I am in contact with a nearby shop, the owner is a master welder, does aluminum tanks, and has a son apprenticing who does CAD plasma cutting. If anyone can provide me a set of plans, I will work with them on a preproduction sample, letting them work from the plans, and with the tank from my 88, while it is off the road this winter. I will test it in my car, and post updates during the process. I would plan to coordinate a production run using advice from PFF members, pricing at whatever sweet spot would get volume and reasonable return, and handle the order processing and shipping myself. What level of support could I expect in this effort, and what variables will I encounter? I don't have a pet mouse, but I can rent a hedgehog...
------------------ 1988 Pontiac Fiero Formula, Yellow, original. (CJB #118) 1977 Pontiac Le Mans Can-Am W72, original, unrestored. 1977 Pontiac Grand LeMans 2003 Pontiac Grand Prix GTP L67/MN7 (Parts Car) 2001 Pontiac Grand Prix GTP L67/MN7 (DD) 2005 Pontiac Grand Prix L26 (Wife's DD)
I have long wanted a custom fuel tank to increase the "usable capacity to 12+ gallons and be 100% compatible with E85.
With those being "my" goals the design criteria would be as follows:
Tank geometry to match the tank tunnel geometry as close as possible (no sharp corners at the top)
Tank should fill the entire tunnel at the front and back of the cavity - move the hose connections to the side to allow the tank to extend further rearward.
Allow the tank to be 1/2" below the floor board with a slight taper from side to side and to the rear (like a boat bottom - but very gradual) to help fuel stay around the pickup in low fuel conditions (increase "usable" capacity). Using a large holley hydromat in the bottom would also work - but they are not cheap.
Use thin material (preferably stainless) so wall thickness doesn't reduce tank capacity and keeps weight of tank close to stock (using 1/4" aluminum will result in tank that is heavier than stock - before the additional fuel). Also, in the event of a wreck, you want the tank to bend, not crack.
Keep seams along the lower surface to a minimum (bend the sides, front and back upwards from the bottom panel. Then make the top in sections that match the tunnel contour). Less risk for leaks, plus less overall welding which is needed to keep cost reasonable.
Design it to use a remote expansion tank - again to maximize volume. Do the math to allow for the fuel expansion with a 75 degree temperature change. 25% in the tank, and 100% in the remote expansion tank.
Keep the stock pickup, sender and water pump assembly - just extend the internal tubes to the lower bottom.
The easiest way to accomplish a tank design than maximizes the results is to cut the entire center tunnel out of a Fiero and take it to the tank place. Flip it over on a bench, put a tarp in the tunnel, fill it with liquid and see what the maximum available capacity is for the fuel tank cavity. If you can capture 90-95% of this capacity (or 100+% if you make it 1/2" deeper than the floor pan) then you would really have something...
If you were closer, I would loan you the fuel tank tunnel section I have sitting on the shelf.
[This message has been edited by fieroguru (edited 08-07-2019).]
That is exactly the level of detail and clarity needed. Thank you for the input. I am able to shoulder some development costs, so I would be willing to pay shipping both ways for a loan of the tunnel section, or one way if you are willing to sell it. I intend to offer the shop my 88 for the winter as a development buck, but your idea would have better outcomes, especially since I am not allowing the shop to flip my whole car over. The Holley mat item would be an option, but only on special order where it could be incorporated during the tank build. I expect only autocrossers would be willing to pay that level of upcharge. The ultimate goal should be allowing many owners to ditch their marginal tanks for an easy install replacement, while offering them the ability to add their own accesories, like external EFPs, upgraded lines, easier routings, and maybe a newer model of drop-in sender/pickup assembly. If the tank also increases holding capacity, that would be a bonus.
It would be nice to have plans to start from, but I think this round will start without them. I have a Fiero, a tank, a couple of jpegs, a serious craftsman, and already a nice amount of input and interest. I am currently framing out our new garage, so that is my current priority. My car spends the NH winters safely tucked away, so that period will be ideal for experimentation, and an aim to road test the prototype next spring. I am hoping the finished tanks will incorporate the marine type sender/pickup, which screw into the flat top, use a simple flat gasket, and eliminate entirely the locking ring goofiness. If someone wants to reuse their stock assembly, that will probably be an option.
If you can manage to produce this I am sure many would purchase it. Having old tanks like ours is only a matter of time before they start showing "more" signs of age.
