Racing requirements for fuel tank

[Santiago]

FWIW, I think Chad's skepticism on the stock tank location is helpful. I still favor that location, but now I'm thinking I may weld in an additional bar to better brace an engine-side firewall. Were it not for wanting passenger capability, I'd probably put the fuel cell in the passenger area and box it as Chad has in mind. Shouldn't be too tough...just as soon as he figures out how to hang his doors. =)

Speaking of bumpers, have you worked anything out yet Chad? The more I look at it the more I'm not happy about the fact that even a light tap can take out your ability to shift gears. Thoughts?

Best,
-j

[C.Plavan]

I will be welding in a "Push" bumper a little higher and behind than the trans. Then it will be bent to match the curve of the rear bumper. It will all be on the inside.

I just cant decide on which to do first, Wing mount or bumper. You do not want to incorporate the two in case you get tapped. You do not want the wing angle to change.

One tap without an add on bumper, kiss your trans goodbye (linkage etc). Maybe even a gear or two depending on what gear you are in when hit. Not to mention the rear bumper AND side pods will fold like cardboard.

Prepare for the worst I say.

[Mechie3]

One tap without an add on bumper, kiss your trans goodbye (linkage etc). Maybe even a gear or two depending on what gear you are in when hit.

Just popped into this thread for the first time. You might be interested in something I'm going to machine tomorrow. Others have shown how the shift linkage can actually touch the rear bumper during normal shifting. This new lever arm replaces the stock steel fork and the FFR add on piece. The transverse cable doesn't move, simply rotate the reciever and the ball stud 180 degrees and it lines up with the new aluminum piece. The forward/back cable will need to be shifted forward a bit (~1.3").

The picture is jumbled if you don't know what you're looking at. On the right is the factory piece and the FFR addon. At the bottom is the ball stud and receiver. You'll see two ball studs and 1 receiver at the bottom. This shows what I was describing earlier with just flipping that bottom receiver. The new design and the FFR/OEM design are aligned where the dowel pin goes through. All total, this gives you an extra 1.4" of room between your linkage and the rear bumper.

[wleehendrick]

This new lever arm replaces the stock steel fork and the FFR add on piece. The transverse cable doesn't move, simply rotate the reciever and the ball stud 180 degrees and it lines up with the new aluminum piece. The forward/back cable will need to be shifted forward a bit (~1.3").

Craig, you plan to offer that for sale? Any idea of its compatible with the K-tuned shifter as is or with modification? I just pulled the OEM bracket off the back of my tranny last night and have started looking at the shift linkage.

[Mechie3]

I've only seen 1 picture of the K tuned/VCP setup and don't remember where I saw it. IIRC, they flipped the linkage upside down. If that's all they do is rotate the FFR bracket upright, then this should work.

After I machine it I'll test fit it, see if it works, get it quoted, and then see if it's worth trying to sell them.

[Bill Waters]

Chad, Craig, et al; very good points abut the push bumper. I would think an ideal one should have a "crumple zone," or self-sacrificing aspect, and thereby be replaceable. We will need to figure out the best design and the best attachment points for that and, as Chad suggests, the wing. I have seen, but can't recall, exactly how the FFR R one is rigged. Weld-in brackets would be nice parts for someone to produce.

I have been struggling, over the past two years, to talk myself out of buying a tube bender. Now y'all have given me the perfect rationalization to do so. (Not much of a push required).

By the way, I think it's fine for the thread's focus to wander in this direction, since it's all related. I would probably put my fuel cell in the passenger location if it were not for the desire to have a passenger seat. I may still have to.

Bill

[DodgyTim]

Is it an option to have a fuel cell located behind the passenger seat only?
I presume the passenger has a little more legroom ( no pedals ) than the driver side, and my passengers will generally be shorter than me

Also, the car may be better balanced, at least with a full tank, with fuel load offsetting driver weight.

[Santiago]

Well, if we're going with the 11" width figure Bob gave, then you might just do a quick review of readily available FIA-FT3 cells for such a plan.

For example, Fuel Safe's 15 gallon Sportsman cell lists its outside can dimensions as 26" long x 17.875" wide x 9.5" tall. If you put that behind the passenger you would have approx. 6.875" of lost space. So say 7" of intrusion into the passenger compartment for a nice round figure. That sounds like a fair amount to me, but to each to their own. Their cans stay that wide down through 12 gallons. You have to go with a 10 gallon cell to get a modest 10.125" width (which would require no intrusion into the passenger space). ATL's cells have similar dimensions (in their comparable lines).

