The Ute II: E350 RB 7.3 ZF6

[naterry]

I finally got all this plumbing sorted and now the van runs again! As fun as it is to improve the package I still hate having it out of commission. It feels like my Armageddon Kit is broken, and it's just too big for a lawn ornament...

So we're now rolling electric fuel with enough capacity to double the power if I ever go that route (highly unlikely) and a pieced together 4" CAI with NAPA 6637 filter (made possible by the removal of the fuel bowl). I had some bogging at higher throttle positions and decided to eliminate the weak links in the fuel system all together (in tank screen, FPR spring on the bowl, irregular pressure across the rails, etc). There are multiple ways to do both of these modifications and mine is by no means the best or most bad ars route. It's somewhere in the middle, with durability and reliability at the top of the requirements list. No time for a test drive today, I'll report back if there are any improvements.

The following are some pics showing a few of the key points required to switch the fuel and squeeze in the CAI-

Here's the OEM mechanical lift pump and fuel filter bowl. Note the OEM FPR on the side of the fuel bowl. Anyone who's replaced this pump on a van knows what an epic PITA it is, adios mechanical pump!:

The OEM swirl pot/sending unit has to be gutted to make room for the new pickup tube. This can be done with compression couplers, and the pickup tube should be 1/4" to 1/2" off the bottom of the tank (triple check this). Note that the return line drains back into this can:

From the tank the fuel goes to a pre-filter/water separator (CAT 175-2949), then a Bosch 044 pump (lots of options here, I've just had good luck with the 044's), and finally a post filter (CAT 1R-0750 Fuel Filter, 2 micron):

After the filters it's pretty obvious- -8 line going to a "T" feeding two -6 lines to one end of each head, out the other end and into the FPR which then has one -6 return output back to the tank:

I chose to mount the FPR on the roof of the engine bay away from major vibration. I saw lots of guys mounting it on the motor which I don't think is a good idea. 62 psig (factory says 45-65):

With the fuel bowl out of the way there is ~4.5" tall by 6" wide gap between the firewall and HPOP reservoir. Here you can see one end of the 4" to 3" 90 degree reducing elbow coming off the turbo through said gap:

Zoomed out:

Here is the reducing elbow from the rear:

For reference here is the new 4" intake configuration next to the OEM assembly (the reducing elbow is not shown on the left):

The NAPA 6637 (8.5" Dia x 11" long) just BARELY fits between the radiator core support and the HVAC assembly. I trimmed the spot-welded lip and welded it back together to make this cleaner and not tear up the filter during the install and future cleaning:

With filter in the hole and the elbow on the snail the rest is just bloody knuckles and hose clamps:

The single aluminum section is there because the gap between the radiator and the HVAC assembly is almost exactly 4.125". This is too tight for the plastic tubing OD because it has a thicker wall than the aluminum tubing:

While I was in there I also got rid of the old spider boots, they were long overdue:

Next I'm going to fab a little box to keep the hot air away from the filter, and then back to the camper conversion bits.

Cheers!

 

[Bbasso]

Impressive

 

[89s rule]

Very Nice. Have considered moving my batteries to the frame rail for this purpose. Keep us posted on MPG/responsiveness, etc. after and before the mods. Really considering the fuel mods as that fuel bowl is a pain.

 

[SHAFT]

This flipping build is so rad.....

 

[naterry]

Cheers, it's a fun van!

Keep us posted on MPG/responsiveness, etc. after and before the mods. Really considering the fuel mods as that fuel bowl is a pain.

It's been a few weeks so feedback time. Back in school I was taught to change only one variable in a system at time in order to isolate causation. That would have been ideal but there was no way I was going to spend any more time behind that dog house than I had to so I did everything I could "while in there"...

The good news is that all of the symptoms suggesting fuel or air starvation are gone. Way gone. The van drives better than it ever has on my watch but I'm not certain which "fix" to credit. That said, there are a few quantifiable differences to note. The main one is that I am now getting ~25lb's of boost pressure compared to the low/mid teens before. This suggests that I had a boost leak, so check your spider boots or better yet replace them because they are cheap and easy. Next is the night and day difference in throttle transition smoothness. Tip-in off idle is like butter now, and all changes in throttle positions partial to full and everywhere in between are notably smoother. Lastly, the van smokes less. A lot less. It used to puke fuel at higher throttle (I think this was/is related to the improved boost noted above).

The rest of the improvements are more subtle. It seems like it starts easier, runs quieter, and has more power but I'm hesitant to make any claims on these observations because they are subjective. Unfortunately my butt dyno is not certified, or even calibrated. No info on fuel economy yet, but coming soon-

 

[naterry]

In other news here's my sliding pop-top I'm gathering parts for:

 

[ohpyramids]

I cannot wait to see this top

 

[Abitibi]

Every once in a while someone comes up with something different than the cookie cutter template. And that sliding roof on top of the pop up roof is proof there's still hope in the world of custom build.

Naterry that is one cool concept! Back up next to a pool and you've got your own private diving board! Seriously though, you've got yourself an opening roof that doubles as a rear awning! Pretty cool.

About your fuel bowl removal, do you think it'd be the same for the later 7.3's? I did something similar to yours and bypassed it but didn't remove it yet. I thought there might be sensors attached to it... Also on my remote filters I build a"cage" to protect them.

Also did you just replace the original air filter cause you could or you see a benefit there? Unless you're thinking of going this route?

