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New Fuel Tank Design

How important is capacity to you?

  • 17 gallons is good enough

    Votes: 20 10.3%
  • 18-20 gallons is better

    Votes: 103 53.1%
  • 23 gallons is preferred

    Votes: 50 25.8%
  • 23 gallons is not enough

    Votes: 21 10.8%

  • Total voters
    194

nvrstuk

Contributor
Just a Bronco driver for over 50 yrs!
Joined
Jul 31, 2001
Messages
8,604
I have sat in the drivers seat many, many times burning an entire aftermarket 23 gal tank... but this was years ago. I ran an 11 gal aux also and tried to fill up in Canada as little as possible at 2x the price-- typically of what a US gal costs... so for me back in the day MAX capacity was important. I did the same for a boat we hauled up to BC also. I put in an additional tank so I wouldn't be paying double.

Now I only burn about 17-20 gal/week...every week except when the roads are so slick I'm not just cruising.

I get along fine now with a 22 gal tank that I've done major modifications on 4 times now. Important things: all the things Yeller said... having the option for EFI and replacement parts... trick one of a kind stuff is cool till you actually use your Bronco somewhere out in the sticks and your vacation is now "on hold" because you need to order a replacement of the one of a kind part... :(

I would rather have a tank hang down a bit than be out of gas on a 100 mile one way trip into the Grand Canyon... all on a dirt road w/o a single business much less a gas station. Or fishing trips in BC where I would rather drive an extra 5 hours just to make sure I don't see anyone else... Guess my use is different than 90% of the rest of you! :)
 
Last edited:

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
I'm putting in a request for an integrated rollover valve built into top of tank for the evap canistor system. I'm having a dickens of a time locating an external rollover valve, and I need one, when tank is full, slowing down pushes gas into evap vent line.
 

ransil

Bronco Guru
Joined
Sep 6, 2003
Messages
8,122
I'm putting in a request for an integrated rollover valve built into top of tank for the evap canistor system. I'm having a dickens of a time locating an external rollover valve, and I need one, when tank is full, slowing down pushes gas into evap vent line.

I route the the tubing up along the filler neck and as high up as I can then back to the frame to continue normal routing.
rollover would be nice to have.
 

EricLar80

Bronco Guru
Joined
Jun 14, 2001
Messages
2,170
The results of the poll are showing that a 17-20 gallon capacity is desirable for an alternative. After starting mock up and doing some calculations it is looking like the total capacity will be in the 20 gallon range with a useable somewhere between 17-18 gallons. Of coarse you could squeeze a few more in to get the capacity up to the total however it will negate the expansion chamber that all of the other makes are using to achieve their 23 gallon capacity and this does lead to fuel coming out of the fill tube as well as filling up the evaporations system or charcoal canister. Just something to think about. It will have baffles, they are most important when you are below a half tank to avoid starvation. Straps are OK but we have found that they do interfere with the exhaust routing when going to a 3" outlet. We are also designing new exhaust systems at the same time so 3" clearance for routing around the tank is a must. When finished this will work with most if not all of Duff products that are existing or in development as well as many of the current other vendor exhaust systems and suspensions. We are eliminating the strap design as well as the track design. It will be a very clean, robust and strong installation. I am also starting the search on OE style fuel pick ups now that I have some preliminary mock ups done. Looking for an off the shelf unit that is currently in production and easy to get a hold of but it also has to be easily upgraded with an aftermarket pump for higher HP applications for those needing more fuel supply. So far the results have not been as favorable as an aftermarket unit but I am looking.

Where were you a year ago when I was working on modifying my 23 gallon down to the 18-20 gallon range? If you want to compare notes, I have a design in solidworks that maximizes the volume of the tank while taking up the least amount of ground clearance. Seems to line up with everything you are intending to do. PM me if you want me to create an engineering drawing of what you have planned for purposes of quoting, etc.
 

bigmuddy

Contributor
Bronco Guru
Joined
Dec 28, 2004
Messages
7,001
Loc.
Marthasville Missouri
So keep in mind I have a 2" body lift and the skid plate which hangs down an extra inch. But the BC tank which is 23 gal, from ground to the bottom of the plate is 17" of clearance and well above my rear bumper. From the bottom of the frame to the bottom of skid plate the tank hangs down 8" below the frame, without the skid plate it would hang down 7" below the frame.

For a 23 gal tank, I am happy with the clearance but as said before I don't like the lack of a drain port of the crappy sending unit, but I have new cylindrical sending unit that will hopefully fix that issue.

For those that may not have seen it, Skeeters hotrods makes a fuel gauge module that is supposed to make any sending unit work with any fuel gauge?
 

