Need a bigger engine/more power.

[madhat]

I have a 1997 international amtran. 11 window with the 7.3 intl powerstroke and allison trans. When I bought the bus I didn't know that the engine is underpowered and after I completed the conversion it started struggling on hills. I go 50 mph @ 2200 rpm and it really struggles on hills. It overheats often going up the mountains. Its already converted and I live in it, also I would want to keep living in it so I need help finding out which way to go with my skoolie

I am a new member, just registered and I don't know if a thread like this already exists.

Thanks for reading

Madhat

[EastCoastCB]

I'd upgrade the transmission first. Its where all the heat/slip comes from. If it has the 545, that is. Which I'm sure it does.

[Booyah45828]

You don't need more power, you need different rear gearing.

[madhat]

Originally Posted by Booyah45828

You don't need more power, you need different rear gearing.

Some old time trucker told me that if I were to upgrade to different rear end gearing I will lose all the torque and the bus will have a higher top speed but still struggle on the mountains.

Wonder if there is some sort of exaggeration in that statement..

[o1marc]

Originally Posted by madhat

Some old time trucker told me that if I were to upgrade to different rear end gearing I will lose all the torque and the bus will have a higher top speed but still struggle on the mountains.

Wonder if there is some sort of exaggeration in that statement..

ALL is definitely an exaggeration. Torque and horsepower don't change with a gear change in the rear, it just moves the power band. A higher gear for highway speed will slow your execration off the line, but give you higher speed at the same RPM. A lower gear would get you faster off the line, but sacrifice top speed.
Depends on how much you change the rear gear.

[madhat]

Originally Posted by o1marc

ALL is definitely an exaggeration. Torque and horsepower don't change with a gear change in the rear, it just moves the power band. A higher gear for highway speed will slow your execration off the line, but give you higher speed at the same RPM. A lower gear would get you faster off the line, but sacrifice top speed.
Depends on how much you change the rear gear.

First. I just want to say thanks to everyone for looking out. I am new to the skoolie community and you guys have been really helpful really quick!


So I was reading a different thread on rear end swaps and someone said they instead swapped the transmission and gained a ton of top speed and still have the low end torque

Originally Posted by Dragonpop

My suggestion would be to leave the rear end alone and change out
the transmission to a 5 or 6 speed model like the Allison 2060 or md3060
which are 6 speed transmissions which are double overdrive which will
give you the lock up converter for mileage and a the low gear starting
power. My bus has an MD3060 but only has 5 speeds open with 6th gear
locked out at present. With 12r22.5 tires it is doing 65mph at 2000rpm.
my differential ratio is 5.38, top speed at 2400 rpm is 85mph.

[EastCoastCB]

Originally Posted by EastCoastCB

I'd upgrade the transmission first. Its where all the heat/slip comes from. If it has the 545, that is. Which I'm sure it does.

Originally Posted by madhat

First. I just want to say thanks to everyone for looking out. I am new to the skoolie community and you guys have been really helpful really quick!


So I was reading a different thread on rear end swaps and someone said they instead swapped the transmission and gained a ton of top speed and still have the low end torque

Yep. Like I said- biggest upgrade for the $$ would be transmission.

[madhat]

Originally Posted by EastCoastCB

Yep. Like I said- biggest upgrade for the $$ would be transmission.

I found allison md3060 for about 1000 bucks.
Is there another way to go about finding a transmission? Maybe someone would take the trans off my skoolie as a trade in?
And also one last question. How do you find a shop big enough that could work on the bus ?

EastCoastCB

[EastCoastCB]

Originally Posted by madhat

I found allison md3060 for about 1000 bucks.
Is there another way to go about finding a transmission? Maybe someone would take the trans off my skoolie as a trade in?
And also one last question. How do you find a shop big enough that could work on the bus ?

EastCoastCB

Any shop that works on big diesels should be able to help you.
To make the 3060 work you'd need a TCM, TPS, and some other stuff. But not a bad price.
Or buy a rusty bus with a good drivetrain and take the parts you want or need, scrap/sell the rest.

That's where I'm at. I need an engine overhaul, and its cheaper just to buy another bus for the engine.
If you have a 545 trans you'll be lucky to even give it away... ask Tango.

For a bus of your year/engine a 643 would be a nice upgrade and not too expensive or complex.

[cadillackid]

on a 444E dont go Allison 3000 series.. go 1000 or 2000.. the 3000s require a crossmember be installed for extra support on the V-8 diesels..



if tyour chassis on your bus is a true 97 then you are WTECIII (J1939) ready so your engine will talk to the electronics of a 1000/2000.



I have a whole thread about my trans swap.. but ultimately getting a Lockup converter on it, at least one OD gear if not 2.. with a 50 MPH 2200 RPM.. you probably max out at what 60? a 5th or 6th gear would help out from a standppoint that you could probably lower the rear end gear slightly and gain a bit more torque on the hills.. esp if you had a 6th gear with a .64 or .61 OD..



getting Hot in a 444E - really common issue.. the cooling system in them is quite small capacity for the engine displacement.. the result is that you get hopt even on shorter hills.. abd of course it cools down quickly when you slow down.. I did some updates to mine that involved changing the fan clutch and going to a higher performance coolant.. my trans swap also made my engine run much cooler..



abother route is to custom mod it so you have a full radiator and full turbo cooler..



EC has a DT466E with the full rad and turbo cooler that could likely be retro'd into a 444E bus .. the part numbers may very well fit.. I was going to do it but i havent had any over-temp issues in the hills since my trans swap.



-Christopher

[Booyah45828]

Sure, an OD trans would do him wonders. Odds are though, if he was capable of doing the swap himself, he wouldn't have came here asking the question. And I'd hate to see what a shop would charge to do all the work that christopher did.

