6.9 in a bus needs radiator. Upgrades?

franklin2

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Those are for ford stuff. We're talking medium duty with an Allison at545. An at545 can use a vacuum modulator, but most diesels use a cable one, unless it's an electronic engine, then it will use an electronic solenoid. The electronic allisons are clutch to clutch which requires real specific and accurate timing, I'm not aware of a functional aftermarket shift controller for an allison. Most custom guys use allison controllers and programming, but modified to suit their needs.
Why not ditch the allison and it's complications, and go with a E4OD or something like that. If he is not turbo charged, I don't see the engine ruining a rebuilt and updated E4OD or similar late model transmission that would bolt up.
 

Booyah45828

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Why not ditch the allison and it's complications, and go with a E4OD or something like that. If he is not turbo charged, I don't see the engine ruining a rebuilt and updated E4OD or similar late model transmission that would bolt up.
Because it's in a 30+ foot IH school bus? I'm not sure if you've overlooked that part, but this isn't a truck or e-van chassis

An e4od would be more complicated and likely not even up to the task. You'd be removing the SAE flywheel housing, installing the ford adapter, fabbing motor mounts to suit the flywheel housing removal, changing the driveline to accomodate the smaller u-joints, etc. He'd also likely run into issues with the e4od's 2.71 first gear, as that's not near enough in a heavy vehicle IMO.
 

Luke_IDI

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It's an interesting thought. I suppose a heavier-built pickup automatic would be the only way to get an overdrive without an auxiliary transmission or going Allison computer-controlled. It seems like the E4OD's 2.71 first multiplied by the 5.57 rear would be similar to the AT545's 3.45 first with something around a 4.5 rear. The E4OD setup would also end up with a taller 4th gear (similar overall ratio to a theoretical 3.95 rear direct-driven) than the AT545 with a regear. So the E4OD would accomplish the same thing as a simple regear, with an even wider spread of gears (the AT/MT is pushing it at the gearing we are talking about), not to mention no lockup. And it's electronic. Sounds like a lot of adapting to do what could be much better and much more easily done by swapping a 4.33 or 4.78 gearset into the rear and an MT643.

With the computerized swap, I was assuming a donor vehicle-type situation. I will definitely check out that thread on 4BTswaps and do some more reading to better understand the lay of the land. But after kicking different possibilities around in this thread, I think it's quite unlikely I will go that route. After thinking a bit more about my driving needs, too, I'm considering that I'm not a fast highway driver, especially not in a bus, and especially not with fuel prices the way they are. 60-65 mph at 2200-2400 rpm, maybe with enough rpm and power for a 75-80? mph top speed will be plenty sufficient for me. And that should be given by a 4.33-4.78 with a mechanical Allison, either the existing AT545 or an MT643.

Speaking of which, any idea how much it costs to get an MT643 core rebuilt?
 

Luke_IDI

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Interestingly enough, one of the first turbo kits available for the pickups/engines mounted the turbo off a custom exhaust manifold on the driver's side. They were called rayjay or rotomaster kits, and they're not really all that common anymore. Now, a fun fact is that an IDI exhaust manifold ports are symmetrical, meaning you can mount the exhaust manifold to both the right or left head. So I found and bought a rayjay manifold off of facebook, and intended on mounting it on the passenger side head. The manifold uses a t4 flange, and I'm going to try and use a powerstroke tp38 turbo with it. The tp38 is reverse rotation compared to traditional turbo chargers, and that reverse rotation should position the turbine housing away from the valve cover and over the frame rail, which would work out really well. I'd then use the original driver's exhaust manifold, build a custom cross over pipe, and likely route the turbo outlet through a 90° bend, down and past the frame rail, and out under the passenger's step well, hugging then underneath the frame rail in a similar position that the exhaust currently travels.
Also, there are definitely plans for a turbo around the same time as these driveline modifications. So the next question becomes, what would be a sufficient hp/tq goal to move a bus with this gearing? Did you have any power goals when you laid out your turbo setup?

One method that comes to mind, to get a ballpark, is figuring the percent increase in gearing and shooting for a corresponding percent increase in hp. I'm going to go with 4.33 to get an upper end of how much power I might need. 5.57 / 4.33 = ~1.29. So maybe I should be looking for approximately 30% more power. The 6.9 IDI has about 170 hp stock. Adding 30% to that gives 221 hp. Thewespaul in his turbo selection thread gives 2.75 hp per cc of fuel, which would mean I would need about 80 cc of fuel to make that power. I've read the stock IP maxes out at 70-75 cc. So maybe not quite there.

