Fuel Cell Installation Help Needed

R

RX767

New member
I am attempting to install a "Fuel Safe" 15 gallon cell in my ITA 1st generation RX7. Underneath the rear of the car I have recently installed the "G-Force" panhard set-up and I have 3in. exhaust begining prior to the axle to the muffler. It seems like a tight fit. I would greatly appreciate help with the following questions:

1. Should I cut a large square hole from the trunk deck and drop the cell in from above? Or, should I cut an oblong hole in the spare tire well and mount it to the bottom?

2. I have already constructed a frame from L channel that fits around the corners. What is a good method to attach the cell to the car and build a bulkhead per SCCA rules?

3. I would like to run the steel braided fuel lines close to the stock location. Is this the best way?

Any help or suggestions are greatly appreciated. Thank you.

Bill Emery
 
Bill,

I'll answer your questions in order...

1. I have seen it done both ways and it really depends on your application. Keep in mind the minimum clearence per the GCA when installing it from below. I have mine dropped in from above BUT....It hurts my ability to install a roll-center that mounts behind the chunk.

2. I would say yes! But, if you install it from below, then all you have to really do is install an "access panel."

3. If your going to run stainless steel braided, you can pretty much run them anywhere. You'll note on the pics of our install, we ran stainless through the car. Either way is "ok" and a matter of preference, IMHO.

Others may have additional thoughts. Below is a link to my server (which has been acting up ever since I went to wireless in the house) that has a pictorial journey of my install.

Hope it helps!


http://www.balz.myip.org/racing%20stuff/Fu...w%20suspension/




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Balz
#67 IT-7
www.balz.myip.org
"I live my life one Apex (seal) at a time"
 
Bill,

I'll answer your questions in order...

1. I have seen it done both ways and it really depends on your application. Keep in mind the minimum clearence per the GCA when installing it from below. I have mine dropped in from above BUT....It hurts my ability to install a roll-center that mounts behind the chunk.

2. I would say yes! But, if you install it from below, then all you have to really do is install an "access panel."

3. If your going to run stainless steel braided, you can pretty much run them anywhere. You'll note on the pics of our install, we ran stainless through the car. Either way is "ok" and a matter of preference, IMHO.

Others may have additional thoughts. Below is a link to my server (which has been acting up ever since I went to wireless in the house) that has a pictorial journey of my install.

Hope it helps!


http://www.balz.myip.org/racing%20stuff/Fu...w%20suspension/




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Balz
#67 IT-7
www.balz.myip.org
"I live my life one Apex (seal) at a time"
 
RX767,

I know exactly what you're going through since I just went through the same dilemma (see earlier posts) I'll share with you what I decided and why. My installation was also the 15 gallon fuel safe (steel can with the sump tank option) and I also have the G-Force Trilink set-up and GTPanhard.


I mounted mine from below so I 1) didn't have to cut so much floor out, 2) didn't have to fabricate some sort of 3-dimensional box to create a bulkhead over the cell and the top fittings, 3) could mount lower for C.O.G. purposes.

I welded 1" box steel between the frame rails to create a "ceiling" to mount the cell to. These cross members are placed so they fall just inside of the rows of bolts on the top of the can...they cross right over the corners of the can. VERY IMPORTANT, I trial fitted the cell many times with the fittings on top so I could keep all BELOW the plane of the rear deck in the hatchback area. The only thing I cut out of the deck was 90% of the spare tire well. With the 1" box steel in place, I lifted the cell in place underneath and fabricated 3 straps to hold in place using 1/8" X 2" hot rolled steel (as recommended by FuelSafe). Two strap go front to back and one goes side to side.
On the inside of the deck, i cut a piece of sheet metal to cover what was the spare tire wheel well opening. I attached this with stainless screws, then removed it and added a hinged hatch door so I could easily access the filler. For now, I use a simple wing nut to hold the hatch door closed.
While I was doing all the above, I put a new carter fuel pump in the same area (just fore of the cell directly above where my G-Force GTPanhard frame bracket is).

I will probably add some more "mounting structure" around the cell in the offseason for the sole purpose of providing some protection from a rear-impact...but recognize the rules don't allow for adding protection (go figure).

Hope this helps. I wish I could offer pictures, but don't have any nor have I jumped on the digital camera bandwagon yet.

And I'm not saying my approach was best...but it meets my criteria.
 
