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50 Gallon Fuel Tank

After a recent fuel stop in Oregon. The highest mileage range I've seen yet. I love that 50 gallon tank.


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Anyone have a "distance to empty" reading after fillup with the 50 gallon fuel tank
I just topped off this morning. It started at 716, then went up to 760 before going back down. Now it's around 685 after putting on 129 miles today.
 
Question for you with the 50 Gallon Tank - what settings did you change in Alfa OBD to make it work?

Did you use a Titan Tank with the stock sending unit, or something eles?
 
Okay - Follow up - 2021 Ram 2500 Mega.

Installed the Titan 50 Gallon today - OEM, I repeat, OEM! sending unit. I only changed this setting:


DTE - VehConfig3 - Fuel Capacity - 194.000 liters

Using AlfaOBD. Works perfectly. 860 miles to empty.
 

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Okay - Follow up - 2021 Ram 2500 Mega.

Installed the Titan 50 Gallon today - OEM, I repeat, OEM! sending unit. I only changed this setting:


DTE - VehConfig3 - Fuel Capacity - 194.000 liters

Using AlfaOBD. Works perfectly. 860 miles to empty.
With the 17.3 mpg avg there, that's to be expected. I can get around 1000 mile range if I am unloaded and on freeway using cruise. Get about 20 mpg then in my dually. But I daily drive my truck for work and pleasure. So my mileage is typically much lower as my commute is 6 miles each way to work.
 
Filled up the Titan for the first time and got a DTE of 620. I was on a bit of an incline while filling, however some are getting over 800 DTE.

A bit weird there's a big disparity. Perhaps filling up completely flat will add a couple more gallons.
 
So excuse my question as it may be a dumb one since I think I've over done it on the apple pie. As I mentioned, if I we're to get an aux fuel tank put it in my bed and secure it, all I was planning on doing was the simple gas line out the bottom to trickle into T- connection kit you put into fuel line. You guys talk about changing the tank size in obdll to calibrate your new bigger fuel capacity. How does the gauge/ system know how much fuel is in the aux tank portion to read out to you? Originally I figured the gauge would just stay on full until aux tank was empty. What am i missing here? Or is my friend missing here, he's really confused. Just asking for a friend.
A gravity feed fuel tank in the truck bed is ignored on the MTE calculation. it just adds fuel when the valve in the bed is opened. Then it's a slow fill of the stock fuel tank.
 
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Filled up the Titan for the first time and got a DTE of 620. I was on a bit of an incline while filling, however some are getting over 800 DTE.

A bit weird there's a big disparity. Perhaps filling up completely flat will add a couple more gallons.
The disparity is based on what fuel mileage you were getting between fill ups. Mine, in town, consistently will show around 600 range when filled up. I average 11 to 12 in town as most my driving is in city. If I am out on the interstate where I can get up 20 mpg, then my RTE when filling up with be well over 800 to maybe 900. But that is only after I get back on the road and am averaging the 20 mpg. I have a feeling that the fuel sending unit on my original 32 tank, isn't the same as the optional 50 gallon factory tank in 2020 model. But nothing to back that claim other than a gut feeling. It takes a bit for the fuel level to start dropping on a full tank, even with it set at 194 liters.
 
The disparity is based on what fuel mileage you were getting between fill ups. Mine, in town, consistently will show around 600 range when filled up. I average 11 to 12 in town as most my driving is in city. If I am out on the interstate where I can get up 20 mpg, then my RTE when filling up with be well over 800 to maybe 900. But that is only after I get back on the road and am averaging the 20 mpg. I have a feeling that the fuel sending unit on my original 32 tank, isn't the same as the optional 50 gallon factory tank in 2020 model. But nothing to back that claim other than a gut feeling. It takes a bit for the fuel level to start dropping on a full tank, even with it set at 194 liters.
Ah okay. Makes sense.
 