I have a feeling his engine is overheating because it's redlined, not because the torque converter isn't locked.

IMHO, a lockup converter won't change his top speed, or lower his rpm anything substantial on the highway, therefore it won't fix his overheating.

Figure out your current rear gear, and we'll go from there.

In all honesty, you might have to do a gear change and a trans upgrade to get what you want. Or find a place that will swap in a allison 2000 at a reasonable price.

[EastCoastCB]

Originally Posted by Booyah45828

Sure, an OD trans would do him wonders. Odds are though, if he was capable of doing the swap himself, he wouldn't have came here asking the question. And I'd hate to see what a shop would charge to do all the work that christopher did.

I have a feeling his engine is overheating because it's redlined, not because the torque converter isn't locked.

IMHO, a lockup converter won't change his top speed, or lower his rpm anything substantial on the highway, therefore it won't fix his overheating.

Figure out your current rear gear, and we'll go from there.

In all honesty, you might have to do a gear change and a trans upgrade to get what you want. Or find a place that will swap in a allison 2000 at a reasonable price.

If your transmission is slipping, its adding a lot of heat to the cooling system.

[Ronnie]

Not trying to be too fussy, but if his trans is "slipping" he has real problems. So really we are talking torque converter slippage. that will add a lot of heat for sure.

[o1marc]

Originally Posted by Ronnie

Not trying to be too fussy, but if his trans is "slipping" he has real problems. So really we are talking torque converter slippage. that will add a lot of heat for sure.

Apparently you are new here and haven't followed all the posts concerning the AT545 that has no locking torque converter, so once it gets to speed, unlike a locking torque converter, the tranny is always running on the fluid and never locked to the motor. Long stretches of highway speeds or mountain grades heat that tranny up quickly and will destroy it. This is normal and not "real problems". Since the trans cooler uses the same fluid as the motor, overheating the tranny adds heating to the motor cooling system taxing it also.

[cadillackid]

with a 444E its multi-fold...



1. the cooling system is barely adequete at best when in a hard-pull warm weather situation.. an unloicked converter adding heat doesnt help..


2. Booyah has it right.. RPMs on a 444E create lots of heat.. i can give you real data on this .. as ive done it.. ive been all over this.. I had a 545 in a short bus with a bad fan clutch, then a good but stock fan clutch, then a high performance fan and clutch, then an allison overdrive..



what i can say is to this day on a high 80s day WITH a locked converter on flat ground doing 65 which is 2500 RPM in my bus.. even with my cooling upgrades its gonna run warm... it wont likely over-temp but im gonns be looking at 210-215.. climb a hill and im going to inch my way towards 220... 235 is alarm-bells on a 444E..



now with overdrive.. ill sit at 195-205 (fan on 205, off at 195).. sometimes I just run the fan on hot days knowing im going to climb hills if im in a mountainness area.. when I do that ill flucturate between 188 and 195 (high 80s out).. so that when I climb the hill and give it the kickdown to 4th and up to 2000+ RPM, i have a cooler system already so it takes much longer to inch its way upwards.. by then ive either hit cooler weather because im ascending, or slowed down because the traffic is killer... top the hilll and cools right down..


reality is the 444E cooling system is crap .. the radiator capacity in a ford F-250 with a 7.3 is higher than that split rad om tje school busses..


-Christopher

[EastCoastCB]

444e cooling system is marginal at best. Couple it with a slippy 545 and you got one unhappy machine at highway speeds.

[Johnny Mullet]

My T444E with an AT545 runs best at around 57 mph and has never gotten warmer than 190 degrees on the temp gauge. Running 65+ in my bus runs the rpm's high and beyond it's power band, but I really don't like running my bus at interstate speeds anyway. What's the hurry?

[david.dgeorge07]

I have a 3060 in my 13 window, 210 hp CAT 3126 and when towing my Jeep I am still slow on hills and against headwinds. It seems like most full-size school busses can’t just maintain speed on a hill as though they were sedans.

Lockup and overdrive will help, but it will still be a school bus.

I was cruising 60-65 for a lot of the day today, but Monteagle mountain in TN had me down to 35.

One road in CA had me maxed out at 9MPH! Steepest grade I drove on the trip was 16%.

[Ronnie]

Originally Posted by o1marc

Apparently you are new here and haven't followed all the posts concerning the AT545 that has no locking torque converter, so once it gets to speed, unlike a locking torque converter, the tranny is always running on the fluid and never locked to the motor. Long stretches of highway speeds or mountain grades heat that tranny up quickly and will destroy it. This is normal and not "real problems". Since the trans cooler uses the same fluid as the motor, overheating the tranny adds heating to the motor cooling system taxing it also.

I am referring to the difference of a slipping transmission as in the bands or clutches are slipping, versus just slippage of the non locked converter. So the comment his transmission is slipping while most of us will know he means torque converter slipping , some may really believe he means just what he said, that the trans is slipping. So just a note on the grammar that was used.

Now having said that it seems you have some real experience with building vehicles, so I would assume you are familiar that most hot rodders spec a torque converter with a stall speed to match it intended use. Do you know if there is a torque converter available with a lower stall speed for the bus in question? This is going to be a possible solution for the bus. Not total by any means, but a step in the right direction if he does not want to change the trans.

This helped my old Dodge with the cummins5.9 a lot in terms of heat. Also a separate trans cooler with it's own fan NOT in front of the radiator. I mounted it under the flatbed.

[pbeggs]

find your local heavy truck garage if you need work done they have the bays and lifts to take your bus, after all, it is a heavy truck underneath