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4bt bronco,

The 7.3l Powerstroke (DI 94.5 and newer) tach signal starts as a tone ring under the front cover used to time the injectors. This signal is then fed into the PCM, where (if I'm not mistaken) it is transformed into a pulse train that is sent to the tach in the instrument cluster. More pulses = higher rpm. The IDI 7.3l (and 6.9l) had a sensor that picks up the teeth on the gear that drives the injection pump which was then sent to the instrument cluster. You may be able to use the crank shaft pulley - If memory serves there was a pulley that came with teeth. Stick a sensor next to it and you'd be in business.

Cj
 

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Discussion Starter #22
One of the first things you probably need to address is finding an engine. You have a known vehicle to put it in but don't yet have the engine. Until you find one it will be kind of hard to figure out what else to do and how much it will cost. As for cost, probably need to plan in the $8000-10000 range if no major issues crop up. You might beat those numbers but we've seen guys go way beyond that. You can easily have $6000 in the engine and that nothing very fancy.
From the online browsing I've done it's looking like a rebuild no-frills engine would hit somewhere between 3-4k. Now I'm not sure how hard these specific engines are to rebuild but I'm not opposed to doing that either.

I'm a more function over form type of guy and I don't mind sourcing what I can from junkyards and the such.
 

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Discussion Starter #23
4bt bronco,

The 7.3l Powerstroke (DI 94.5 and newer) tach signal starts as a tone ring under the front cover used to time the injectors. This signal is then fed into the PCM, where (if I'm not mistaken) it is transformed into a pulse train that is sent to the tach in the instrument cluster. More pulses = higher rpm. The IDI 7.3l (and 6.9l) had a sensor that picks up the teeth on the gear that drives the injection pump which was then sent to the instrument cluster. You may be able to use the crank shaft pulley - If memory serves there was a pulley that came with teeth. Stick a sensor next to it and you'd be in business.

Cj

Right off the bat that sounds a bit easier.

Tach is probably going to be lower on the list of concerns but it would be nice to have it one day. And if it's easier to set up while the engine is out then I might just do that.

Thanks for the tip.
 

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Rebuilding a 4bt is pretty basic. These are not extremely complex engines so long as you stay with the 4bt. Just be aware that these critters are heavy. Base dry weight is around 750 lbs or a bit more depending on injection pump, flywheel assembly, etc. Never attach the engine to a stand by bolting to the transmission adapter. Good recipe to make bad things happen. If the engine only needs some basics like gaskets, seals, and bearings, give yourself about a $1000 budget. Might beat that but better to guess high. If it needs boring, pistons, rings, etc then the cost goes up. There are some improvements you can make like head studs instead of bolts that won't break the bank. Depending on what power level you seek there can be other changes needed. A lot can depend on that injection pump and turbo the engine has.
 

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Discussion Starter #25
Rebuilding a 4bt is pretty basic. These are not extremely complex engines so long as you stay with the 4bt. Just be aware that these critters are heavy. Base dry weight is around 750 lbs or a bit more depending on injection pump, flywheel assembly, etc. Never attach the engine to a stand by bolting to the transmission adapter. Good recipe to make bad things happen. If the engine only needs some basics like gaskets, seals, and bearings, give yourself about a $1000 budget. Might beat that but better to guess high. If it needs boring, pistons, rings, etc then the cost goes up. There are some improvements you can make like head studs instead of bolts that won't break the bank. Depending on what power level you seek there can be other changes needed. A lot can depend on that injection pump and turbo the engine has.
Yeah the more research I do the longer my time frame for this project gets.
I'm happy with the torque specs how they are but I'd like to try to pump up the hp a bit. To me the first obvious thing would be upgrade the turbo but what can you tell me about the pumps?
Now ideally I'd get a 4bta but I'm not sure if that's going to happen.
 