The disparity is based on what fuel mileage you were getting between fill ups. Mine, in town, consistently will show around 600 range when filled up. I average 11 to 12 in town as most my driving is in city. If I am out on the interstate where I can get up 20 mpg, then my RTE when filling up with be well over 800 to maybe 900. But that is only after I get back on the road and am averaging the 20 mpg. I have a feeling that the fuel sending unit on my original 32 tank, isn't the same as the optional 50 gallon factory tank in 2020 model. But nothing to back that claim other than a gut feeling. It takes a bit for the fuel level to start dropping on a full tank, even with it set at 194 liters.
I believe the reason it takes so long for the fuel gauge to start dropping is due to the tank geometry and the location of the float. For the S&B tank (52 gallons) I recently installed, there are about 5 gallons of capacity ABOVE the top of the float. Therefore, fuel level for the gauge will only drop once below that line. Please see the illustration I have marked up. The other picture is from S&B with marks indicating levels on the tank. I have reached out to both S&B and Alexi from AlfaOBD to see how to tune/calibrate the float for accuracy based on the tank geometry because the float drop won't be linear (and the first few gallons won't be registered). Ideally, I would like to correspond the float voltage with the capacity remaining in the specific tank - this is something S&B is working on.
 

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Okay - Follow up - 2021 Ram 2500 Mega.

Installed the Titan 50 Gallon today - OEM, I repeat, OEM! sending unit. I only changed this setting:


DTE - VehConfig3 - Fuel Capacity - 194.000 liters

Using AlfaOBD. Works perfectly. 860 miles to empty.
@rfullen280 - I have a 2018, so maybe something is different... My fuel thank was Full and the Fuel Gauge was reading Full. When I changed the DTE - VehConfig3 - Fuel Capacity - 194.000 Liters, the Fuel Gauge went from Full down to 2/3.. Maybe I just needed to drive it some and some on/off of the key would have 'fixed' the fuel gauge reading?
 
I also just finished installing the S&B 52 Gal this past weekend on our 2020 RAM 3500 MC and also used the OEM sending unit. Everything works as it should after changing the DTE - VehConfig3 - Fuel Capacity - 197.000 Liters,
 
I also just finished installing the S&B 52 Gal this past weekend on our 2020 RAM 3500 MC and also used the OEM sending unit. Everything works as it should after changing the DTE - VehConfig3 - Fuel Capacity - 197.000 Liters,
Question for you:
For my 52 gallon S&B tank, the fuel gauge and DTE will indicate I am empty when I still have at least 8 gallons remaining in the tank (measured at fill up). As the fuel float at empty is at the bottom of the sending unit, I don't know if the sending unit can suck up those last 8 gallons but I am hesitant to try driving in the "empty" zone. Have you driven when the fuel gauge says empty? How far have you gone? I am concerned that the S&B tank only has 42-44 gallons of "usable" fuel capacity but I cannot get anyone at S&B to respond to my question. See attached illustration.
 

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Question for you:
For my 52 gallon S&B tank, the fuel gauge and DTE will indicate I am empty when I still have at least 8 gallons remaining in the tank (measured at fill up). As the fuel float at empty is at the bottom of the sending unit, I don't know if the sending unit can suck up those last 8 gallons but I am hesitant to try driving in the "empty" zone. Have you driven when the fuel gauge says empty? How far have you gone? I am concerned that the S&B tank only has 42-44 gallons of "usable" fuel capacity but I cannot get anyone at S&B to respond to my question. See attached illustration.
Other than the sag of the tank you should be fine getting most of the fuel out just remember even with the oem tank there seems to be a 5 gallon discrepancy when it shows empty most likely a built in reserve… the S&B tank sits the pump low enough to get the bottom of the tank from my quick look
 
Other than the sag of the tank you should be fine getting most of the fuel out just remember even with the oem tank there seems to be a 5 gallon discrepancy when it shows empty most likely a built in reserve… the S&B tank sits the pump low enough to get the bottom of the tank from my quick look
Thank you for your response. Is the pump inlet lower than the float bottom?
 
Thank you for your response. Is the pump inlet lower than the float bottom?
The pump inlet should be right on the bottom of tank +- 1/8 of an inch just because the float can go past the bottom of the pump does not mean thats where it reads low fuel
 
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