BruiserOutdoors

Full Member
Joined
Aug 22, 2013
Messages
735
We would prefer a 20 gallon tank and also why hasn't anybody made an AUX tank like the factory one under the drivers seat for extra capacity?? EFI Compatible? Most broncos already have two filler necks, might as well use them. Right?


We would love max fuel range without giving up ground clearance.
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,344
I think I've heard that they're too shallow for a decent pump setup and an air gap at the top. Seems like it should still be doable to me though. With a bit of extra cleverness.

Paul
 

tripleJs15

Jr. Member
Joined
Jun 20, 2020
Messages
157
Hey guys and gals, I am looking to make a new fuel tank for the EB to offer. As most of you know we (Lick Creek Restorations) have been working very closely with James Duff Inc. to bring some awesome new products to market. We are addressing items that we have found to be issues or lacking features etc. in the building side of things and Duff has been working with us to make them. One item we have coming up is the fuel tank and I need to get an accurate gauge of interest on the features. Some questions I have primarily run to fuel capacity and how important it is to you. For example we all know the stock tanks are lacking realistic capacity however with the 23 gallon tanks they hang down pretty low and with no or 1" body lift they can be intrusive for mild off roading not to mention a bit ugly like a baby diaper full of crap... Anyways here is the questions, please spend some time thinking about it and please feel free to comment. All of this info will help to better guide the design of this tank to try and check off as many boxes as possible that actually fill the needs of most.

Capacity while more is better it sometimes is not always necessary, thinking of trying to get it in the 18-20 gallon range is a thought. Coming form someone who has done a lot with their bronco, travel, off road etc. I honestly have never sat in the seat long enough to burn the entire capacity of the tank up in one go. The most I have used before my back and butt said they needed to stretch was 17 gallons and that was towing my pop up to Michigan 2 years ago. So I am trying to think on the level of practical compromise here by reducing the hang down some for off road use as well as aesthetics. Please let me know your thoughts on this.


I’ll be interested in this tank - I’m picking up the 4 link setup next week, so having an option that’s compatible would be key for me.

Few other points:
Recessed AN ports and access
Return and returnless (can be capped/plugged)
Fuel basket/surge setup that can handle slush and multiple standard pumps ( like the forge setup)
Drain plug
Stainless
Optional skid plate
Angled on the back side (for clearance)


Sent from my iPhone using Tapatalk
 

73azbronco

Contributor
Bronco Guru
Joined
Nov 11, 2007
Messages
7,796
I route the the tubing up along the filler neck and as high up as I can then back to the frame to continue normal routing.
rollover would be nice to have.
I will do that routing trick, as well I have sourced the only reasonable priced real live rollover valve using 1/4 hose ends. My previous find of using a rollover valve from a get this DeLorean, finally cracked after sitting in the heat for 2 years.

https://www.murraymotorsport.com/roll-over-valve

Yeah, $50, plus some $30 shipping from UK, beats all US versions by 300 or so bucks. Yeah, $400 was a best price for similar US made valve.
 

blksn8k

Sr. Member
Joined
Sep 28, 2003
Messages
528
Whatever you do please include a reasonably accurate sending unit. The ones I have tried so far only seem to be accurate at the top or when the tank is nearly full. That's kinda ridiculous when most people would (or should) be more interested in knowing when they are approaching empty.
I currently have an older BC tank that was rated at 24 gal when I bought it back in 2004 but may have been re-rated to 23? Anyway, it has a partially angled bottom to increase departure angle which is probably playing havoc with the sending unit as well.
What I have found with the solid vertical rod sending unit design which uses a doughnut shaped float is that there seems to be too much resistance in the rod at the lower fuel levels which causes the gauge to read too low. For example, my tank has about 10.5 gal in it right now which equates to right at 6" of fuel and the gauge reads right on "E".
My thoughts are that the vertical rod that the composite float slides on needs to be tapered so that it is smaller near the bottom which would create less resistance in the rod at lower fuel levels and thus a higher, and hopefully more accurate, reading on the gauge.
I don't care what the gauge says when the tank is full. I want to know when I'm going to run out of gas. With what I have now if I fill up every time the gauge reads "E" my effective driving range wouldn't be much better than if had kept the original tank. All I have gained is a lot of useless extra weight.
 

blksn8k

Sr. Member
Joined
Sep 28, 2003
Messages
528
For a 23 gal tank, I am happy with the clearance but as said before I don't like the lack of a drain port of the crappy sending unit, but I have new cylindrical sending unit that will hopefully fix that issue.

For those that may not have seen it, Skeeters hotrods makes a fuel gauge module that is supposed to make any sending unit work with any fuel gauge?

I'd be curious to hear your results with the cylindrical sending unit.