The same calculation for 4.56 gears:
5.57 / 4.56 = ~1.22
1.22 x 170 hp = 207 hp
207 hp / 2.75 cc per hp = ~75 cc

That hp goal is potentially within the capabilities of the stock pump, even. Might as well try a turbo install on the stock pump and if it's really not enough, drop a 90 cc pump in there for a little extra headroom. I do like the idea of being able to run stock pumps purchased used, though, should there be any problems, as towing a bus from the side of the road is a situation I absolutely want to avoid. And it would be nice to not have to worry about running WMO etc. through an expensive built IP.

I've been doing a little more turbo reading and the TP38/GTP38 seems like a pretty good turbo for an IDI application, really, especially considering they seem to be pretty plentiful and cheap. R&D analyzes a map for the GTP38 in this thread. It sounds like some have had success switching to the smaller .87 A/R exhaust housing for a faster spool as well. It looks a bit big for a stock IP though--I wonder if it would be useless with the stock IP, or provide a mild improvement with plenty of room to grow into fueling mods. Were you thinking you would run a 90 cc IP?
 

franklin2

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Because it's in a 30+ foot IH school bus? I'm not sure if you've overlooked that part, but this isn't a truck or e-van chassis

An e4od would be more complicated and likely not even up to the task. You'd be removing the SAE flywheel housing, installing the ford adapter, fabbing motor mounts to suit the flywheel housing removal, changing the driveline to accomodate the smaller u-joints, etc. He'd also likely run into issues with the e4od's 2.71 first gear, as that's not near enough in a heavy vehicle IMO.
I hear what you are saying, but some of it doesn't compute. There would be some fab work of course, nothing insurmountable in my opinion. Where ever he sourced the E4OD, he could look for the adapter also.

The motor mounts are something foreign to me, are they made onto the bellhousing?

What doesn't compute or add up is how all these guys on this board are modifying their engines, using a lot of boost, and using them to pull thousands of pounds with a truck/trailer combination, and they seem to be doing ok. Would there be any difference in a heavy truck/trailer combination and a heavy bus? With the very high rear gear ratios he is contemplating, it would be even easier on the drivetrain wouldn't it?
 

IDIBRONCO

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So the next question becomes, what would be a sufficient hp/tq goal to move a bus with this gearing?
I don't know what you mean by having sufficient power to move your bus. It was built and used without a turbo so there's that. Being full of kids, even if they're all around8 years old will add quite a bit of extra weight to that bus and then there's all of their school supplies. Overall, I think that this engine used to haul around a lot of weight.
Might as well try a turbo install on the stock pump and if it's really not enough, drop a 90 cc pump in there for a little extra headroom.
This what I would try first.
I do like the idea of being able to run stock pumps purchased used, though, should there be any problems,
Now just remember that you have an International, not a Ford. The throttle cables attach to the pumps differently and (I believe) the Internationals are governed at a much lower RPM than the Fords are. That will detract from the amount of boost that you'll see out of a turbo. Sure, you can turn up the governor, but you were talking about just sticking a used pump on the engine if something happened. It's also MUCH more difficult to find a used International pump than it is a used Ford pump.
 

Luke_IDI

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I don't know what you mean by having sufficient power to move your bus. It was built and used without a turbo so there's that. Being full of kids, even if they're all around8 years old will add quite a bit of extra weight to that bus and then there's all of their school supplies. Overall, I think that this engine used to haul around a lot of weight.
The bus was spec'd by the military, probably to move personnel around an Air Force base somewhere in the panhandle of Florida, so it most likely never saw speeds above 45, maybe 50 mph or so. That's where it feels comfortable with the current gearing. I'm looking to increase the top speed and decrease the cruising RPM at highway speeds, so I imagine an increase in power will be necessary. Maybe not, though, depending on how light we keep the bus. Probably will do the gear swap first and try to have turbo parts on hand to be ready for the pipe fabrication and install.

