficient route is electric inverter A/C.. while demetic doesnt sell their inverter units here in the USA.. LG I believe is selling window A/Cs with inverter technologoly, so they vary their speed and have no hard-start like a traditional window unit.. yeah the yhave electronics.. but thus far it seems like things have gotten better with the inverter A/Cs when it comes to boards i nthe last few years.. my original install of my minisplits at home in 09 resulted in if anything impeded the outdoor fan it would burn up the MOSFETs on the board.. so first winter out of the box we had a blizzard and then it warmed up and my outdoor units came on when the system switched to heatpump and burned up the MOSFETS on 2 units.. the manufacturer never thought of snow.. so they made bnew boards and sent me 3 brand new units.. by then I learned how to fix and improve the original boards.. I dont hear about near as many issues with the electronics on these as I did for awhile..



anyway maybe the solution for Noise of APU is to be able to run battery at night when sleeping (and cooling load is less).
-Christopher

[junkyardroad]

I am going to add a\c to the dash one way or another. Ill pull the dash apart to see if it has the wiring in the factory pigtail for the oem switch. My biggest obstacle is finding out if the airbox is different and maybe reflashing the ecu?

I'm very familiar with automotive wiring, so that part I easy. Mine is a 1999 GMC 3500 Minibird BTW.

[Kubla]

There is only so much sound insulation you can put in a unit when weight is an issue, which also covers the size of the muffler you can use on your single cylinder diesel. To be truly effective, the muffler would weigh over 50 pounds itself. If the units were made for RV's where you could have a unit that weighs 200 pounds more, they could be much quieter

[Danjo]

All this AC talk and looking at my bus, and Christopher’s post about thinking twice has led me to conclude that I should keep my AC. I was going to use the evaporator space for a black tank. I guess I’m going with the cassette toilet.

[Ronnie]

Originally Posted by Danjo

All this AC talk and looking at my bus, and Christopher’s post about thinking twice has led me to conclude that I should keep my AC. I was going to use the evaporator space for a black tank. I guess I’m going with the cassette toilet.

Good idea, yes by all means much better to have it and keep it.

[TheArgobus]

Just to add another data point, after I pulled out my rear AC, and brought it in to a shop to get the dash air working, as the controls didn't do anything. They looked at it and I don't remember exactly what the situation was up front, but they said they'd basically have to rebuild the dash air system from scratch and would be $2300. Seeing as how I paid $2500 for the bus, I opted to go with no AC for the time being. Driving around in 100F weather, the windows work just fine. I'd like to add a small window unit and perhaps a generator, but that's pretty low on my priorities. The only other thing I really want to add is a defroster heater/fan on top of the dash.

[Sharee100]

I also have a Chevy Express 3500. I took it out for its maiden voyage this week. AC would not work. Discovered it had no freon. It took 5 lbs of freon. I don't know what that means. It works for about 10 minutes then no cool air. After about 15 minute of no ac I can turn it back on for about 10 minutes again. Needless to say this cut my trip short. My son said he let the freon out when he was replacing some parts on the ac system. He says there are no holes or cracks.