On the fuel gauge module, I spoke to one of the tech guys at Autometer yesterday and one of my questions for him was whether or not the similar module they make would be able to correct the sending unit/fuel gauge issues I'm having.

In my case, I have an Autometer gauge rated for 73 Ohms empty and 10 Ohms full. The solid vertical rod sending unit I currently have in the tank shows 73.4 Ohms empty and 10.7 Ohms full on my multi-meter. Should be fine, right? The problem is that with about 10.5 gallons in the tank it measures 53.1 Ohms at the gauge end of the wire which reads "E" on the gauge. The 18 gage wire by itself measures an insignificant 0.4 Ohms over its entire length.

His answer was no, Autometer's "Fuel Bridge, Fuel Signal Adapter" is only designed to correct the signal from the sending unit when the Ohm (resistance) ranges of the sending unit and the gauge are not compatible. In other words, it can adjust the signal if you are using say a GM sending unit and a Ford gauge or vice versa but it cannot fix issues with sending units and gauges that are rated for the same Ohm range.

I'm guessing the Skeeters module would be the same?

Edit: After reading Autometer's description again I'm still not convinced that what the tech guy told me is correct. Here's the part of the description that gives me hope:

Configurable option with linear adjustments at 5 points (F, ¾, ½, ¼, & E) anywhere between 0-1000 or 1000-0 ohms
 
Last edited:

toddz69

Sponsor/Vendor
Bronco Guru
Joined
Nov 28, 2001
Messages
10,079
I'd be curious to hear your results with the cylindrical sending unit.

On the fuel gauge module, I spoke to one of the tech guys at Autometer yesterday and one of my questions for him was whether or not the similar module they make would be able to correct the sending unit/fuel gauge issues I'm having.

In my case, I have an Autometer gauge rated for 73 Ohms empty and 10 Ohms full. The solid vertical rod sending unit I currently have in the tank shows 73.4 Ohms empty and 10.7 Ohms full on my multi-meter. Should be fine, right? The problem is that with about 10.5 gallons in the tank it measures 53.1 Ohms at the gauge end of the wire which reads "E" on the gauge. The 18 gage wire by itself measures an insignificant 0.4 Ohms over its entire length.

His answer was no, Autometer's "Fuel Bridge, Fuel Signal Adapter" is only designed to correct the signal from the sending unit when the Ohm (resistance) ranges of the sending unit and the gauge are not compatible. In other words, it can adjust the signal if you are using say a GM sending unit and a Ford gauge or vice versa but it cannot fix issues with sending units and gauges that are rated for the same Ohm range.

I'm guessing the Skeeters module would be the same?

So sorry to hear that your solid vertical rod unit seems to be worse than the old swing arm unit it replaced. I was really hoping it would be a nice accurate replacement for the swing arm units.

Before I got rid of my BC tank, I was going to try one of the cylindrical units but didn't get it ordered/installed before I decided to ditch the tank. Tanks Inc sells one that I was going to try.

As far as tank shape is concerned, my new WH tank is shaped a lot like the BC tank with the sloping rear bottom and the ISSPRO sending unit (cylindrical) they use is the most accurate I've ever had in an aftermarket tank. Still doing measurements/fill-ups to get a feel for accuracy but right now I'm seeing about 3-3.5 gallons left in the tank when it gets to 'E', which is pretty good in my book.

Todd Z.
 

duffymahoney

Contributor
Bronco Guru
Joined
Apr 26, 2015
Messages
2,556
We welded stainless AN Fittings (JIC) to my tank, that really worked out well. So vent, pickup and return were all JIC fittings on the tank. Easy and simple way to hook up lines. I would also put a drain in the lowest point. Being able to drain fuel has proved to be important a few times.

Biggest question in my mind is in tank pump or external.
 

blksn8k

Sr. Member
Joined
Sep 28, 2003
Messages
528
So sorry to hear that your solid vertical rod unit seems to be worse than the old swing arm unit it replaced. I was really hoping it would be a nice accurate replacement for the swing arm units.

Before I got rid of my BC tank, I was going to try one of the cylindrical units but didn't get it ordered/installed before I decided to ditch the tank. Tanks Inc sells one that I was going to try.

As far as tank shape is concerned, my new WH tank is shaped a lot like the BC tank with the sloping rear bottom and the ISSPRO sending unit (cylindrical) they use is the most accurate I've ever had in an aftermarket tank. Still doing measurements/fill-ups to get a feel for accuracy but right now I'm seeing about 3-3.5 gallons left in the tank when it gets to 'E', which is pretty good in my book.

Todd Z.

Thanks Todd.

