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Old 10-17-2016, 02:24 AM   #1
Mini-Skoolie
 
Join Date: Aug 2016
Location: Florence Oregon
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Year: 2000
Coachwork: Amtran
Chassis: RE 35'
Engine: T444E
Rated Cap: 72 passenger
T444E safe operating RPMs at highway speeds

How many RPMs can I safely run with a T444E on a freeway? My 35' 2000 International RE with a T444E is running around 2500 RPMs at 58 to 60 MPH. What are the safe RPMs for the T444E ? How many RMPs are these engines designed to run at highways speeds? I would like to be able to cruise between 65 and 70 on the freeway. Do I need to have the rear end ratios changed? Or can the T444E handle 3000 RPMs at freeway speeds?
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Old 10-17-2016, 03:47 AM   #2
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2500-2600 RPM's is about as tight as I would want to turn one of those on a regular basis.

3000 RPM's is really asking for trouble IMHO.
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Old 10-17-2016, 07:05 AM   #3
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Join Date: May 2009
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ther T-444E should be limited to 2700 from the factory... maybe the 210 HP version is 3000? I do know they max out their power and torque curve at 2300.. which is a good optimal balance of economy and power there...

the bottom end on these things can take more.. ford ran them up to 3200, but the fords i believe have a slightly thicker head gasket than the IHC so you can run higher RPM wothout slapping a piston at the top of the cylinder.

even with 210 HP, i cant imagine being able to have enough power to run a big heavy RE bus at 65-70 with a T-444E..

when you regear you also lose torque at the tires... a good test is does your bus want to slow down any on mild hills? if you are floored and drop speed a little now on hills you would drop speed even more if you re-geared the rear...

-Christopher
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Old 03-01-2017, 05:12 AM   #4
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Join Date: Feb 2016
Location: Lee, Florida
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Year: 1995
Chassis: International 3800
Engine: T444E
Rated Cap: 36 adults
My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.
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Old 03-01-2017, 06:11 AM   #5
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Quote:
Originally Posted by Dana View Post
My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.
so far i have put about 4000 miles on my 444E running it over the highway..

your 444E is probably computer speed-limited at 65 so thats why your RPMs drop going down hill as the vehicle speed limiter lowers throttle input..

if I was going to make an upgrade for that kind of money I would likely upgrade to an allison 1000 / 2000 transmission before id re-engineer a gear overdrive unit...

ive been researching such an upgrade both with a new / reman transmission and with a used transmission..

-Christopher
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Old 03-01-2017, 05:08 PM   #6
Mini-Skoolie
 
Join Date: Aug 2016
Location: Florence Oregon
Posts: 11
Year: 2000
Coachwork: Amtran
Chassis: RE 35'
Engine: T444E
Rated Cap: 72 passenger
This is great info. Is the Alison 1000 2000 an over drive trans? Wouldn't it be less expensive to just change out the pumpkin/ rear end to a better gear ratio ?
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Old 03-01-2017, 05:11 PM   #7
Mini-Skoolie
 
Join Date: Aug 2016
Location: Florence Oregon
Posts: 11
Year: 2000
Coachwork: Amtran
Chassis: RE 35'
Engine: T444E
Rated Cap: 72 passenger
Quote:
Originally Posted by Dana View Post
My 95 Int. T444e with the AT545 trans (4 speed) is limited to 2600 RPMs and runs down the highway at 65MPH. As far as I know it should not hurt the engine to run 2600 all day. The t444e (the 175 hp version) HP peaks around 2200 RPMs and the torque (460) around 1400. So the engine "lives" in that range.

International T444E Specs & Info

One thing that I found interesting when I started driving trucks for a living was most truck (I drove) would be flat out, 100% throttle on the highway. You just stand on it and let the truck run where she likes.

I live in Florida so its flat roads except for bridges. I find the bus keeps speed (65) over most large bridges. On the downhill side the RPMs will actually come down a tick as the bus passes 65MPH.

As long as your water temps are within normal range (mine runs about 206) and oil pressure is good, running 65 all day at 2600 RPMs should be fine for the engine.

These buses are just not made for highways. So they seem a bit uncomfortable on them. Mine likes to cruise at 50 MPH. At that speed it is turning about 2100 RPMs.

I am thinking of adding a Gear Vendors over-drive unit. It would have be a Divorced unit, meaning it would replace a carrier bearing in the driveshaft. Then the bus should run at 70MPH and turn about 2100 RPMs. I don't think I want to go much faster than 70mph.

But the over-drive unit is $3100 and then it would need to be mounted and the driveshafts would need to be shortened. I estimate the whole thing would be about $4500 and I only paid $2300 for the bus.

But then again I did just drop $2700 on 6 new tires. Seems like the parts are more expensive than the whole.
Thanks for the info. I thought about a gear venders over drive also. What about just changing out the pumpkin/ rear end drop out, for on with a better ratio ? Wonder what that would cost?
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Old 03-01-2017, 05:16 PM   #8
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Join Date: May 2009
Location: Columbus Ohio
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Chassis: International S3800
Engine: DT360
Rated Cap: 7 Row Handicap
if you can get lucky enough to find a rear gear set on a used bus that will fit, then yeah on most its a pretty easy swap to pull the 3rd member and swap it into another assuming the housings are the same... but if you have to buy a bunch of parts and then set up the carrier and all it gets a lot pricier and tougher t odo.. though not impossible with standard air tools by any means...

I was only looking at it from an aspect of using a separate overdrive gear... I myself would drop in the OD transmission and have its computer programmed to my Spec... but im also starting with an AT545 which if a taller gear is put on that you'll end up over-temp the transmission much easier as you slig the torque converter... and on a 545 too low of RPM's you'll run low line pressure and slip the clutches esp in 4th gear.. with an MT-643 those issues womnt occur as it has lockup and runs higher line pressures at lower RPMs.
-Christopher
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Old 03-02-2017, 05:32 PM   #9
Mini-Skoolie
 
Join Date: Aug 2016
Location: Florence Oregon
Posts: 11
Year: 2000
Coachwork: Amtran
Chassis: RE 35'
Engine: T444E
Rated Cap: 72 passenger
Well, then the MT-643 sounds like the way to go if the cost is reasonable. Would it work with the current 4 speed shift handle/set up that is on the dash of the bus? Or would that need to be changed? Is the drive shaft on the RE bus the same for both trans? Is is a drop in or would there be other stuff to change out as well? Wondering what the cost is for a good used or rebuilt MT-643? Any trade in value for the good 545?
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Old 03-02-2017, 05:36 PM   #10
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I'd look for a good used 643. The driveshaft will need to be shortened some, and I'm not sure what bell housing the 444E has. You may need a bell housing adapter, too. If you're gona do this upgrade I'd look for a 643 with a retarder. Would be two huge upgrades in one! I've seen them for as little as $600. $750 all day.
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