6bt w/ at545 upgrade?

[EastCoastCB]

Originally Posted by dalez

You're probably right

But I bet I can turn up that 6bt to more HP than my stock 84 dt466 (185hp) as long as I can cram in a gearbox that can handle that!

Huge downgrade on the engine and trans? man I'd cut the ass end off my bus to make it the length you're after before I'd give up the good drivetrain.

[dalez]

Originally Posted by EastCoastCB

the 380k miles would scare me off. I wonder how many 545's it takes a bus to even get to that mileage.

On that note... I just reviewed the pictures I took and realized that the speedo/odo gauge doesnt match the others exactly... and the hour meter, which does, only shows ~3500 hours. Unless that bus regularly drove 110mph, something is off here. I think the fleet operator replaced a broken odo with one from a junk bus with lots more miles... If the original looking hour meter (which matches all the other gauges) is correct it's almost certainly under 200k, probably towards 150k... which explains the fairly ungreasey engine, decent body, etc...

A test drive will tell as to the condition of the 545... guy finally got the tire back on the rim and discovered the valve core was bad, so I can test drive it this weekend!

[dalez]

Pic of dash:

[magnakansas]

The only way my bus, gets to 60 mph is down hill. 1994 bluebird tc2000, 6bta 545 transmission, 10r22.5 tires, 4.33 gear ratio. 16,000 lbs. lowest fuel mileage 8.4, best mileage 12.5 mpg

Word is a 1000 series/ 2000 series will plug into the same hole as the 545. See the article by Cadillackid on his bus “redbyrd”

My plan is to copy his route, except that I intend a 2400 or 2500 transmission.

I will purchase TCU and programming help from Jason at transmissiontuner.com - at least I think that is the place.

I expect to have to shorten the driveshaft and do a speedometer change, my Speedo is mechanical and I will have to go to eletronic.

I think the wire harness and tuning will take the most time.

William

[dalez]

Welp, the guy came WAY down on the price, took it home at 5500$. The rear tires are brand new (recaps) with paperwork and will sell nice on my old bus... It only goes 60 on the flat, so right on the money for the gearing and 2500rpm redline. The converter is "tight", it doesnt take much throttle to get it to start rolling unlike other at545 buses I tested. Probably just less worn out? I could detect no faults with the operation of the transmission or engine. Very very light puffing of smoke from the 6bt's oil fill cap, considerably less than my dt466 that supposedly has half the miles. Exhaust was clean, even at smashed pedal takeoff with unspooled turbo.

Now I need to price out one of those nice CAC Allison 2400 upgraded rebuilts with a programmable TCU... need to get cadillackid on this thread

[dalez]

I found controls labeled "Trans/Air" that seem to control the AC unit over the driver's head... but I cant find any that do anything for the AC unit in the rear. Any bluebirb owners got any hints for me?

Also there's a hole in the control panel w/ all the light/fan/etc controls that has a light inside that stays on all the time, except when I turn off the battery disconnect. No label on it. Upper left side.

[Oldyeller]

Congrats on the new bus.

[cadillackid]

is there 2 sets of Trans/AIR switches on the dash? and only one does something?



if a Transair system leajks its freon out then not even the inside fans will function.. the red ps light comes on (if you have the EM1 control)and the A/C wont run at all..


it could be that they wired both systems to one set of switches.



transair is still in business and is considered factory A/C for bluebirds for a long time.. you can contacxt them with your VIN and they will have all the info for your Air conditioners.. ie how many systems, compressors, switches, wiring diagrams, etc..



I got a whole bunch of stuff from the on my red bus.. my A/C was lackluster when i got the redbyrd. after replacing a fan, flushing and properly recharging it and some new relays. it cools like a champ..

[dalez]

Hello!

One set of switches that I could find, pictured below. When turned on, the red P/S light does come on, and the fan over the driver's head does... stuff. It acts like either the bearings are very sticky, the brushes are worn out, or the switch itself is making poor contact. It would intermittantly speed up to what seemed close to it's proper speed, although I dont know what it SHOULD sound like, but a lot of the time it was barely turning over. I fiddled with it about 5 minutes (pouring sweat) and was unable to determine definitively which. The air coming out WAS slightly cooled vs the inside air temp, but far from cold.

Thanks for the heads up about contacting Trans Air, will be doing so!

[dalez]

Also, the 'main control panel' - note the obviously not stock "engine SOMETHING" switch I havent fiddled with yet, and the hole/indicator light in the upper right side that stays perpetually on as long as the battery is connected.

[dalez]

Figured out the "engine *something*" switch is the fan clutch.... That's interesting. Wonder if the coolant temp switch failed and this was their "fix"

Still no idea what the mystery always on indicator is.

[Oldyeller]

Originally Posted by dalez

Figured out the "engine *something*" switch is the fan clutch.... That's interesting. Wonder if the coolant temp switch failed and this was their "fix"

Still no idea what the mystery always on indicator is.

Hmmm, I was thinking it might control a flux capacitor. That would have meant the bus could do 88 mph.

[dalez]

Originally Posted by Oldyeller

Hmmm, I was thinking it might control a flux capacitor. That would have meant the bus could do 88 mph.

I'm sure it can if I find a sufficiently tall cliff

[La Camioneta]

Word is a 1000 series/ 2000 series will plug into the same hole as the 545. See the article by Cadillackid on his bus “redbyrd”

My plan is to copy his route, except that I intend a 2400 or 2500 transmission.

I will purchase TCU and programming help from Jason at transmissiontuner.com - at least I think that is the place.

I expect to have to shorten the driveshaft and do a speedometer change, my Speedo is mechanical and I will have to go to eletronic.

I think the wire harness and tuning will take the most time.

