Racing requirements for fuel tank

[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.

[FFRSpec72]

So the answer I got from NASA NW was that the tank that FFR supplies is OEM and thus allowed, if you use another tank other than the OEM tank it must be an approved fuel cell that meets NASA requirements. So if you feel safe with racing w/o a fuel cell then you need to use the FFR supplied tank otherwise the Boyd or other tanks will not be accepted as it must be a fuel cell that meets NASA requirements. I bet NASA keeps a close eye on this since this car is new.

[SixStar]

So the answer I got from NASA NW was that the tank that FFR supplies is OEM and thus allowed, if you use another tank other than the OEM tank it must be an approved fuel cell that meets NASA requirements. So if you feel safe with racing w/o a fuel cell then you need to use the FFR supplied tank otherwise the Boyd or other tanks will not be accepted as it must be a fuel cell that meets NASA requirements. I bet NASA keeps a close eye on this since this car is new.

This is the same answer I got. Mainly because it meets the letter of the rules. It's a little scary that wording allows the use of a stamped steel Chinese tank vs. a welded aluminum just because that's what comes with the kit but oh well.

[Scargo]

This is the same answer I got. Mainly because it meets the letter of the rules. It's a little scary that wording allows the use of a stamped steel Chinese tank vs. a welded aluminum just because that's what comes with the kit but oh well.

stamped steel Chinese tank... Really? That's what come with 818s?