The problem with most of the off-the-shelf items is that they seem designed to keep the fuel load as low as possible (which makes sense in terms of minimizing weight transfer). This requires wide cells for the fuel capacity most are likely to want. So using one still requires that a portion of your fuel cell is in the area that some folks are trying to avoid in the first place. But if you're just looking for more leg-room for the driver, then this approach fits that bill.

If you're ok with the stock tank placement, then things change. That's what makes Harmon's 12, 14, & 16 gallon tapered cells so enticing. Apart from the fact they're FIA-FT3 rated, they're all only 10" wide (differing only in length, and all but the 16 gal. widths will fit in the 818's stock space w/little effort).

Best,
-j

[nkw8181]

This is great info. Keep it coming!

[Bill Waters]

John
The floor for the gas tank is 11" x 47"
The FFR firewall has a lip that takes up the front 1.5", but you can design that differently.
Big question is, Will you have enough leg room moving the firewall forward.
Bob

Bob - when you answered Santiago's request to measure the stock gas tank with this response earlier in this thread, I was a bit confused. If the stock one fits at 11 inches width of its base, and the Harmon tank is only 10" wide, why would there need to be any modification of the firewall?

Thanks,

Bill

[Bob_n_Cincy]

Bob - when you answered Santiago's request to measure the stock gas tank with this response earlier in this thread, I was a bit confused. If the stock one fits at 11 inches width of its base, and the Harmon tank is only 10" wide, why would there need to be any modification of the firewall?

Thanks,

Bill

Hi Bill
The pocket for the gas tank is 11"
The gas tank has some tabs that sick out the front by maybe 1 1/4 inches.
The fire wall has a 1 1/4 lip on the front that sits on top of the gas tank tabs.
The FFR tank is only 9 3/4 front to back plus the tabs.
If you remove some of the firewall lip. You can move it forward a bit to fit the Hammond tank.
Does this make sense?
Bob DSC05794_zps4f882677.jpgtank stock.jpg

[Bill Waters]

Thanks, Bob; the details you provide make everything make sense. If I understand correctly, the pocket for the gas tank is 11", 1 1/4' of which is taken up by the firewall and its lip. Therefore, the fuel cell would need to be about 9" to fit properly and with some space between it and the firewall. Harmon makes custom tanks, and I don't think they are significantly more than stock ones when you change only one minor dimension. Their tanks don't use mounting tabs (based on pictures); we'd use restraining straps. So, maybe the total width would have to be even less to allow room for these.

Many Thanks, Bob

[Scargo]

I just have one issue with this thread. A FIA certified fuel cell is not the same as an unregulated "gas tank" that anyone can get or make. While a certified fuel cell can be used in any application, the opposite is not true.

Are makers of certified fuel cells allowed to arbitrarily change the shape (make a custom size) without re-certification? This seems to be the case. This seems like it would be really helpful to some of us. Then there is seeing if there is any consensus as to a safe and race legal location to mount it. I see no need for over a 10 gallon capacity (no enduros/no team). At (I think a conservative) 8 mpg that should equate to around 30 laps or an hour's driving on a 2.5 mile road course, similar to WGI. Does this seem plausible?

With regards to a race car application, and meeting FIA FT3 specifications and NASA/SCCA rules, a cell installation seems somewhat involved, if not complicated, to do really well. I want to be safe. I want anyone who might drive or buy the car to be safe.
Can anyone build the box that encloses the fuel cell? It's manufacture is not part of any certification process, is it? Is anyone fabricating these boxes from LDPE (Marlex) or does everyone use steel or aluminum? I see a drain is required. I see the enclosure can't be attached to the roll cage. Technically, where does a roll cage end and the frame or an acceptable mounting point for an enclosure begin?
I know I'm asking a lot of questions. Besides NASA rules in section 15.4 is there more info on this issue? Someone to talk to? Examples?

[FFRSpec72]

Chad, if you're working with Fuel Safe, they are only a few minutes from my house if I can help in any way I'd be glad to.
Also Pyrotect is very close by too. http://www.pyrotect.com/product.php?...&cat=38&page=1

Like you, I would not go on track, or even on street, without a real fuel cell in this car. There are a lot of thermal and electrical ignition sources next to the tank.

