Vehicle: I have a 1990 E350 retired U-Haul that I built into a motorhome. 7.3 IDI w/ Banks turbo, pump up 1 flat, ZF5, BW1356 and Dana 60 up front.
I am happy with the power and torque of the motor as well as the mileage, but the motor has a lot of miles on it and will need a rebuild soon. everything else is newish. I have a spare motor to build and swap when complete if I go that route, but if I do That would include; lowered compression, ceramic coated pistons, gapless comp rings, head studs, Inconel ex valves, and a few other items. $$$
According to my meas tape a 6BT is too long, but a 4BT would fit nicely. I like the IDI motors just not in a van cab, I have insulated like no other and the doghouse gets too hot to touch. A 4BT would get the turbo and exhaust away from everything and still have room to work on.
Question: can a 4BT be turned up to be comparable to the turbo'd IDI and still be reliable for say 200k miles. My vehicle is 10k ponds and shaped like a brick and I sometimes tow with it.

 

A wrap on the turbo and up pipe will really help keep under hood temps down. A 4BT will be able to do the job, they were swapped into P30 chassis bread vans and the like, but it's a crude engine. Very very rough idle, loud, and a low top RPM. You will need to add noise insulation, and regear to take full advantage of the different torque curve.

 

I have a turbo blanket, wrapped wye pipe and wrapped down pipe. Up pipe is 2 1/4" tubing and down pipe is 3" so being a van cab it doesn't leave for much room. They are touching the doghouse insulation. I am pondering scooting the motor forward about an inch. As far as the noise I don't think it would be a problem because it came stock with the diesel so firewall and doghouse are insulated.

 

I've driven two 4bt swaps both in dodge Dakotas and wasn't really impressed vs the 6bt. The 4bts can fetch quite a premium as well. They were pretty sluggish/smoky on the bottom end, and like he said low top rpm.

Maybe with headstuds, injectors, and a hx35 swap it would probably make you really proud. But that's just more money

 

Don't. Just... don't. It won't net you anything; IDIs like their compression. I ran a set of decompression gaskets(extra thick), and while it started... it kind of sucked until you got boost. Also, much harder to start, and lots of white/gray smoke on startup. Needed much more advanced timing to even start at all.
Went back to stock gaskets and... night and day difference.

Plus, considering all of the high HP IDIs are running basically stock compression... why bother?
You can get 250 at the wheels with a bone-stock 7.3 IDI(with turbo), and up to 350 safely with a set of headstuds, and beyond that, the limit is the connecting rods.

 

Huge difference in noise. A direct injected engine will be louder than am IDI, just by the nature of the injection system. If you want an idea of noise, try driving a first through third gen Cummins powered Dodge. I used to regularly drive a 24valve 99 Ram 3500, and it was LOUD inside. Even with the factory sound damping, you could not carry a conversation without yelling to each other. It was about on par with my 69 F250 7.3 conversion without sound damping.
If you must have a 4cyl diesel, I would actually recommend one of the Isuzu diesels, specifically the 5.2l used in the NPR trucks. It had plenty of power, good mileage, and aside from a coarse idle on par with the 4BT, pleasant to drive. It is also designed to shove around heavy boxy vehicles, and can be diagnosed using a standard OBDII code reader.

 

They aren't near as rough as people make them out to be. As for the noise though, yes, they are loud.

As for the low top RPM and sluggish/smoky comments, I will put my 4BT up against 95% of turboed IDI's on here and clean their clock with opacity, low end torque, top end power, fuel mileage, startability, etc.

 

I wish I was closer to you... I'd put my turbo idi up against your 4BT any day.
The fuel mileage, well, pretty sure you'll win that. Everything else... Not convinced.

What do you have your 4BT in, btw? I don't see it in your signature.

 

1990 F350 4X4 - Should be in my sig (at least I see it).

You might be one of the 5% that would be able to keep up.

I'm still 100% sure that I would win startablility and exhaust opacity.

Let's put it this way. I took an engine that could produce about 180 HP and added a turbo. You took and engine capable of producing 180 HP and added a turbo. We should be on a pretty level playing field.

 

Put 15k behind that puppy and see if you can see my tailgate in a few miles, fuel efficiency and exhaust opacity yes, but not sheer torque,

 

​​​​Try 20k. You think I built an F350 to use as a car? Off idle you will have more grunt, but once I get to about 1200 rpm the turbos come alive and off we go.

 

We should all chip in and have a big sled pull competition somewhere in the middle of the country so everyone can come.

We'll get a Chinook to pick Macrobb up!

 

Sounds like a plan! :P

 

I understand that you can build a 4bt to smoke an idi and you can build an idi to smoke a 4bt, the sky's the limit with enough money. I like both motors and have a 6bt in my90 f350 4x4. If I could fit one of those in the van cab I would. The idi is a motor I'm rather fond of if built properly, but in a van cab they suck to work on. A Cummins with industrial manifold would put the turbo in a really good place which is why I would like it. Seeing as how it's a motorhome I don't want it to smoke when taking off so what I'm wondering is if I hopped up a 4bt to perform sufficiently would be dumping smoke. I'm thinking head studs, valve springs, turned up pump, bigger injectors, either twin turbos or just bigger turbo.
Redneck 1972- Seeing as how you have one I'd like more input from you please. Yours is a common rail? I am thinking of a P-pumped 8v just to keep things simple.

 

Nope, mine's just a puny VE pumped 8 valve with a set of run-o-the-mill flow honed 5X12 injectors, head studs, O-ringed head, and an HX30W over a 60mm H1C.