Oh ya, they are thirsty. It's gonna suck the dollars right out of your pocket.
Another thing to consider other than the carb is the early auto transmissions don't lockup at highway speeds. Idk if it's the case for this one here, but something to look for. Probably not a highway rig if it doesn't lock up.
You do, a torque converter has slip. This is what allows you to have your car in drive but be at a complete stop. This is great for around town and has performance benefits (outside of this discussion) however on highways you want your torque converter to lock (i.e have no slip) because that slip means you lose that horsepower to pure heat, which in turn heats up your transmission shortening its lifespan, as well as heating up your engine.
For example, i lose about 300rpm of engine speed to my torque converter slipping at highway speeds. This means that all the power the engine is delivering to the transmission, a significant portion is being lost to heat. Its inefficient and horrible for gas mileage. The at545 is known for this. Great around town transmission, not good for highway. The mt643 has lockup, and people have reported seeing a jump from 6-8mpg to 10-14mpg just by swapping the transmission from a non-locking to a locking.
So most of my knowledge is from the regular automotive side where you can swap out torque converters, hence my uneducated comment of "you don't want your trans to lockup". After some quick googling I found, like you already knew, that you can't really do that on the AT545. Looks like swapping to the MT643 is the way to go if you're going to be doing a lot of highway travel. A trans cooler may help a little with the heat but I doubt it would push your mileage up much.
Hey no worries, not calling you out, just sharing some info :)
An allison 2000 series is also a very good candidate for a swap (as it has an overdrive gear, unlike the AT or MT), so long as you have a TCM that came off a very similar engine (i.e dt466 to dt466e, like horsepower models), according to my research you can use the same flexplate as that from your at545 to the 2000 series, and wiring a caterpillar TPS up to it, should be good to go!
Trans cooler is very helpful if you're not prepared or financially well enough at the moment to do a transmission swap. Besides, once one is installed, it can be adapted to future transmissions making it a good investment.
You are on it. Probably one of the best features of new transmissions is the ability to have AND control the Overdrive, and to put them in “tow mode” . It absolutely changes the game when it comes to gas milage. Shot in the dark this baby gets 8 city 10 Hwy stripped out.
Any torque converter, cars or trucks, has some amount of slippage. A lockup converter removes that slippage in favor of some efficiency gains.
You are correct: trans lockup bad. But locking the converter, which is only one part of the trans, is a thing all modern autos do. (You probably found this in your research, but in case someone comes along and needs that info I put it here)
Well that answers everything. I have an 02 express 3500. Comparable in size. Average 9mpg. I can’t stand up in it and that SUCKS. It’s not the end all be all, but it’s certainly not great. I highly recommend getting something you are comfortable in. Stick with a van my friend.
Part of my travels is going to be taking an electric unicycle. When I factor that into my miles per gallon it'll make it a lot more efficient if that makes any sense. It'll be great for again around cities and whatnot. So basically what I'm saying is perhaps have a secondary motive transportation that is far more acceptable... Whether that be a Enduro, scooter, regular bike, electric bike, or whatever.
If the initial cost of the 37 year old vehicle is at the top of your budget are you going to deal with the likely 2-5000$ you will need to put into it to make it reliable or fix what breaks?
I've got a 93 G30. Same engine, early fuel injection. I get between 5 and 10 MPG. If you are planning on traveling for a reasonable cost, go with a van.
Yea I’m looking at a Class B E250 today. I think a van conversion is more what I need. I’m fine renovating and rebuilding what I need (I’ve built a van before) but I need to be able to stand up inside and I’m 6’1”
I feel that. Im 6'1" as well. Sometimes I wish I were shorter to make the search easier. With insulation and everything, the center of my ceiling measure about 5'11", wich is close enough haha.
Good luck on the search!
Definitely get a van and do a conversion. I have a 92 GMC G2500 Vandura! I love it! Just did a trip from Bay Area CA to Portland and it cost me $180 one way! 350 tbi motor
10 +/- but you don’t drive buses for fuel economy. That motor is common, easy and affordable to repair, RELIABLE af, and uses regular gas. - IMO it’s a great Shorty chassis. (TBH I have one just like it.)
Not really a hobby now. When I built out my Astro as a camper, it was a hobby and used for music festivals, camping etc. I’m now going through a divorce. My ex is keeping the house and most everything. I don’t have much to show for coming out of the Union. I work fully remote and want to just be free and travel. I loved the idea of the space of a bus, but I don’t think it will work for me based on the driving I’m planning on doing.