I totally agree, so maybe I can work with Sgt. Gator if he lives close to Fuel Safe as we run in the same race league here in the NW to get a real fuel cell in this car.

Seems like this one from Fuel Safe might be a starting point http://www.fuelsafe.com/store/specia...cing-cell.html

[Santiago]

Are makers of certified fuel cells allowed to arbitrarily change the shape (make a custom size) without re-certification? This seems to be the case. This seems like it would be really helpful to some of us.

I'm not sure if they are "re-certified" per se, but they do seem to be able to deliver an FIA FT3 cert on a custom cell. At least, that's what they advertise, and I am assuming they've run this rodeo before.

Then there is seeing if there is any consensus as to a safe and race legal location to mount it. I see no need for over a 10 gallon capacity (no enduros/no team). At (I think a conservative) 8 mpg that should equate to around 30 laps or an hour's driving on a 2.5 mile road course, similar to WGI. Does this seem plausible?

I get 7-8mpg on track in my 330hp Mustang. I had a WAG of getting 6-8 out of the engine I plan to use. Still, I too thought 10 gals should do it for me...but ending on fumes in some scenarios. Thus my interest in a modest buffer (12 gal) and some additional safeguard against fuel starvation on track. I'd like to hear other folks chime in on this, esp. those who've tracked 400hp Subie mills. A 10 gal tank opens up quite a few possibilities - incl. Bob's front mount.

With regards to a race car application, and meeting FIA FT3 specifications and NASA/SCCA rules, a cell installation seems somewhat involved, if not complicated, to do really well.... I see the enclosure can't be attached to the roll cage. Technically, where does a roll cage end and the frame or an acceptable mounting point for an enclosure begin?
I know I'm asking a lot of questions. Besides NASA rules in section 15.4 is there more info on this issue? Someone to talk to? Examples?

You might want to contact your regional director or fish around your regional website to see if they list a head of tech that you can contact with specific questions. Another route would be to contact a NASA approved tech shop that is authorized to sign off on your car (they should have a link to a list on the regional websites). Since these shops are the ones who would be looking over the car anyway, they would be the ones who would best be able to answer your questions. Better to run by them any plans you have for such things first and get their feedback. If your region's website doesn't have a link, you can try throwing out a feeler in the regional area of the NASA forums. I'm sure plenty of folks there would point you to a good local shop willing to offer consultation and/or do the install for you if you think that would be best.

Best,
-john

[Scargo]

My 400 WHP GR STi hatch, with aero, uses 4 + gallons in an average 20 minutes session. I have calculated that to be about 5 MPG.

[FFRSpec72]

My 400 WHP GR STi hatch, with aero, uses 4 + gallons in an average 20 minutes session. I have calculated that to be about 5 MPG.

The Subaru guys in the NW run in the ST class and run a 10:1 ratio so ~310hp to 3100lb, they burn 12gal for a 30 min race. So going to need at least a 12gal tank as I expect with lighter weight and a 2.0l engine I will burn less fuel

[Bill Waters]

I have recently received chassis # 114 and will be moving it from my barn to my shop very soon (donor deconstruction concluding). When I do, I'm going to measure with firewalls in place, check with Harmon about clearances for restraining straps, order the tank and fit it. I will keep you guys posted.

Bill

[FFRSpec72]

I have recently received chassis # 114 and will be moving it from my barn to my shop very soon (donor deconstruction concluding). When I do, I'm going to measure with firewalls in place, check with Harmon about clearances for restraining straps, order the tank and fit it. I will keep you guys posted.

Bill

In looking at the frame, I would want to put more structure to prevent the engine pushing through that firewall and into the fuel tank, I would not trust putting in a fuel cell w/o some sort of cage.

[Santiago]

The Subaru guys in the NW run in the ST class and run a 10:1 ratio so ~310hp to 3100lb, they burn 12gal for a 30 min race. So going to need at least a 12gal tank as I expect with lighter weight and a 2.0l engine I will burn less fuel

I suppose more data points like this would be nice, but I think I'm pretty set on a 12 gal cell since I anticipate putting about the same hp to the wheels.

As for framing, looks like it should be easy to weld in two or three vertical square tubes between the two bars that run across the lower part of the rear bulkhead.

Looking forward to seeing how the Harmon goes in Bill! That's my current favorite option. I should contact them about e85 compatibility...

Best,
-j

[Scargo]

The Subaru guys in the NW run in the ST class and run a 10:1 ratio so ~310hp to 3100lb, they burn 12 gal for a 30 min race.

