I must be getting old, getting a little forgetfull....The 87 & 88 tanks, held an extra gallon of fuel. I asume, the diffrent part numbers may be for diffrent manufacturers. I currently have an 88 fuel tank in my 86 GT Fiero.
[This message has been edited by James Bond 007 (edited 04-22-2017).]
45 liters would be a volume. Did they change the shape for different models?
yes, larger, but not in overall shape and they added an expansion tank (87 & 88), acording to my mechanic, he's never seen an expansion tank and isn't necessary.
What is the diff in volume between these 3 tank part #'s? The P&I catalog says they are all approx. 45 liters. 10031918 84 10037262 85-86 10041442 87-88
My 84 O/M says the tank is 38.6 liters (10.3) gallons
The larger 87-88 tank has 11.9 gallons. On my 88, I normally fill up and can get about 10.3 gallons in it.
The expansion tank is in the passenger side wheel well.
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 an understanding of the expansion range.
Yes. With the baffle in place, the pickup sock isn't on the bottom of the tank and with the length of the tank, it is nearly impossible to empty the tank of gas, so there will be about 1-2 gallons of gas that you won't be able to use under normal circumstances. If you cut the base of the baffle out and used a holley hydromat you would be able to use nearly all the gas in the tank. https://www.holley.com/prod...el_systems/hydramat/
[This message has been edited by fieroguru (edited 04-22-2017).]
Fieroguru....Could you elaborate/show pics/diagrams of what exactly needs to be done? My 85 has gotten to a point where I can basically only get 8 gallons of use out of it...I ran it to where it was cutting out in mild turns and then was able to get 8.5 approx' in it. I have a 87/88 tank to install....an improvement...But if I could improve on it that would be even better. Also, what is the best way/place to get the tank cleaned before I install it?
Fieroguru....Could you elaborate/show pics/diagrams of what exactly needs to be done? My 85 has gotten to a point where I can basically only get 8 gallons of use out of it...I ran it to where it was cutting out in mild turns and then was able to get 8.5 approx' in it. I have a 87/88 tank to install....an improvement...But if I could improve on it that would be even better. Also, what is the best way/place to get the tank cleaned before I install it?
Here is a pic of the stock fiero gas tank baffle. It sits on top of the metal floor of the tank, so removing the bottom of this baffle and converting to the holley hydromat would get you more capacity. How exactly to do that will be the challenge as you only have the top opening of the tank to work through.
Next time you install your fuel pump, wire tie a nail to the return line to verify the bottom of the tank and how close the sock filter is. When I did this for my 4.3 CPI swap, the pump was within 1/4" of the bottom of the baffle. If I wanted to lower it some, I could cut the return line and use a sleeve and silver solder to lower the bottom of the pump as low as possible w/o restricting flow of fuel through the sock.
Another usable capacity trick came from 84Bill from 10 years ago. Raise the vent tube to allow you to fill the tank with more fuel, but you will have less expansion area. I wouldn't recommend doing this unless you have the 87-88 expansion tank. https://www.fiero.nl/forum/A...100421-2-082612.html
My LS4/F40 fiero has a mod very similar to 84bill's, except I just added a 2nd vent tube with a little bit of a snorkle. My car is an 88 with the expansion tank and even with the raised vent and snorkle there is still about 2" open air space to the top of the tank. The 87-88 tank filled completely up is just under 12 gallons (I verified this when I used vinegar to remove the rust in my tank) and I have put 10.3 gallons in it without running out of gas or it sputtering. I haven't ran the car completely out of gas to see the maxumum usable capacity with this mod.
One of these days I will make a new/larger tank. I cut the fuel tank tunnel out of a parts fiero several years back and have it sitting in storage for the sole purpose of using it to make a new tank that maximizes the available space. When I convert to flex fuel and run E85, I will need a larger tank to keep my fuel range between fill ups.
[This message has been edited by fieroguru (edited 04-23-2017).]
Fieroguru, Looking at the older link you posted did you ever verify the original snorkel you did in the tank actually fell off or just didn't work? I will be dropping my tank at some point soon to change out pumps and checking for rust. I would not mind modding it some to be able to add more fuel. Especially since I will be running a 4.9l soon.
I never verified if the snorkel fell off on my original fuel capacity mod on my 4.3 CPI car.
If you try this, use your finger to seal the tank side of the vent tube and a rubber nipple air line on the other end. You need to pressurize it to verify if it has a secondary hole, which is my suspicion. If it has a secondary hole then the snorkel mod using the stock vent tube will not work unless you run a new tube inside the old one.