Balz and Rlekun,

Thank you for your replies. Balz I have gone through your pictures several times and your fabrication is impressive. In an attempt to get the car back on the track I am going to use Rlekun's method since it deals with less construction. I may opt for the drop-through method this winter since the cell looks more protected. In trial fitting the cell from underneath, I have a few concerns that maybe someone can help with. The 15 gallon Fuel Safe is big. It just fits between the frame rails and I am about 1.5 inchs from the exhaust on the front/passenger side corner.
1) Are heat shields being used with fuel cells? If so, what works?
2) By mounting from below, is anyone runnning into clearence problems or surprises when loading the car? - Currently I have 6in. by 8in. hole cut out around the lower left quadrent of the spare tire well. The cell fits to the bottom of the car at a slight angle. I seem to be maybe a 1/2 inch above the lowest part of my muffler.
Should I remove more of the spare tire well? Or am I missing something that should be added or cut out.
Rlekun, you removed 90% of the spare tire well. Did you remove metal from the sides to raise the cell up?
3) I plan on using the L channel frame that I have welded together to attach the cell to the car. I will have the vertical L channel on each corner extend through four holes in the deck and bolt to additional channel that will be welded to the deck. Does anyone find fault with this method?

Thank you.

Bill Emery
 
Bill:
With your car height @ five inches the bottom of the fuel cell should be @six inches. I would recomend 1" square tubing to mount your fuel cell. Make a frame to set it in then make a bottom that looks like a tic tac toe game. Then put two bars up each side to connect it to the frame. The front and rear bars of the upper frame should be cut so that they just fit between the frame rails.(When you make this it actually looks like a basket)Then cut out the entire floor section between the rear frame rails side to side and between the last two cross members front to back. Put four 1/4" plates on your car frame where the fuel cell frame will be welded in. This opening can be covered with a sheetmetal panel.(I did some bead rolling on mine to stiffen it up)Then you will need to make an access door to your filler cap.Then take and make a shield out ot SS and put it across the front and down the right side of the fuel cell cage. But before final installation I put Styrofoam between the shield and the fuel cell to help keep the heat from the exhaust from warming the fuel.I saw where you stated that you were going to use angle iron. I'm sorry but I would not. I broke an axle three years ago and the wheel went under the car. The car then landed on the fuel cell cage that I made to these specs. If it had not been for the safety of that cage I know my accident would have been much worse. You can never be to safe. A special THANKS goes to Estus White for telling me how to build this fuel cell cage.

#99 IT7 Rick Thompson
 
Originally posted by RX767:
Rlekun, you removed 90% of the spare tire well. Did you remove metal from the sides to raise the cell up?

I removed enough of the spare wheel well so I could raise the cross bars up a couple of inches into the space between the frame wells. Again, after I added the Aeroquip 90 degree fittings on top, the top of the fittings are probably 1/4" below the plane of the rest of the rear floor deck. I also moved the fuel pump up into this area as well.

3) I plan on using the L channel frame that I have welded together to attach the cell to the car. I will have the vertical L channel on each corner extend through four holes in the deck and bolt to additional channel that will be welded to the deck. Does anyone find fault with this method?

I agree with Hotshoe....I'd use box steel whereever possible.

Hotshoe's installation provides clearly more protection than my approach. Where his includes a cage to protect the cell, I use straps merely to mount the cell. My cell is no more protected than stock (other than by raising it slightly its more protected by the frame and bumper.

Hope that helps!



[This message has been edited by rlekun (edited September 11, 2002).]
Click to expand...
 
I can offer this idea for you, having done this two years ago to another "hatch" design.

Mount the can from below after cutting away the spare tire well and replacing it with a straight/flat panel. We used two panels with joined flanges welded together longitudinally, which was placed at the edge of the cell/can. This eliminated the "oil-can" effect of a large panel, and created enough stiffness in the floor that you can stand on it at the point of the cell installation with out bending the panel.

The panel is opened (holes) for the filler/vent/outlet and a small box was built/bolted to the floor to conform to the rules. We use an 8 gal cell in this location. This was all prepared prior to welding to the car.

The cell we used had a narrow lip on the can which made precise placement in the large hole (if mounted from above) difficult as to mounting-hole-allignment.

The only difficult part is to raise the cell up into position...needs a few hands while the mounting bolts/nuts are installed.

Hope this helps.

Bill
 
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