I'm not saying you're wrong, but this does not compute to me.
I have a 7.9:1 car and I never burn more than five gallons in a 20 minute session on the track. Sure, it's HPDE, not flat out racing all the time, but I'm trying to be fast and a good lap is only a couple of seconds off a winning STU time at one track. I would think that they would have to be running ungodly aero and/or a super-rich tune for that to be true.
I wish FFR would weigh in on this.

[FFRSpec72]

I'm not saying you're wrong, but this does not compute to me.

I burn 7-8 gal of fuel in my Challenge car, these guys run in my group and I know they put in 15gal for each race.

[Santiago]

Tony, are you saying you burn 7-8 gal in a 20 min session or for a full 40 min race? Or were you saying the other Challenge guys put in 15 gal/race? Or were you saying the NW Subaru guys put in 15 gal of fuel for a 40 min race?

Sorry, I just wasn't sure who was referenced over what period of run time.

Best,
-j

[FFRSpec72]

Tony, are you saying you burn 7-8 gal in a 20 min session or for a full 40 min race? Or were you saying the other Challenge guys put in 15 gal/race? Or were you saying the NW Subaru guys put in 15 gal of fuel for a 40 min race?

Sorry, I just wasn't sure who was referenced over what period of run time.

Best,
-j

My FFR challenge car (330 rwhp) FFR class conformant burns 7-8 gals in a 30 min race (40 min if you count pace and cool down).

The Subaru guys in the ST class (a 10:1 ratio class) burn ~12 gals in the same 30 min race (they are in the same run group as me, so conditions are the same).

The numbers may be hard to believe but they empty 3 5gal jugs in their car before they head out each race

[Doowop]

well, it seems like people have different needs, but for me I werant a second seat in the car, so locating a fuel cell in the passenger area is not an option.
Gator, Fuel Safe makes custom cell. I wonder if we could get enough people interested in 1 design to get them to build us one for a reasonable price. Since you offered, could you go talk to somebody there and see if they are willing to do anything for us? thanks

[Santiago]

Thanks for the clarification Tony.

-j

[Sgt.Gator]

I'm also interested in safety but want to maintain my passenger seat.

Sgt. Gator Do you have a stock 818 tank? Would you be able to bring one over to them and see what it would take to make it safer/legal? I would be willing to pay one of these guys that has an extra to ship it to your house if you don't have one.

Sorry for the delay LongIslandWRX. No, I don't have any parts yet. If one is shipped to me I could take it to their office. I'd be little worried since I don't have the rest of the car to to do some test fitting. Personally I would want to design the fuel cell to allow the extra legroom.

[Sgt.Gator]

Yes, I'd be happy to talk with Fuel Safe and Pyrotect too. I'll review the fuel tank threads and then go meet with them. I need to go over to the Pyrotect office for some new belts anyway.

[Sgt.Gator]

To Spec a tank for a group buy I need to get a consensus on several questions, most of these are right on the Fuel Safe FAQ website:

1) Minimum Gal capacity? (I race enduros, I'd want at least 15 gallons)

2) Setup for extra legroom? (I need that too!) The Boyd tank is 10 gallons, has room for 2" more legroom and is 46.5" x 6.5" x 10" . Is there room to go higher if we want both more fuel and more legroom? Any other ideas for a design with more legroom and will hold 15 gallons?

3) Will you be filling at the cell, at a fender, or with a dry break? ( I'm guessing most will want to fill at the fender? Is this the same for both the S and the R?)

4) What size vent do you require?

5) What size fuel lines will you require? AN fittings?

6) In-tank pump or external? I know the instructions are for an In Tank, but we may want to go External.

7) Is there a need for a return fitting?

8) If you will be using more than 80% of your fuel capacity before refueling, do you want to install a collector? Good idea!

9) Will there be a sender; if so, what ohm range does your gauge need?

If you haven't priced fuel cells you may be in for sticker shock, plus the cost of replacing the bladder and foam every five years if you want to stay current for racing.

[Xusia]

^I have a fuel tank. I don't make it to Bend, well, like ever. Do you come to Eugene much?

