I just watched a commercial for Titan fuel tanks for diesel trucks.

I thought I should ask if anyone knows anybody who makes larger tanks for the fiero...

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AL' Owner of:
88 Coupe crashed
(hit and run, White 80's F-150)
87 GT V6 crashed
("my fault" old people in a Lexus)
86 2M4 IMSA w/Holley
(needs fuel pump and rear brake job)
85 SE V6
(needs a fuel pump and trans flush)

i know the 85 to 88 had larger fuel tanks than the 84 but i think it was only by a gallon or so. otherwise there really isnt room for one.

That would be only the '88 that had the larger tank.

No one currently makes anything that upgrades the stock fuel tank. The relative problem is not only the tank's position in the car, but the position it sits in relation to the underside of the chassis. Even if you somehow make something that increases the capacity, it's likely not going to be by much considering that there's not a lot of room under there to begin with...

quote Originally posted by Fiero84Freak: That would be only the '88 that had the larger tank. No one currently makes anything that upgrades the stock fuel tank. The relative problem is not only the tank's position in the car, but the position it sits in relation to the underside of the chassis. Even if you somehow make something that increases the capacity, it's likely not going to be by much considering that there's not a lot of room under there to begin with...

I realized this is true, I have found someone willing to custom make one out of aluminum for $250.00.
I have come to the conclusion that the front and back of the tanks can be extended out about a foot more in total giving maybe 13 gallons.
also the OE tank is a two piece that had been stamped/ welded together at the half tank mark. the stamped/welded flaring extends an additional 2-3 inches (total) out from the sides. Since the guy doing this for me is using plates of aluminum, I should me able to send him a tank to mock up and to further extend the max volume over the OE one.

[This message has been edited by AL87 (edited 12-27-2010).]

Note there are differences in the filler connections of the smaller and larger tanks. The larger tank uses a 'overfill' expansion tank seperate from the main tank. The earlier ones don't.

quote Originally posted by AL87: In the Haynes repair manual it lists like this... 84: 10.5 gallons 85-86: 10.3 gallons. (and if I'm correct) 87-88's had 11.9 gallon tanks...

ya thats where i saw the comparison for fuel tanks i was wrong on the years tho but close enuf it was around a gallon.

THE OVER FILL TANK ON MY 88 GT HAS BEEN REMOVED . WHAT ( OTHER THAN CAPACITY) EFFECTS WILL RESULT?

I believe that "overfill" tank you are referring to is an expansion tank to give a place to go when you have a full tank on a hot day.

AL87 - I would be interested in getting a larger tank. There have been a few interesting threads on the subject. 84bill posted info on modding the vent tube to allow more fuel into the tank. There was also a tank design that a kitcar builder had thought up that incorporated two side tanks along with the main center tank. I don't have the links handy but do a search and read up on the plus and minuses, you might be able to incorporate some of the ideas into your custom tank. Keep the forum updated on your progress, other may be interested in the tank.

quote Originally posted by Terry_w: I believe that "overfill" tank you are referring to is an expansion tank to give a place to go when you have a full tank on a hot day.

Yes. It protect the EVAP can from liquid fuel. EVAP can hates Liquid fuel and ruins it. Dumping overflow fuel = safety problem as well.

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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)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

quote Originally posted by AL87: In the Haynes repair manual it lists like this... 84: 10.5 gallons 85-86: 10.3 gallons

LOL! Minor differences

I actually am interested in seeing someone come up with something that increases fuel capacity. I do think the way you described for elongating the tank is the ideal way to increase capacity. What I was originally eluding to in my post is as we all know the fuel tank sits rather low to the chassis relative to it's stance to the ground (it's not in the back raised up, like most vehicles). The only way to increase capacity would be to extend either forward or backwards. Additionally, I bet if one constructed the tank more in a configuration as you described where the flaring extends further downward instead of curving back inwards that would increase capacity as well.

quote Originally posted by AL87: I realized this is true, I have found someone willing to custom make one out of aluminum for $250.00. I have come to the conclusion that the front and back of the tanks can be extended out about a foot more in total giving maybe 13 gallons. also the OE tank is a two piece that had been stamped/ welded together at the half tank mark. the stamped/welded flaring extends an additional 2-3 inches (total) out from the sides. Since the guy doing this for me is using plates of aluminum, I should me able to send him a tank to mock up and to further extend the max volume over the OE one.