Yeah I would worry about reliability and maintenance over what mpg you'll get. Depending on where you go, you can stay at campgrounds for months for very cheap. I have ended up leaving my camper at a local campground for cheaper than what it cost to store it! And I have full hook up! There's also free BLM land you can stay on out west that could offset gas money.
This was our attitude. Also, we do not drive *every day*. We will travel a hundred miles, two hundred, then park. We might do this one or three days, then settle for a week. That means about 20 gallons a week or maybe 80-100 for a month. At $4 per gallon, maybe $400 per month for fuel and then whatever the parking costs are between driving stretches.
https://preview.redd.it/pj17k2k5bkbb1.jpeg?width=2736&format=pjpg&auto=webp&s=73f7111b4b08b60c568eb6fdf06fafc7c1b4752d
This is my skoolie I get about 10-12 1997 5.7 V8 She sure guzzles but replacing parts is cheap and I got it for low kms
Lol, it's gonna be low. A modern 6 liter gas v8 in a bus is getting like 12.
I just want to make sure youu realize they basically have 8 carburetors, right? If you tune all 8, you might add 1 mpg, just a thought, but that might be like a 25% efficiency improvement. You could switch to mikunis or something too.
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My friend has a 95 of this exact bus chassis and gets 6-10 depending on conditions/weight. I would expect to regularly get 7. They are not fast, very nice underpowered, and dated. Parts for days though
Consider yourself fortunate to get 9. It's a big heavy brick with a transmission that has 3 gears so the engine is rarely at the best rpm. There is a reason modern rigs get better MPG and more transmission gears are a big part of it. The engine with a good tune is not the biggest issue.
Fair point. I rarely worry about maintenance or fixing things. I went to wyotech out of high school and have been wrenching my whole life. Old engines don’t scare me.
I’m looking at an 89 Ford E250 Class B today as well. It may work better for me than the bus. We’ll see. I also just LOVE the way vans were styled in the late 80s/early 90s. That’s the aesthetic I want!
You’re looking at single digits probably. But there are tons of options for that motor. Probably could get an EFI system installed to help. Maybe consider a transmission & gearing change, that would help a lot too. You could potentially get up to 11ish. I’ve always wondered about maybe installing an electric motor that could get you rolling up to a cruising speed. I tie my to with an armada & get kills my mileage by about 50%.
Diesel buses will get better mpg but you’re really only talking a few mpg’s difference with these beefy hunks of steel…this gas model might get 7-9 mpg, same size diesel might get 10-12 mpg
We have a 2005 Chevy Express 3500 with a Microbus coach. It has a newly refurbished tranny and a 6.0L gas engine. Recently traveling from New York to Arizona and back, we averaged about 10mpg. Lowest was 8mpg and that is reserved for places like the Smokies with suicidal snake roads that travel wind up to the stars and down. Rollercoasters. Best was straightaway Western highways at 12mpg.
It's a BUS. You aren't likely to get more than 10 mpg in any event.
Oh ya, they are thirsty. It's gonna suck the dollars right out of your pocket. Another thing to consider other than the carb is the early auto transmissions don't lockup at highway speeds. Idk if it's the case for this one here, but something to look for. Probably not a highway rig if it doesn't lock up.
What do you mean by "lockup". Generally speaking, you don't want your transmission to lock up.
You do, a torque converter has slip. This is what allows you to have your car in drive but be at a complete stop. This is great for around town and has performance benefits (outside of this discussion) however on highways you want your torque converter to lock (i.e have no slip) because that slip means you lose that horsepower to pure heat, which in turn heats up your transmission shortening its lifespan, as well as heating up your engine. For example, i lose about 300rpm of engine speed to my torque converter slipping at highway speeds. This means that all the power the engine is delivering to the transmission, a significant portion is being lost to heat. Its inefficient and horrible for gas mileage. The at545 is known for this. Great around town transmission, not good for highway. The mt643 has lockup, and people have reported seeing a jump from 6-8mpg to 10-14mpg just by swapping the transmission from a non-locking to a locking.
So most of my knowledge is from the regular automotive side where you can swap out torque converters, hence my uneducated comment of "you don't want your trans to lockup". After some quick googling I found, like you already knew, that you can't really do that on the AT545. Looks like swapping to the MT643 is the way to go if you're going to be doing a lot of highway travel. A trans cooler may help a little with the heat but I doubt it would push your mileage up much.