Cheers
Mr. D

 

[naterry]

Back up next to a pool and you've got your own private diving board! Seriously though, you've got yourself an opening roof that doubles as a rear awning! Pretty cool.

About your fuel bowl removal, do you think it'd be the same for the later 7.3's? I did something similar to yours and bypassed it but didn't remove it yet. I thought there might be sensors attached to it... Also on my remote filters I build a"cage" to protect them.

Also did you just replace the original air filter cause you could or you see a benefit there? Unless you're thinking of going this route?

Cheers
Mr. D

Haha, yep. Awning and patio. I designed and analyzed the frame around a 500lb point load at the end of the platform. This load will result in ~.5" deflection with a factor of safety over 3. Two of what I'm calling "lockout frames" hinge up in the raised and extended position making it a usable cantilevered platform 126" up. These frames aren't required in the lowered position. I wanted to be able to sleep under the stars inside the van and/or have an upper deck.

AFAIK the fuel bowl is in the same position in newer 7.3's. The only sensors on mine were the fuel heater and water sensor. I like your fuel cage BTW, looking forward to copying it!

Regarding the intake: No plan for a snorkel (yet). I'm not a diesel expert but theorized that my symptoms might have been related to choked intake flow. One thing I do know about diesels is that they almost always like more air. It was low hanging fruit with the fuel bowl deleted, and it also significantly cleans up the engine bay.

 

[mk216v]

In other news here's my sliding pop-top I'm gathering parts for:

Stargazers unite!

 

[vwteleman]

That's very similar to the GTRV lifting mechanism. Very cool.

 

[gtbensley]

Such an awesome van! Thanks for documenting this. Any idea if a transfercase used on a quigley conversion can be used with the zf6? I have a 1995 quigley 7.3 and would LOVE to swap in a stick. Not much of a fabricator though, never welded anything.

 

[E350]

naterry: Interesting. Thank you for documenting your build.

First: What are your differential ratios and what is your mpg with the manual transmission?

Second: Do the earlier 7.3's have an in tank fuel pump? My 2002 E350 7.3L diesel has a frame rail fuel pump and only a sender (with various screens) in the tank. My 1995 5.8L gas Bronco has a pump on the sender in the tank (which looks a lot like or identical to the one you removed). I just recently replaced the Bosch fuel pump on the Bronco's sending unit.

Third: Your home base is S.F. Do you ski in the Sierra's? How are you planning to heat the fuel to keep it from gelling now that you have eliminated the fuel bowl which contains a fuel heater?

Fourth: Did only the earlier 7.3's have the air box? I am pretty sure that my air filter tubing does not have that air box? What does it do? Is it a resonator?

Fifth: The vanes on your turbo look very good IMHO. I am afraid of dusting the turbo and piston rings by poor sealing of the stock air filter box. So I have been thinking of doing what you did on the air filter. But the original air filter box has scoops which point to the front of the vehicle while your (my possible) set up does not have those scoops. Do you think you are getting more or less air via your new air filter set up?

 

[naterry]

Any idea if a transfercase used on a quigley conversion can be used with the zf6?

Chris would know this. My guess is yes but not certain.

naterry: Interesting. Thank you for documenting your build.

First: What are your differential ratios and what is your mpg with the manual transmission?

Second: Do the earlier 7.3's have an in tank fuel pump? My 2002 E350 7.3L diesel has a frame rail fuel pump and only a sender (with various screens) in the tank. My 1995 5.8L gas Bronco has a pump on the sender in the tank (which looks a lot like or identical to the one you removed). I just recently replaced the Bosch fuel pump on the Bronco's sending unit.

Third: Your home base is S.F. Do you ski in the Sierra's? How are you planning to heat the fuel to keep it from gelling now that you have eliminated the fuel bowl which contains a fuel heater?

Fourth: Did only the earlier 7.3's have the air box? I am pretty sure that my air filter tubing does not have that air box? What does it do? Is it a resonator?

Fifth: The vanes on your turbo look very good IMHO. I am afraid of dusting the turbo and piston rings by poor sealing of the stock air filter box. So I have been thinking of doing what you did on the air filter. But the original air filter box has scoops which point to the front of the vehicle while your (my possible) set up does not have those scoops. Do you think you are getting more or less air via your new air filter set up?

1- I'm running 3.73 diffs and was getting mid-upper teens before the fuel and intake (depending on the terrain). I'm expecting slightly better but don't know yet.
2- Nope, the early 7.3's only had the mechanical i show above that mounts next to the fuel bowl and runs off the cam.
3- Absolutely! Waking up to snow plows is a frequent event for me. The heater is on the same circuit as the injector control module and glow plug relay, and if it shorts the truck dies. People have been unplugging the heater for years to eliminate this possibility without issues. There's a healthy debate about whether it matters or not. I also run fuel treatment to prevent gelling well below zero in the winter.
4- Mine's a 96, so not sure how early you're curious about. Yes it's a damper/resonator, and totally jams up the space of the motor. Glad it's gone.
5- Sorry, I have no clue if I'm actually getting more air flow, just following the herd with the NAPA 6637.

 

[DzlToy]

Cool build man, just read the entire thread.

How do you find the power with 3.73's and 35" tires? IIRC, the NC271/3 is a 2.72 ratio and you have a granny first, so crawling should be half decent, but that seems to be a big tire for that gear in a loaded van.

cheers