Drop-In Tank Install

Thought I would start a new thread to catalog my tank install.

Its a standard 68 Mustang 22 gallon drop-in tank built by Ricks Tanks out of El Paso.It has internal baffling and fuel pump sump. It came with Walbro 600 hp fuel pump and fuel sending unit installed. Its made to order. I had them alter the filler neck location to be centered.





I'll begin cutting up the trunk floor in the coming weeks as soon as I get a game plan together.

 

I enjoy my drop in tank

 

Here's some pics of my front template width,length, and height is wrote on them. The. Lip the tank sits on needs to be 1" and attatches with 3/8 head self tappers per oem.

Edit* can't get em up from my phone ill attach later

 

here they are

 

looks like I have 3 options for doing my drop in tank:

1- Mount tank from existing floor. The problems here are I'd have to trim the fuel filler tube to meet the tank AND biggest problem, because I have an enlarged tank, the top of the tank would protrude into the trunk space by 2 inches. This means that the trunk floor would not be flat and luggage, tools, spare tire... other things would be resting on top of the tank.

2- Mount the tank below the tail support beam. In order to do this, I'd have to fill in the remaining portion of this beam to support the tank. Would this make the tank sit too low? Ideally, the tank and the rear gravel pan should make a seamless transition sort of like a rear diffuser.

3- Mount the tank below the floor surface but further fwd to avoid the rear beam. I'd have to extend the filler tube forward to meet it by 1". This idea moves the weight of the tank forward reducing the effective weight over the rear end. For general performance, its best to keep the weight of the vehicle between the wheel both fore and aft or as close as possible.

Speaking of weight... I removed all the paneling from the trunk and weighed it. 40 lbs. The old tank weighed 20. Not sure what the removed floor pan weighed but was prob another 20. Total weight removed was say 80lbs. My new tank alone weighs 60lb. So I've got 20lbs to play with before.

pics of the mess I've made.

 

Ran into a couple problems. Notice the tailpipes in the above pictures? They had to go. Hopefully my exhaust guy can tweak them and make them work without charging me to much money. Luckily I had him install disconnects just after the mufflers so the tailpipes could be removed. No cutting was involved in removing them.

When cutting out the hole in the floor, I noticed some bondo, and more bondo, and more.... Luckily, the drop in pan is essentially a patch panel itself so most of the trouble will be reinforced with better heavier ga. material.

Here is the mock up piece made of poster board


Installed




I took the form to a local steel fab shop and had them cut and bend up the forms for me. I welded it up and here it is in place.




I should get the tub welded in place today and the fuel tank dropped in.

More to come....

 

Almost done. Just need to wire and plumb it.

 

Sweet!!!!!!!!!

 

That looks really nice.

 

Very Nice!! I have been wanting to do something like that for a long time.

 

Finished up the tank over the weekend. Its all in place and oddly enough, just my looking at it, I cant see a difference. I take it to the exhaust shop tomorrow to have new tail pipes bent for it. The fuel pump, being internal is much quieter. I do have a fuel vapor problem I need to sort out though. I get lots of fumes in the trunk. Not sure why. I've got it vented thru the trunk floor. More research.

 

You could have a pinhole leak somewhere causing the vapor smell

 

I found the problem. The fuel level sending unit mounts front the top of the tank and had a leak around the base at the seal. After making several runs at the autocross, I opened the trunk to display my handiwork only to find that fuel had sloshed out from that spot and had puddled up around the outer flanges. I decided to try and tighten the screws to see if that was the problem and found that one of the screws were stripped out. The tank vendor was at the show so I drove the car over to their booth to show them and see if they had a replacement screw. Unfortunately they did not. They are sending me a new seal kit and screws to correct the problem. For the rest of the weekend, after every run, I opened the trunk to let the vapors out and sop up the fuel with a paper towel. I'll fix it and clean up the mess this weekend before the next event.

 

Finished the trunk off. The replacement seal and screws fixed the problem with the fumes. So I covered it up.

 

Great work, I like the flat floor in the trunk.