William[/QUOTE]

I'm doing the 5.9 swap from at545 to at1000. Hopefully the shop its at can handle it. Scored a 1000 w TCM and takeout harness really reasonably from a guy that deals busses in GA.

They come from his 6.0 PSD busses he parts and scraps due to the engine undesirability.

PM for his contact info.

[Dirtdoctor]

Stay with what you have. 545 is NOT an upgrade. Pulling a trailer will be the end of it. But then you can replace
It with something bigger
One of
My trucks has the 545 and its a really weak trans for pulling a load.
Cheers

[dalez]

Originally Posted by Dirtdoctor

Stay with what you have. 545 is NOT an upgrade. Pulling a trailer will be the end of it. But then you can replace
It with something bigger
One of
My trucks has the 545 and its a really weak trans for pulling a load.
Cheers

What I have is a at545. I want to upgrade from it to an Allison 2400.

[Free Bird]

Everybody on this forum has been giving great advice but I particularly like Old Yeller's line.
"Just be sure to wave goodbye to that DT466 and the 643 as they leave, you'll probably miss them. :big grin:"
-----------------------------

Now that you've gone and done it here's my two bits worth.

-Don't sell the 466 until you're happy with the Cummins.

-Sounds like your AT545 is working good so test drive the bus just like it is for now. Changing the transmission is unlikely to have any effect on fuel mileage. (The 545 is not a long term solution but it saves the engine from abuse, the engine will run at optimum rpm for the load)

-Hook up your trailer and go for a good drive.

-Record fuel mileage, temp and speed.

-Switch buses, repeat.

At this point the writing should be on the wall but if you still want to juice up your engine go ahead, just be certain to install a nice big EGT guage up by the windshield.

[dalez]

Originally Posted by Free Bird

Everybody on this forum has been giving great advice but I particularly like Old Yeller's line.
"Just be sure to wave goodbye to that DT466 and the 643 as they leave, you'll probably miss them. :big grin:"
-----------------------------

Now that you've gone and done it here's my two bits worth.

-Don't sell the 466 until you're happy with the Cummins.

-Sounds like your AT545 is working good so test drive the bus just like it is for now. Changing the transmission is unlikely to have any effect on fuel mileage. (The 545 is not a long term solution but it saves the engine from abuse, the engine will run at optimum rpm for the load)

-Hook up your trailer and go for a good drive.

-Record fuel mileage, temp and speed.

-Switch buses, repeat.

At this point the writing should be on the wall but if you still want to juice up your engine go ahead, just be certain to install a nice big EGT guage up by the windshield.

You make good points, but some circumstances prevent me from doing that. The old trailer suffered 3 of the 4 tires having belts separate whilst sitting in my driveway, and i dont intend to replace them as it's going to be repurposed as a shed. There is a new trailer in the works, which I intended on being longer than the current trailer - too long to tow legally behind the old big bus w/o an oversize load permit.

You dont think running the engine closer to it's torque peak at cruise, with a locked converter, will help highway fuel economy? Or is it that you dont think I'll have the HP near the torque peak to maintain 55-60 under such loads and it'll have to run in a lower gear anyways?

EGT gauge at the very least is a given before touching anything, and EGT will be tested pulling the intended load under the intended conditions BEFORE touching the fuel to get a baseline.

My partner loves the new bus, a lot more than she liked the old one, so I'm stuck with it and need to make it work :P

[cadillackid]

When I blew the 545 in my dt360 I replaced it with a 643, I gained a solid 1.5 to 2 MPG over the 545… my fan almost never kicks on high where with the 545 it ran all the time in hot weather using more fuel..

I’m not making heat I’m making power.. I’m almost never running up against my dev limiter because with the lockup I don’t need to floor it as much..

My 545 in that bus was a pretty tight one too.. it worked perfectly till one day it spun a pump bearing and broke.. no warning just snap and neutral ..

[magnakansas]

air speed over the vehicle......

engine rpm

friction losses

the air speed and drag of the vehicle is significant... if you can run the engine and the transmission in the most "efficient" mode... the lower air speed will prevail.

If you have a 20 mph tail wind, you might be able to run at a higher engine rpm and still gain fuel mileage. just like with a head wind, you "MIGHT" gain fuel economy if you run in a lower gear and at a lower air speed.

real world test is the way to find this out. testing takes time.

engine rpm, lower rpm in most cases will gain mileage, until you bring the rpm down so low that there is not enough torque to maintain. also in the case of a diesel - you can put too much heat into the exhaust and/or lug the engine down to the point of detonation. This part of what happens when you "lug" a diesel... some gasoline engines too.

The lower rpm thing is why bmw had the 528e, in the late 1980's

some transmissions have the lowest friction losses in direct drive, other transmissions have the lowest friction losses in some gear other than direct drive. I expect you could find this information from "in house" engineering studies. This type of information is not often found elsewhere.


I would expect an automatic with lock up converter to be able to lower losses over a non lock up transmission. Used to be manual transmission "COULD" deliver better mileage. But the knowledge and skill of the operator was a huge part of the input. Not so today. I think with the best programming possilbe- not often achieved - an automatic will deliver better fuel mileage every day.

Now, can I drop in a six speed manual and do better than a six speed auto? In most cases I think I can. In a few cases I dont think I can. Racing - I mean big bucks all out racing... If I wanted first place, I am looking at an automatic shifting transmission first. For in town driving, I think I will get very tired of a manual transmission... on the open road, not so much.

my fuel mileage special is my 1954, nv5600 six speed, 3.73 gears, camera side view no vents, pipes, racks or stuff on the roof, undertrays, the rear of the bus a little lower than the front at highway speeds. and geared to run 1875 at 65 mph in 6th and 2525 in fifth -- weight 12,000 lbs and I expect to get 14 mpg maybe as much as 18 mpg.

william