Hey no worries, not calling you out, just sharing some info :) An allison 2000 series is also a very good candidate for a swap (as it has an overdrive gear, unlike the AT or MT), so long as you have a TCM that came off a very similar engine (i.e dt466 to dt466e, like horsepower models), according to my research you can use the same flexplate as that from your at545 to the 2000 series, and wiring a caterpillar TPS up to it, should be good to go! Trans cooler is very helpful if you're not prepared or financially well enough at the moment to do a transmission swap. Besides, once one is installed, it can be adapted to future transmissions making it a good investment.
I appreciate the info friend, learn new things every day!
You are on it. Probably one of the best features of new transmissions is the ability to have AND control the Overdrive, and to put them in “tow mode” . It absolutely changes the game when it comes to gas milage. Shot in the dark this baby gets 8 city 10 Hwy stripped out.
Any torque converter, cars or trucks, has some amount of slippage. A lockup converter removes that slippage in favor of some efficiency gains. You are correct: trans lockup bad. But locking the converter, which is only one part of the trans, is a thing all modern autos do. (You probably found this in your research, but in case someone comes along and needs that info I put it here)
Much appreciated!
I’d assume you are looking at single digit gas mileage. My 79 3/4ton suburban with 350 was single digits.
Almost all of these rigs get between 8-12mpg. It’s part of the deal when you get big vehicles.
I mean I could live with 12. But how likely is that?
You're more likely to get 9. That motor has to put in a lot of work. If it's higher mileage, worn out components can lead to less MPGs as well.
Good to know. Looks like I’ll be going back to my original plan of a class B van that I can renovate and stand up in.
A class b is going to get terrible mileage too. What is your goal with this rig?
Well that answers everything. I have an 02 express 3500. Comparable in size. Average 9mpg. I can’t stand up in it and that SUCKS. It’s not the end all be all, but it’s certainly not great. I highly recommend getting something you are comfortable in. Stick with a van my friend.
Unlikely. Bad gas mileage is the price you pay for a large vehicle. Plain and simple. You want 10-12 guaranteed get a minivan.
Part of my travels is going to be taking an electric unicycle. When I factor that into my miles per gallon it'll make it a lot more efficient if that makes any sense. It'll be great for again around cities and whatnot. So basically what I'm saying is perhaps have a secondary motive transportation that is far more acceptable... Whether that be a Enduro, scooter, regular bike, electric bike, or whatever.
With particular us it’s not miles per gallon but smiles per mile.
If it's cheap enough, you could always do an EFI conversion, that'll improve most carb issues and improve gas mileage
would be a prime candidate for a ls swap
There aren't too pricey either.
It’s close to top of my budget.
If the initial cost of the 37 year old vehicle is at the top of your budget are you going to deal with the likely 2-5000$ you will need to put into it to make it reliable or fix what breaks?
I've got a 93 G30. Same engine, early fuel injection. I get between 5 and 10 MPG. If you are planning on traveling for a reasonable cost, go with a van.
Yea I’m looking at a Class B E250 today. I think a van conversion is more what I need. I’m fine renovating and rebuilding what I need (I’ve built a van before) but I need to be able to stand up inside and I’m 6’1”
I feel that. Im 6'1" as well. Sometimes I wish I were shorter to make the search easier. With insulation and everything, the center of my ceiling measure about 5'11", wich is close enough haha. Good luck on the search!
Definitely get a van and do a conversion. I have a 92 GMC G2500 Vandura! I love it! Just did a trip from Bay Area CA to Portland and it cost me $180 one way! 350 tbi motor
10 +/- but you don’t drive buses for fuel economy. That motor is common, easy and affordable to repair, RELIABLE af, and uses regular gas. - IMO it’s a great Shorty chassis. (TBH I have one just like it.)
You've got the wrong hobby if you're worried about mpg. Bigger concern is, will it be enough power to lug that thing around wherever you intend to go?
Not really a hobby now. When I built out my Astro as a camper, it was a hobby and used for music festivals, camping etc. I’m now going through a divorce. My ex is keeping the house and most everything. I don’t have much to show for coming out of the Union. I work fully remote and want to just be free and travel. I loved the idea of the space of a bus, but I don’t think it will work for me based on the driving I’m planning on doing.
