Dual Fueler questions...

CamTom12

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I bought this truck used and am not 100% sure of the mods on it, but it for sure has the ATS dual fueler kit and a large-ish non-vgt turbo.

Ever since I've owned it (12 months and ~15k miles) it's had poor fuel economy. Like around 15mpg highway. I drive pretty conservatively, too.

I noticed some fuel around the CP3 so I took it to a local diesel shop to see if he could find/repair the issue. He found the leak (fuel lines) and can fix it, but mentioned my poor fuel mileage was likely the CP4 failing. Is that likely?

Is it more likely that I have crappy mileage because of the dual fuel pumps or because the CP4 is failing? Would I have any other indications of a failing CP4 in a dual pump setup?

Thanks!
 

Black AOD

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I bought this truck used and am not 100% sure of the mods on it, but it for sure has the ATS dual fueler kit and a large-ish non-vgt turbo.

Ever since I've owned it (12 months and ~15k miles) it's had poor fuel economy. Like around 15mpg highway. I drive pretty conservatively, too.

I noticed some fuel around the CP3 so I took it to a local diesel shop to see if he could find/repair the issue. He found the leak (fuel lines) and can fix it, but mentioned my poor fuel mileage was likely the CP4 failing. Is that likely?

Is it more likely that I have crappy mileage because of the dual fuel pumps or because the CP4 is failing? Would I have any other indications of a failing CP4 in a dual pump setup?

Thanks!

A dual fuel 6.7 powerstroke with a good sized Non VGT, what you're getting isnt terribly far off. What size wheels and tires are you on? Does the truck have bigger injectors/nozzles? What tuning is on it?
 

CamTom12

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A dual fuel 6.7 powerstroke with a good sized Non VGT, what you're getting isnt terribly far off. What size wheels and tires are you on? Does the truck have bigger injectors/nozzles? What tuning is on it?


295/70R18 on the factory wheels. No idea on the nozzles or the tunes, though. It had a decent tune on it when I bought the truck, but I tried some tyrant tunes that I didn’t like as much so I went back to the mystery tune. Fuel mileage was about the same with the tyrant tunes.

That’s good to hear that I’m around the appropriate MPG. I was nervous about a big $$ repair. Although slightly disappointing that this truck will just have poor mileage it’s whole life, lol.

I’ve been thinking about swapping the non-VGT out for a VGT since I tow with this truck, but I wouldn’t guess that would effect the mileage much.
 

CamTom12

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Took some pictures from a highway drive the other day. This is empty on a generally flat road with calm winds.

071095496c42c2babd3501c68a7d2e2d.jpg


1d6f2bc62ab434d5ac2eaaa52bdbe1c5.jpg


That’s with the cruise set at 75mph gps speed. Speedo’s a little off.
 

pog

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meh. at 75mph what do you expect. its an 8000lb brick.
 

Petro

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I don't think 15 is bad to be honest. From the people I talk to, I think 15 is kind of on the upper end of what most people get with 6.7s. I've never personally owned a 6.7, but out of the 20+ 7.3, 6.0 and 6.4 trucks I've had, none of them ever did alot better than middle teens ever.
 

DieselJpower

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A small set of injectors say 45%-60% might be worth looking into. My truck with 60% and 70/87 s400 with dual fuel will knock down 18 mpg all day in town driving it pretty hard. Would probably see 21-22 no problem if I took it easier on it. Lives in the 850 hp file too. With stock injectors had just a single 10mm cp4 and 15.9 ish was as good as it would get with the same driving habits.
 

CamTom12

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A small set of injectors say 45%-60% might be worth looking into. My truck with 60% and 70/87 s400 with dual fuel will knock down 18 mpg all day in town driving it pretty hard. Would probably see 21-22 no problem if I took it easier on it. Lives in the 850 hp file too. With stock injectors had just a single 10mm cp4 and 15.9 ish was as good as it would get with the same driving habits.


Interesting thought!

Did you keep the 10mm CP4 or go to a new stock one when you went dual fuel?

How’s your setup tow with the larger injectors? Mine gets under the turbo below around 1600 rpm and I don’t like that. I’m not even entirely sure what turbo specs I have… here’s a picture measured across the inlet. Best I can guess is that it’s an Aurora 4000? I think maybe a 63mm inducer? There’s pretty limited info from ATS on their older powerstroke stuff these days.

2d241924cdea8cde41eae7f0a38131ff.jpg


Also, I forgot to mention that my truck usually gets between 1-2 mpg better hand-calculating than the dash shows. I don’t hand-calc every full-up though. Is your 18-ish backed up with any hand-calcs?

Thanks!
 

DieselJpower

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Kept the 10mm in the valley

This truck hasn't had a trailer attached for some time now so can't say for certain. I've had the bed loaded pretty heavy with this setup and the charger seeming to enjoy the added load and buit boost faster. I have a built trans too but converter is on the tight side. My other truck used to have a 369/10mm on stock injectors and it towed strong and came up a lil quicker then this s400 sized unit. Get familiar with the button shifter if you need it.



Hand calc I've seen the same thing as you a few times, drove from FL to AZ and it showed 19.6 average but hand calc 21-22. Averaged 85-90 mph the whole time too. However it's usually accurate or 1 mpg less. Guessing the the constant rolling burnouts are to blame

20220102-204942.jpg
 

CamTom12

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Kept the 10mm in the valley

This truck hasn't had a trailer attached for some time now so can't say for certain. I've had the bed loaded pretty heavy with this setup and the charger seeming to enjoy the added load and buit boost faster. I have a built trans too but converter is on the tight side. My other truck used to have a 369/10mm on stock injectors and it towed strong and came up a lil quicker then this s400 sized unit. Get familiar with the button shifter if you need it.



Hand calc I've seen the same thing as you a few times, drove from FL to AZ and it showed 19.6 average but hand calc 21-22. Averaged 85-90 mph the whole time too. However it's usually accurate or 1 mpg less. Guessing the the constant rolling burnouts are to blame

20220102-204942.jpg


Nice, thanks for the info!

Who did your tune?
 

Black AOD

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My 2017 F350 had an exergy 10mm pump, exergy 45% nozzles, 64mm VGT/FI S480 compounds, lowered on 33's and I got about 16 MPG averaged out between city/highway unloaded. On a 625HP tune.
 

DieselJpower

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Andrew , I've seen a few guys say they didn't see any mpg gains after injectors with the exception of Dillehay's 17. Some have theories that the vgt results in more fueling in the file but who knows.

CamTom , message me
 

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