I am looking for a fuel cell that will bolt in the stock location of a 1st gen or at least fit with some minor fab work. Is there one out there? Or should I start cutting out the spare tire well and fabbing one up there. I will do the work if needed but prefer not to.

 

You will need to cut the spare tire well to do it correctly.

We normally cut approx 1/2" down from the floor inside the spare tire well. We cut all the way around. This leaves a rolled lip around the huge gaping hole you just cut in the floor.

You will then need to fab the hangers for the cell itself.

We then cover the hole with steel sheet cut into a circle 1" or so larger than the hole in the floor then tack it in place. This keeps the cell outside the chassis and you will not need to fab a big box in the trunk area to close off the cell. Cut an access panel in the steel sheet above the filler. Hinge it in place.


-billy

 

Thanks for the info, but here is one more quick question. What effect will premix have on the fuel cell foam?

 

It may break it down slightly over time but then it may not. I would not worry to about it to much.

-billy

 

bwaits gave you some good installation advice.

I have not had any problem with pre-mix hurting my fuel cell foam (10 years now.) I think that normal pump gas is not near as harmful to fuel cell foam as the high octane race gas is. I think race gas degrades fuel cell foam pretty bad. I think premix oil is benign to fuel cell foam.

 

Your foam is not 10 years old, is it? Most manufacturers recommend replacment every 5 years or so. The foam will deteriorate over time, even with pump gas pre-mixing or not. Deteriorated foam will clog your pump and burn it up (as in my case on track - 9yr old ATL cell) and/or clog filters.

 

I just replaced my foam and had my case powdercoated. When I pulled the bladder it was dated 1993, so the foam was 14 years old! The foam was crap, but the bladder was soft and pliable. Cleaned it , inspected it closely, installed new foam and reinstalled it. Have you priced a bladder lately?

 

I prefer to make a frame to drop the cell into, or at the least two runners between the stock frame rails the cell can sit on. Helps prevent a failure like Mark experienced where the cell drops out the bottom. I use either 1" square tube or 1" angle iron with 2 "loops" under the cell. Doesn't take more than 30 minutes to fab up and protects the cell, too.

I cut out a big enough hole that the cell is easy to R&R and put it low enough (unless its a deep cell) that a flat plate inside the car can cover the cell and pickups.

Of course, this is in cars that have a cage and therefore the spare tire well isn't doing much for chassis stiffness anyway.

 

Thank you all for the help.

 

Read this thread if you have not - https://www.rx7club.com/race-car-tech-103/fuel-cell-install-help-scca-rules-too-667586/

I'd recommend cutting the spare tire area....just don't plumb it like my pictures, it's completely wrong, that's another topic.