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The two road use injection pumps were the Bosch VE and P7100. There were about a half dozen other pumps used in various applications and a few of those could be used on a road vehicle. The VE pump can get to around 300 HP with twin turbos and upgraded injectors. A P7100 can go way beyond that, but when you start thinking super high HP there will be a lot of other mods involved. A common power number many shoot for is around 200 HP. That can be done with stock injectors and a single turbo. Just remember, as the HP goes up so does the torque. A 200 HP 4bt will have in the neighborhood of 450 lb ft of torque, give or take a little. That's as much as most big block gas engines and it comes full on in the 1800 RPM area. That torque can be a friend or an enemy depending on how you use or abuse it. If you found a basic VE pump engine, the first major change would be the turbo. Those engines came in 105 and 120 HP versions and had an H1C turbo. It was OK for that power level, but not much potential for a higher lever. Change it to a 44mm HX30W or a 46mm Super HX30W for better performance. Injectors should be checked to see they are in good working order, but no need for bigger sticks. A few minor adjustments to the injection pump and you'd pretty much have 200 HP. If you got an engine with the P7100 it would already have a 40mm HX30W which is a decent turbo. There you'd check the injectors and make a few pump mods and you'd be there. No huge cash outlay except maybe a better turbo. For less than $1000 you can change either style engine into a pretty healthy power plant. That's so long as it doesn't need the injection pump rebuilt. That's gets a bit costly.
 

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Darn thing double posted again. This is really getting on my nerves and this new system has no delete key.
 

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Discussion Starter #28
200 hp would make me more than happy. While the thought of pushing 300 would certainly be cool I think I'll leave that "Pandoras box" unopened for now.

That information was pretty much what I was hoping for. I can get some nice hp without having to get super spendy on injection pumps.

Now I've heard that an intercooler isn't "required" but I'd imagine since I have the space it'd go a ways to boosting performance?
 

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Now I've heard that an intercooler isn't "required" but I'd imagine since I have the space it'd go a ways to boosting performance?
Not required for a stock, unmodified 105 horsepower 4bt engine. The stock calibration limits the RPM and fuel to produce "safe" exhaust gas temperatures (i.e. below the melting point of aluminum pistons).

As I suggested in Post # 15, You need to slow down and get a better understanding of Diesel theory and operation.

More horsepower produces more heat. Minimum instrumentation includes a Exhaust Gas Temperature (EGT) pyrometer, boost gauge and tachometer so that you can make sense of the changes produced my your modifications.

Not everyone agrees with me, but a fuel pressure gauge at the output of the final fuel filter is an excellent diagnostic tool.
 

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Yeah, don't even think about raising the HP level without an intercooler. Even the 120 HP VE pump model had a water to air aftercooler. The 130 HP P pump model used an air to air intercooler. Raising the power level means adding more fuel and boost from the turbo. That causes the air from the compressor to get very hot. Can be over 300 deg F. That's why the hose boots on the plumbing are silicone rubber which can stand up to 500 deg F. Most people will use the air to air type because it's cheaper. Water to air can be done effectively but the cost goes up quite a bit. Fords latest 6.7 diesel is water to air. The second radiator for the cooler is over 4 feet wide. The system used on the 120 HP 4bt was only minimal and used the engine cooling system. You were only adding 15 HP there. Another area for improved performance is heat control in the turbo. There you want to keep the heat in and not shed it. The hot exhaust gas is the driving power for the turbine. Either some type of heat insulating wrap or the best is ceramic coating the manifold and turbine housing. For a quality ceramic coating that isn't cheap. You can even gain a bit of performance by some minor exhaust porting work on the head and manifold. You don't go nuts there. The idea is to place the gasket on the manifold and make the ports match the opening. Then do the head but leave about a 1/16" border in the head port. That mismatch causes an increase of flow velocity. If you build an engine for more power, be sure you add proper gauges as Russ mentioned. You'll want a tach, turbo boost, and EGT gauges at a minimum. Two other gauges that can be nice to have are fuel pressure and exhaust back pressure. No such thing as having too much info on the engines conditions. In your first comment, the HP can be a Pandora's box. Adding more can be addictive. Up to around 200 HP you aren't terribly straining the engine. Up in that 300 HP level things are more stressful and the engine needs some special attention to keep that in check.
 

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Bronco,

The intercooler isn't required for the stock power level (and I don't yet have one in my 97 7.3l). BUT, the intercooler is everything in terms of keeping the egts down. If the air going into the engine is cooler it will come out cooler as well with the same and higher loads. Cooler, denser air in the combustion chamber is easier to compress and would be helpful in reducing smoke out the tail pipe. I'm not sure how an intercooler impacts performance in terms of mpg (I'm not sure that it would change the mpg by a lot - perhaps wiser folks here will chime in), but as Char points out any performance upgrades you wish to do will need an intercooler to avoid any unpleasant meltdowns. As the others have pointed out gauges are a must.