Now just remember that you have an International, not a Ford. The throttle cables attach to the pumps differently and (I believe) the Internationals are governed at a much lower RPM than the Fords are. That will detract from the amount of boost that you'll see out of a turbo. Sure, you can turn up the governor, but you were talking about just sticking a used pump on the engine if something happened. It's also MUCH more difficult to find a used International pump than it is a used Ford pump.
Thanks for pointing that out. I knew the IH pumps were governed lower, but I didn't know there was a different throttle linkage. I will have to get the two side by side to see if I can adapt the IH throttle linkage to a Ford pump. I already have a Ford pump sitting on a core engine. It would be a nice security measure to have that extra pump aboard the bus, provided it could be adapted to the commercial engine. I suppose worst case scenario, bolt it in and yank on whatever throttle linkage is there with a random length of wire or string to limp it to a safe place to work on it....
 

IDIBRONCO

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I will have to get the two side by side to see if I can adapt the IH throttle linkage to a Ford pump.
If I remember right, that part's easy enough (but I may not be remembering that right). It's the fact that the throttle cables aren't the same. The International cables may be longer than the Ford cables and aren't easy to interchange.
 

Booyah45828

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I hear what you are saying, but some of it doesn't compute. There would be some fab work of course, nothing insurmountable in my opinion. Where ever he sourced the E4OD, he could look for the adapter also.

The motor mounts are something foreign to me, are they made onto the bellhousing?

What doesn't compute or add up is how all these guys on this board are modifying their engines, using a lot of boost, and using them to pull thousands of pounds with a truck/trailer combination, and they seem to be doing ok. Would there be any difference in a heavy truck/trailer combination and a heavy bus? With the very high rear gear ratios he is contemplating, it would be even easier on the drivetrain wouldn't it?
I wouldn't call it insurmountable either. But I just don't think that's the route I would take.

A bus like this is at least 15k lbs empty. I know there are guys who run a truck/trailer that heavy, but I'd be surprised if an e4od can put up significant mileage like that unless it's built. A built e4od isn't cheap last I checked.

On an IH chassis you have a motor mount on each side of the flywheel housing. Then they run the a 3rd/4th mount under the harmonic damper up front. Ford ran motor mounts off the side of the middle of the block, with a trans mount in the rear. You'd have to fab all 3 new IMO for an e40d to work.

A 2400 allison can be equipped with an sae 3 or 2 housing, making the current mounting setup okay. It'd also have 6 speeds, with 1st gear being close to what he currently has. It'd also be up to the task in stock form, no "building" required.
 

Booyah45828

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I think the lever on the pump is the same. At least the 2 IH engines that I have, have the same throttle lever that I've seen on ford trucks.

The pump/engine in the bus is a 3500 rpm unit, not the 2500 rpm that I'm told would have been stock. If he's got a 2500 rpm governor, he wouldn't get up to 55 mph. He's got the same engine/gearing/tires and transmission that I have, and I'm doing over 2500 at 55.
 

Booyah45828

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It's an interesting thought. I suppose a heavier-built pickup automatic would be the only way to get an overdrive without an auxiliary transmission or going Allison computer-controlled. It seems like the E4OD's 2.71 first multiplied by the 5.57 rear would be similar to the AT545's 3.45 first with something around a 4.5 rear. The E4OD setup would also end up with a taller 4th gear (similar overall ratio to a theoretical 3.95 rear direct-driven) than the AT545 with a regear. So the E4OD would accomplish the same thing as a simple regear, with an even wider spread of gears (the AT/MT is pushing it at the gearing we are talking about), not to mention no lockup. And it's electronic. Sounds like a lot of adapting to do what could be much better and much more easily done by swapping a 4.33 or 4.78 gearset into the rear and an MT643.

With the computerized swap, I was assuming a donor vehicle-type situation. I will definitely check out that thread on 4BTswaps and do some more reading to better understand the lay of the land. But after kicking different possibilities around in this thread, I think it's quite unlikely I will go that route. After thinking a bit more about my driving needs, too, I'm considering that I'm not a fast highway driver, especially not in a bus, and especially not with fuel prices the way they are. 60-65 mph at 2200-2400 rpm, maybe with enough rpm and power for a 75-80? mph top speed will be plenty sufficient for me. And that should be given by a 4.33-4.78 with a mechanical Allison, either the existing AT545 or an MT643.

Speaking of which, any idea how much it costs to get an MT643 core rebuilt?
You came to the same conclusion that I did. I just didn't feel comfortable with a 1st gear that steep. Which is why I was leaning towards a 2 speed or aux trans. I could leave it in low or direct for around town, then shift it into high or OD when on the interstate.

I had no intentions of doing 80 mph. Just wanted to cruise without being against the governor. The engine will take being against the governor all day long, and I've done it before, it's just doesn't sit right with me.