Thank you, I will relay that to the craftsman. I agree that time is working against us, that the dwindling number of usable tanks may lead to cars taken off the road, to drivable cars parted out, to enormous prices for tanks, and to marginal or even dangerous tank repairs or fabrications. It would serve the hobby to have a standardized, professionally fabricated line of tanks available. I am not a welder, but I have time and resources to gather the needed info, to relay that to a fabricator, to do some R&D testing, and to communicate each step here for forum members comments. If it leads to a working design, I will finance a production run that keeps a small stock on hand so orders can be shipped as soon as received. For that to work, the tank design will have to be standardized, aftermarket senders used, and additional fill capacity will be a secondary consideration.
Originally posted by CJB118: and what variables will I encounter?
Racing often require OE fuel tanks and/or "Certified" aftermarket Fuel Cells/Tanks. Damage to OE tank or using non cert tanks can fail Race Inspections. Repairs can fail too. Whatever Race Org/Com often has no clue and doesn't care who repair them and will think any repair is trash.
Bigger tank can be problems... Like Back closer to engine and exhaust can make the fuel to heat up and expand more then either OE tanks. IOW If your guess for expansion space is wrong then you will have Liquid Gas force up the vent line wrecking the EVAP can at a minimum.
Suggest you find a lawyer. Making/selling gas tanks will need a lawyer to inc llc etc to protect your home and so on before you get sued. That problem above can burn the car, whatever inside of same and building(s) next to or inside of. Longer tanks might fail in a wreck as engine or front hit the tank. Very Carefully watch Fiero crash test videos on YT and remember many speed limits are now 65+ MPH. I think crash test speed were ~ 35MPH.
The buyer, friends, family, and more can sue the maker and seller for gas tanks that leak, fails in a crash, etc. Buyer's Car Insurance Co may pay but not enough etc and maybe sue you too. NHTSA can even order a Recall for aftermarket products w/ problems. One famous was Altezza aftermarket taillight w/ bogus markings etc covered at http://fmvss108.tripod.com/ and others years ago. They ordered several Tire Recalls too, not just Tires on car from the factory. Side note: CBP seized 4000 Chinese tires [CBP.gov] in June.
A few other vendors have call their lawyers before selling/making whatever and got told some "upgrades" are bad ideas for same reasons.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
I don't let any of this legal nonsense scare me. It's my car and if I want to luminum tank that's my business.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I drew up the tank a few years ago, even did the internal baffle. Was going to do them out of stainless, but just don't have the time. I should still have the file someplace. Do you know what kind of CAD they are using? I can send a 3D file.
Thank you for that offer. It will be a while before I have any info on the CAD subject, but as I understand, it would be a simple 2d plot for a plasma cutter. A printout might be sufficient if it includes dimensions. I plan to loan him my 88 tank, some pics of previous models, and any technical info I can gather, including printouts of CAD files. All of that would be for them to transform into a working prototype in their most efficient manner, to generate a record of production cost and a dollar figure that would keep them on-board for a production run.
That's a good starting point, it will be included with the early info dump. Some features will be nerfed to make a universal fit, all years and models, etc., but the dimensional drawings will covey the complexity of the needed shape.
Like all Fiero aftermarket parts, the issue is business model . . . how many do you sell before you start seeing a return on investment?
The market for our parts is dwindling fast. Cars are disappearing, and many of the cars still out there are owned by folks who won't spend exorbitant amounts of money.
This issue is exacerbated when the part cannot be used on any other model vehicle.
For the record, I would be willing to buy one of these just to keep "on the shelf" in case ever needed.
[This message has been edited by USMUCL (edited 08-15-2019).]
Let me toss in my two cents. If you want to produce a product that has a chance of any return on investment you need to improve on the orginal. Yes there is a small market for replacement fuel tanks due to rust. Thre how ever is a larger market for a product that is better than the stock tank. First I would suggest you simply make the tank hold more fuel, It seems you are already thinking along those lines. Second and just as important. How about making the tank use an extrenal fuel pump.. who likes dropping the tank to change those?? And why not make one that uses a different, cheaper fuel level sending unit? Yes this will take the dreaded R and D money. But if you just make a straight replacement I do not see alot of us shelling out much money. My tanks do not leak (yet.. knock on wood) and I am not looking to replace something that is not broke with the basic same thing... Again my two cents and its not really worth that.
They can be molded from plastic. My son owned a GM Alero when he first began driving. One day he drove over a branch in the road. It came up and split his plastic fuel tank open. So much for plastic fuel tanks. I guess that is good enough reason for a steel tank.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I am pretty sure when I did the volume calculation on those tank drawings from Lambo Lounge, it didn't reach 15 gallons... I think he eventually mentioned he had installed an overflow or expansion tank as well.