Cj
 

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Discussion Starter #32
Thank you all for the input.
I don't feel the need to raise hp super high.

I'm not trying to build a dragster. Or a sleeper-racer.

Really what my goal here is to be able to pull onto the interstate from a stop without holding everyone up for a mile. And to be able to pass on a 2 lane road.

170-180 would probably more than do me.

As for an intercooler/upgraded turbo would that be something I could do a bit after she's already running and roadworthy? Without too much trouble that is?

And as to what Russ mentioned. I'm not even close to jumping into this project yet. I still have a bunch of research to do and things to figure out before I'm ready to buy anything.

I hope me picking your brains isn't coming across the wrong way. I'm not desperate for info bc I'm roaring to go, I genuinely respect the knowledge and experience that you folks posses. I'd like to get as much pertinent information as I can upfront so that when the time comes I can make educated and confident decisions on what I'm doing.
 

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> "I hope me picking your brains isn't coming across the wrong way."
You are OK, we are trying to keep you from making expensive mistakes.

It is hard to distill years of reading this website into a few simple paragraphs. I had successfully completed a couple of gasoline engine swaps - It still took me about a year to get my simple (Ford / 4bt Cummins into a Ford) running. A stock 105 Horsepower (non-intercooled from the factory) should survive OK in your swap. It will work great for running the back roads to the feed store.

Read my signature below - other than a governor spring upgrade (more RPM) and a turbo from a 120 HP 4bt - the engine is unmodified. Gave me 150+ HP on a chassis dyno. Effortlessly cruises the interstate at speeds that could get me a ticket. The 5 speed overdrive, rear axle ratio, and oversize rear wheels/tires bring the RPMs down to the sweet spot - It took me several years of gradual modification to get there.

Due to packaging constraints, the intercooler is undersized. I DO have to watch the pyrometer when climbing hills. I did successfully pull the Grapevine (I-5, CA) towing a 1962 Volvo - I had to watch my pyrometer , slow down and run my truck speed/engine RPM in the safe zone (I did actually pass a couple of SWIFT semi-trucks).

Maybe build your truck, and each winter, upgrade it as your checkbook and skills improve?

Russ
 

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Depending on what engine you end up with, you could install it in bare stock power level and see how it performs. If you're not used to driving a diesel, it takes a bit of getting used to, especially the older type engine. Power comes on a bit slower than a gas engine but that torque is your friend. You might start out from a stop light and everyone leaves you, but your power starts to build and you'll soon catch up. Have to wait for that turbo to kick in. That's the one item that usually needs attention on the engine, especially the VE pump units. For 170-180 HP you'll need a better turbo unless you wind up with the P pump engine. If you change the turbo then you're going to need the intercooler. You'll literally have to rebuild you intake and exhaust plumbing over again which seems like a lot of unnecessary work. The HX30W is about 1.5" longer than the stock VE turbo so exhaust moves. Unless you wind up with a commercial model, the compressor outlet is different as well. You have a '90 Bronco so you've got a large engine bay. Same size as my '90 F250. With a 4bt you shouldn't need a huge radiator. The stock gas model is usually more than enough, and in fact certain ones may be too big depending on which size radiator you have. With a little work you can fit the intercooler from the early model Powerstroke 7.3. If you look for one of those be sure it's the all aluminum model. Early units had plastic tanks and those should be avoided. Another issue to consider is brakes. Diesels don't have vacuum so you have to decided either to add a vacuum pump to the engine or convert the vehicle to hydroboost. The F Superduty diesels from the same time period had hydroboost and that setup would bolt right up to your Bronco. On the later performance upgrades you need to ask yourself whether you want to tear it all apart again to get what you want.
 

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Char...

Correct me if I'm wrong... hydroboost didn't come into vogue till at least mid 99 for the Fords. Least ways, I know my 97 F350 is vacuum boost.

Cj
 

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Discussion Starter #36
You are OK, we are trying to keep you from making expensive mistakes.