MT643 rebuild will be a few thousand. I've got a core mt643 on the floor now. I was going to rebuild it myself, but lkq had some remans that were NOS in Missouri for 600 bucks or so, which was less then what the rebuild kit would cost me. So I hung off on buying the kit and rebuilding mine.

Look up transmissions and axles for sale on lkqheavytruck.com, I found a couple ra39's that were geared 4.56 or 4.78 for sale used. Do your due diligence when purchasing as they might be used junk.
 

Booyah45828

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Also, there are definitely plans for a turbo around the same time as these driveline modifications. So the next question becomes, what would be a sufficient hp/tq goal to move a bus with this gearing? Did you have any power goals when you laid out your turbo setup?

One method that comes to mind, to get a ballpark, is figuring the percent increase in gearing and shooting for a corresponding percent increase in hp. I'm going to go with 4.33 to get an upper end of how much power I might need. 5.57 / 4.33 = ~1.29. So maybe I should be looking for approximately 30% more power. The 6.9 IDI has about 170 hp stock. Adding 30% to that gives 221 hp. Thewespaul in his turbo selection thread gives 2.75 hp per cc of fuel, which would mean I would need about 80 cc of fuel to make that power. I've read the stock IP maxes out at 70-75 cc. So maybe not quite there.

The same calculation for 4.56 gears:
5.57 / 4.56 = ~1.22
1.22 x 170 hp = 207 hp
207 hp / 2.75 cc per hp = ~75 cc

That hp goal is potentially within the capabilities of the stock pump, even. Might as well try a turbo install on the stock pump and if it's really not enough, drop a 90 cc pump in there for a little extra headroom. I do like the idea of being able to run stock pumps purchased used, though, should there be any problems, as towing a bus from the side of the road is a situation I absolutely want to avoid. And it would be nice to not have to worry about running WMO etc. through an expensive built IP.

I've been doing a little more turbo reading and the TP38/GTP38 seems like a pretty good turbo for an IDI application, really, especially considering they seem to be pretty plentiful and cheap. R&D analyzes a map for the GTP38 in this thread. It sounds like some have had success switching to the smaller .87 A/R exhaust housing for a faster spool as well. It looks a bit big for a stock IP though--I wonder if it would be useless with the stock IP, or provide a mild improvement with plenty of room to grow into fueling mods. Were you thinking you would run a 90 cc IP?
As much as I could get.

Plan was to max a stock IP. I was on the fence about switching to arp studs. If I kept the bolts, I'd just max the stocker and let it go until/if it blew the gaskets. If I upgraded pumps, I feel you'd have to install studs. If I'm going to install studs, I might as well build the spare 7.3 and have more displacement and thicker studs.

TP38 should have worked fine. I wasn't wanting 400 hp and 50 psi, just something better then NA that wouldn't cut down on reliability. I actually had that .84 housing bookmarked, along with a kc s300 turbine wheel and a wicked wheel 2. I was on the fence between the .84 housing and the 1.0 housing. I figured I wasn't burning enough fuel with a stock pump to worry about the .84 being too small.

I think I remember years ago reading that calvin(towcat) had a favorable review on a tp38 swapped IDI, but I can't find that post any more.
 

Luke_IDI

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I think the lever on the pump is the same. At least the 2 IH engines that I have, have the same throttle lever that I've seen on ford trucks.

The pump/engine in the bus is a 3500 rpm unit, not the 2500 rpm that I'm told would have been stock. If he's got a 2500 rpm governor, he wouldn't get up to 55 mph. He's got the same engine/gearing/tires and transmission that I have, and I'm doing over 2500 at 55.
I think mine must be governed around 3000. 65 mph is right about the best it can do.
 

Ferdy Mint

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Yeppers, watch those skinny stock head bolts if you turbo your 430 cid (6.9) because my understanding is you may have problems. One guy out here, I think, drilled and tapped his block so he could run 7.3 heads and those bigger bolts. Studs would be even better of course, I bet he did that and I just forgot the details. Maybe he'll see your thread.

Else, best limit your boost to whatever Banks does. Banks is always conservative. You won't be cruising a bus at 65-70 mph with only 4 psi of boost, frankly.

All this radiator talk makes me grateful that our IDIs all run cool. Remarkably cool even here in Texas. But we toss the AT and put in a ZF5. And we have pickups, not buses.

fyi
 
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