I am in the camp that would pay good money for a large capacity, stainless steel tank that keeps the stock fuel pump assembly. If it had 13 usable gallons (14 gallons capacity) and met all of my design criteria, I would gladly pay $750 for it.
Without the capacity increase, stainless steel, or use of the stock fuel pump sender assembly, I wouldn't give $50 for one. For me it is all about the capacity increase and the ability to run E85 w/o ruining a stock 87-88 tank in the process.
What is the argument in favor of using the stock sender/pump assembly? I would think that would be a self-imposed limitation, where newer senders, which almost all use a standardized hole and bolt pattern, and no welded ring, and simple reliable flat gasket, coupled with an external EFP, would allow the tank buyer much more range in finishing a tank to either high flow specs, or E85 compatibility, or both.
They can be molded from plastic. My son owned a GM Alero when he first began driving. One day he drove over a branch in the road. It came up and split his plastic fuel tank open. So much for plastic fuel tanks. I guess that is good enough reason for a steel tank.
I suspect your son's experience is an outlier in the world of plastic fuel tanks. Many vehicles use plastic tanks with no issues.
What is the argument in favor of using the stock sender/pump assembly? I would think that would be a self-imposed limitation, where newer senders, which almost all use a standardized hole and bolt pattern, and no welded ring, and simple reliable flat gasket, coupled with an external EFP, would allow the tank buyer much more range in finishing a tank to either high flow specs, or E85 compatibility, or both.
I have zero interest in a fuel tank that weighs significantly more than stock aside from the increased capacity. What this means is that if steel is used, it must be about 20ga (0.035"). If aluminum is used, it can't be any thicker than 0.105". So even if 1/8" aluminum is used, it will add weight. Make it out of 1/4" aluminum and you have a tank that is twice as heavy as stock even before adding any fuel. Now how well will a bolt on flange with gasket seal on thin material tanks actually seal? There is a reason GM used this sender/pump assembly seal... it works very well on thin material tanks and provides a leak free seal for 30+ years.
OEMs put the fuel pumps in the tanks because they run cooler, last longer, and are quieter... doing anything different is just reducing reliability. When you have engines in 430 to 600 hp range and put 8000 - 10,000 miles on them per year and take 3000 mile trips in 6-7 days... all those benefits become even more significant.
[This message has been edited by fieroguru (edited 08-16-2019).]
The last post on this thread being over a year old, is anyone still considing building tanks? If so, I'll add my thoughts on the subject. First off in order to simplify things & keep the welds at a minimum consider the the bottom & sides one piece, two bends. The top & ends, one piece four bends. Forget the bat wings. With the exception of rounded edges along the top sides, this accomodates pretty much all of Fiero Guru's requirements. With a liitle tweaking of what I just outlined, the top & bottom could still be one piece each as described, it would just require a liitle more detail & bending along that joint due to the "step" on the top of the tank. Design the tank for maximum length within the constraints of the tunnel. There is however. a wee bit of room for additional length extending beyond the rear of the tunnel if there were a small step to accomodate the lip at the rear of the tunnel. As for the fuel pump, without sacrificing a tank just for that lock ring section, I see no way to salvage the stock Fiero FP assy, especially if the tank is to be any deeper than stock. Even so, the fabrication of that locking system is perhaps beyond the capabilities of the project. IF that lock ring design could be accomodated without destroying a tank, I see nothing wrong with utilizing a FP assy salvaged from a later model car having the depth & capacity to to meet our requirements. Like Guru, I would like to get at least a 300 mile range out of a tank.
When I expressed interest in the other aforementioned thread and got my hands on the plans, I was contacted by a member here with the nick Source who found someone to make the tanks. I think the name he gave me was the original guy in Florida who was making them some years ago. You can reach out to him. His guy was making them as recently as October 2020.
What I was told is that Aluminum is not ideal for E85. My own googling has turned up mixed information on this. However, it's something to consider if you are going to use E85.
If anyone needs those original fuel tank plans, please drop me a PM with an email address and I will forward them over to you!
Please contact Rodney if you are interested in a new tank. Mine is good, but you never know when or if it will start leaking. I would like to have a spare, just like I have spare front bearings and tail lights for my 88GT.
Send your info to Roddy Dickman, he is getting ready with a stock gas tank look. You know the quality will be top notch..
If the tank fits is made of stainless steel, has the right fill connections, baffles, uses the stock fuel pump mount, fuel sender/float and has all of the stock connections. It should be a good seller. I would probably buy one.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