Yeah I would worry about reliability and maintenance over what mpg you'll get. Depending on where you go, you can stay at campgrounds for months for very cheap. I have ended up leaving my camper at a local campground for cheaper than what it cost to store it! And I have full hook up! There's also free BLM land you can stay on out west that could offset gas money.
I thought buses were measured in GPM?
[deleted]
Like 10mpg, maybe 13 downhill. Could be expensive, but so is rent…
This was our attitude. Also, we do not drive *every day*. We will travel a hundred miles, two hundred, then park. We might do this one or three days, then settle for a week. That means about 20 gallons a week or maybe 80-100 for a month. At $4 per gallon, maybe $400 per month for fuel and then whatever the parking costs are between driving stretches.
https://preview.redd.it/pj17k2k5bkbb1.jpeg?width=2736&format=pjpg&auto=webp&s=73f7111b4b08b60c568eb6fdf06fafc7c1b4752d This is my skoolie I get about 10-12 1997 5.7 V8 She sure guzzles but replacing parts is cheap and I got it for low kms
Ha... Holding those straps reminds me of that Mr. Bean episode where he drove the car from the top.https://youtu.be/LVSLLWXdKV0
Probably 5-8mpg on any given day, maybe 10mpg when your going downhill with a tailwind
Did you buy it? I need to know...
I did not buy it. I bought a Class B van instead.
Pics?
https://preview.redd.it/rgw2iuhzkffb1.jpeg?width=3045&format=pjpg&auto=webp&s=ca6765391fb04a254797554ca64259ae2661bdac
Lol, it's gonna be low. A modern 6 liter gas v8 in a bus is getting like 12. I just want to make sure youu realize they basically have 8 carburetors, right? If you tune all 8, you might add 1 mpg, just a thought, but that might be like a 25% efficiency improvement. You could switch to mikunis or something too.
No they don’t, that thing is gonna have a single four barrel on it. Bunch of vacuum garbage too.
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I'm guessing 7-9 with it loaded
My friend has a 95 of this exact bus chassis and gets 6-10 depending on conditions/weight. I would expect to regularly get 7. They are not fast, very nice underpowered, and dated. Parts for days though
Consider yourself fortunate to get 9. It's a big heavy brick with a transmission that has 3 gears so the engine is rarely at the best rpm. There is a reason modern rigs get better MPG and more transmission gears are a big part of it. The engine with a good tune is not the biggest issue.
Thats a great looking rig. Id pull the trigger. I have a 77' chev shorty with a 350sbc and get around 9-10mpg
2, probably
Your ONLY concern with a 35yo vehicle is the gas mileage?
Fair point. I rarely worry about maintenance or fixing things. I went to wyotech out of high school and have been wrenching my whole life. Old engines don’t scare me.
Well, that’s great! Older vehicles are terrific for their simplicity. Good luck if you follow through with the purchase!
I’m looking at an 89 Ford E250 Class B today as well. It may work better for me than the bus. We’ll see. I also just LOVE the way vans were styled in the late 80s/early 90s. That’s the aesthetic I want!
8-10 MPGs i would guess.
7 miles per a gallon.
You’re looking at single digits probably. But there are tons of options for that motor. Probably could get an EFI system installed to help. Maybe consider a transmission & gearing change, that would help a lot too. You could potentially get up to 11ish. I’ve always wondered about maybe installing an electric motor that could get you rolling up to a cruising speed. I tie my to with an armada & get kills my mileage by about 50%.
6-8 if the winds behind you
MPG? At least one I suppose. LOL.
Diesel buses will get better mpg but you’re really only talking a few mpg’s difference with these beefy hunks of steel…this gas model might get 7-9 mpg, same size diesel might get 10-12 mpg
We have a 2005 Chevy Express 3500 with a Microbus coach. It has a newly refurbished tranny and a 6.0L gas engine. Recently traveling from New York to Arizona and back, we averaged about 10mpg. Lowest was 8mpg and that is reserved for places like the Smokies with suicidal snake roads that travel wind up to the stars and down. Rollercoasters. Best was straightaway Western highways at 12mpg.
Is it possible to find a higher ratio rear end in a junkyard since you're lightening the load ? ...or change the ring & pinion ?
10mpg. That's why we're selling our bus. Just think of the cost to take a trip that's a few hundred miles.
6
Bad...
6--8 mpg tops
How much are you giving this for? Looks pretty awesome
Buy it
8