Just asking...how would you remove the tank if you extended it a foot on the forward and back? You need access to disconnect the hoses. It's tight enough as it is to get the hoses on and off.

quote Originally posted by masospaghetti: Just asking...how would you remove the tank if you extended it a foot on the forward and back? You need access to disconnect the hoses. It's tight enough as it is to get the hoses on and off.

I was thinking the same thing!

quote Originally posted by masospaghetti: Just asking...how would you remove the tank if you extended it a foot on the forward and back? You need access to disconnect the hoses. It's tight enough as it is to get the hoses on and off.

I meant a total gain of about a foot, 6 inches more on the front and 6 inches more on the rear.
I feel though that the gain will be there and in the width increase. There is a lip protruding on the sides of the tank from being stamped/welded together, that is all dead space.

I have an idea for the guy to get the most out of the tank he will make,
1st thing you have to do is find a fiero that will be scrapped, then flip it over to expose the underside.
then let the man use the chassis as a sort of jig to maximize the gain in volume.

seriously though, I'm gonna mock up some cardboard cutouts and create a skeleton of the fuel tank bay for the guy to go over and replicate.

[This message has been edited by AL87 (edited 12-27-2010).]

rci makes an aluminum fuel cell with gm sending unit already but i dont think it enlarges the capacity any.

quote Originally posted by mera7: rci makes an aluminum fuel cell with gm sending unit already but i dont think it enlarges the capacity any.

link please? I have also been trying to find a manufacturer for replacement tanks.

AL87 - PM sent

quote Originally posted by PaulJK: AL87 - PM sent

Right back at'cha dude! XD

I'd say relocate the spare to the trunk and put a fuel cell where the spare was,Racers had this. Use that and the original gas tank together.

quote Originally posted by 2.5: I'd say relocate the spare to the trunk and put a fuel cell where the spare was,Racers had this. Use that and the original gas tank together.

I'll put it in for consideration, thank you.

quote Originally posted by 2.5: I'd say relocate the spare to the trunk and put a fuel cell where the spare was,Racers had this. Use that and the original gas tank together.

While this will certainly increase the capacity, it's not ideal for two reasons. The first is that you're relocating the weight of a rather heavy spare tire from acting directly on the front axle and then exacerbating the weight reduction in the front by placing the tire behind the rear axle, removing even more weight off the front through leverage. The second reason is that by having an auxiliary tank on top of the front axle, your car's front to rear weight distribution will change as you drive. Depending on how large a tank you place up there, this could change the handling noticeably between empty and full. While I have no first hand experience with this sort of thing, I was interested to find while reading Archie's Lambourghini Muira replica thread that this was one of the Muira's noteworthy shortcomings.

how many miles per gal. you getting? ytZfPk

If you are looking for a larger capacity tank the only way i know to do this is to have one made. You should check out this web site a friend of myn owns the company and i work there as well. I have been kinda bugging him to build one for my car but not on the list yet customers come first. The web site is Boydwelding.com if your interested we dont open back up till the 3rd of january though.

Just wondering, how many miles do you need to go on one tank of gas?

quote Originally posted by Bloozberry: While this will certainly increase the capacity, it's not ideal for two reasons. The first is that you're relocating the weight of a rather heavy spare tire from acting directly on the front axle and then exacerbating the weight reduction in the front by placing the tire behind the rear axle, removing even more weight off the front through leverage. The second reason is that by having an auxiliary tank on top of the front axle, your car's front to rear weight distribution will change as you drive. Depending on how large a tank you place up there, this could change the handling noticeably between empty and full. While I have no first hand experience with this sort of thing, I was interested to find while reading Archie's Lambourghini Muira replica thread that this was one of the Muira's noteworthy shortcomings.

I guess one could adjust their suspension to compensate for more rear weight. I don't have alot of experience in it either. Susprising threy tuned the Fiero so much to need the spares weight.
I suppose the only other way is just put the extra fuel tank in the rear trunk, but that too puts weight in the rear, and requires more work to connect the two tanks.

i really think the only way to get a larger tank in there would be to widen or stretch the body unfortunatly.because bringing the tank down would bring it to close to the street back would be to close to the engine and forward isnt possible unless you cut out the debris guard which i wouldnt recomend. so that pretty much sums it up.