I just got off the phone with a guy from A Plus Rod & Kustom. I had messaged them to ask if they sold the Tanks, Inc cylindrical sending unit in the 73-10 Ohm range since they didn't list that range on their website. He confirmed that they do.
However, I told him I wasn't ready to try that option just yet and explained what I have tried so far and that I had already ordered an Autometer signal adapter module. We had a really good conversation about their cylindrical sending unit and whether or not he thought the Autometer module would fix my problem. He told me they sell a different brand module but that he also thought the Autometer module would do exactly what I need. It was really good to talk to someone who knew what he was talking about. Autometer could learn a few things from him.
I told him that if I decide to go with a cylindrical type sending unit I would definitely be giving him a call.
At this point I think I can make either of the sending units I have usable by adding the signal adapter module. I still believe the solid vertical rod sending unit will be the more reliable option simply because it has only one moving part and that is the composite float.
 
OP
OP
englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
I’ll be interested in this tank - I’m picking up the 4 link setup next week, so having an option that’s compatible would be key for me.

Few other points:
Recessed AN ports and access
Return and returnless (can be capped/plugged)
Fuel basket/surge setup that can handle slush and multiple standard pumps ( like the forge setup)
Drain plug
Stainless
Optional skid plate
Angled on the back side (for clearance)


Sent from my iPhone using Tapatalk

Everything in your list will be accomplished with this. The fuel cartridge we are designing will accommodate a large variety of internal as well as external pumps even dual pumps if the power need is there.
 
OP
OP
englewoodcowboy

englewoodcowboy

Lick Creek Restorations
Joined
Jul 25, 2010
Messages
4,200
Whatever you do please include a reasonably accurate sending unit. The ones I have tried so far only seem to be accurate at the top or when the tank is nearly full. That's kinda ridiculous when most people would (or should) be more interested in knowing when they are approaching empty.
I currently have an older BC tank that was rated at 24 gal when I bought it back in 2004 but may have been re-rated to 23? Anyway, it has a partially angled bottom to increase departure angle which is probably playing havoc with the sending unit as well.
What I have found with the solid vertical rod sending unit design which uses a doughnut shaped float is that there seems to be too much resistance in the rod at the lower fuel levels which causes the gauge to read too low. For example, my tank has about 10.5 gal in it right now which equates to right at 6" of fuel and the gauge reads right on "E".
My thoughts are that the vertical rod that the composite float slides on needs to be tapered so that it is smaller near the bottom which would create less resistance in the rod at lower fuel levels and thus a higher, and hopefully more accurate, reading on the gauge.
I don't care what the gauge says when the tank is full. I want to know when I'm going to run out of gas. With what I have now if I fill up every time the gauge reads "E" my effective driving range wouldn't be much better than if had kept the original tank. All I have gained is a lot of useless extra weight.

A lot of this issues has to do with the tank design, fuel measuring devices are based on a perfect box shape tank or cylinder shape. Due to the angled rear for departure clearance it throws them off. Getting a custom wound sending unit is not worth the expense however I am trying to mitigate and offset the issue in this tank design which should greatly improve the accuracy. I am working hard to have a functional prototype at Super Cel.
 

blksn8k

Sr. Member
Joined
Sep 28, 2003
Messages
528
A lot of this issues has to do with the tank design, fuel measuring devices are based on a perfect box shape tank or cylinder shape. Due to the angled rear for departure clearance it throws them off. Getting a custom wound sending unit is not worth the expense however I am trying to mitigate and offset the issue in this tank design which should greatly improve the accuracy. I am working hard to have a functional prototype at Super Cel.

There is a potential answer to the gauge accuracy issue. If the Autometer Fuel Signal Adapter that I have on order actually does what the description says, that type of module should be able to adjust the signal coming from the sending unit to the gauge so that you have more accurate readings. It can make adjustments at five separate points on the gauge. It can also send a low fuel level signal to a warning light or relay. Prices I have seen for the Autometer module are in the $70-$80 range. There are several other brands available as well. I only went with the Autometer because I already had a full set of Autometer gauges.

https://www.amazon.com/gp/product/B085D76YX6/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
 

matts460

Sr. Member
Joined
Feb 3, 2013
Messages
581
I haven't read threw the whole thread but, for me a 18 gallon plastic fuel tank while looking/fitting like the stock 1977 fuel tank would be great! My 77 has a 12 gallon main and 7 gallon aux, both plastic. My 1972 F100 has a stock 18 gallon tank a very common fuel capacity for all old f-series trucks and cars back then. Also like the idea of plastic tank for safety and wont rust! Added fittings for optional fuel injection system would be cool. (not something id use) but know many do now. At least an 18 gallon could be good compromise considering fitting issue and not hanging down like a loaded diaper!
 
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