[Doowop]

Thanks Gator.
What I'd like for sure:
-dual pickup with AN fittings. In a fuel cell especially a tall one, I'd want to have a fuel pickup in each bottom corner to make sure we are getting fuel even in hard cornering.
-Return fitting should be there in case we want to use it. I did in my previous race car. People can always cap it if not used.
-A sender would be nice, especially if the car will be used for some street use as mime will be. It can be make to match what comes with the WRX.
-I'd rather see an external pump personally.
-Seeing where the tank will be, if we still are looking behind the seat, filling at the fender would be great. We can always add one of those fuel filler on there.

[Sgt.Gator]

I get over to Eugene once a year.
We have a track day coming up in March at ORP in Grass Valley. I'll be there if you are interested in coming over for a very cheap track day or Team Continental driver's school (counts towards your ICSCC racing license).
http://www.motorsportreg.com/index.c...1#.UvKsRvldV8E

[longislandwrx]

1) Minimum Gal capacity? (I race enduros, I'd want at least 15 gallons)

Yeah stock capacity to 15gal would be nice.


2) Setup for extra legroom? (I need that too!) The Boyd tank is 10 gallons, has room for 2" more legroom and is 46.5" x 6.5" x 10" . Is there room to go higher if we want both more fuel and more legroom? Any other ideas for a design with more legroom and will hold 15 gallons?

I don't need the leg room, (5'8 here) theres room to make the tank taller, but youd have to get creative with the wiring/ ebrake etc etc


3) Will you be filling at the cell, at a fender, or with a dry break? ( I'm guessing most will want to fill at the fender? Is this the same for both the S and the R?)

The fender for now, a dry break wouldn't be too hard to add with the stock config later though.

4) What size vent do you require?

bigger is always better?

5) What size fuel lines will you require? AN fittings?

5/16 works, AN is a plus. price will be the factor. all these would be nices could send the cell into the $2000 range!


6) In-tank pump or external? I know the instructions are for an In Tank, but we may want to go External.

I'll be using in tank

7) Is there a need for a return fitting?

Yes

8) If you will be using more than 80% of your fuel capacity before refueling, do you want to install a collector? Good idea!

depends on price.

9) Will there be a sender; if so, what ohm range does your gauge need?

0-100ohm

[longislandwrx]

When does your kit come?

If it would help and Jerome still has his i'll pay to ship it to you... PM me your address.

[FFRSpec72]

I get over to Eugene once a year.
We have a track day coming up in March at ORP in Grass Valley. I'll be there if you are interested in coming over for a very cheap track day or Team Continental driver's school (counts towards your ICSCC racing license).
http://www.motorsportreg.com/index.c...1#.UvKsRvldV8E

I should be able to drop my tank off to you at ORP or have someone from my area that is going take it down to ORP that weekend.

[Sgt.Gator]

Well, if we're going with the 11" width figure Bob gave, then you might just do a quick review of readily available FIA-FT3 cells for such a plan.

If you're ok with the stock tank placement, then things change. That's what makes Harmon's 12, 14, & 16 gallon tapered cells so enticing. Apart from the fact they're FIA-FT3 rated, they're all only 10" wide (differing only in length, and all but the 16 gal. widths will fit in the 818's stock space w/little effort).

Best,
-j

The Harmon tanks are 10" wide, which is great for legroom, but they are all 10" tall too, plus we have to account for the filling/vents/connections on top. Is that too tall to work? If not the 14 gal one looks good, but the connections would need to be on the other end? http://www.harmonracingcells.com/Tapered_End.html

[Bob_n_Cincy]

My 818S will be DD, Autodross/Track day car.
The fuel cell is going in front box. (no room behind seat) Help me decide on fuel line routing.
Option 1: run fuel line with coolant tubes down the outside of cockpit. vulnerable to side impact.
Option 2: run fuel line in shifter tunnel inside of the cockpit.

Please suggest the safest way with suggestions for improvement.
thanks
Bob

[C.Plavan]

My 818S will be DD, Autodross/Track day car.
The fuel cell is going in front box. (no room behind seat) Help me decide on fuel line routing.
Option 1: run fuel line with coolant tubes down the outside of cockpit. vulnerable to side impact.
Option 2: run fuel line in shifter tunnel inside of the cockpit.

Please suggest the safest way with suggestions for improvement.
thanks
Bob

Option 2. Porsches are that way. You will be fine.

[Xusia]

Bob, I plan to run mine down the center tunnel.

[Bob_n_Cincy]

Bob, I plan to run mine down the center tunnel.

Thanks Chad

Xusia, are you going to use steel tubing or braided hose?
What do you think about putting the lines inside a steel 1" tube?
Bob