It is hard to distill years of reading this website into a few simple paragraphs. I had successfully completed a couple of gasoline engine swaps - It still took me about a year to get my simple (Ford / 4bt Cummins into a Ford) running. A stock 105 Horsepower (non-intercooled from the factory) should survive OK in your swap. It will work great for running the back roads to the feed store.

Read my signature below - other than a governor spring upgrade (more RPM) and a turbo from a 120 HP 4bt - the engine is unmodified. Gave me 150+ HP on a chassis dyno. Effortlessly cruises the interstate at speeds that could get me a ticket. The 5 speed overdrive, rear axle ratio, and oversize rear wheels/tires bring the RPMs down to the sweet spot - It took me several years of gradual modification to get there.

Due to packaging constraints, the intercooler is undersized. I DO have to watch the pyrometer when climbing hills. I did successfully pull the Grapevine (I-5, CA) towing a 1962 Volvo - I had to watch my pyrometer , slow down and run my truck speed/engine RPM in the safe zone (I did actually pass a couple of SWIFT semi-trucks).

Maybe build your truck, and each winter, upgrade it as your checkbook and skills improve?

Russ
Amazing. Thats just the information I was looking for.
I might just leave it at stock hp for a while to see how It preforms.
I'd really like to find a p pump engine either one that I could pull or a core to rebuild but they seem to be in higher demand and more expensive. If I get lucky then fantastic. However I'm not opposed to pulling an engine over a winter sometime to do some upgrdes.
 

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Discussion Starter #37
Depending on what engine you end up with, you could install it in bare stock power level and see how it performs. If you're not used to driving a diesel, it takes a bit of getting used to, especially the older type engine. Power comes on a bit slower than a gas engine but that torque is your friend. You might start out from a stop light and everyone leaves you, but your power starts to build and you'll soon catch up. Have to wait for that turbo to kick in. That's the one item that usually needs attention on the engine, especially the VE pump units. For 170-180 HP you'll need a better turbo unless you wind up with the P pump engine. If you change the turbo then you're going to need the intercooler. You'll literally have to rebuild you intake and exhaust plumbing over again which seems like a lot of unnecessary work. The HX30W is about 1.5" longer than the stock VE turbo so exhaust moves. Unless you wind up with a commercial model, the compressor outlet is different as well. You have a '90 Bronco so you've got a large engine bay. Same size as my '90 F250. With a 4bt you shouldn't need a huge radiator. The stock gas model is usually more than enough, and in fact certain ones may be too big depending on which size radiator you have. With a little work you can fit the intercooler from the early model Powerstroke 7.3. If you look for one of those be sure it's the all aluminum model. Early units had plastic tanks and those should be avoided. Another issue to consider is brakes. Diesels don't have vacuum so you have to decided either to add a vacuum pump to the engine or convert the vehicle to hydroboost. The F Superduty diesels from the same time period had hydroboost and that setup would bolt right up to your Bronco. On the later performance upgrades you need to ask yourself whether you want to tear it all apart again to get what you want.
I'd love to be able to pull an intercooler off some other ford. It looks like that'd be a long term upgrade but something I'm interested in nonetheless.

As for brakes. To be honest I've been so focused on drivetrain and go-power that I hadn't even though about stopping power.
I need to put some more research into that.
 

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6.0L intercoolers fit 92-97 trucks really good, it will probably fit your truck too.

If it's primarily an offroad truck don't rule out the 4 speeds.
 

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Discussion Starter #39
Out of curiosity.

What would be an "undersized" intercooler? And how would I measure that?
 

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Cj, the hydroboost in the Ford trucks started with the 1987 F Superduty diesel (F450) chassis cabs. The regular diesel pickups were vacuum boost brakes up until around 1999 when all the HD trucks received the name Super Duty. Ford actually had hydroboost long before that. It was used on some Ford station wagons and Lincoln cars starting back in the late 1970's.

On the engines. If you can find a P pump 4bt there will be no question about an intercooler. It has to have one. As far as intercooler size, the general rule is the bigger the better so long as it will fit. I can give you the dimensions of the Ford unit I mentioned. About the only mod you will need to make outside of cutting holes for the pipes is modifying the hood latch support brace. You need to measure your radiator width. Some Broncos had a very wide radiator and won't fit the Ford F series intercooler. Space between the pipes is about 31". Here's a photo of what one looks like.
 

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