MPG for me would have to be something higher than 300 miles on 12 gallons with an 88' Duke with stock TH125C

I averaged about 30mpg highway at 80mph (3750-4000 rpm) over the period of about 3.75 hours, which I recorded when I drove my 88' Duke 298 miles to pick a friend up from his aunt's and take him back home near me.
(I still had at least a gallon (maybe 2) left when I got into town and met my friend, I then had him show me the nearest gas station)
which was in town (10 more miles))

4 additional gallons would be a dream, but I am shooting for at least two more gallons, maybe 3.

This would be a big help to me in V6 or higher engine application.
A stock 88' V6 fiero averages about 20 mpg (240 miles with a TH125C).

after reading this i was thinking how about a 5 gal or one 2.5 gal can full of gas in the trunk. fill it up in a rest stop when you stop to tinkle. though not the safeist.

I have drawings (not mine) for what is suppose to be a larger fuel tank for a lambo replica. It has extended bat wings at the rear in the double firewall panel. Anyone who wants a copy, just PM me your email address.

All years have a fairly large air pocket at the top of the tank (the area above the filler vent tube), by raising the elevation of the vent tube, you can increase the amount of fuel that fits within the fuel tank. You should add some kind of expansion tank if you do this modification on a car w/o one.
https://www.fiero.nl/forum/A...100421-2-082612.html


When I looked into doing a variant of the 84Bill modification, I went ahead and did the math to see exactly how much the fuel could expand and the available room for increased capacity.

quote Originally posted by fieroguru: Fuel expands/contracts with changes in temperature and it is important to ensure there is enough room in the tank for it to expand or it could push fuel into the evap canister. Gasoline expands at a rate of 0.00069 per degree F. So a 100 degree change in temperature with a 12 gallon tank will require .828 gallons of additional space. Expecting a 100 degree change is probably extreme, but it provides a sence of scale. Since my car is an 88, it has an external expansion tank on the upper passenger frame rail (I never measured it, but it might be .5 gallon). The top of the fuel fill vent tube is about 3" from the top of the tank. This creates an air pocket about 3" x 7" x 20" which is room for about 1.8 gallons of fuel (1 gallon more than needed for a 100 degree change - and assuming there was no secondary expansion tank). The goal is to lessen the size of this air pocket and allow more fuel in the tank.

Realisticly, you probably need to account for a 50 degree swing in temperature, that would be about the capacity of the 88 over flow tank. That should allow the 88 tank to be increased by about 1.5 to 1.8 gallons.

The other item to check is to ensure the fuel pickup is as close to the bottom of the tank as possible. This will lessen the unusable pool of fuel that is in the tank that the pump just can not pull out of the tank.

quote Originally posted by fieroguru: I also took the time to see how close the fuel pump was to the bottom of the tank. With a nail wire tied to the bottom of the pump and sticking out about 1.5" from the bottom, the assy was put back into the tank. The nail hits the bottom first and then is pushed up the side of the pump. Make sure the pump assy is properly seated in the tank and then remove being careful not to bump the nail. On my tank the pump is within about 1/4" of the bottom and that is close enough for me. The next step is to get the fuel sender reading correctly... reading E when the tank is within a gallon of being empty, not with 2-3 gallons of fuel left.

quote Originally posted by jim94: after reading this i was thinking how about a 5 gal or one 2.5 gal can full of gas in the trunk. fill it up in a rest stop when you stop to tinkle. though not the safeist.

LOL! that is exactly what I did! but, I actually need the extra space, and also, I can't handle the fumes getting on everything, backpack, trunk carpet, food... I know that is dumb but I didn't like going to school with a backpack that smelled like gas, especially around friends who would then think "what if...???" it would be a fire ball. and I left cookies in there with a full emergency tank once for a 15 minute drive home those good cookies quickly made me puke.

any who, first things first. I gotta get a car running... then I'll talk with with the guy that is gonna make me a tank.
I also have to print out the plans I recieved from another member...

or you could just remove the whole passenger side and put one huge 50 gallon fuel tank where the passenger side area used to be... although even though this is the most amount of fuel i could think of getting into the car it would also be the stupidest snd most unsafe idea i could think of

oops.

[This message has been edited by Fieroseverywhere (edited 01-02-2011).]

I would think that any car that has had the exhaust rerouted to the trunk area could make use of the space aft of the OEM tank where the cat used to mount. That could add a considerable amount of fuel in a relatively safe location.

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RickN
White 88GT 5spd (<10K miles)
White 85GT (SC3800 Series II w/ AOD)
White 99 F250SD 7.3PSD 6spd
1956 Ford 860 Tractor w/ Freeman Loader
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