Fuel Cells

[eightiron]

I need to replace my stock fuel tank in a 91 Mazda RX7 and am considering a fuel cell instead as replacement. No idea where to begin. On-line I am finding $250-$1000. Is there a difference in the cell or am I viewing an incomplete system and will later need to buy additional components. Any suggestions on purchase and install will be helpful

[Dave Gomberg]

You need to be sure that the cells you are looking at meet the GCR requirements. See section 9.3.26. I don't think you will find any $250 cells that meet the requirements.

Dave

[joeg]

big exception for IT in the GCR--you can use a less expensive rotary molded cell.

[Andy Bettencourt]

This is a debatable section for IT. Maybe the CRB needs a letter to clarify.

[Dave Gomberg]

No, it isn't debatable. While a fuel cell is not required in IT, if you are going to use one, it must meet the requirements of 9.3.26. That includes 9.3.26.4 - rotary molded cells.

Dave

[Andy Bettencourt]

No, it isn't debatable. While a fuel cell is not required in IT, if you are going to use one, it must meet the requirements of 9.3.26. That includes 9.3.26.4 - rotary molded cells.

Dave

That is how I read it but some do not. I am sure Patullo will chime in.

[dickita15]

Jeez Andy, I don’t think I am the only one on this side.
Dave I am surprised to hear such a definitive statement from you. We have discussed this item here before a couple of times. The way the good book is written it appears to say that all cars except IT, SM, SS & touring need to meet FIA FT-3 and that the rotary molded cells not meeting that standard are allowable in those classes. This wording has been static for a number of years and there are a lot of cars that have been built and logbooked using this interpretation.
My understanding for the reason for this is that Prod and GT cars require a higher standard as they are allowed to remove the OEM bumper systems that we are required to retain.

[Dave Gomberg]

Dick:

Why are you surprised? We are in violent agreement here.

Dave

[dickita15]

Dick:

Why are you surprised? We are in violent agreement here.

Dave

Ok reading is fundamental and I guess I misread your post. I thought you were saying a FIA FT-3 was required in an IT car. Just to make sure we agree, a rotary molded cell that does not meet FIA FT-3 is legal in Improved Touring per 9.3.26.4.
Maybe I should not post so early in the morning.
I have an 8 gallon one of these in one of our cars, cheap money.
http://www.jazproducts.com/pro_sport_fc.html

[Andy Bettencourt]

Jeez Andy, I don’t think I am the only one on this side.

Just the only one who writes here Dick!

[Chip42]

to the OP-

fuel cells vary widely in price depending on cerification and materials. that said, a "surge tank" with trap doors, such as the ATI "black box" helps in the later stages, particularly on long corners and in wide/shallow cells. it is not a requirement. also, pump / filters / etc... are usually NOT included in the purchase price. your stock or stock-like units can work, you simply need to devise a system to locate it in the cell. all matter or bulkhead fittings and wiring pass-throughs are available.

you will need to have a support system and straps, etc.. installed in the car unless you use the spare tire well molded parts, typically rotary molded as described above.

also keep in mind that the plumbing in the interior of the car (where it is likely to be) will need to be stainless braided unless it is fully obscured to the driver compartment by a bulkhead. as the 2nd gen 7 is in need of weight over the rear axle (or so I hear, I only play with pistons) this sort of mod should not scare you off, but might cost more than you are interested in spending - both in time and money.

the thing about cells is to ask questions, do your homework, and make it worth doing - a stock tank works well and is not that expensive comparitively. cells can be better, particularly in enduros and for moving weight around, but have price and pickup issues that need to be overcome.

[Scooter]

I'm curious as to what percentage of IT cars are running fuel cells?

I've always thought that the stock tank was in a pretty good location on my car and the added complexity of changing it out is not worth it.

[Greg Amy]

No, it isn't debatable.

ANTHROPOMORPHIC GLOBAL WARMING IS REAL!!! I'M REALLY, REALLY SERIAL!!!

https://improvedtouring.com...ad.php?t=23937

[Andy Bettencourt]

SO to summarize:

GCR

All cars must be equipped with a safety fuel cell complying with these specifications, except for Showroom Stock, Touring, Spec Miata, and Improved Touring. All safety fuel cells shall be constructed and certified in accordance with the FIA FT-3 or higher (FT-3.5, FT-5, etc.) specifications. All safety fuel cells shall consist of a foam-filled fuel bladder enclosed in a metal container at minimum.

ITCS
The stock fuel tank may be replaced with a fuel cell. The fuel cell shall be located within twelve (12) inches of the original fuel tank location. Additional reinforcement may be added to support the fuel cell, but such reinforcement shall not attach to the roll cage. Floor pan may be modified for installation.

I read it like this: All cars must be equipped with a fuel cell except certain classes. ALL fuel cells must be FIA FT-3 or higher.

IT cars MAY add one, with a restriction on it's location - but the certification has been defined.

What is grey (to me) is what the first line is saying. All cars must be equiped with a fuel cell - except X, Y, and Z classes - OR - All cars must be equipped with a fuel cell of XXX certification - except X, Y and Z classes (meaning those classes are exempt from said certification).

Effectively, if it's the latter, you could build your own cell. Want that? At the very least, it is NOT crystal clear to me even though I think it read like #1.

[dickita15]

SO to summarize:

GCR


I read it like this: All cars must be equipped with a fuel cell except certain classes. ALL fuel cells must be FIA FT-3 or higher.

IT cars MAY add one, with a restriction on it's location - but the certification has been defined.

What is grey (to me) is what the first line is saying. All cars must be equiped with a fuel cell - except X, Y, and Z classes - OR - All cars must be equipped with a fuel cell of XXX certification - except X, Y and Z classes (meaning those classes are exempt from said certification).

Effectively, if it's the latter, you could build your own cell. Want that? At the very least, it is NOT crystal clear to me even though I think it read like #1.

Andy I could understand that reading except that the GCR also says:
9.3.26.4. Rotary Molded Cell
The use of rotary molded fuel cells not having a bladder, or not contained in a metal can, is allowable in those cars that do not require the use of a fuel cell, but where they are an allowed option.

Unless I am mistaken rotary molded cell do not meet FIA FT-3. So there would be no reason for that section is your first interpretation was true.

[dickita15]

I'm curious as to what percentage of IT cars are running fuel cells?

I've always thought that the stock tank was in a pretty good location on my car and the added complexity of changing it out is not worth it.

Scooter, you are right in most newer cars the stock tank works fine. In my first gen however the stock tank is much more vulnerable that in your car. Add to that the fact that rust free stock tanks for older cars are hard to come by. Now as a plus I was able to drop a couple of pounds and reduce sloshing it becomes worth the effort.